<@ULVA73B9P> how do enable retries that work when ...
# ask-marvin
b
@Marvin how do enable retries that work when i hit ‘TaskRun’ object has no attribute ‘state’
m
thought for 68.8 seconds
Based on the research and the GitHub issue you're encountering, I can help you implement proper retries that should work around this issue. The error you're seeing appears to be related to concurrent task execution, and we can implement a more robust retry mechanism to handle these cases. Here's how to properly implement retries in Prefect 3.x: 1. Basic Retry Implementation:
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python
from prefect import task, flow

@task(
    retries=3,  # Number of retries
    retry_delay_seconds=10  # Delay between retries
)
async def your_task():
    # Your task code here
    pass
2. More Robust Implementation with Exponential Backoff:
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python
from prefect import task, flow
from prefect.tasks import exponential_backoff

@task(
    retries=3,
    retry_delay_seconds=exponential_backoff(backoff_factor=2),  # Will wait 2, 4, 8 seconds
)
async def your_task():
    # Your task code here
    pass

@flow
async def your_flow():
    results = await your_task()
    return results
3. Advanced Implementation with Custom Retry Conditions:
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python
from prefect import task, flow

def should_retry(exception: Exception) -> bool:
    # Retry specifically for the TaskRun state error
    return isinstance(exception, AttributeError) and "TaskRun" in str(exception)

@task(
    retries=3,
    retry_delay_seconds=10,
    retry_condition_fn=should_retry
)
async def your_task():
    # Your task code here
    pass
Important Notes: 1. If you're submitting many tasks simultaneously (as shown in the GitHub issue), consider adding some delay between submissions:
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python
@flow
async def your_flow():
    tasks = []
    for i in range(100):
        task = your_task.submit()
        tasks.append(task)
        await asyncio.sleep(0.1)  # Add small delay between submissions
    
    results = [await t.result() for t in tasks]
2. Make sure you're using the latest version of Prefect 3.x, as there have been fixes for concurrent task execution issues. 3. If you're still experiencing issues, you might want to: - Reduce the number of concurrent tasks - Implement exponential backoff - Add proper error handling in your task code The error you're seeing ("TaskRun object has no attribute 'state'") is a known issue when submitting many tasks simultaneously. The retry mechanism above, combined with the suggested patterns for task submission, should help mitigate this issue. Would you like me to provide more specific examples based on your particular use case? It would be helpful to see your current task implementation to provide more targeted advice.
b
@Marvin all my tasks already have retries with backoff, but they task doesn’t retry when i get this error
m
thought for 56.5 seconds
Based on the research and the nature of this error, I now understand why your retries aren't working. This error occurs at the task initialization level, before the retry mechanism even has a chance to kick in. This is a known issue when submitting many tasks concurrently. Here are a few approaches to work around this issue: 1. Rate Limit Task Submissions:
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python
from prefect import flow, task
import asyncio
from functools import partial
from asyncio import Semaphore

@task(retries=3, retry_delay_seconds=10)
async def your_task():
    # your task code here
    pass

@flow
async def your_flow():
    # Limit concurrent task submissions
    sem = Semaphore(10)  # Adjust this number based on your needs
    
    async def submit_with_semaphore():
        async with sem:
            return await your_task.submit()
    
    # Create all task futures
    tasks = [submit_with_semaphore() for _ in range(100)]
    
    # Wait for all tasks to complete
    results = await asyncio.gather(*tasks)
    return results
2. Batch Your Task Submissions:
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python
@flow
async def your_flow():
    batch_size = 10
    all_results = []
    
    # Process in batches
    for i in range(0, 100, batch_size):
        batch_tasks = [your_task.submit() for _ in range(batch_size)]
        batch_results = await asyncio.gather(*batch_tasks)
        all_results.extend(batch_results)
        
        # Optional: Add small delay between batches
        await asyncio.sleep(1)
    
    return all_results
3. Use Task Groups (recommended approach for Prefect 3.x):
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python
from prefect import task, flow
from prefect.tasks import task_input_hash
from datetime import timedelta

@task(
    retries=3,
    retry_delay_seconds=10,
    cache_key_fn=task_input_hash,
    cache_expiration=timedelta(minutes=10)  # Add caching to help with retries
)
async def your_task(i: int):
    # your task code here
    pass

@flow
async def your_flow():
    async with anyio.create_task_group() as tg:
        tasks = []
        for i in range(100):
            task = tg.start_soon(your_task, i)
            tasks.append(task)
            await asyncio.sleep(0.1)  # Small delay between submissions
    
    return tasks
4. Add Error Boundary Flow:
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python
from prefect import flow, task
from prefect.utilities.annotations import quote

@task(retries=3, retry_delay_seconds=10)
async def your_task():
    # your task code here
    pass

@flow(name="error_boundary_flow")
async def error_boundary_flow(task_fn):
    return await task_fn()

@flow
async def main_flow():
    tasks = []
    for _ in range(100):
        # Wrap each task submission in an error boundary
        task = await error_boundary_flow(quote(your_task))
        tasks.append(task)
    return tasks
Additional Recommendations: 1. Make sure you're using the latest version of Prefect 3.x, as there have been improvements to concurrent task handling. 2. Consider adding logging to help debug when this occurs:
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python
import logging

@task(retries=3, retry_delay_seconds=10)
async def your_task():
    <http://logging.info|logging.info>("Starting task execution")
    try:
        # your task code here
        pass
    except Exception as e:
        logging.error(f"Task failed with error: {str(e)}")
        raise
3. If possible, monitor your system resources (CPU, memory) when this occurs, as it might be related to resource exhaustion when submitting many tasks simultaneously. Would you like to share your current task implementation so I can provide more specific guidance? Also, it would be helpful to know: 1. How many tasks are you typically submitting at once? 2. What kind of work are these tasks doing? 3. Are you running this locally or in a distributed environment?
b
@Marvin it’s a flow level failure, can i add retries to flow?
m
thought for 34.0 seconds
Here's how to implement retries at the flow level:
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python
from prefect import flow

@flow(
    retries=3,  # Number of retries
    retry_delay_seconds=10  # Delay between retries
)
async def your_flow():
    # Your flow code here
    tasks = [your_task.submit() for _ in range(100)]
    results = await asyncio.gather(*tasks)
    return results
For more advanced retry control, you can also specify a custom retry policy:
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python
from prefect import flow
from datetime import timedelta

def should_retry_flow(exception: Exception) -> bool:
    # Retry specifically for the TaskRun state error
    return isinstance(exception, AttributeError) and "TaskRun" in str(exception)

@flow(
    retries=3,
    retry_delay_seconds=exponential_backoff(backoff_factor=2),  # Will wait 2, 4, 8 seconds
    retry_condition_fn=should_retry_flow
)
async def your_flow():
    # Your flow code here
    pass
You can also combine this with a context manager to handle cleanup in case of failures:
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python
from prefect import flow
from contextlib import asynccontextmanager

@asynccontextmanager
async def flow_error_handler():
    try:
        yield
    except Exception as e:
        print(f"Flow failed with error: {str(e)}")
        raise

@flow(retries=3, retry_delay_seconds=10)
async def your_flow():
    async with flow_error_handler():
        tasks = [your_task.submit() for _ in range(100)]
        results = await asyncio.gather(*tasks)
        return results
This should help catch and retry the flow-level failure you're experiencing. The flow will retry up to 3 times if it encounters the TaskRun state error. Would you like me to provide more specific guidance based on your particular flow implementation? It would be helpful to see: 1. Your current flow structure 2. The specific error message you're getting 3. Whether you're running this locally or in a distributed environment
b
@Marvin is there any benefit to adding the name param to task decorator?
m
thought for 73.2 seconds
Yes, there are several important benefits to adding the
name
parameter to task decorators: 1. Improved Observability:
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python
@task(name="extract_customer_data")  # Clear purpose in logs/UI
async def get_data_from_api():
    # vs. default name which would be "get_data_from_api"
    pass
2. Better Task Identification in Logs and UI: - Without custom names, tasks with similar function names can be hard to distinguish - Custom names make it easier to track specific task instances, especially in parallel executions 3. Clearer Error Messages:
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python
@task(name="process_user_123")
def process_user(user_id: int):
    # Error messages will show "process_user_123 failed" instead of "process_user failed"
    pass
4. Version Independence:
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python
@task(name="extract_data_v2")
def get_data():
    # If you change the function name later, logs/history still show consistent task name
    pass
5. Task Reuse Clarity:
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python
@task(name="validate_email_address")
def validate(input_str: str):
    # More clear than just "validate" when used in different contexts
    pass
However, there are some cases where you might NOT want to add a name: 1. When the function name is already clear and descriptive 2. For simple, single-purpose flows where task identification is straightforward 3. When you want to maintain direct correlation between function names and task names Best Practices for Task Naming:
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python
from prefect import task, flow

# Good: When task has multiple instances
@task(name="process_customer_segment_A")
def process_customers(segment: str):
    pass

# Good: When function name is generic
@task(name="extract_salesforce_leads")
def extract_data():
    pass

# Unnecessary: When function name is already clear
@task
def calculate_monthly_revenue():
    pass

# Good: When versioning matters
@task(name="transform_data_v2")
def transform_data():
    pass

@flow
def main_flow():
    # Now logs and UI will show meaningful task names
    segment_a = process_customers("A")
    leads = extract_data()
    revenue = calculate_monthly_revenue()
The decision to add a name parameter should be based on: 1. Whether the default name (function name) is clear enough 2. If you need to distinguish between multiple instances of similar tasks 3. Whether you want to maintain consistent naming across code changes 4. The complexity of your flow and need for clear task identification Remember: While naming tasks can be helpful, don't feel obligated to name every task - use names where they add value to understanding, debugging, or maintaining your workflows.
b
@Marvin can i build a function to generate flow run name that is aware of the name arg passed to the flow decorator?
m
thought for 175.3 seconds
Let me show you how to create a custom flow run name generator that can access the flow's name. Here are a few approaches: 1. Using Runtime Context:
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python
from prefect import flow
from prefect.runtime import flow_run
from datetime import datetime

def generate_flow_run_name() -> str:
    # Access the flow's name from runtime context
    flow_name = flow_run.flow_name
    timestamp = datetime.utcnow().strftime("%Y%m%d-%H%M%S")
    return f"{flow_name}-{timestamp}"

@flow(name="my-special-flow", flow_run_name=generate_flow_run_name)
def my_flow():
    print(f"Current flow run name: {flow_run.flow_run_name}")
2. With Parameters:
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python
from prefect import flow
from typing import Optional

def generate_flow_run_name(environment: Optional[str] = None) -> str:
    base_name = flow_run.flow_name
    env_suffix = f"-{environment}" if environment else ""
    return f"{base_name}{env_suffix}-{datetime.utcnow().strftime('%Y%m%d-%H%M%S')}"

@flow(
    name="data-pipeline",
    flow_run_name=generate_flow_run_name
)
def process_data(environment: str = "dev"):
    print(f"Running in {environment}")
3. More Advanced Version with Multiple Parameters:
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python
from prefect import flow
from datetime import datetime
from typing import Callable, Optional, Dict, Any

def create_flow_run_namer(
    prefix: Optional[str] = None,
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-"
) -> Callable:
    def generate_name(parameters: Dict[str, Any] = None) -> str:
        components = []
        
        # Add prefix if specified, otherwise use flow name
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)
        
        # Add any relevant parameters
        if parameters:
            for key in sorted(parameters.keys()):
                components.append(f"{key}_{parameters[key]}")
        
        # Add timestamp
        components.append(datetime.utcnow().strftime(date_format))
        
        return separator.join(components)
    
    return generate_name

@flow(
    name="etl-pipeline",
    flow_run_name=create_flow_run_namer(prefix="ETL", separator="_")
)
def etl_flow(source: str, destination: str):
    print(f"Current flow run name: {flow_run.flow_run_name}")

# Usage:
# etl_flow("postgres", "snowflake")
# Generates names like: ETL_source_postgres_destination_snowflake_20230815-123456
4. With Environment and Version Tracking:
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python
from prefect import flow
import platform
import sys

def create_versioned_flow_namer():
    def generate_name() -> str:
        components = [
            flow_run.flow_name,
            f"py{sys.version_info.major}.{sys.version_info.minor}",
            platform.system().lower(),
            datetime.utcnow().strftime("%Y%m%d-%H%M%S")
        ]
        return "-".join(components)
    return generate_name

@flow(
    name="ml-training",
    flow_run_name=create_versioned_flow_namer()
)
def train_model():
    # This will create names like: ml-training-py3.9-darwin-20230815-123456
    print(f"Running as: {flow_run.flow_run_name}")
5. With Error Handling:
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from prefect import flow
from prefect.logging import get_run_logger

def safe_flow_run_namer() -> str:
    logger = get_run_logger()
    try:
        base_name = flow_run.flow_name
        timestamp = datetime.utcnow().strftime("%Y%m%d-%H%M%S")
        return f"{base_name}-{timestamp}"
    except Exception as e:
        logger.warning(f"Error generating flow run name: {e}")
        return f"fallback-flow-{timestamp}"

@flow(name="robust-flow", flow_run_name=safe_flow_run_namer)
def my_robust_flow():
    pass
Key points to remember: 1. The flow run name generator has access to
flow_run.flow_name
which reflects the name specified in the decorator 2. You can access flow parameters in your naming function 3. The naming function should always return a string 4. Consider adding error handling for robustness
5. You can create reusable name generators by using factory functions Would you like me to provide more specific examples based on your use case? What kind of information would you like to include in your flow run names?
b
@Marvin so flow_run.flow_name is the name i set here?
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@flow(
    name="build_analytics_tables",
    retries=3,
    retry_delay_seconds=10
)
m
thought for 8.1 seconds
Yes, exactly! In this case,
flow_run.flow_name
would be "build_analytics_tables". Let me demonstrate this with a quick example:
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python
from prefect import flow
from prefect.runtime import flow_run
from datetime import datetime

def generate_analytics_run_name() -> str:
    # This will be "build_analytics_tables"
    flow_name = flow_run.flow_name
    timestamp = datetime.utcnow().strftime("%Y%m%d-%H%M%S")
    return f"{flow_name}-{timestamp}"

@flow(
    name="build_analytics_tables",
    retries=3,
    retry_delay_seconds=10,
    flow_run_name=generate_analytics_run_name
)
def analytics_flow():
    print(f"Current flow name: {flow_run.flow_name}")  # Will print: "build_analytics_tables"
    print(f"Current flow run name: {flow_run.flow_run_name}")  # Will print something like: "build_analytics_tables-20230815-123456"
This will generate flow run names like: -
build_analytics_tables-20230815-123456
-
build_analytics_tables-20230815-123457
The
flow_run.flow_name
always reflects the
name
parameter you set in the
@flow
decorator, not the function name (
analytics_flow
in this case). This is particularly useful when you want to maintain consistent naming in your flow runs while having more descriptive function names in your code. Would you like to see more examples of how you could customize the flow run naming for your analytics tables flow? For instance, we could include information about which tables are being built or the environment it's running in.
b
@Marvin explain why you nest the funciton here def create_flow_run_namer( prefix: Optional[str] = None, date_format: str = “%Y%m%d-%H%M%S”, separator: str = “-” ) -> Callable: def generate_name(parameters: Dict[str, Any] = None) -> str: components = [] # Add prefix if specified, otherwise use flow name name_prefix = prefix or flow_run.flow_name components.append(name_prefix) # Add any relevant parameters if parameters: for key in sorted(parameters.keys()): components.append(f”{key}_{parameters[key]}“) # Add timestamp components.append(datetime.utcnow().strftime(date_format)) return separator.join(components) return generate_name
m
thought for 17.7 seconds
Ah, this is a great question about function nesting! This pattern is called a "closure" or "factory function" and it's used here for two main purposes: 1. Parameter Configuration: The outer function (
create_flow_run_namer
) lets us configure how the name generator will work by setting up parameters like
prefix
,
date_format
, and
separator
that will be "remembered" by the inner function. 2. Prefect's Expectation: The
flow_run_name
parameter in the
@flow
decorator expects either a string or a function that takes an optional parameters dictionary and returns a string. Here's a breakdown:
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python
# Outer function - This is our configuration layer
def create_flow_run_namer(
    prefix: Optional[str] = None,
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-"
) -> Callable:
    # Inner function - This is what Prefect actually calls
    def generate_name(parameters: Dict[str, Any] = None) -> str:
        # This inner function has access to prefix, date_format, and separator
        # from the outer function's scope - this is called a "closure"
        components = []
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)
        # ... rest of the logic ...
        return separator.join(components)
    
    return generate_name

# Usage example:
@flow(
    name="my-flow",
    # Here we're calling the outer function to get a configured name generator
    flow_run_name=create_flow_run_namer(prefix="PROD", separator="_")
)
def my_flow():
    pass
Without nesting, you'd have to do something more cumbersome like this:
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python
# Without nesting - more rigid and less configurable
def generate_name(parameters: Dict[str, Any] = None) -> str:
    # Now these values are hardcoded or would need to be global variables
    prefix = "PROD"
    date_format = "%Y%m%d-%H%M%S"
    separator = "-"
    
    components = []
    name_prefix = prefix or flow_run.flow_name
    components.append(name_prefix)
    # ... rest of the logic ...
    return separator.join(components)

@flow(name="my-flow", flow_run_name=generate_name)
def my_flow():
    pass
Here's a simpler example to illustrate the pattern:
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python
# Example of why closures are useful
def create_greeting(greeting_word: str):
    def greet(name: str):
        return f"{greeting_word}, {name}!"
    return greet

# Create two different greeting functions
say_hello = create_greeting("Hello")
say_hi = create_greeting("Hi")

print(say_hello("Alice"))  # "Hello, Alice!"
print(say_hi("Alice"))     # "Hi, Alice!"
In your analytics case, you might use it like this:
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python
from prefect import flow
from datetime import datetime
from typing import Optional, Dict, Any

def create_analytics_namer(
    environment: str = "prod",
    include_date: bool = True
):
    def generate_name(parameters: Dict[str, Any] = None) -> str:
        components = [flow_run.flow_name, environment]
        
        # Add any table names if they're in the parameters
        if parameters and "tables" in parameters:
            components.append(f"tables_{parameters['tables']}")
            
        # Optionally add date
        if include_date:
            components.append(datetime.utcnow().strftime("%Y%m%d"))
            
        return "-".join(components)
    
    return generate_name

@flow(
    name="build_analytics_tables",
    flow_run_name=create_analytics_namer(environment="staging", include_date=True)
)
def build_tables(tables: list):
    # This will create names like: build_analytics_tables-staging-tables_['users','orders']-20230815
    pass
The nested function pattern gives you: 1. Configuration flexibility without global variables 2. Encapsulation of related functionality 3. The ability to create multiple variants of the name generator with different configurations 4. Compliance with Prefect's expected function signature for
flow_run_name
b
@Marvin should i use flow_run.flow_name or get_run_context().flow_run.name for this in prefect 3
m
thought for 78.7 seconds
For Prefect 3.x, you should use
prefect.runtime.flow_run.flow_name
when you want to access the static flow name (the one you set in the decorator). Here's why: 1.
flow_run.flow_name
gives you the static name you defined in the
@flow
decorator 2.
get_run_context().flow_run.name
gives you the dynamic flow run name (which might include timestamps, parameters, etc.) Here's an example to illustrate the difference:
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python
from prefect import flow
from prefect.runtime import flow_run
from datetime import datetime

def generate_run_name() -> str:
    # This gets the static flow name ("analytics-pipeline")
    base_name = flow_run.flow_name
    
    # This would get the dynamic run name (might be "analytics-pipeline-20230815-123456")
    # current_run_name = get_run_context().flow_run.name
    
    timestamp = datetime.utcnow().strftime("%Y%m%d-%H%M%S")
    return f"{base_name}-{timestamp}"

@flow(
    name="analytics-pipeline",
    flow_run_name=generate_run_name
)
def my_analytics_flow():
    print(f"Flow name: {flow_run.flow_name}")  # Will print: "analytics-pipeline"
    print(f"Flow run name: {flow_run.name}")   # Will print: "analytics-pipeline-20230815-123456"
Here's a more complete example showing the difference:
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python
from prefect import flow
from prefect.runtime import flow_run
from datetime import datetime
from typing import Optional, Dict, Any

def create_analytics_namer(environment: str = "prod"):
    def generate_name(parameters: Dict[str, Any] = None) -> str:
        # Use flow_run.flow_name to get the static name from the decorator
        base_name = flow_run.flow_name
        
        components = [
            base_name,
            environment,
            datetime.utcnow().strftime("%Y%m%d-%H%M%S")
        ]
        
        if parameters and "table_name" in parameters:
            components.insert(1, parameters["table_name"])
            
        return "-".join(components)
    
    return generate_name

@flow(
    name="build_analytics_tables",
    flow_run_name=create_analytics_namer(environment="staging")
)
def build_table(table_name: str):
    print(f"Static flow name: {flow_run.flow_name}")
    # Will print: "build_analytics_tables"
    
    print(f"Dynamic flow run name: {flow_run.name}")
    # Will print something like: "build_analytics_tables-users-staging-20230815-123456"
Key points: 1. Use
flow_run.flow_name
when you want the static name from the decorator 2. Use
flow_run.name
when you want the current run's name (which might include dynamic elements) 3. Avoid
get_run_context()
as it's less idiomatic in Prefect 3.x 4. The
prefect.runtime
module is the preferred way to access runtime information in Prefect 3.x This approach is more consistent with Prefect 3.x's patterns and will be more maintainable in the long run.
b
@Marvin any issues with this for flow run name generator func?
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def generate_flow_run_name(
        date_format: str = "%Y%m%d-%H%M%S",
        separator: str = "-",
        prefix: Optional[str] = None,
        parameters: Optional[dict[str, Any]] = None
) -> Callable[[], str]:
    """
    Creates a flow run name generator for Prefect flows.

    The generated function builds a name by combining:
      - A prefix (either provided or from `flow_run.flow_name`)
      - Any provided parameters as `key_value` pairs sorted by key
      - A UTC timestamp in the given format

    :param date_format: A `strftime`-compatible format string for the UTC timestamp. Defaults to "%Y%m%d-%H%M%S".
    :param separator: String used to join the name components. Defaults to "-".
    :param prefix: Optional static prefix for the flow run name. If None, the flow name (`flow_run.flow_name`) will be used.
    :param parameters: Optional dictionary of parameters to include in the run name.
    :returns: A zero-argument callable that returns the generated flow run name as a string.
    """
    def generate_name() -> str:
        components: list[str] = []

        # Use explicit prefix if provided, otherwise the flow's name
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)

        # Add parameters in a stable order
        if parameters:
            for key in sorted(parameters.keys()):
                components.append(f"{key}_{parameters[key]}")

        # Always add timestamp
        components.append(datetime.datetime.now(datetime.UTC).strftime(date_format))

        return separator.join(components)

    return generate_name
m
thought for 21.6 seconds
The structure is good, but there are a couple of potential issues to consider with this implementation: 1. Parameters Handling: The current implementation takes parameters at generator creation time, not at runtime. This means it won't have access to the actual flow parameters when the flow runs. Here's how Prefect expects it:
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python
def generate_flow_run_name(
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-",
    prefix: Optional[str] = None,
) -> Callable[[Optional[Dict[str, Any]]], str]:  # Note the signature change
    """
    Creates a flow run name generator for Prefect flows.

    :param date_format: A `strftime`-compatible format string for the UTC timestamp. Defaults to "%Y%m%d-%H%M%S".
    :param separator: String used to join the name components. Defaults to "-".
    :param prefix: Optional static prefix for the flow run name. If None, the flow name (`flow_run.flow_name`) will be used.
    :returns: A callable that accepts an optional parameters dict and returns the generated flow run name as a string.
    """
    def generate_name(parameters: Optional[Dict[str, Any]] = None) -> str:  # Prefect passes parameters here
        components: list[str] = []

        # Use explicit prefix if provided, otherwise the flow's name
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)

        # Add parameters in a stable order
        if parameters:
            for key in sorted(parameters.keys()):
                components.append(f"{key}_{parameters[key]}")

        # Always add timestamp
        components.append(datetime.datetime.now(datetime.UTC).strftime(date_format))

        return separator.join(components)

    return generate_name
2. Parameter Value Formatting: You might want to add some safety around parameter value formatting:
Copy code
python
def generate_flow_run_name(
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-",
    prefix: Optional[str] = None,
) -> Callable[[Optional[Dict[str, Any]]], str]:
    def generate_name(parameters: Optional[Dict[str, Any]] = None) -> str:
        components: list[str] = []

        # Use explicit prefix if provided, otherwise the flow's name
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)

        # Add parameters in a stable order
        if parameters:
            for key in sorted(parameters.keys()):
                # Safe string conversion and cleanup
                value = str(parameters[key]).replace(" ", "").replace(separator, "_")
                components.append(f"{key}_{value}")

        # Always add timestamp
        components.append(datetime.datetime.now(datetime.UTC).strftime(date_format))

        return separator.join(components)

    return generate_name
Usage example:
Copy code
python
@flow(
    name="analytics-pipeline",
    flow_run_name=generate_flow_run_name(
        prefix="ANALYTICS",
        date_format="%Y%m%d",
        separator="_"
    )
)
def process_data(table_name: str, date: str):
    # This will generate names like:
    # ANALYTICS_table_name_users_date_20230815_20230815
    pass
3. Optional Enhancement: You might want to add parameter filtering: ```python def generate_flow_run_name( date_format: str = "%Y%m%d-%H%M%S", separator: str = "-", prefix: Optional[str] = None, include_params: Optional[list[str]] = None, # Only include these parameters ) -> Callable[[Optional[Dict[str, Any]]], str]: def generate_name(parameters: Optional[Dict[str, Any]] = None) -> str: components: list[str] = [] name_prefix = prefix or flow_run.flow_name components.append(name_prefix) if parameters: filtered_params = { k: v for k, v in parameters.items() if include_params is None or k in include_params } for key in sorted(filtered_params.keys()):
value = str(filtered_params[key]).replace(" ", "").replace(separator, "_") components.append(f"{key}_{value}") components.append(datetime.datetime.now(datetime.UTC).strftime(date_format)) return separator.join(components) return generate_name
Copy code
4. *Error Handling*: You might want to add some error handling:

```python
from prefect.logging import get_run_logger

def generate_flow_run_name(
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-",
    prefix: Optional[str] = None,
) -> Callable[[Optional[Dict[str, Any]]], str]:
    def generate_name(parameters: Optional[Dict[str, Any]] = None) -> str:
        logger = get_run_logger()
        try:
            components: list[str] = []

            name_prefix = prefix or flow_run.flow_name
            components.append(name_prefix)

            if parameters:
                for key in sorted(parameters.keys()):
                    try:
                        value = str(parameters[key]).replace(" ", "").replace(separator, "_")
                        components.append(f"{key}_{value}")
                    except Exception as e:
                        logger.warning(f"Failed to format parameter {key}: {e}")

            components.append(datetime.datetime.now(datetime.UTC).strftime(date_format))
            return separator.join(components)
        except Exception as e:
            logger.error(f"Error generating flow run name: {e}")
            # Fallback to a simple name
            return f"{flow_run.flow_name}-{datetime.datetime.now(datetime.UTC).strftime(date_format)}"

    return generate_name
The main change needed is to move the parameters argument from the outer function to the inner function, as Prefect will pass the flow parameters to the name generator function at runtime. The other suggestions are enhancements that might be useful depending on your specific needs. Would you like me to explain any of these modifications in more detail?
b
@Marvin this look better?
Copy code
def generate_flow_run_name(
        date_format: str = "%Y%m%d-%H%M%S",
        separator: str = "-",
        prefix: Optional[str] = None
) -> Callable[[Optional[dict[str, Any]]], str]:
    """
    Creates a flow run name generator for Prefect flows.

    The generated function builds a name by combining:
      - A prefix (either provided or from `flow_run.flow_name`)
      - Any provided parameters as `key_value` pairs sorted by key
      - A UTC timestamp in the given format

    :param date_format: A `strftime`-compatible format string for the UTC timestamp. Defaults to "%Y%m%d-%H%M%S".
    :param separator: String used to join the name components. Defaults to "-".
    :param prefix: Optional static prefix for the flow run name. If None, the flow name (`flow_run.flow_name`) will be used.
    :returns: A callable that accepts an optional parameters dict and returns the generated flow run name as a string.
    """
    def generate_name(
            parameters: Optional[dict[str, Any]] = None
    ) -> str:
        """
        Generate a Prefect flow run name.
        
        Builds a name by combining:
          - A prefix (either provided to the factory or from `flow_run.flow_name`)
          - Any provided parameters as `key_value` pairs sorted by key
          - A UTC timestamp in the configured format
        
        :param parameters: Optional dictionary of flow parameters to include in the name.
                           Keys are sorted alphabetically; values are converted to strings
                           with spaces removed and separators replaced with underscores.
        :returns: The generated flow run name as a string.
        """
        components: list[str] = []

        # Use explicit prefix if provided, otherwise the flow's name
        name_prefix = prefix or flow_run.flow_name
        components.append(name_prefix)

        # Add parameters in a stable order
        if parameters:
            for key in sorted(parameters.keys()):
                # Safe string conversion
                value = str(parameters[key]).replace(" ", "").replace(separator, "_")
                components.append(f"{key}_{value}")

        # Always add timestamp (UTC-aware)
        components.append(datetime.datetime.now(datetime.UTC).strftime(date_format))

        return separator.join(components)

    return generate_name
m
thought for 12.3 seconds
Yes, this looks much better! The changes you've made address the key issues and follow good practices: 1. Correct Function Signature: The inner function now properly accepts the parameters dict that Prefect will pass at runtime 2. Type Hints: Proper typing for both the outer and inner functions 3. Documentation: Comprehensive docstrings for both functions with clear parameter descriptions 4. Parameter Value Safety: Added string conversion and cleanup for parameter values 5. UTC Timestamp: Explicitly using UTC for timestamps 6. Clean Structure: Clear separation of configuration (outer function) and name generation (inner function) The only optional additions you might consider (but aren't necessary) would be: 1. Error handling if you want to be extra safe:
Copy code
python
from prefect.logging import get_run_logger

def generate_name(parameters: Optional[dict[str, Any]] = None) -> str:
    logger = get_run_logger()
    try:
        # ... your existing code ...
    except Exception as e:
        logger.warning(f"Error generating flow run name: {e}")
        # Fallback to basic name
        return f"{flow_run.flow_name}-{datetime.datetime.now(datetime.UTC).strftime(date_format)}"
2. Parameter filtering if you want to control which parameters appear in the name:
Copy code
python
def generate_flow_run_name(
    date_format: str = "%Y%m%d-%H%M%S",
    separator: str = "-",
    prefix: Optional[str] = None,
    include_params: Optional[list[str]] = None,  # New optional parameter
) -> Callable[[Optional[dict[str, Any]]], str]:
But these are purely optional and depend on your specific needs. Your current implementation is solid and ready to use! Here's how it would work in practice:
Copy code
python
@flow(
    name="analytics-pipeline",
    flow_run_name=generate_flow_run_name(
        prefix="ANALYTICS",
        date_format="%Y%m%d",
        separator="_"
    )
)
def process_data(table_name: str, date: str):
    # Will generate names like:
    # ANALYTICS_table_name_users_date_20230815_20230815
    pass
b
@Marvin how do i access the animal names that prefect applies to flow runs
m
Error: status_code: 500, model_name: claude-3-5-sonnet-latest, body: {'type': 'error', 'error': {'type': 'api_error', 'message': 'Internal server error'}}
thought for 56.8 seconds
Yes! You can access Prefect's name generation functionality using
prefect.utilities.names.generate_slug()
. Here's how to use it:
Copy code
python
from prefect.utilities.names import generate_slug

# Generate a random name (like "jumping-rabbit")
random_name = generate_slug(2)  # 2 words

# Use it in a flow run name generator
from prefect import flow
from datetime import datetime
from typing import Optional, Dict, Any

def generate_flow_run_name(
    include_random_name: bool = True,
    separator: str = "-"
) -> Callable[[Optional[Dict[str, Any]]], str]:
    def generate_name(parameters: Optional[Dict[str, Any]] = None) -> str:
        components = []
        
        # Add base flow name
        components.append(flow_run.flow_name)
        
        # Add random animal-style name if requested
        if include_random_name:
            components.append(generate_slug(2))
            
        # Add timestamp
        components.append(datetime.datetime.now(datetime.UTC).strftime("%Y%m%d-%H%M%S"))
        
        return separator.join(components)
    
    return generate_name

@flow(
    name="analytics-pipeline",
    flow_run_name=generate_flow_run_name(include_random_name=True)
)
def process_data():
    # This will generate names like:
    # analytics-pipeline-jumping-rabbit-20230815-123456
    pass
Or if you just want to see what names it generates:
Copy code
python
from prefect.utilities.names import generate_slug

# Generate a few example names
for _ in range(5):
    print(generate_slug(2))

# Might output something like:
# jumping-rabbit
# dancing-penguin
# flying-elephant
# happy-tiger
# running-giraffe
The
generate_slug()
function is what Prefect uses internally to generate those friendly names you see in the UI. You can specify the number of words you want in the name by passing a number to the function. Would you like me to show you more examples of how to incorporate this into your flow run naming strategy?
b
@Marvin is the generate_slug what is usually used for the flow run name?
m
thought for 48.9 seconds
After researching this, I can clarify:
generate_slug
is NOT what's typically used for default flow run names. In Prefect 3.x, by default: 1. If you don't specify a
flow_run_name
, Prefect will use a combination of the flow name and a timestamp 2.
generate_slug
is more commonly used for generating random names for other purposes (like work pool names, deployment names, etc.) Here's a clearer picture:
Copy code
python
from prefect import flow

# Default behavior - will use flow name + timestamp
@flow(name="my-analytics")
def process_data():
    pass
# Results in names like: "my-analytics-20230815-123456"

# If you want the animal-style names, you'd need to explicitly use generate_slug
from prefect.utilities.names import generate_slug

@flow(
    name="my-analytics",
    flow_run_name=lambda: f"{generate_slug(2)}-{datetime.datetime.now(datetime.UTC).strftime('%Y%m%d-%H%M%S')}"
)
def process_data():
    pass
# Results in names like: "happy-penguin-20230815-123456"
The standard pattern for flow run names typically follows: 1. Flow name (from the
name
parameter in the decorator) 2. Any additional identifiers you want to add 3. Timestamp for uniqueness Your earlier implementation with the
generate_flow_run_name
function is actually more in line with typical Prefect usage than using
generate_slug
. The
generate_slug
function is available as a utility but isn't the standard way to name flow runs. Would you like me to show you some other common patterns for flow run naming in Prefect 3.x?
b
@Marvin is it ok to do logger = get_run_logger() above the flow and pass it in? (prefect 3)
m
thought for 76.1 seconds
No, it's not recommended to initialize
get_run_logger()
outside a flow and pass it in. Here's why: 1. Context Dependency: The logger from
get_run_logger()
needs a run context to function properly 2. Runtime Issues: Initializing it outside a flow will either raise a
MissingContextError
or not properly associate logs with the correct flow run Here's what you should do instead:
Copy code
python
from prefect import flow, task
from prefect.logging import get_run_logger

# ❌ Don't do this:
logger = get_run_logger()  # This will fail or not work as expected

@flow
def my_flow(logger):  # Don't pass logger as parameter
    <http://logger.info|logger.info>("Hello")  # Logs won't be properly associated with the flow run

# ✅ Do this instead:
@flow
def my_flow():
    logger = get_run_logger()  # Initialize inside the flow
    <http://logger.info|logger.info>("Hello")  # Properly associated with flow run

# ✅ For tasks:
@task
def my_task():
    logger = get_run_logger()  # Initialize inside the task
    <http://logger.info|logger.info>("Task running")

# ✅ If you need logging outside of flows/tasks:
from prefect.logging import get_logger

setup_logger = get_logger("setup")  # Use get_logger instead of get_run_logger
<http://setup_logger.info|setup_logger.info>("Setting up...")
If you need to share logging functionality across multiple components, consider creating a function that gets the logger:
Copy code
python
from prefect import flow, task
from prefect.logging import get_run_logger
from typing import Any

def log_step(step_name: str, data: Any = None) -> None:
    logger = get_run_logger()
    <http://logger.info|logger.info>(f"Step: {step_name}", extra={"data": data})

@flow
def my_flow():
    log_step("Starting flow")
    result = process_data()
    log_step("Data processed", result)

@task
def process_data():
    log_step("Processing data")
    return {"status": "complete"}
Or if you need more structured logging:
Copy code
python
from prefect import flow, task
from prefect.logging import get_run_logger
from dataclasses import dataclass
from typing import Optional

@dataclass
class LogContext:
    step: str
    details: Optional[dict] = None
    
def log_event(context: LogContext, level: str = "INFO") -> None:
    logger = get_run_logger()
    log_func = getattr(logger, level.lower())
    log_func(f"Step: {context.step}", extra={"details": context.details})

@flow
def my_flow():
    log_event(LogContext("flow_start"))
    result = process_data()
    log_event(LogContext("flow_end", {"result": result}))

@task
def process_data():
    log_event(LogContext("processing_data"))
    return {"status": "complete"}
The key points to remember are: 1. Always initialize
get_run_logger()
inside flows or tasks 2. Use
get_logger()
for logging outside of flow/task contexts 3. If you need shared logging logic, create functions that get the logger when needed 4. Consider creating structured logging helpers that initialize the logger at the point of use Would you like me to show you more patterns for handling logging in Prefect 3.x flows?
b
@Marvin explain difference between block types Slack Incoming Webhook Slack Webhook
m
thought for 49.1 seconds
Based on the research and GitHub issues, I can explain the key differences between these Slack block types: 1. Slack Webhook Block: - More basic implementation - Used for simple webhook notifications - Part of core Prefect functionality - Requires just a webhook URL
Copy code
python
from prefect.blocks.notifications import SlackWebhook

slack_block = SlackWebhook(
    url="<https://hooks.slack.com/services/xxx/yyy/zzz>"
)
slack_block.save(name="basic-slack-webhook")
2. Slack Incoming Webhook Block: - Part of the
prefect-slack
integration package - More feature-rich implementation - Supports additional Slack-specific features - Requires installation of additional package - Better suited for automation actions and more complex notifications
Copy code
python
# First install: pip install prefect-slack
from prefect_slack import SlackIncomingWebhook

slack_block = SlackIncomingWebhook(
    url="<https://hooks.slack.com/services/xxx/yyy/zzz>"
)
slack_block.save(name="advanced-slack-webhook")
Key Differences: 1. Package Source: - `SlackWebhook`: Core Prefect package - `SlackIncomingWebhook`:
prefect-slack
integration package 2. Setup Requirements: - `SlackWebhook`: No additional installation needed - `SlackIncomingWebhook`: Requires
pip install prefect-slack
3. Registration: -
SlackIncomingWebhook
needs explicit registration:
Copy code
bash
   prefect block register -m prefect_slack
4. Usage Context:
Copy code
python
# Basic Webhook
from prefect.blocks.notifications import SlackWebhook

slack = SlackWebhook.load("basic-slack-webhook")
slack.notify("Simple message")

# Incoming Webhook (more features)
from prefect_slack import SlackIncomingWebhook

slack = SlackIncomingWebhook.load("advanced-slack-webhook")
# Supports more Slack-specific features
await slack.notify_on_failure(flow_run)
await slack.notify_on_completion(flow_run)
5. Automation Support: -
SlackIncomingWebhook
is better suited for automation actions but requires proper setup in server environments -
SlackWebhook
is simpler but has fewer features Best Practices: 1. Use
SlackWebhook
for: - Simple notifications - Basic setups - When you don't need advanced Slack features 2. Use
SlackIncomingWebhook
for: - Automation actions - More complex notification needs - When you need Slack-specific features - When you're using the broader Slack integration capabilities Remember to handle the setup appropriately, especially in server environments:
Copy code
bash
# When using SlackIncomingWebhook, always register the blocks
prefect block register -m prefect_slack

# Verify registration
prefect block type ls
Would you like me to provide more specific examples of how to use either block type in your workflows?
b
@Marvin does run context have prefect vars?
m
thought for 68.6 seconds
Yes! Prefect's run context has many useful variables available through the
prefect.runtime
module. Here's a comprehensive overview: 1. Flow Run Context:
Copy code
python
from prefect import flow
from prefect.runtime import flow_run

@flow
def my_flow():
    # Flow run details
    print(f"Flow Run ID: {flow_run.id}")
    print(f"Flow Name: {flow_run.flow_name}")
    print(f"Flow Run Name: {flow_run.name}")
    print(f"Parameters: {flow_run.parameters}")
    print(f"Tags: {flow_run.tags}")
    print(f"UI URL: {flow_run.ui_url}")
    
    # Parent/Root flow information
    print(f"Parent Flow Run ID: {flow_run.parent_flow_run_id}")
    print(f"Root Flow Run ID: {flow_run.root_flow_run_id}")
    
    # Deployment information
    print(f"Parent Deployment ID: {flow_run.parent_deployment_id}")
    
    # Timing information
    print(f"Scheduled Start: {flow_run.scheduled_start_time}")
    
    # Run metadata
    print(f"Run Count: {flow_run.run_count}")
    print(f"Flow Version: {flow_run.flow_version}")
2. Task Run Context:
Copy code
python
from prefect import task
from prefect.runtime import task_run

@task
def my_task():
    print(f"Task Run ID: {task_run.id}")
    print(f"Task Name: {task_run.task_name}")
    print(f"Task Run Name: {task_run.name}")
    print(f"Parameters: {task_run.parameters}")
    print(f"Tags: {task_run.tags}")
    print(f"UI URL: {task_run.ui_url}")
    print(f"Run Count: {task_run.run_count}")
3. Deployment Context:
Copy code
python
from prefect import flow
from prefect.runtime import deployment

@flow
def my_flow():
    if deployment.id:  # Only available when run from deployment
        print(f"Deployment ID: {deployment.id}")
        print(f"Deployment Name: {deployment.name}")
        print(f"Deployment Version: {deployment.version}")
        print(f"Deployment Parameters: {deployment.parameters}")
4. Practical Example:
Copy code
python
from prefect import flow, task
from prefect.runtime import flow_run, task_run
from datetime import datetime

def get_context_info():
    """Helper to get relevant context info"""
    context = {
        "timestamp": datetime.utcnow().isoformat(),
        "flow_name": flow_run.flow_name,
        "flow_run_id": flow_run.id,
        "flow_run_name": flow_run.name,
    }
    
    # Add task info if in task context
    try:
        context.update({
            "task_name": task_run.task_name,
            "task_run_id": task_run.id
        })
    except RuntimeError:
        pass  # Not in task context
        
    # Add deployment info if available
    if deployment.id:
        context.update({
            "deployment_name": deployment.name,
            "deployment_id": deployment.id
        })
        
    return context

@task
def process_data():
    context = get_context_info()
    print(f"Processing with context: {context}")
    # Your task logic here

@flow
def my_flow():
    context = get_context_info()
    print(f"Flow started with context: {context}")
    process_data()
5. Using Context in Error Handling:
Copy code
python
from prefect import flow
from prefect.runtime import flow_run
from prefect.logging import get_run_logger

@flow
def my_flow():
    logger = get_run_logger()
    try:
        # Your flow logic here
        raise ValueError("Something went wrong")
    except Exception as e:
        logger.error(
            f"Error in flow run {flow_run.name} ({flow_run.id})",
            extra={
                "flow_run_url": flow_run.ui_url,
                "parameters": flow_run.parameters,
                "error": str(e)
            }
        )
        raise
These context variables are particularly useful for: - Logging and debugging - Creating unique identifiers - Building URLs to the Prefect UI - Accessing run-specific parameters - Understanding the execution hierarchy - Tracking deployment information Would you like me to show more specific examples of how to use these context variables in your workflows?
b
@Marvin why is this erroring out
Copy code
try:
        # Test the block directly
        slack_webhook = await SlackWebhook.load("slack-notifications")
        await slack_webhook.notify("Test message")
        logger.debug("✅ Test Slack notification sent successfully")
    except Exception as e:
        logger.exception(f"❌ Failed to send test Slack notification: {e}")
Failed to send test Slack notification: Unable to find block document named slack-notifications for block type slack-webhook
m
thought for 15.0 seconds
This error occurs because there's a mismatch between the block type name in your code and how it's registered in Prefect. Let me help you fix this. The error message
Unable to find block document named slack-notifications for block type slack-webhook
suggests that either: 1. The block hasn't been saved with that name, or 2. The block type name is incorrect (case sensitive) Here's how to fix it: 1. First, let's check how the block was saved:
Copy code
python
from prefect.blocks.notifications import SlackWebhook

# When you saved the block, it should have been like this:
slack_webhook = SlackWebhook(
    url="your-webhook-url"
)
slack_webhook.save(name="slack-notifications")  # This is the name you're trying to load
2. To verify the block exists and its exact name:
Copy code
python
# You can run this in a Python shell or script
from prefect.blocks.notifications import SlackWebhook

# List all saved blocks of this type
blocks = SlackWebhook.load_all()
for block in blocks:
    print(f"Found block: {block.name}")
3. Here's the corrected version of your code:
Copy code
python
from prefect.blocks.notifications import SlackWebhook
from prefect.logging import get_run_logger

logger = get_run_logger()

try:
    # Make sure the block name matches EXACTLY what you saved it as
    slack_webhook = await SlackWebhook.load("slack-notifications")
    await slack_webhook.notify("Test message")
    logger.debug("✅ Test Slack notification sent successfully")
except Exception as e:
    logger.exception(f"❌ Failed to send test Slack notification: {e}")
If you're still having issues, you can: 1. List all block types and their saved instances:
Copy code
python
from prefect.blocks.core import Block

# List all blocks
for block in Block.list_blocks():
    print(block)
2. Or check via CLI:
Copy code
bash
prefect block ls
3. If you need to create the block, you can do it programmatically:
Copy code
python
from prefect.blocks.notifications import SlackWebhook

# Create and save the block
slack_webhook = SlackWebhook(
    url="your-webhook-url"
)
slack_webhook.save(name="slack-notifications", overwrite=True)  # overwrite=True if you want to update existing

# Then try loading and using it
loaded_webhook = await SlackWebhook.load("slack-notifications")
await loaded_webhook.notify("Test message")
4. Or create it via the Prefect UI: - Go to Blocks in the UI - Click "Add Block" - Select "Slack Webhook" - Enter your webhook URL - Save it with the name "slack-notifications" Would you like me to help you troubleshoot further? It would be helpful to know: 1. How did you initially create/save the block? 2. What does
prefect block ls
show? 3. Are you using any specific naming convention in your block management?
b
@Marvin the block name is correct this is my import
Copy code
from prefect.blocks.notifications import SlackWebhook
m
thought for 49.8 seconds
The import looks correct. Let's verify the block type and try a different approach:
Copy code
python
from prefect.blocks.notifications import SlackWebhook
from prefect.blocks.core import Block
from prefect.logging import get_run_logger

logger = get_run_logger()

# First, let's check what blocks are available
all_blocks = Block.list_blocks()
<http://logger.info|logger.info>(f"Available blocks: {all_blocks}")

# Then check specifically for slack webhooks
slack_blocks = SlackWebhook.load_all()
<http://logger.info|logger.info>(f"Available Slack webhook blocks: {[block.name for block in slack_blocks]}")

try:
    # Load using the full block type path
    slack_webhook = await SlackWebhook.load("slack-webhook/slack-notifications")
    await slack_webhook.notify("Test message")
    logger.debug("✅ Test Slack notification sent successfully")
except Exception as e:
    logger.exception(f"❌ Failed to send test Slack notification: {e}")
If that doesn't work, let's try creating a new block to ensure it's registered correctly:
Copy code
python
from prefect.blocks.notifications import SlackWebhook
from prefect.logging import get_run_logger

logger = get_run_logger()

# Create and save the block
slack_webhook = SlackWebhook(
    url="your-webhook-url"  # Replace with your actual webhook URL
)

# Save with explicit block type
try:
    slack_webhook.save(name="slack-notifications", overwrite=True)
    <http://logger.info|logger.info>("Block saved successfully")
    
    # Now try to load and use it
    loaded_webhook = await SlackWebhook.load("slack-notifications")
    await loaded_webhook.notify("Test message")
    logger.debug("✅ Test Slack notification sent successfully")
except Exception as e:
    logger.exception(f"❌ Error: {e}")
Can you try running this diagnostic code to help us understand what's happening:
Copy code
python
from prefect.blocks.notifications import SlackWebhook
from prefect.blocks.core import Block
from prefect.logging import get_run_logger

async def diagnose_slack_block():
    logger = get_run_logger()
    
    # 1. Check all available blocks
    <http://logger.info|logger.info>("Checking all available blocks...")
    all_blocks = Block.list_blocks()
    <http://logger.info|logger.info>(f"Available blocks: {all_blocks}")
    
    # 2. Check specifically for slack blocks
    <http://logger.info|logger.info>("Checking Slack webhook blocks...")
    try:
        slack_blocks = SlackWebhook.load_all()
        <http://logger.info|logger.info>(f"Found Slack blocks: {[block.name for block in slack_blocks]}")
    except Exception as e:
        logger.error(f"Error loading Slack blocks: {e}")
    
    # 3. Try different loading approaches
    try:
        # Try with just the name
        <http://logger.info|logger.info>("Trying to load with just name...")
        block1 = await SlackWebhook.load("slack-notifications")
        <http://logger.info|logger.info>("Success!")
    except Exception as e:
        logger.error(f"Failed with name only: {e}")
    
    try:
        # Try with full path
        <http://logger.info|logger.info>("Trying to load with full path...")
        block2 = await SlackWebhook.load("slack-webhook/slack-notifications")
        <http://logger.info|logger.info>("Success!")
    except Exception as e:
        logger.error(f"Failed with full path: {e}")

# Use this in your flow
@flow
async def test_flow():
    await diagnose_slack_block()
This will help us understand: 1. What blocks are actually available 2. How the Slack block is registered 3. What loading method works Can you run this diagnostic code and share the output? That will help us pinpoint exactly what's wrong and how to fix it.
b
@Marvin this is how i made it
Copy code
from prefect_slack import SlackWebhook

slack_webhook_url = os.environ["SLACK_WEBHOOK_URL"]
block_name = "slack-notifications"


def create_slack_webhook_block():
    block = SlackWebhook(
        url=SecretStr(slack_webhook_url)
    )
    block.save(block_name, overwrite=True)
    <http://logger.info|logger.info>(f"✅ Saved SlackWebhook notification block as '{block_name}'")
m
thought for 11.3 seconds
Ah! Now I see the issue. You're using
prefect_slack
but trying to load with
prefect.blocks.notifications
. These are different implementations. Let's fix the loading code to match how you created it:
Copy code
python
from prefect_slack import SlackWebhook  # Note: same import as creation
from prefect.logging import get_run_logger

logger = get_run_logger()

try:
    # Load using the same SlackWebhook class from prefect_slack
    slack_webhook = await SlackWebhook.load("slack-notifications")
    await slack_webhook.notify("Test message")
    logger.debug("✅ Test Slack notification sent successfully")
except Exception as e:
    logger.exception(f"❌ Failed to send test Slack notification: {e}")
The key differences: 1.
from prefect.blocks.notifications import SlackWebhook
# Wrong for your case 2.
from prefect_slack import SlackWebhook
# Correct, matches your creation code This is happening because: 1.
prefect_slack
is a separate package with its own implementation of
SlackWebhook
2. The block type is registered under `prefect_slack`'s namespace 3. When you try to load with
prefect.blocks.notifications.SlackWebhook
, it's looking for a different block type Make sure you: 1. Have
prefect-slack
installed:
Copy code
bash
pip install prefect-slack
2. Have registered the blocks:
Copy code
bash
prefect block register -m prefect_slack
3. Use consistent imports between creation and usage:
Copy code
python
# Both creation and usage should use the same import:
from prefect_slack import SlackWebhook
Would you like me to show you more examples of how to use the
prefect_slack
webhook implementation?
b
@Marvin so all i needed to change was the import?
m
thought for 9.1 seconds
Yes, exactly! All you needed to change was the import statement because: 1. The block was created using
prefect_slack.SlackWebhook
2. You were trying to load it with
prefect.blocks.notifications.SlackWebhook
3. These are different implementations, even though they have the same class name It's like trying to open a file with the wrong program - the file exists, but you need to use the right tool to open it. Here's a visual of what happened:
Copy code
python
# How you CREATED the block:
from prefect_slack import SlackWebhook  # ✅ Created with this implementation
block = SlackWebhook(url=SecretStr(slack_webhook_url))
block.save("slack-notifications")

# How you tried to LOAD the block:
from prefect.blocks.notifications import SlackWebhook  # ❌ Different implementation
await SlackWebhook.load("slack-notifications")  # Failed because wrong implementation

# How it SHOULD be:
from prefect_slack import SlackWebhook  # ✅ Same implementation as creation
await SlackWebhook.load("slack-notifications")  # Works!
This is a common gotcha because: 1. The class names are identical 2. Both are part of the Prefect ecosystem 3. Both handle Slack notifications Best practice is to stay consistent with your imports between creation and usage of blocks.
b
@Marvin if i validated the webhook is working, why won’t my automation send notificaitons?
m
thought for 73.2 seconds
Based on the research, there are several common reasons why automations might not send notifications even when the webhook itself works. Here's what to check: 1. Block Type Registration:
Copy code
bash
# Make sure the Slack blocks are registered
prefect block register -m prefect_slack
2. Block Type Verification:
Copy code
python
from prefect.blocks.core import Block

# List all registered block types to verify
blocks = Block.list_blocks()
print([b for b in blocks if "slack" in b.lower()])
3. Automation Configuration: - Make sure you're using the correct block type in the automation - For
prefect-slack
blocks, use "Slack Incoming Webhook" (not "Slack Webhook") - The block should be visible in the UI under Blocks 4. Common Fixes:
Copy code
python
from prefect_slack import SlackWebhook

# 1. Try recreating the block with a different name
slack_webhook = SlackWebhook(
    url=SecretStr(slack_webhook_url)
)
slack_webhook.save("slack-notifications-new", overwrite=True)

# 2. Update your automation to use the new block
5. Debugging Steps: - Check the automation logs in the UI - Verify the trigger conditions are being met - Ensure the block is accessible to the automation Can you check: 1. What block type is selected in your automation? 2. Are you seeing any error messages in the automation logs? 3. Is the trigger condition being met (can you see the automation being triggered)? This will help us pinpoint exactly why the automation isn't sending notifications even though the webhook works directly.
b
@Marvin do i need to import that in every flow i want to notify on via automation?
m
thought for 9.8 seconds
No! You don't need to import the Slack webhook in flows that you want to notify via automation. Automations work at the Prefect server level, completely separate from your flow code. Once you've: 1. Created and saved the Slack webhook block 2. Set up the automation with that block The automation will work for any flow that matches the trigger conditions, regardless of what's imported in the flow code. Here's a visualization:
Copy code
Your Flow Code                  Prefect Server
-------------                   --------------
@flow                          Automation
def my_flow():                 - Trigger (e.g., "flow run completed")
    # No Slack imports         - Action (uses saved Slack block)
    # needed here!            
    pass                       ↓
                              Sends Slack notification
The only time you need to import and use the Slack webhook directly in your flow code is if you want to send notifications programmatically from within the flow itself. For automation-based notifications, the block just needs to exist and be properly configured in your Prefect environment. Would you like me to show you examples of different ways to set up automation triggers for your notifications?
b
@Marvin the webhook is on this app, and that test message just came from my flow run. but my automation is not sending anything, are there logs i can view? logs: Test Slack notification sent successfully
m
thought for 12.3 seconds
Yes! You can view automation logs in Prefect. Since we know the webhook works (as evidenced by your test message) but the automation isn't firing, let's check the automation logs to debug. You can find automation logs in two places: 1. In the UI: - Go to "Automations" - Click on your specific automation - Look for the "Events" tab - This will show you when the automation was triggered (or why it wasn't) 2. Via API/CLI: - Recent automation events - Whether triggers were matched - Any errors in the automation execution You can also check if your automation is being triggered at all: 1. Check the automation's trigger conditions: - Are they matching what you expect? - Is the flow name correct? - Are the states you're monitoring (e.g., "Completed", "Failed") correct? 2. Check the automation's event history: - Look for "prefect.automation.triggered" events - Look for any "prefect.automation.action.failed" events If you're seeing the automation being triggered but notifications aren't being sent, there might be a mismatch between: - The block type used in the automation (should be "Slack Incoming Webhook" if using
prefect-slack
) - The block name referenced in the automation - The permissions/access of the automation to use the block Would you like me to show you specific commands to check these logs, or would you prefer guidance on where to look in the UI?
b
@Marvin here are the automation logs
Copy code
{
  "id": "068942ee-8b45-79e0-8000-091a20f4cd3d",
  "event": "prefect.automation.action.failed",
  "occurred": "2025-08-07T04:43:20.704Z",
  "payload": {
    "reason": "The notification block was invalid: UnknownBlockType(\"No block class found for slug 'slack-incoming-webhook'. Please ensure that the block class is available in the current environment.\")",
    "invocation": "068942ee-8990-760f-8000-05a59512b651",
    "action_type": "send-notification",
    "action_index": 0
  },
  "received": "2025-08-07T04:43:20.704Z",
  "related": [],
  "resource": {
    "prefect.posture": "Reactive",
    "prefect.resource.id": "prefect.automation.96eaa544-0481-42f1-b493-9b9ac95745d5",
    "prefect.trigger-type": "event",
    "prefect.resource.name": "Flow run slack alerts"
  }
}
m
thought for 11.4 seconds
Ah! The error message is clear:
"No block class found for slug 'slack-incoming-webhook'. Please ensure that the block class is available in the current environment."
This means the Prefect server doesn't have the
prefect-slack
blocks registered. Even though your local environment can use the webhook (which is why the test worked), the server needs the blocks registered too. Here's how to fix it: 1. Register the blocks on the server:
Copy code
bash
prefect block register -m prefect_slack
2. Verify the registration:
Copy code
bash
prefect block type ls
Look for
slack-incoming-webhook
in the list. 3. In your automation: - Make sure you're using "Slack Incoming Webhook" (not "Slack Webhook") as the block type - The block name should match exactly what you saved it as ("slack-notifications") If you're running Prefect server in a container or different environment, you need to: 1. Install
prefect-slack
in that environment 2. Register the blocks in that environment 3. Restart the server to ensure it picks up the new block types The reason your test worked but automation didn't: - Test: Runs in your local environment where
prefect-slack
is installed and blocks are registered - Automation: Runs on the Prefect server where the blocks weren't registered Would you like me to show you how to verify the block registration on the server side?
b
@Marvin wrong, the notification i showed you came from prefect server. the same flow run also generated that automation fail event.
m
thought for 10.9 seconds
Ah, you're absolutely right - I apologize for the confusion! This is a really interesting case because: 1. The server CAN use the webhook (as shown by your successful test message) 2. BUT the automation is failing with
UnknownBlockType
for 'slack-incoming-webhook' This suggests there's a mismatch in how the block is being referenced. Since we know the server can use the block (your test worked), let's check: 1. What block type is selected in your automation? - In the UI, when setting up the automation action - It should match EXACTLY how you created it: if you used
prefect_slack.SlackWebhook
, you need "Slack Webhook" (not "Slack Incoming Webhook") 2. Check your block's actual type:
Copy code
python
from prefect_slack import SlackWebhook
block = SlackWebhook.load("slack-notifications")
print(f"Block type: {block._block_type_slug}")  # This will show the actual block type slug
The error suggests the automation is looking for 'slack-incoming-webhook' but your working block might be registered as 'slack-webhook' or something else. Could you check: 1. What block type is selected in your automation UI? 2. Can you show the code you used to create the block again? This will help us align the automation's expected block type with how you actually created it.
b
@Marvin the
block_type_name
in the db is
Slack Incoming Webhook
slack-notifications,"""***""",c7f4a527-f22d-477f-9bd9-b17198ff8eaf,7ecde64e-35ef-41e3-b369-d1e1992eb131,false,Slack Incoming Webhook
m
thought for 11.1 seconds
Ah, now we're getting somewhere! If the block is stored in the database as "Slack Incoming Webhook" but you created it using
prefect_slack.SlackWebhook
, there might be a version or registration mismatch. Let's verify the exact setup: 1. Check what version of
prefect-slack
you're using:
Copy code
bash
pip show prefect-slack
2. Let's try recreating the block with the explicit correct type:
Copy code
python
from prefect_slack.webhooks import SlackWebhook  # Note the .webhooks import
# or
from prefect_slack import SlackIncomingWebhook  # Depending on your version

slack_webhook = SlackIncomingWebhook(  # Note: IncomingWebhook, not just Webhook
    url=SecretStr(slack_webhook_url)
)
slack_webhook.save("slack-notifications", overwrite=True)
The fact that: - The test works - The DB shows "Slack Incoming Webhook" - But automation fails with "slack-incoming-webhook" slug error Suggests there might be a mismatch between how the block is registered and how the automation system is trying to use it. Could you share: 1. The output of
pip show prefect-slack
2. Whether you're using
SlackWebhook
or
SlackIncomingWebhook
in your creation code? This will help us ensure everything aligns correctly.
b
@Marvin there is no such thing as SlackIncomingWebhook in prefect_slack. you need to look for other examples of UnknownBlockType on slack incoming webhook automation discussions
m
thought for 34.6 seconds
Ah, now I see - this is actually a known issue! The problem is that while the Slack webhook block works for direct usage (like your test), there's a current limitation with using it in automations. This is tracked in issues #14418 and #16336. The workaround is to use the core Slack Webhook block type instead of the Slack Incoming Webhook block type for automations. Here's what to do: 1. Create a new block using the core Slack Webhook type:
Copy code
python
from prefect.blocks.notifications import SlackWebhook  # Note: different import

slack_webhook = SlackWebhook(
    url=SecretStr(slack_webhook_url)
)
slack_webhook.save("slack-notifications-core", overwrite=True)
2. Update your automation to use this new block (in the UI): - Edit the automation - Change the notification block to use the new "slack-notifications-core" block - Make sure to select "Slack Webhook" (not "Slack Incoming Webhook") as the block type This should resolve the
UnknownBlockType
error and get your automation notifications working. The core
SlackWebhook
block is fully supported in automations, while the integration package's webhook has this known limitation. Would you like me to show you how to migrate your existing notifications to use the core webhook block?
b
@Marvin thanks for finding that. give me the issue links so i can track them
m
thought for 8.5 seconds
Here are the relevant issue links from the Prefect GitHub repository: 1. Main issue tracking this problem: https://github.com/PrefectHQ/prefect/issues/14418 "support integration
NotificationBlock
types for automation actions" 2. Related issue with the same error: https://github.com/PrefectHQ/prefect/issues/16336 "Automation Action Type
Send a notification
fails when using Slack Incoming Webhook block" 3. Another related issue with detailed reproduction steps: https://github.com/PrefectHQ/prefect/issues/15302 "KeyError('No class found for dispatch key 'slack-incoming-webhook' in registry for type 'Block'.')" You can "watch" or subscribe to these issues on GitHub to get updates when they're resolved.
b
@Marvin can blocks of diff types have same name?
m
thought for 50.1 seconds
Yes, blocks of different types can have the same name! Each block is uniquely identified by the combination of its type and name, not just the name alone. For example, you can have:
Copy code
python
# These can coexist because they're different types
from prefect.blocks.notifications import SlackWebhook
from prefect_slack import SlackWebhook  # Different implementation

# Both can use the same name
slack1 = SlackWebhook(url="...")
slack1.save("my-notifications")  # Type: slack-webhook

slack2 = SlackWebhook(url="...")
slack2.save("my-notifications")  # Type: slack-incoming-webhook

# When loading, you specify both type and name
from prefect.blocks.core import Block

# These load different blocks despite same name
block1 = Block.load("slack-webhook/my-notifications")
block2 = Block.load("slack-incoming-webhook/my-notifications")
This is actually useful in your case because you can: 1. Keep your existing
slack-notifications
block of type
Slack Incoming Webhook
2. Create a new block with the same name but of type
Slack Webhook
for automations 3. Use them for different purposes while maintaining similar naming Would you like me to show you how to set this up with your existing block name?