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<@ULVA73B9P> a simple docker image to run a simple...
# ask-marvin
c
@Marvin a simple docker image to run a simple flow in work pool type docker
m
✅ thought for 93.9 seconds
Great! I'll provide you with a complete example of how to set up a simple Docker flow. Here's a step-by-step guide: 1. First, create a simple Python file named 
flow.py
with a basic flow:
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python
from prefect import flow, task

@task
def say_hello(name):
    return f"Hello, {name}!"

@flow
def hello_flow(name: str = "world"):
    message = say_hello(name)
    print(message)
    return message
2. Create a simple 
Dockerfile
in the same directory:
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dockerfile
# Use the official Python image
FROM python:3.9-slim

# Set working directory
WORKDIR /app

# Copy requirements and install dependencies
COPY requirements.txt .
RUN pip install -r requirements.txt

# Copy your flow code
COPY flow.py .

# Set the command to run your flow
CMD ["python", "flow.py"]
3. Create a 
requirements.txt
file:
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prefect>=3.0.0
4. Create a Docker work pool using the CLI:
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bash
prefect work-pool create my-docker-pool --type docker
5. Create a deployment script named `deploy.py`:
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python
from prefect.deployments import Deployment
from prefect.infrastructure.docker import DockerContainer
from flow import hello_flow

if __name__ == "__main__":
    docker_container = DockerContainer(
        image="my-flow-image:latest",
        image_registry={"dockerfile": "Dockerfile"},
    )

    deployment = hello_flow.deploy(
        name="docker-example",
        work_pool_name="my-docker-pool",
        infrastructure=docker_container,
    )
6. Build and deploy your flow:
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bash
# Run the deployment script
python deploy.py
7. Start a worker to run your flows:
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bash
prefect worker start --pool my-docker-pool
8. Run your flow:
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bash
prefect deployment run hello-flow/docker-example
Some important notes: 1. Make sure Docker is installed and running on your system 2. The worker needs to have access to Docker to build and run containers 3. All required dependencies should be listed in your 
requirements.txt
4. The Docker work pool will handle building the image and running the container for each flow run This is a minimal setup that demonstrates the basic concepts. You can enhance it by: - Adding more dependencies to 
requirements.txt
- Customizing the Dockerfile with additional system packages or configuration - Adding environment variables or secrets management - Implementing more complex flows with multiple tasks The Docker work pool will handle the container lifecycle, ensuring each flow run gets its own isolated environment. Links for further reading: - Docker Infrastructure Guide - Work Pools and Workers Guide Would you like me to explain any part of this setup in more detail?
c
@Marvin (venv) PS C:\opt\mds-test\mdsstack> py deploy.py Traceback (most recent call last): File "C:\opt\mds-test\mdsstack\deploy.py", line 8, in <module> flou.deploy(name="localflou", work_pool_name="local-pool", image="prefecthq/prefect:3-latest") ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\asyncutils.py", line 351, in coroutine_wrapper return run_coro_as_sync(ctx_call()) File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\asyncutils.py", line 207, in run_coro_as_sync return call.result() ~~~~~~~~~~~^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\_internal\concurrency\calls.py", line 365, in result return self.future.result(timeout=timeout) ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\_internal\concurrency\calls.py", line 192, in result return self.__get_result() ~~~~~~~~~~~~~~~~~^^ File "C:\Users\caio.brito\AppData\Local\Programs\Python\Python313\Lib\concurrent\futures\_base.py", line 401, in __get_result raise self._exception File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\_internal\concurrency\calls.py", line 441, in _run_async result = await coro ^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\asyncutils.py", line 188, in coroutine_wrapper return await task ^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\asyncutils.py", line 341, in ctx_call result = await async_fn(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\flows.py", line 1561, in deploy deployment_ids = await deploy_coro ^^^^^^^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\asyncutils.py", line 341, in ctx_call result = await async_fn(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\deployments\runner.py", line 1254, in deploy image.build() ~~~~~~~~~~~^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\docker\docker_image.py", line 73, in build with generate_default_dockerfile(): ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^ File "C:\Users\caio.brito\AppData\Local\Programs\Python\Python313\Lib\contextlib.py", line 141, in enter return next(self.gen) File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\utilities\dockerutils.py", line 619, in generate_default_dockerfile raise RuntimeError( ...<2 lines>... ) RuntimeError: Failed to generate Dockerfile. Dockerfile already exists in the current directory. (venv) PS C:\opt\mds-test\mdsstack>
m
✅ thought for 21.5 seconds
Make sure you have created your Docker work pool first:
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bash
prefect work-pool create local-pool --type docker
Choose one of the two approaches I outlined above (either use your existing Dockerfile or let Prefect generate one), modify your 
deploy.py
accordingly, and try running it again. Would you like me to: 1. Help you debug your existing Dockerfile setup? 2. Show you what should be in your Dockerfile if you want to keep using it? 3. Help you set up the automatic Dockerfile generation approach? Just let me know which path you'd prefer to take!
c
@Marvin i dont know i just take to guide of you pass me in the first message
m
✅ thought for 23.5 seconds
Now, let's create a complete working example. Create these files in your project directory: 1. First, your flow file (
flow.py
):
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python
from prefect import flow, task

@task
def say_hello(name):
    return f"Hello, {name}!"

@flow
def hello_flow(name: str = "world"):
    message = say_hello(name)
    print(message)
    return message

if __name__ == "__main__":
    hello_flow()
2. Your `requirements.txt`:
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prefect>=3.0.0
3. Your `Dockerfile`:
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dockerfile
FROM prefecthq/prefect:3-latest
COPY requirements.txt .
COPY flow.py .
4. And finally, your `deploy.py`:
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python
from prefect.deployments import Deployment
from prefect.infrastructure.docker import DockerContainer
from flow import hello_flow

if __name__ == "__main__":
    docker_container = DockerContainer(
        image="my-flow-image:latest",
        image_registry={"dockerfile": "Dockerfile"}
    )

    deployment = hello_flow.deploy(
        name="docker-example",
        work_pool_name="local-pool",
        infrastructure=docker_container
    )
Now, follow these steps: 1. Make sure all these files are in the same directory 2. Run the deployment:
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bash
python deploy.py
3. Start a worker:
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bash
prefect worker start --pool local-pool
4. In a new terminal, run your flow:
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bash
prefect deployment run hello-flow/docker-example
This should work correctly. The main differences from what you were trying are: 1. We're using 
DockerContainer
to properly configure the Docker infrastructure 2. We're specifying the Dockerfile explicitly 3. We're using the correct deployment structure If you get any errors with these steps, please share them and I'll help you debug them. Also, make sure: 1. Docker is installed and running on your system 2. You're in the correct directory when running these commands 3. All the files have exactly the content shown above Would you like me to explain any part of this in more detail?
c
@Marvin (venv) PS C:\opt\mds-test\mdsstack> py deploy.py Traceback (most recent call last): File "C:\opt\mds-test\mdsstack\deploy.py", line 1, in <module> from prefect.deployments import Deployment File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\deployments\__init__.py", line 23, in getattr return getattr_migration(name)(attr_name) ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^ File "C:\opt\mds-test\mdsstack\venv\Lib\site-packages\prefect\_internal\compatibility\migration.py", line 156, in wrapper raise PrefectImportError( f"`{import_path}` has been removed. {error_message}" ) prefect.exceptions.PrefectImportError: 
prefect.deployments:Deployment
has been removed. Use 
flow.serve()
, 
flow.deploy()
, or 
prefect deploy
instead. (venv) PS C:\opt\mds-test\mdsstack>
m
✅ thought for 29.6 seconds
Great! I see you already have the 
local-pool
work pool created. Now follow these steps: 1. Make sure all the files are saved with the correct content 2. Run the deployment:
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bash
python deploy.py
3. Start a worker in a separate terminal:
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bash
prefect worker start --pool local-pool
4. In another terminal, run your flow:
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bash
prefect deployment run hello-flow/docker-example
This should work now with the corrected code. The error you encountered was because Prefect 3.x has simplified the deployment process and removed the older 
Deployment
class in favor of the more straightforward 
.deploy()
method. If you encounter any other errors, please share them and I'll help you resolve them. Also, make sure: 1. Docker is running on your system 2. You're in the directory containing all these files when running the commands 3. Your virtual environment is activated and has Prefect 3.x installed Would you like me to explain any part of this in more detail?
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