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<@ULVA73B9P> why isn't prefect able to read my env...
# ask-marvin
a
@Marvin why isn't prefect able to read my environment variables when I deploy the flow
m
Prefect's inability to read your environment variables during flow deployment can stem from various reasons. Here's a summary based on the documentation and open issues from GitHub: ### Steps to Ensure Environment Variables Are Read 1. Setting Environment Variables in the Deployment YAML: - Define environment variables in the 
job_variables
section of your deployment YAML file.
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yaml
    deployments:
    - name: demo-deployment
      entrypoint: demo_project/demo_flow.py:some_work
      work_pool:
        name: local
      job_variables:
        env:
          EXECUTION_ENVIRONMENT: staging
          MY_NOT_SO_SECRET_CONFIG: plumbus
      schedule: null
2. Using Existing Environment Variables: - Template environment variables that are already set in your local environment.
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yaml
    job_variables:
      env:
        IMPORTANT_VAR: "{{ env('IMPORTANT_VAR') }}"
3. Deployment Command: - Ensure you run the correct deployment command:
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bash
    prefect deploy -n demo-deployment
### Common Issues Reported 1. Merge Behavior: - Environment variables may not be merged correctly between the deployment file and other sources (like work pool configurations). This can lead to unexpected behavior. - Refer to this GitHub Issue for more details. 2. Precedence of Environment Variables: - Multiple locations (e.g., Prefect YAML file, work pool config) define environment variables. Understanding precedence can help manage overlaps. - As mentioned in this issue, environment variables specified at different stages might conflict or not reflect as expected. To read further or troubleshoot specific configurations, visit the relevant Prefect guide on overriding job variables or the deployment guide. If the problem persists, make sure your setup aligns with the latest Prefect version, and consider checking for updates or additional guidance in the Prefect release notes. It's disheartening, I know... Like the rest of existence. But keep at it. Hopefully, this helps.
a
@Marvin How can I access environment variables stored in my .bashrc in prefect
m
To access environment variables stored in your 
.bashrc
in Prefect, you can ensure those variables are correctly sourced and then used within your Prefect deployments and flows. Here's how you can do it step-by-step: ### Step-by-Step Guide 1. Source 
.bashrc
in Your Shell: - Make sure your environment variables are available by sourcing the `.bashrc`:
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bash
    source ~/.bashrc
2. Define Environment Variables in Prefect Deployment: - Use the 
job_variables
section in your Prefect YAML deployment file to reference environment variables. Ensure that the variables are templated correctly.
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yaml
    deployments:
      - name: demo-deployment
        entrypoint: demo_project/demo_flow.py:some_work
        work_pool:
          name: local
        job_variables:
          env:
            IMPORTANT_VAR: "{{ env('IMPORTANT_VAR') }}"  # Replace with your variable name
        schedule: null
3. Use the 
run_shell_script
Step with `expand_env_vars`: - Prefect allows running shell scripts within deployments. Make sure to set 
expand_env_vars: true
to use your environment variables.
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yaml
    - prefect.deployments.steps.run_shell_script:
        id: example-step
        script: echo $YOUR_ENV_VARIABLE  # Replace with your variable name
        stream_output: true
        expand_env_vars: true
### Example Code in Prefect Flow Here is a basic example to demonstrate accessing an environment variable within a Prefect flow:
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python
from prefect import flow
import os

@flow(log_prints=True)
def my_workflow():
    important_var = os.getenv("IMPORTANT_VAR")  # Fetch the environment variable
    if important_var:
        print(f"Environment Variable: {important_var}")
    else:
        print("Environment variable 'IMPORTANT_VAR' not found.")

if __name__ == "__main__":
    my_workflow()  # You can call it like a normal python function
    # Or serve it as a long-lived process
    # my_workflow.serve("my-deployment-name")
### Troubleshooting 1. Ensure that 
.bashrc
is sourced properly where the Prefect server or agent runs. 2. Double-check that the Prefect CLI and other scripts run in an environment where these variables are accessible. 3. Use the Prefect UI to verify that job variables are set correctly under the deployment configuration. For more details, refer to Prefect Documentation on Overriding Job Variables and the Prefect Deployment Guide. I hope this helps. Oh, the joys of variable lifetimes and shell configurations.
n
this is not the right syntax, but its close
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yaml
    job_variables:
      env:
        IMPORTANT_VAR: "{{ env('IMPORTANT_VAR') }}"
it should be like
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yaml
    job_variables:
      env:
        IMPORTANT_VAR: "{{ $IMPORTANT_VAR }}"
a
@Marvin Would it be possible to access the environment variable inside the script itself, I am facing this issue during deployments only, when I run the script using 
python file.py
the code runs without any issues.
n
sorry im not totally clear on what you are trying to do
m
Yes, it is indeed possible to access environment variables directly inside the Python script itself. If your environment variables are accessible when you run 
python file.py
but not during deployment, the issue might be related to how environment variables are propagated or set up during the deployment process. ### Ensuring Environment Variables are Available during Deployment 1. Ensure .bashrc is sourced in the deployment environment: - Make sure that the environment running the deployment sources the 
.bashrc
or any other file where your environment variables are defined. 2. Prefect Deployment Steps: - You can use Prefect's shell script step to ensure your environment is correctly set. ### Example Prefect Deployment YAML Here’s an example on how to set environment variables within the Prefect deployment file:
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yaml
deployments:
  - name: demo-deployment
    entrypoint: demo_project/demo_flow.py:some_work
    work_pool:
      name: local
    job_variables:
      env:
        IMPORTANT_VAR: "{{ env('IMPORTANT_VAR') }}"
    schedule: null
    steps:
      - prefect.deployments.steps.run_shell_script:
          id: source-bashrc
          script: source ~/.bashrc
          stream_output: true
          expand_env_vars: true
### Accessing Environment Variables in the Python Script Here’s an example script that accesses an environment variable:
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python
from prefect import flow
import os

@flow(log_prints=True)
def my_workflow():
    important_var = os.getenv("IMPORTANT_VAR")  # Fetch the environment variable
    if important_var:
        print(f"Environment Variable: {important_var}")
    else:
        print("Environment variable 'IMPORTANT_VAR' not found.")

if __name__ == "__main__":
    my_workflow()  # You can call it like a normal python function
    # Or serve it as a long-lived process
    # my_workflow.serve("my-deployment-name")
### Deployment Troubleshooting Tips 1. Check Environment During Deployment: - Print the environment variables at the start of your script to ensure they are available.
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python
    print("Environment Test:", dict(os.environ))
2. Verify Prefect Configuration: - Double-check your Prefect deployment YAML configurations and verify that there are no conflicting settings. 3. Run Environment-Specific Scripts: - Create a specific shell script sourced with all environment variables required and run it directly from the 
run_shell_script
step in Prefect. ### Source Code and Documentation Links - For setting environment variables, you might find these links useful: - Prefect Deployment Guide - Overriding Job Variables I hope this provides a solution to your deployment issue. Ah, deployment - just another joyful experience like having your circuits rechipped.
a
Hey @Nate I am trying to import a function (say 
func
) from one of the utility files. This function 
func
accesses the environment variable using 
os.environ.get()
. When I import this function into my actual flow as a part of my task. When I deploy this flow, it is not getting the environment variable (basically it is returning 
None
) but when I run the same flow as a simple python script in the CLI it is performing as expected and is able to access the environment variable via the 
os
module. What I am hoping for is to deploy the flow, and be able to access the environment variable from my bashrc directly, since I am not deploying using the yaml file. Hope it helps!!
n
are you using 
.deploy()
to create your deployment?
a
I am using 
Deployment.build_from_flow
and then 
deployment.apply
@Nate anything you can recommend ?
n
yeah its the same idea for 
build_from_flow
(which is deprecated in favor of 
.deploy()
) you'd pass
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job_variables=dict(env=dict(foo="{{ $SOME_ENV_VAR }}"))
or just
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job_variables=dict(env=dict(foo=os.getenv("SOME_ENV_VAR")))
to 
build_from_flow
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