Himanshu
07/15/2024, 4:26 AMMarvin
07/15/2024, 4:26 AMHimanshu
07/15/2024, 5:41 AMMarvin
07/15/2024, 5:41 AMHimanshu
07/15/2024, 5:57 AMMarvin
07/15/2024, 5:57 AMprefect work-pool create my-managed-pool --type prefect:managed
For more detailed guidance, you can visit the Prefect documentation on work pools: https://docs.prefect.io/latest/concepts/work-pools/
Selecting the type of work pool depends on your specific infrastructure and execution environment needs.Himanshu
07/15/2024, 6:10 AMMarvin
07/15/2024, 6:10 AMprefect work-pool create my-process-pool --type process
2. Kubernetes Worker Pool
prefect work-pool create my-k8s-pool --type kubernetes
3. Docker Worker Pool
prefect work-pool create my-docker-pool --type docker
After creating the work pool, you can start the corresponding worker with the command:
prefect worker start -p <work-pool-name>
For more detailed steps and options, refer to the Prefect documentation on setting up work pools: https://docs.prefect.io/latest/concepts/work-pools/Himanshu
07/15/2024, 6:11 AMMarvin
07/15/2024, 6:12 AMHimanshu
07/15/2024, 6:13 AMMarvin
07/15/2024, 6:13 AMHimanshu
07/15/2024, 11:35 AMMarvin
07/15/2024, 11:35 AM--limit
option when creating a worker is not specified explicitly in the provided excerpts.
To safely ascertain the default, you can either:
1. Consult the Prefect CLI documentation for the most up-to-date information.
2. Run the following command in your CLI to see the details and default options for worker creation:
prefect worker start --help
This should provide information about default values and configurable options for creating a worker.Himanshu
07/15/2024, 11:36 AMMarvin
07/15/2024, 11:36 AMprefect gcl
(global concurrency limit) command. For example:
- Create a Concurrency Limit:
prefect gcl create my-concurrency-limit --limit 5 --slot-decay-per-second 1.0
- Update a Concurrency Limit:
prefect gcl update my-concurrency-limit --limit 10
- Inspect a Concurrency Limit:
prefect gcl inspect my-concurrency-limit
- Delete a Concurrency Limit:
prefect gcl delete my-concurrency-limit
### Task Concurrency Limits
Task concurrency limits use task tags to specify the maximum number of concurrent task runs. These limits ensure that no more than a set number of tasks with a specific tag are running simultaneously.
For more details, refer to the documentation on:
- Global Concurrency Limits: https://docs.prefect.io/latest/guides/global-concurrency-limits/
- Task Concepts: https://docs.prefect.io/latest/concepts/tasks/
These tools allow you to control and manage the concurrency levels effectively when using agents.Himanshu
07/15/2024, 11:38 AMMarvin
07/15/2024, 11:38 AMHimanshu
07/16/2024, 4:42 AMMarvin
07/16/2024, 4:42 AMpython
from prefect import flow
@flow(name="Hello Flow")
def hello_world(name="world"):
print(f"Hello {name}!")
if __name__ == "__main__":
hello_world("Marvin")
When you run this script, it will output the following:
$ python hello.py
15:11:23.594 | INFO | prefect.engine - Created flow run 'benevolent-donkey' for flow 'hello-world'
15:11:23.594 | INFO | Flow run 'benevolent-donkey' - Using task runner 'ConcurrentTaskRunner'
Hello Marvin!
15:11:24.447 | INFO | Flow run 'benevolent-donkey' - Finished in state Completed()
Running the flow directly like this executes the flow immediately without the need for any agents or workers.
For more information on running Prefect flows, you can refer to the Prefect documentation on flows: https://docs.prefect.io/latest/concepts/flows/Himanshu
07/16/2024, 4:44 AMMarvin
07/16/2024, 4:44 AMPREFECT_WORKER_QUERY_SECONDS
setting.
Default Polling Interval:
- Polling Frequency: Every 15 seconds by default.
- Configurable Setting: PREFECT_WORKER_QUERY_SECONDS
.
Factors Affecting Job Picking Time:
1. Latency: Remote workers might experience network latency compared to local workers.
2. Infrastructure Start Time: The time it takes for the infrastructure to start might vary based on the worker's location and deployment method.
3. Configuration: Both local and remote workers can configure settings such as prefetch and polling intervals.
Therefore, while the base mechanism for job picking is the same, network conditions and infrastructure start times might introduce variability in job picking times between local and remote workers.
For more details, please refer to:
- Worker Polling: https://docs.prefect.io/latest/concepts/work-pools/Himanshu
07/16/2024, 4:45 AMMarvin
07/16/2024, 4:45 AMprefect work-pool ls
- Inspect details of a work pool: prefect work-pool inspect
- Preview scheduled work: prefect work-pool preview
UI Access:
- You can also see and edit configured work pools in the Prefect UI.
For more information, please refer to the work pools documentation: https://docs.prefect.io/latest/concepts/work-pools/Himanshu
07/16/2024, 4:46 AMMarvin
07/16/2024, 4:47 AMHimanshu
07/16/2024, 4:47 AMMarvin
07/16/2024, 4:48 AMHimanshu
07/16/2024, 4:49 AMMarvin
07/16/2024, 4:49 AMHimanshu
07/16/2024, 4:50 AMMarvin
07/16/2024, 4:51 AMHimanshu
07/16/2024, 4:52 AMMarvin
07/16/2024, 4:52 AMHimanshu
07/16/2024, 5:02 AMMarvin
07/16/2024, 5:02 AMPREFECT_API_URL
.
2. Flow and Task Decorators:
- Flows and tasks are annotated with Prefect decorators like @flow
and @task
, which enable Prefect to manage their execution and state transitions.
- Example:
python
from prefect import flow, task
@task
def say_hello(name: str):
print(f"Hello {name}!")
@flow
def hello_world():
say_hello("Marvin")
hello_world()
3. Execution Management:
- When a flow runs, it's tracked and managed by the Prefect API server, which facilitates logging, state management, retries, and observability.
- The orchestration layer ensures that each flow and task transition through states seamlessly and provides a UI for monitoring.
4. Prefect CLI and UI:
- The Prefect CLI can be used to manage flows and tasks, configure settings, and view statuses.
- The Prefect UI provides a rich interface for tracking and debugging workflows.
For further details, refer to:
- Prefect Open Source: https://www.prefect.io/opensource
- Prefect API and Configuration: https://www.prefect.ioHimanshu
07/16/2024, 5:04 AMMarvin
07/16/2024, 5:04 AMsrc/prefect/server/api
directory. This directory contains various modules and endpoints that are part of the Prefect API.
For further details, you can explore the Prefect GitHub repository:
- GitHub Repository: https://github.com/PrefectHQ/prefect
- Prefect Server API Directory: https://github.com/PrefectHQ/prefect/tree/main/src/prefect/server/apiHimanshu
07/18/2024, 8:33 AMMarvin
07/18/2024, 8:34 AMPREFECT_API_DATABASE_CONNECTION_URL
to include the necessary connection options.
Here's how you can configure the connection URL to increase the pool size:
1. Edit the Connection URL:
Update the PREFECT_API_DATABASE_CONNECTION_URL
setting in your Prefect configuration to include the pool_size
parameter.
2. Set the Configuration:
Use the Prefect CLI to set the updated database connection URL.
Example:
sh
prefect config set PREFECT_API_DATABASE_CONNECTION_URL="<postgresql+asyncpg://user:password@localhost:5432/dbname?pool_size=20>"
This example sets the pool size to 20. Adjust the pool_size
parameter as needed for your requirements.
3. Verify Configuration:
Confirm that the configuration has been set correctly.
sh
prefect config view --show-sources
Note: Make sure to replace user
, password
, localhost
, and dbname
with your actual database user, password, host, and database name respectively.
For more information on configuring Prefect with PostgreSQL, you can refer to the hosting and configuration guide: https://docs.prefect.io/latest/guides/host/Himanshu
07/18/2024, 8:34 AMMarvin
07/18/2024, 8:35 AMpool_size
for PostgreSQL connections in Prefect's configuration is not explicitly mentioned in the documentation excerpts. Typically, in many database management systems, a default pool size is often around 5-10 connections, but the exact value for Prefect should be confirmed in their configuration or documentation.
To explicitly set or verify the pool_size
, it is recommended to:
1. Consult the Database Connection Settings:
Use the Prefect configuration settings to explicitly set the pool_size
parameter as needed.
2. Verify and Set Configuration:
sh
prefect config set PREFECT_API_DATABASE_CONNECTION_URL="<postgresql+asyncpg://user:password@localhost:5432/dbname?pool_size=10>"
3. Check Prefect's Documentation:
Refer to the Prefect documentation or configuration file to verify the default settings.
For further information, refer to the hosting and configuration guide: https://docs.prefect.io/latest/guides/host/
If you need specific default values, it might be helpful to check Prefect's source code in their repository or raise an issue for clarification: https://github.com/PrefectHQ/prefectHimanshu
07/18/2024, 8:36 AMMarvin
07/18/2024, 8:36 AMmax_connection
for PostgreSQL database in Prefect Orion, you need to configure the PREFECT_API_DATABASE_CONNECTION_URL
by including the parameter max_connections
.
Here's how you can do it:
1. Update Connection URL:
Set the PREFECT_API_DATABASE_CONNECTION_URL
to include the max_connections
parameter.
2. Example Command:
sh
prefect config set PREFECT_API_DATABASE_CONNECTION_URL="<postgresql+asyncpg://user:password@localhost:5432/dbname?max_connections=20>"
3. Verify Configuration:
Check the Prefect configuration to ensure that the max_connections
parameter is correctly applied.
sh
prefect config view --show-sources
Replace user
, password
, localhost
, and dbname
with your actual PostgreSQL credentials and connection details.
For more detailed settings, you can refer to the Prefect hosting and configuration guide: https://docs.prefect.io/latest/guides/host/
Adjusting the max_connections
parameter helps control the maximum number of connections allowed to the PostgreSQL database, ensuring better resource management and preventing potential exhaustion of database connections.Himanshu
07/18/2024, 8:55 AMMarvin
07/18/2024, 8:56 AMpool_size
, max_connections
, and other connection-specific parameters might not be recognized natively by the asyncpg
PostgreSQL adapter used in Prefect's connection string. These parameters are typically managed at the database client or ORM level.
To properly configure the connection pool size for PostgreSQL in Prefect, you might need to set the connection pool settings directly in PostgreSQL's client library configuration or adjust the database settings.
Alternative Steps:
1. Check PostgreSQL Configuration:
Ensure that the PostgreSQL server itself is configured to support the desired number of connections. This can be set in the postgresql.conf
file or via SQL commands:
sql
ALTER SYSTEM SET max_connections = 100;
2. Configure Connection Pool in Prefect's Client:
Prefect uses the asyncpg
library for asynchronous database communications. You might need to use settings specific to asyncpg
to configure the pool size.
Example Using environment variables (if supported):
Set environment variables for connection parameters directly in Prefect:
sh
export PREFECT_API_DATABASE_CONNECTION_URL="<postgresql+asyncpg://user:password@localhost:5432/dbname>"
export ASYNC_PG_POOL_SIZE=20
3. Custom Configuration within Prefect:
Modify Prefect's internal database connection handling code if applicable, to explicitly set the connection pool size programmatically using asyncpg
. This might involve altering Prefect's startup scripts or custom initialization.
Example:
python
import asyncpg
from prefect import config
async def main():
pool = await asyncpg.create_pool(
dsn=config.PREFECT_API_DATABASE_CONNECTION_URL,
min_size=1,
max_size=20
)
async with pool.acquire() as connection:
# Use your connection here
pass
if __name__ == "__main__":
import asyncio
asyncio.run(main())
For Detailed Configuration:
Refer to the asyncpg documentation: https://magicstack.github.io/asyncpg/current/api/index.html#connection-pools
If you are experiencing the TypeError
, it may be due to improper usage of connection string parameters. Always ensure that the parameters are compatible with the library and environment used by your Prefect setup.Himanshu
07/18/2024, 8:59 AMMarvin
07/18/2024, 9:00 AMmax_connections
configuration has been applied to your PostgreSQL database in Prefect, you can use several methods:
1. Verify Configuration:
Check if the environment variable PREFECT_API_DATABASE_CONNECTION_URL
is set correctly.
sh
prefect config view --show-sources
2. Query PostgreSQL Database:
Use a SQL query to verify current connection settings.
sql
SHOW max_connections;
3. Monitor Active Connections:
Query the PostgreSQL system catalogs to see active connections and pool usage.
sql
SELECT * FROM pg_stat_activity;
4. Logs and Metrics:
Monitor Prefect and PostgreSQL logs for any indications of connection pool configurations and usage.
5. Using asyncpg
in Python:
If you configured the connection pool programmatically, you can inspect and validate the pool size directly in the Python script.
Confirm Through SQL Query:
Execute the following SQL query to check the maximum allowed and active connections:
sql
SELECT setting FROM pg_settings WHERE name = 'max_connections';
SELECT COUNT(*) FROM pg_stat_activity WHERE state = 'active';
This will show the max_connections
setting and the number of currently active connections to the database.
By using these methods, you can confidently validate if the max_connections
configuration has been applied and is functioning as expected.Himanshu
07/18/2024, 9:07 AMMarvin
07/18/2024, 9:07 AMASYNC_PG_POOL_SIZE
is not showing in the prefect config view
output, it suggests that the environment variable might not be recognized or applied correctly. Instead, you can validate and manage the connection pool size in alternative ways:
### Validating and Managing Connection Pool Size in PostgreSQL:
1. Using SQL Queries:
Directly query PostgreSQL to see the pool size and active connections.
sql
-- Get the configured max connections
SHOW max_connections;
-- Check the number of active connections
SELECT COUNT(*) FROM pg_stat_activity;
2. Environment Variables Not Visible:
Some settings may not show up in prefect config view
but can still be active if properly configured in the environment.
### Applying Configuration Programmatically in Prefect:
If ASYNC_PG_POOL_SIZE
isn't being recognized, try setting the connection pool size programmatically within your Python code, especially if using asyncpg
.
Example using asyncpg
:
python
import asyncpg
from prefect import config
async def main():
pool = await asyncpg.create_pool(
dsn=config.PREFECT_API_DATABASE_CONNECTION_URL,
min_size=1,
max_size=20 # Set your desired pool size here
)
async with pool.acquire() as connection:
# Use your connection here
pass
if __name__ == "__main__":
import asyncio
asyncio.run(main())
Key Steps:
1. Set the Connection URL:
Ensure PREFECT_API_DATABASE_CONNECTION_URL
is properly set.
sh
prefect config set PREFECT_API_DATABASE_CONNECTION_URL="<postgresql+asyncpg://user:password@localhost:5432/dbname>"
2. Run Database Initialization or Connection Pool Setting Script:
Use a custom script to ensure the connection pool size is as desired.
### Monitoring and Debugging:
- Monitor logs from Prefect and PostgreSQL to check for indications that the connection pool size has been configured and is being utilized correctly.
- Use database monitoring tools to see active connections and pool usage.
To ensure the connection pool size is applied, follow the steps above, and query your PostgreSQL server to monitor the active connections. Programmatic control ensures settings are applied as specified.Himanshu
07/18/2024, 11:49 AMMarvin
07/18/2024, 11:49 AMsh
prefect worker start -p "my-pool"
This command will start a worker to pick up flows from the work pool named "my-pool".
2. Inspect the Work Pool:
To ensure that the work pool is correctly configured and being polled, you can inspect its status.
Inspect Work Pool Command:
sh
prefect work-pool inspect "my-pool"
3. Create or Update Work Pools and Queues:
If you need to create or update work pools and queues, you can use the corresponding CLI commands.
Create a Work Pool Command:
sh
prefect work-pool create my-new-pool --type "process"
Update Work Pool Command:
sh
prefect work-pool update my-pool --base-job-template path/to/base_template.json
Note:
- Ensure that the names of your work pools and queues are properly configured.
- You can manage work pools and queues through the Prefect UI as well for easier visualization and control.
For more detailed information, refer to the documentation on work pools: https://docs.prefect.io/latest/concepts/work-pools/