Add Docker and container registry support

[serroba]

What?

This PR adds support to create docker images locally against the current working environment
Additionally, this PR is adding the required scripts to automatically create docker images and publish them to public repositories -Docker Hub and GitHub Container Registry (ghcr), as a package.

When publishing to Docker Hub, in this PR, we are publishing images built for linux/amd64 and linux/arm64. Additional platform can be easily expanded if there is more need for that.

Why?

This can greatly accelerate the exploration of this library. As an external user, the ability to interact with the library and potentially spin up servers and play with the clients can drastically reduce the need to learn the more lower level aspects of the library. This also makes very easy the ability to import the library in a larger project using docker-compose.

Additionally, this is a continuation of the conversation I had with @janiversen a few weeks ago: 4b57def#r86307726

Testing/Proof

I tested this against my own fork. I tried several times until I got it working.

The GH actions can be seen here:

https://github.com/serroba/pymodbus/actions

Of particular interest:

• Publishing to Docker Hub: https://github.com/serroba/pymodbus/actions/runs/3297517052/jobs/5438427074
• Publishing as a GitHub package or ghcr: https://github.com/serroba/pymodbus/actions/runs/3297517075/jobs/5438427120

Container Images Registries

Docker Hub

To test proper integration with Docker Hub, I created my own repository with the equivalent of this project. The images can be seen on: https://hub.docker.com/repository/docker/serroba/pymodbus

GitHub Container Registry

To test this, the integration is native, so no need to do anything outside this PR here: https://github.com/serroba/pymodbus/pkgs/container/pymodbus

Examples and usage with Docker Compose:

I have forked an existent public repository https://github.com/huntabyte/tig-stack and the now created image using this PR

Example:

  pymodbus-server:
    container_name: pymodbus-server
    image: serroba/pymodbus:v3.0.0dev5
    command: ["./examples/server_sync.py"]

Things are working as expected:

Also, we can just things directly in the container:

docker run -it serroba/pymodbus:v3.0.0dev5 examples/server_sync.py

Or enter the REPL using the images:

docker run -it serroba/pymodbus:v3.0.0dev5 pymodbus.server run --modbus-server tcp --framer socket --unit-id 1 --unit-id 4 --random 2

[janiversen]

Without having actually tried it but only reviewed it, it looks good.

However you need to add documentation, so that users know it exist.

If I looked right you need me to add a user/password to secrets (if my powers allow it) anything else?

[janiversen]

Added DOCKER_USERNAME / DOCKER_PASSWORD to secrets. Username is janiversen (which you need for documentation).

Can you make the action so I e.g. can create docker images with some of the examples ?

[serroba]

@janiversen the only thing required was the creation of those credentials. Thank you for adding them to the secrets. Nothing else is required on your end.

WRT documentation, one thing is updating the readme, which I'm happy to do.

Added DOCKER_USERNAME / DOCKER_PASSWORD to secrets. Username is janiversen (which you need for documentation).

I'm not sure what you mean here. Do you mean adding comments to the YML files where those values are used?

Can you make the action so I e.g. can create docker images with some of the examples ?

I don't understand what you mean. Can you please clarify. Thanks

[janiversen]

You need to document in the README that there are a docker image available, where and how to use it.

[janiversen]

I was thinking of having e.g, docker images with: a standard server, a repl server and a forwarder.

However I am unsure how a user could effectively configure these images.

[serroba]

Users can create a docker compose file and add a command instruction. That allows to use the same image with a user-selected command

The example I showed is this:

pymodbus-server:
    container_name: pymodbus-server
    image: serroba/pymodbus:v3.0.0dev5
    command: ["./examples/server_sync.py"]

in this case, the container is spin up and we run the sync server. A different person could add the REPL in place instead.

[janiversen]

your example of compose is good, but that is what needs to be documented.

[janiversen]

CI does not like your text:

../README.rst:252: ERROR: Unexpected indentation.
[628](https://github.com/riptideio/pymodbus/actions/runs/3303097490/jobs/5450746414#step:5:629)
../README.rst:250: WARNING: Inline literal start-string without end-string.
[629](https://github.com/riptideio/pymodbus/actions/runs/3303097490/jobs/5450746414#step:5:630)
../README.rst:250: WARNING: Inline interpreted text or phrase reference start-string without end-string.
[630](https://github.com/riptideio/pymodbus/actions/runs/3303097490/jobs/5450746414#step:5:631)
../README.rst:255: WARNING: Block quote ends without a blank line; unexpected unindent.
[631](https://github.com/riptideio/pymodbus/actions/runs/3303097490/jobs/5450746414#step:5:632)
../README.rst:255: WARNING: Inline literal start-string without end-string.
[632](https://github.com/riptideio/pymodbus/actions/runs/3303097490/jobs/5450746414#step:5:633)
../README.rst:255: WARNING: Inline interpreted text or phrase reference start-string without end-string.

[janiversen]

LGTM.

[serroba]

Thank you @janiversen