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<@ULVA73B9P> When I use prefect.deployments.steps....
# ask-marvin
n
@Marvin When I use prefect.deployments.steps.run_shell_script in the build part of my prefect.yaml, it errors out with ValueError: Step has unexpected additional keys: id, script, stream_output. I'm using Prefect 3.0.1
m
It sounds like you're experiencing a problem with the configuration of the 
run_shell_script
step in your 
prefect.yaml
. The error message you're receiving, "Step has unexpected additional keys: id, script, stream_output," suggests that there may be a mismatch in the expected structure or field names within the step configuration. Here are a few things you should check and try: 1. Verify the Documentation: As per Prefect 3.x documentation for the deployment YAML configuration, ensure that you're using the correct field names and values. From the documentation, an example configuration for 
run_shell_script
looks like this:
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build:
   - prefect.deployments.steps.run_shell_script:
       id: get-user
       script: echo $USER
       stream_output: true
       expand_env_vars: true
Make sure your 
prefect.yaml
follows a similar structure. Note that 
expand_env_vars
can be used if the environment variables are not expanding as expected. 2. Documentation Reference Links: - Prefect Deployment YAML Concepts provides comprehensive details about different deployment steps including 
run_shell_script
. 3. Check for Updates or Breaking Changes: It's possible that in the version you're using, some fields might have been deprecated or changed. Ensure your Prefect 3.0.1 version aligns with the available documentation or consider updating to a newer version if possible. 4. Check Prefect GitHub Discussions: Sometimes issues are discussed in more detail in community forums or GitHub, which can provide further insights. However, no specific known issues related to your error were found in the Prefect GitHub repository at this time. Try adjusting your 
prefect.yaml
based on the above guidelines and see if that resolves the error. If you have further issues, it might be helpful to cross-check your Prefect version and ensure compatibility with the documentation you are following.
n
@Marvin How do I use the output of a run_shell_script in the image_name of the build_docker_image? It should work like string templateing
m
You can use the output of a 
run_shell_script
step as part of the 
image_name
or other fields in the 
build_docker_image
step by utilizing Prefect's templating feature. Here's a concise example of how you can achieve this: 1. Define the 
run_shell_script
step: First, execute the shell script to get the desired output. Assign an 
id
to this step to reference its output later.
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yaml
   build:
   - prefect.deployments.steps.run_shell_script:
       id: get-commit-hash
       script: git rev-parse --short HEAD
       stream_output: false
2. Use the Output in `build_docker_image`: Reference the output of the 
run_shell_script
step using its 
id
and 
stdout
attribute as a template within your 
image_name
.
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yaml
   - prefect_docker.deployments.steps.build_docker_image:
       requires: prefect-docker>=0.3.0
       image_name: my-repo/my-image:{{ get-commit-hash.stdout }}
       dockerfile: auto
In this setup, the 
get-commit-hash.stdout
is dynamically replaced with the output from the 
git rev-parse --short HEAD
command, allowing you to create a Docker image tagged with the current commit hash. For further reference and details, check out the Prefect documentation on this concept: Prefect YAML Concepts
n
@Marvin How do I get the repository name so I can use it in build_docker_image image_name?
m
To retrieve the repository name so you can use it in the 
image_name
of the 
build_docker_image
step, you can use a 
run_shell_script
step to extract the repository name from your Git configuration or URL. Here's a step-by-step explanation of how you can do this: 1. Extract Repository Name Using Git: Use a shell script to extract the repository name from your Git configuration or URL. You can set this up in a 
run_shell_script
step. Example using `git config`:
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yaml
   build:
   - prefect.deployments.steps.run_shell_script:
       id: get-repo-name
       script: basename -s .git `git config --get remote.origin.url`
       stream_output: true
       expand_env_vars: true
This script uses the 
basename
command to strip the 
.git
extension from the repository's URL, giving you just the repository name. 2. Use the Output in `build_docker_image`: Reference the output of the previous step using its 
id
and the 
stdout
attribute as a template in the 
image_name
.
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yaml
   - prefect_docker.deployments.steps.build_docker_image:
       requires: prefect-docker>=0.3.0
       image_name: my-registry/{{ get-repo-name.stdout }}:latest
       dockerfile: auto
       push: true
In this setup, 
{{ get-repo-name.stdout }}
will be replaced with the extracted repository name at runtime, enabling you to dynamically set the image name based on the repository being used. Remember that the effectiveness of this method relies on your Git configuration being correctly set up and accessible from the environment where these commands execute.
n
@Marvin the stdout is "`git config --get remote.origin.url`"
m
It looks like the script is not executing correctly, possibly due to incorrect formatting or the shell environment not interpreting the commands as expected. Let's refine the script to ensure it captures the repository name correctly. We want to execute a one-liner that gets the repository name from the git URL in a more reliable way: 1. Modify the Script: Combine commands with more safeguards to extract and print the repo name.
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yaml
   build:
   - prefect.deployments.steps.run_shell_script:
       id: get-repo-name
       script: |
         url=$(git config --get remote.origin.url)
         basename=$(basename -s .git $url)
         echo $basename
       stream_output: true
       expand_env_vars: true
2. Explanation: - The script now consists of three lines: - First line retrieves the origin URL and assigns it to the variable 
url
. - The second line uses 
basename
with the 
-s
flag to strip the 
.git
extension and assigns the result to 
basename
. - The third line echoes the 
basename
, which is the actual repository name. This approach should correctly capture the repository name and allow it to be used via 
{{ get-repo-name.stdout }}
in subsequent steps. You can then proceed to use it in your Docker image tag or name as follows:
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yaml
   - prefect_docker.deployments.steps.build_docker_image:
       requires: prefect-docker>=0.3.0
       image_name: my-registry/{{ get-repo-name.stdout }}:latest
       dockerfile: auto
       push: true
If the issue persists or the output is still incorrect, make sure that: - Git is accessible and correctly configured within the environment running the Prefect deployment script. - The target repository is set as the origin in your local Git configuration.
n
@Marvin Running into another error: "FileNotFoundError: [Errno 2] No such file or directory: 'url=$(git'"
m
The error suggests that the shell script might be interpreted incorrectly or not fully supported by the environment that Prefect is running in. Let's refine the approach by simplifying the script to capture and execute it properly. ### Approaches to Fix the Issue: 1. Simplify the Script Execution: If using a multi-line script is causing issues, try a single-line approach that chains the commands effectively.
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yaml
   build:
   - prefect.deployments.steps.run_shell_script:
       id: get-repo-name
       script: git config --get remote.origin.url | xargs basename -s .git
       stream_output: true
       expand_env_vars: true
Explanation: - This script uses a pipe (
|
) to send the output of 
git config --get remote.origin.url
directly to 
xargs basename -s .git
, which extracts the repository name. - This minimizes complexity and improves chances of correct execution in constrained environments. 2. Ensure Git Configuration: Double-check that the environment where Prefect is executing the script has: - A valid Git installation and access to the Git executable. - Correct Git repository path configuration, with a remote origin set and accessible. 3. Test Environment: Try running the script directly in the environment (e.g., a terminal in the same Docker container or virtual environment) to ensure it functions correctly outside of the Prefect setup. If the issue persists beyond these fixes, there might be a unique constraint or bug within the Prefect environment. At that point, investigating environmental constraints or reaching out to Prefect community support for more tailored assistance might be helpful.
n
@Marvin How to use the name as variable as defined on top of the prefect.yaml file?
m
To use variables defined at the top of your 
prefect.yaml
file, you can use Jinja templating to substitute those variables throughout the file. This is a neat way to manage configurations and dynamically reference values in multiple places. Here's how you can define and use a variable for the repository name: ### Defining Variables 1. Set Your Variables at the Top: Start by defining the variables at the top of your 
prefect.yaml
using a special 
variables
section, if your Prefect version supports it, or directly use values where applicable. 2. Sample Prefect YAML with Variables:
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yaml
variables:
  repo_name: my-repo

build:
  - prefect_docker.deployments.steps.build_docker_image:
      requires: prefect-docker>=0.3.0
      image_name: my-registry/{{ repo_name }}:latest
      dockerfile: auto
      push: true
### Using the Variable - Referencing the Variable: - Within any part of your 
prefect.yaml
, you can reference the defined variable using the templating syntax, e.g., 
{{ repo_name }}
. - This allows for flexible and scalable configurations, where changing the value of 
repo_name
at the top changes it throughout the deployment script. ### Important Notes: - Jinja Templating: Ensure your Prefect environment supports Jinja syntax within the YAML files. - Variable Scope: The definition and use of variables must be supported by the Prefect version you are using. If you encounter issues with this approach or your Prefect version doesn't support top-level variables, consider managing dynamic settings using environment variables or external configuration management tools that Prefect integrates with.
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