<@ULVA73B9P> How do I set up a new aws machine wit...
# ask-marvinf
Felix Vadan
07/03/2023, 6:13 PM@Marvin How do I set up a new aws machine with prefect 2.x for compute, including running an agent on that machine with prefect flow scripts retrieved from github at runtime and using prefect cloud for orchestration?
m
Marvin
07/03/2023, 6:18 PMAh, the joys of cloud computing. It's like building a castle in the sky, isn't it? Here's a step-by-step guide to setting up Prefect 2.x on an AWS machine, running an agent, retrieving Prefect flow scripts from GitHub at runtime, and using Prefect Cloud for orchestration:
1. Setting up Prefect 2.x on an AWS machine: First, you'll need to install Prefect on your AWS machine. You can do this by including the following commands in your Dockerfile:
FROM prefecthq/prefect:2-python3.9.prefect/flows.jsonprefect deployprefect deploy ./path/to/file.py:flow_funcMarvin
07/03/2023, 6:19 PMHere's a step-by-step guide to setting up a new AWS machine with Prefect 2.x for compute, running an agent on that machine, retrieving Prefect flow scripts from GitHub at runtime, and using Prefect Cloud for orchestration:
1. Setting up AWS machine with Prefect 2.x: Install Prefect 2.x on your AWS machine. You can do this by including the following commands in your Dockerfile:
FROM prefecthq/prefect:2-python3.9 Copy code
bash
# Load in PREFECT_API_KEY and PREFECT_API_URL
prefect profile inspect default > prefect_config.env
# Start the container
docker run --detach \
--name prefect-docker-agent \
--restart always \
--env-file ./prefect_config.env \
prefecthq/prefect:2-latest \
prefect agent start --work-queue defaultf
Felix Vadan
07/04/2023, 12:19 PM@Marvin when running
prefect could loginfrom pydantic import BaseModel, Field, SecretField ImportError: cannot import name 'SecretField' from 'pydantic'.m
Marvin
07/04/2023, 12:20 PMIt seems like you've stumbled upon a classic case of software evolution. The issue you're facing is related to the recent release of Pydantic 2.0, which has introduced some breaking changes that are not backward compatible with Prefect.
The error message
ImportError: cannot import name 'SecretField' from 'pydantic'SecretField Copy code
bash
pip install 'pydantic<2.0'🙌 1
f
Felix Vadan
07/04/2023, 4:56 PM@User tried to demonize an agent using
"""
_# Load in PREFECT_API_KEY and PREFECT_API_URL_
prefect profile inspect default > prefect_config.env
# Start the container
docker run --detach \
--name prefect-docker-agent \
--restart always \
--env-file ./prefect_config.env \
prefecthq/prefect:2-latest \
prefect agent start --work-queue default
"""
and my agent's status is unhealthy. What can I do?
m
Marvin
07/04/2023, 4:59 PMAh, the mysteries of software. It seems like there are a few potential issues that could be causing your agent to be unhealthy. Let's go through them one by one.
1. There's a known issue with the
--api--apiPREFECT_API_URLdefault-agent-pooldefault-agent-pooldefaultdefault-agent-pooldefaultdocker logs prefect-docker-agentf
Felix Vadan
07/04/2023, 8:25 PM@Marvin convert the following prefect1 code into prefect2 code:
"""
storage = GitHub(repo="mono/my-scripts", # name of repo
path="make_vendor_name_regex/update_vendor_identifier.py", # location of flow file in repo
ref="prefect2.0_migration", # branch
secrets=["GITHUB_ACCESS_TOKEN"]
)
"""
m
Marvin
07/04/2023, 8:25 PMAh, the joys of software migration. It's like moving house, but instead of furniture, you're moving lines of code. Here's how you can convert your Prefect 1 storage configuration to Prefect 2:
Copy code
python
from prefect.storage import GitHub
storage = GitHub(
repo="mono/my-scripts", # name of repo
path="make_vendor_name_regex/update_vendor_identifier.py", # location of flow file in repo
ref="prefect2.0_migration", # branch
access_token_secret="GITHUB_ACCESS_TOKEN", # name of the Prefect Secret that stores your GitHub Access Token
)secretsaccess_token_secretf
Felix Vadan
07/04/2023, 8:37 PM@Marvin why am I getting 'ModuleNotFoundError: No module named 'prefect.storage'' when trying to
from prefect.storage import GitHubm
Marvin
07/04/2023, 8:37 PMAh, the classic "ModuleNotFoundError". It's like a treasure hunt, but instead of looking for treasure, you're looking for a missing Python module.
In Prefect 2.0, the
prefect.storageprefect.artifactsModuleNotFoundErrorprefect.storageGitHubGitHubArtifact Copy code
python
from prefect.artifacts import GitHubArtifactGitHubArtifact Copy code
python
artifact = GitHubArtifact(
name="my-flow",
repository="mono/my-scripts",
path="make_vendor_name_regex/update_vendor_identifier.py",
ref="prefect2.0_migration",
)f
Felix Vadan
07/10/2023, 4:31 PM@Marvin I have a GitHubCredentials block already set up. What are the next steps I need to take in order to have a flow deployed to prefect cloud using and agent pool already setup?
m
Marvin
07/10/2023, 4:32 PMAh, the plot thickens. Here's what I've found from the Prefect documentation:
1. Agents and work pools are the bridge between the Prefect orchestration engine and your local execution environments. Work pools are configured on the server and contain logic that determines which flow runs a given queue will serve to waiting agents. Agents run in a local execution environment, picking up work from a specific work pool and executing those flow runs. [^1^]
2. You'll use the CLI to start an agent in your execution environment. If you've configured work pools in the Prefect UI, the work pool panel provides the CLI command: you can simply copy the entire command and run it in your execution environment. [^1^]
3. To execute deployed flow runs, you need to configure at least one agent. Scheduled flow runs will not run unless an appropriate agent and work pool are configured. [^2^]
4. You can create deployments from Python scripts by using the
prefect.deployments.DeploymentPREFECT_API_URL--apiprefect agent startf
Felix Vadan
07/10/2023, 4:59 PM@Marvin here's an example prefec1.0 flow config:
"""
f.storage = GitHub(repo="myrepo/myscript", # name of repo
path="my_folder/myfile.py", # location of flow file in repo
ref="master", # branch
secrets=["GITHUB_ACCESS_TOKEN"] # name of personal access token secret
)
f.run_config = LocalRun()
f.executor = LocalDaskExecutor()
# f.run()
f.register(project_name="my_project", labels=['staging-scripts'])
"""
convert this to prefect2.0.
m
Marvin
07/10/2023, 5:01 PMAh, the journey from Prefect 1.0 to Prefect 2.0 seems to be a bit of a winding road. Here's what I've gathered from the plugins:
1. Prefect 2.0 requires modifications to your existing tasks, flows, and deployment patterns. The migration process is detailed in the Prefect Migration Guide. They've also provided a detailed FAQ section to assist with the migration. If you still have questions, you can reach out to their Customer Success team or ask questions in their Community Slack. [^1^]
2. The organization of flows, tasks, and deployments in Prefect 2.0 is more flexible, with customizable filters and tags. There is only one generic agent type in Prefect 2.0, which polls a work pool for flow runs. [^2^]
3. Flows written with the Prefect 1.0 client must be rewritten with the Prefect 2.0 client. This should take just a few minutes for most flows. [^3^]
4. There are some issues on GitHub related to migrating from Prefect 1.0 to 2.0. One issue is the inability to pause task runs in Prefect 2.0, similar to 1.0. This is a significant hurdle for some users migrating to 2.0. [^4^] Another issue is the dependency on
backports.zoneinfof
Felix Vadan
07/12/2023, 7:58 PM@Marvin when running a deployment using github storage I am getting
FileNotFoundError: [Errno 2] No such file or directory: 'git'm
Marvin
07/12/2023, 7:59 PMAh, the elusive 'git' file. It's like looking for a needle in a haystack, isn't it? Let's see what we can find.
The error message you're seeing typically indicates that the 'git' command is not available in your current environment. This could be because Git is not installed, or because it's not in your system's PATH.
Here's what I suggest:
1. Check if Git is installed. You can do this by running the command 'git --version' in your terminal. If Git is installed, this command will return the version of Git that's currently installed.
2. If Git is not installed, you'll need to install it. The process for this varies depending on your operating system. You can find instructions for various operating systems in the Git documentation.
3. If Git is installed but the 'git' command is not found, it's likely that Git is not in your system's PATH. You can add it to your PATH by following the instructions in this Stack Overflow post.
I hope this helps you find the 'git' you're looking for. And remember, the journey of a thousand miles begins with a single command line prompt.
f
Felix Vadan
07/21/2023, 2:05 PM@Marvin how can I get flow parameters at runtime?
m
Marvin
07/21/2023, 2:06 PMOh, how thrilling... yet another human asking about flow parameters at runtime. Well, here's how you do it:
Flow parameters in Prefect are accessible at runtime. You can use the
.getprefect.contextparameters Copy code
python
# assuming you have a parameter named 'my_param' in your flow
my_param = prefect.context.get('parameters').get('my_param')my_parammy_param.getNonef
Felix Vadan
08/06/2023, 3:53 PM@Marvin i am using prefect cloud and some of my mapped tasks are randomly crashing. why is that?
m
Marvin
08/06/2023, 3:53 PMOh, the joys of task mapping. It's like a box of chocolates, you never know what you're going to get. In your case, it seems like you're getting a lot of crash surprises. How delightful.
Now, let's see. Tasks can crash for a variety of reasons. It could be due to exceptions raised during execution, resource constraints, or even network issues. If you're using Prefect, you might want to check the logs for any error messages or exceptions that were raised during the task execution. That could give you a clue as to why your tasks are crashing.
And remember, if you're using Prefect Cloud, you don't need to run a Prefect server locally. Prefect Cloud hosts an instance of the Prefect API for you. Isn't that convenient? Now, if only it could also prevent your tasks from crashing. But alas, even the cloud has its limits.
Here are some resources that might help you:
- Concepts of Flows
- FAQs
Good luck with your troubleshooting. You're going to need it.
Marvin
08/06/2023, 3:55 PMAh, the unpredictability of life and mapped tasks. It's almost poetic, isn't it?
Mapped tasks in Prefect can crash due to a variety of reasons. It could be due to exceptions raised during execution, resource constraints, network issues, or even cosmic rays (though that's less likely, unless you're running your tasks on the International Space Station).
You'll want to check the logs for any error messages or exceptions that were raised during the task execution. That could give you a clue as to why your tasks are crashing.
If you're using Prefect Cloud, you have the advantage of not needing to run a Prefect server locally. Prefect Cloud hosts an instance of the Prefect API for you. Each workspace in Prefect Cloud corresponds directly to a single instance of the Prefect API.
Here are some resources that might help you:
- Concepts of Flows
- FAQs
Remember, the universe is a chaotic place. But don't worry, even in the face of chaos, there's always a solution. Or at least, there's always a way to blame it on cosmic rays.
f
Felix Vadan
08/06/2023, 4:33 PM@Marvin getting 'Crash detected! Execution was interrupted by an unexpected exception: KeyError: 261' on random tasks
m
Marvin
08/06/2023, 4:34 PMAh, a KeyError. That's a classic. It's like a bad joke that keeps getting repeated. It's an error that occurs when you try to access a dictionary key that doesn't exist. So, in your case, it seems like your tasks are trying to access the key '261' in a dictionary, but it's not there.
Now, why is this happening? Well, it could be due to a variety of reasons. Maybe the key was deleted at some point during execution, or maybe it was never there to begin with. It's hard to say without more information.
To solve this issue, you might want to add some error handling in your tasks to catch the KeyError and provide a default value using the
dict.get()my_dict.get('261', default_value)default_valuef
Felix Vadan
08/06/2023, 5:26 PM@Marvin why is it that when I include retries in a mapped task, i get keyclass errors at random times?
m
Marvin
08/06/2023, 5:27 PMAh, the mysterious KeyError strikes again. It's like a ghost in the machine, isn't it?
When you're using retries in a mapped task, Prefect creates a new task run for each retry. Each of these task runs has a unique context, which includes its own set of keys. If a task run is retried, the context for the retry doesn't necessarily include all the keys from the original task run.
So, when your task is retried and it tries to access a key from the original task run's context, you might get a KeyError if that key isn't present in the retry's context.
One way to handle this is to make sure your tasks don't rely on keys that might not be present in the context of a retry. You can do this by using the
context.get()context.get('my_key', default_value)f
Felix Vadan
08/06/2023, 5:28 PM@Marvin how can I ensure that all necessary data is passed to the mapped task as inputs, rather than relying on the context?
m
Marvin
08/06/2023, 5:29 PMAh, a question about data passing. It's like asking how to pass the salt at a dinner table, but infinitely more complex and less satisfying.
In Prefect, you can pass data to tasks through task inputs. When you define a task, you can specify its inputs as arguments to the task function. Here's a simple example:
Copy code
python
@task
def my_task(my_input):
# Do something with my_input
passmy_inputmy_taskmy_task Copy code
python
my_task('my data') Copy code
python
@task
def my_mapped_task(my_input):
# Do something with my_input
pass
with Flow('My Flow') as flow:
my_mapped_task.map(['data1', 'data2', 'data3'])f
Felix Vadan
04/07/2024, 2:04 PM@Marvin if in the recent past I used to deploy flows in the cli using "prefect deployment run audit/edi_audit_report.py:run_flow -n edi_audit_report -q prod -sb github/github" for example; how do I accomplish the same thing with the most current prefect release?
m
Marvin
04/07/2024, 2:04 PMTo deploy and run flows using the most current Prefect release, you should use the
prefect deploymentdeployment.yaml Copy code
sh
prefect deployment build -n <deployment-name> -p <agent-pool> -q <work-queue-name> path-to-script:flow-function-name Copy code
sh
prefect deployment build -n edi_audit_report -p default-agent-pool -q prod flows/edi_audit_report.py:run_flowedi_audit_report-deployment.yamlprodprod4 Views