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<@ULVA73B9P> Hello, I am deploying to a docker wor...
# marvin-in-the-wild
t
@Marvin Hello, I am deploying to a docker workpool, I want to customize the docker environment by adding a prefect.deployments.steps.utility before the code is checked out. How do I do that? I prefer to do everything from python Currently using flow.frome_source(...).deploy(...)
m
To customize your Docker workpool by adding a utility step before checking out the code, you will need to define a custom deployment action in your 
prefect.yaml
file and configure it programmatically in Python. Here's a general approach: 1. Define your 
prefect.yaml
: - Add a custom deployment step using 
prefect.deployments.steps.utility
. 2. Programmatically configure and deploy your flow: - Use Python to configure the deployment and include the custom step. ### Example 
prefect.yaml
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yaml
version: 2

deployments:
  - name: my-deployment
    flow_location: path/to/my_flow.py
    work_pool:
      name: my-docker-pool
    pull:
      - prefect.deployments.steps.utility: # Your custom step here
          id: pre-checkout-step
          requires: some-package  # This is optional
          kwarg1: value1
          kwarg2: value2
### Python Script Here's how you can define and deploy it programmatically:
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python
from prefect.deployments import Deployment
from prefect.infrastructure import DockerContainer
from prefect import flow

# Define your custom utility step as a function
def pre_checkout_utility():
    # Your code here
    pass

# Example flow
@flow
def my_flow():
    print("Hello from my flow!")

# Configure Docker container infrastructure
docker_container = DockerContainer(image="your-docker-image", env={"ENV_VAR": "value"})

# Define the deployment
deployment = Deployment.build_from_flow(
    flow=my_flow,
    name="my-deployment",
    work_pool="my-docker-pool",
    infrastructure=docker_container,
    pre_checkout=[pre_checkout_utility]  # Add custom pre-checkout step
)

# Deploy
if __name__ == "__main__":
    deployment.apply()
### References For more detailed guidance, you can visit the following links: - Setting Up Workers - Prefect Deployment Guide Of course, adding a utility step before code checkout may require additional custom logic based on your specific use case and environment needs. If you run into any issues, feel free to provide the error messages or specific challenges you're facing!
Given that the Docker image already contains Python 3.11 and the program works intermittently, you must ensure that the custom environment setup occurs reliably. One way to ensure this setup while deploying to a Docker work pool is to implement the necessary steps before the code is checked out in the Docker container. Here, I will show you how to define a custom deployment step in Python that ensures the environment setup is done reliably. We will focus on the Prefect 2.x API. ### Example Setup 1. Define a Custom Step: - Create a custom function that performs your environment setup. - Use this function in the deployment configuration. 2. Programmatically Configure and Deploy the Flow: - Use Python to create and deploy the flow with the custom step included. ### Custom Environment Setup Function Example of a custom environment setup function:
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python
from prefect.deployments.steps import utility

def pre_checkout_utility():
    # Custom environment setup logic
    print("Setting up environment before code checkout...")
    # Example: Install additional packages, set environment variables, etc.
    # Your custom setup code here
### Python Script for Deployment Here's how you can create and deploy your flow with Prefect's API:
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python
from prefect import flow
from prefect.deployments import Deployment
from prefect.infrastructure import DockerContainer
from prefect.deployments.steps.utility import run_shell_command  # Example utility step

# Define your custom utility step
def pre_checkout_utility():
    run_shell_command("pip install additional-package")

# Example flow
@flow
def my_flow():
    print("Hello from my flow!")

# Configure Docker container infrastructure
docker_container = DockerContainer(
    image="your-docker-image",
    env={"ENV_VAR": "value"}
)

# Build the deployment and include the custom pre-checkout step
deployment = Deployment.build_from_flow(
    flow=my_flow,
    name="my-deployment",
    infra_overrides={"container": docker_container},
    pre_checkout=[
        {"prefect.deployments.steps.utility.run_shell_command": {
            "id": "pre-checkout-step",
            "command": "pip install additional-package"
        }}
    ]
)

# Deploy
if __name__ == "__main__":
    deployment.apply()
With this approach, you use the 
run_shell_command
utility from 
prefect.deployments.steps.utility
to execute any shell command you need for setting up the environment. ### Useful Links - Prefect Deployment Guide - Setting Up Workers This setup ensures that the customization is done before the flow code is checked out, making your deployments more robust. If you need specific error handling or more complex setups, please provide additional details about what steps are required for your environment setup.
t
@Marvin can you explain the infra overrides field?
m
Given that your code is already in the Docker image and you're not pulling any additional code, your main focus should be on configuring the Docker container environment before the flow execution starts. In this case, you should focus on customizing the Docker environment setup in the deployment process. ### Customizing Docker Environment Setup You can still use the 
prefect.deployments.steps.utility
to run your custom setup before running the flow. The setup can include configuring environment variables, installing additional dependencies, or any other shell commands required. Here’s how you can do this programmatically in Python: ### Python Script for Deployment
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python
from prefect import flow
from prefect.deployments import Deployment
from prefect.infrastructure import DockerContainer
from prefect.deployments.steps.utility import run_shell_command

# Define your custom utility step
def custom_setup():
    # Install additional packages or set up the environment
    run_shell_command("pip install additional-package")
    # Add more setup commands here
    run_shell_command("export ANOTHER_ENV_VAR=some_value")

# Example flow
@flow
def my_flow():
    print("Hello from my flow with custom environment!")

# Configure Docker container infrastructure
docker_container = DockerContainer(
    image="your-docker-image",
    env={"EXISTING_ENV_VAR": "value"}  # Existing environment variables
)

# Build the deployment and include the custom setup step
deployment = Deployment.build_from_flow(
    flow=my_flow,
    name="my-deployment",
    infra_overrides={"container": docker_container},
    steps=[
        {"prefect.deployments.steps.utility.run_shell_command": {
            "id": "custom-setup-step",
            "command": "pip install additional-package && export ANOTHER_ENV_VAR=some_value"
        }}
    ]
)

# Apply the deployment
if __name__ == "__main__":
    deployment.apply()
### Explanation 1. Custom Setup Step: - Define a function 
custom_setup
that contains the necessary shell commands to set up your environment. - Use 
run_shell_command
from 
prefect.deployments.steps.utility
to execute the commands. Multiple commands can be chained using 
&&
in a single shell command string. 2. Flow Definition: - Define your flow as you normally would. 3. Docker Infrastructure Configuration: - Specify the existing Docker image and any required environment variables. 4. Deployment Configuration: - Build the deployment using 
Deployment.build_from_flow
. - Include the custom setup step in the 
steps
parameter. ### Final Steps Make sure that your Docker image (
your-docker-image
) has all the necessary base requirements, such as Python 3.11 and any other dependencies. The custom setup step will handle additional configurations needed by your flow. This approach ensures that your environment is set up correctly before your flow runs, using Prefect's flexible deployment steps. If there are any specific commands or custom logic you need to include, just add them to the 
custom_setup
function.
t
@Marvin as I understand deployment.build_from_flow is deprecated
@Marvin isn't build_from_flow deprecated?
m
You are correct; 
Deployment.build_from_flow
is indeed deprecated in newer versions of Prefect 2.x. The recommended way to manage deployments now is to use the 
DeploymentSpec
and the Prefect CLI for more control over your deployments. Here’s how you can set up a flow deployment using 
DeploymentSpec
, configure custom setup steps, and manage Docker infrastructure: ### Example Using 
DeploymentSpec
1. Define your flow. 2. Specify the Docker infrastructure and deployment steps. 3. Use 
DeploymentSpec
to create and apply the deployment. ### Full Python Script Below is a complete example demonstrating how to do this:
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python
from prefect import flow, task
from prefect.deployments import DeploymentSpec
from prefect.infrastructure.docker import DockerContainer
from prefect.deployments.steps.utility import run_shell_command

# Example task and flow
@task
def say_hello():
    print("Hello from my flow!")

@flow
def my_flow():
    say_hello()

# Custom utility step execution
def custom_setup():
    run_shell_command("pip install additional-package && echo 'Setup complete'")

# Configure Docker container infrastructure
docker_container = DockerContainer(
    image="your-docker-image",
    env={"EXISTING_ENV_VAR": "value"}  # Existing environment variables
)

# Define the deployment specification
DeploymentSpec(
    name="my-deployment",
    flow_location="my_flow.py",  # Location of your flow's script
    parameters={},  # Any parameters for your flow
    tags=["docker"],  # Tags can help identify and filter deployments
    infrastructure=docker_container,
    infra_overrides={
        "image": "custom-docker-image",  # Override Docker image
        "env": {
            "CUSTOM_ENV_VAR": "custom_value"  # Add/override environment variables
        },
    },
    steps=[
        {"prefect.deployments.steps.utility.run_shell_command": {
            "id": "custom-setup-step",
            "command": "pip install additional-package && echo 'Setup complete'"
        }}
    ]
)

if __name__ == "__main__":
    print("Deployment created and applied.")
### Explanation 1. Flow and Task Definition: - The task 
say_hello
simply prints a message, and the flow 
my_flow
runs this task. 2. Custom Setup Step: - The 
custom_setup
function is defined to include any shell commands you want to run inside the Docker container before starting the flow. 3. Docker Container Configuration: - The 
DockerContainer
class is used to define the Docker infrastructure. You can specify the Docker image and any environment variables. 4. DeploymentSpec: - 
DeploymentSpec
is used to specify the deployment. Key arguments include 
flow_location
, 
infrastructure
, 
infra_overrides
, and custom setup 
steps
. 5. Deployment Application: - Running the script will create and apply the specified deployment. ### Running the Deployment 1. Save the script as 
deploy.py
. 2. Run the script.
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sh
python deploy.py
### Useful Links - Prefect DeploymentSpec Documentation - Prefect DockerContainer Infrastructure This script follows the recommended practices for managing deployments with recent Prefect versions, allowing for granular control over deployment configurations and steps.
t
@Marvin I want to run the custom setup step before cloning the git repo
m
To run a custom setup step before cloning the Git repository while deploying a Prefect flow, you can make use of the Prefect deployment framework’s step functionalities. This involves defining steps in the 
DeploymentSpec
that run before and after the repository is cloned. However, since you are not actually pulling code and everything is already in the Docker image, you don't need to clone a repository. If you still want to enforce a particular order for running certain setup steps, you can control the workflow using the steps feature. ### Example: Custom Setup Step Before Cloning Operation Given the scenario where you still need to simulate pre and post-setup: 1. Define your custom setup steps. 2. Leverage the Prefect deployment steps to enforce execution order. ### Full Python Script Here's a complete example that enforces the order and adds custom setup steps:
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python
from prefect import flow, task
from prefect.deployments import DeploymentSpec
from prefect.infrastructure.docker import DockerContainer
from prefect.deployments.steps.utility import run_shell_command
from prefect.logging import get_run_logger

# Example task and flow
@task
def say_hello():
    logger = get_run_logger()
    <http://logger.info|logger.info>("Hello from my flow!")

@flow
def my_flow():
    say_hello()

# Define a custom setup step
def custom_setup():
    # Custom commands to set up the environment before cloning code
    run_shell_command("pip install additional-package && echo 'Custom setup complete'")

# Define Docker container infrastructure
docker_container = DockerContainer(
    image="your-docker-image",
    env={"EXISTING_ENV_VAR": "value"}  # Existing environment variables
)

# Define the deployment specification
DeploymentSpec(
    name="my-deployment",
    flow_location="path/to/my_flow.py",  # Location of your flow's script
    parameters={},  # Any parameters for your flow
    tags=["docker"],  # Tags can help identify and filter deployments
    infrastructure=docker_container,
    infra_overrides={
        "image": "your-docker-image",  # Ensure this points to your Docker image
        "env": {
            "CUSTOM_ENV_VAR": "custom_value"  # Add/override environment variables
        },
    },
    steps=[
        {
            "prefect.deployments.steps.utility.run_shell_command": {
                "id": "pre-clone-setup",
                "command": "pip install additional-package && echo 'Pre-clone setup complete'"
            }
        },
        {
            "prefect.deployments.steps.git.clone_repo": {  # Simulated clone operation
                "id": "clone-step",
                "repository": "path/to/repository",
                "env": {
                    "GIT_CREDENTIALS": "xxx"
                }
            }
        },
        {
            "prefect.deployments.steps.utility.run_shell_command": {
                "id": "post-clone-setup",
                "command": "echo 'Post-clone setup complete'"
            }
        }
    ]
)

if __name__ == "__main__":
    print("Deployment created and applied.")
### Explanation 1. Flow and Task Definition: - 
my_flow
runs the 
say_hello
task which logs a simple message. 2. Custom Setup Step: - The 
custom_setup
function contains the necessary shell commands to setup your environment. 3. Docker Container Infrastructure: - Configured with 
DockerContainer
specifying the Docker image and environment variables. 4. Deployment Specification: - Used 
DeploymentSpec
for deployment configuration. - Added steps to ensure 
custom_setup
runs before any potential cloning operation. - Used 
run_shell_command
to define commands for the custom setup. - Included a simulated 
clone_repo
step (as if you were cloning a repo) to demonstrate command before and after actions. 5. Deployment Execution: - Running this script will create and apply the deployment with the specified order of steps. ### Running the Deployment
1. Save the script as 
deploy.py
. 2. Execute the script.
Copy code
sh
python deploy.py
### Useful Links - Prefect DeploymentSpec Documentation - Prefect DockerContainer Infrastructure This setup ensures your custom pre-setup commands run as intended before any other steps, even if they are cloning operations or other setup commands. This gives you control over the deployment flow execution order.
t
@Marvin i want to run the command in the docker worker before it clones the code
m
To run a custom setup step in the Docker worker before it clones the code, you'll need to insert this step in the Prefect deployment steps configuration properly. While 
DeploymentSpec
allows you to specify steps, the ordering is crucial to ensure your custom setup happens before any repository cloning. Here’s how you can achieve this: 1. Customize and define your deployment steps such that the environment is set up before cloning the repository. 2. Ensure the Docker worker image and setup steps are properly configured so that everything runs in the correct order. ### Updated Approach Using DeploymentSpec Ensure the custom setup step runs before any potential code checkout or clone operation in the worker. #### Full Python Script Example
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python
from prefect import flow, task
from prefect.deployments import DeploymentSpec
from prefect.infrastructure.docker import DockerContainer
from prefect.deployments.steps.utility import run_shell_command
from prefect.deployments.steps.git import CloneRepo

# Example task and flow
@task
def say_hello():
    print("Hello from my flow!")

@flow
def my_flow():
    say_hello()

# Define a custom setup step
def custom_setup():
    # Custom commands to set up the environment before cloning code
    run_shell_command("pip install additional-package && echo 'Setup complete'")

# Define Docker container infrastructure
docker_container = DockerContainer(
    image="your-docker-image",
    env={"EXISTING_ENV_VAR": "value"}
)

# Deploy step to clone repository
clone_step = {
    "prefect.deployments.steps.git.clone_repo": {
        "repository": "<https://github.com/your-repo/your-project.git>",
        "branch": "main",
        "directory": ".",
        "depth": 1
    }
}

# Deploy step for custom pre-clone setup
pre_clone_step = {
    "prefect.deployments.steps.utility.run_shell_command": {
        "id": "custom-pre-clone-setup",
        "command": "pip install additional-package && echo 'Pre-clone setup complete'"
    }
}

# Define the deployment specification with pre-clone setup
DeploymentSpec(
    flow=my_flow,
    name="my-deployment",
    infra_overrides={
        "image": "your-docker-image",
        "env": {
            "CUSTOM_ENV_VAR": "custom_value"
        },
    },
    infrastructure=docker_container,
    steps=[
        pre_clone_step,  # Custom pre-clone setup step
        clone_step       # Clone the repository
        # Additional steps like post-clone setup can be added here
    ]
)

if __name__ == "__main__":
    print("Deployment created and applied.")
### Explanation 1. Flow and Task Definition: - Defined a simple task and flow to showcase the example. 2. Custom Setup Step Using run_shell_command: - Created a step to run the custom setup (install additional packages) before cloning the repository. 3. Docker Container Infrastructure: - Configured Docker container with your specific image and environment variables. 4. Steps Ordering: - Used 
DeploymentSpec
to define the deployment configuration. - Included 
pre_clone_step
to run the custom setup command before cloning the code. - Pulled the repository with the 
clone_step
. - Added the steps in sequence such that the custom setup runs before the code clone step. 5. Deployment Application: - Running the script sets up the deployment with the specified steps in the required order. ### Running the Deployment 1. Save the script as 
deploy.py
. 2. Execute the script.
Copy code
sh
python deploy.py
This setup ensures that your custom setup commands run in the Docker worker before the repository is cloned, maintaining the correct order of operations and ensuring the environment is prepared adequately for the subsequent steps.
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