Fixes issues #4, #7 target containers & multiple reloaders

[dreamPathsProjekt]

Changelog

• Add requirements.txt to easily pin versions to docker image latest, for contributors. No side-effect upgrade, on the next docker build. Reflect this change, also, on Dockerfile.
• Fixes issue #4 Previously the reloader assumed that a container named *reloader would exist and arbitrarily chose the first on the container list returned. This had the following side-effects, when using volume mounts (workaround was to use RELOAD_DIR):
  • Cannot run more than 1 reloader container, since reload volume mounts were either not found, or the wrong container was targetted (by another container named *reloader)
  • You couldn't name the reloader container, other than *reloader
  • The proposed fix consists of each reloader container to only retrieve its self by id with containers.get() instead of containers.list() (can get this by platform.node(), getting back the id from the container's hostname)

# Example: name of reloaders is reconciler-*, multiple reloaders
docker exec -it reconciler_app-cli bash

>>> import docker
>>> import platform
>>> client = docker.DockerClient(base_url="unix://var/run/docker.sock")

# cannot name it reconciler
>>> client.containers.list(filters={"name": "reloader"})
[]

# multiple reloaders named e.g. reconciler-cli, reconciler-backend, reconciler-frontend
>>> client.containers.list(filters={"name": "reconciler"})
[<Container: bac16483c4>, <Container: 84a2cb39c2>, <Container: fdee64373b>]

# proposed fix, get own container by id
>>> client.containers.get(container_id=platform.node())
<Container: bac16483c4>

• Fixes issue #7 where when RELOAD_CONTAINER is used to target containers, the containers.list() method is used to filter by name. Since this method is invoking docker ps --filter name= semantics, this had the following unwanted side-effects:
  • docker ps --filter name= does a grep like search and might return back multiple items based on the name. No exact name is enforced. This meant that based on what container is at the 0 index of the returned list, the reloader might be targetting the wrong container.
  • The proposed fix uses a regex that enforces a strict name match, otherwise does not find the target. This is done by placing the RELOAD_CONTAINER value strictly at the beginning ^/ and end $ of the word search.
  • This allows us to run multiple reloaders for multiple targets by doing either a 1-1 match (reloader to target) or by targetting multiple containers from a single reloader, using RELOAD_LABEL

# Example: targetting a docker-compose file with app and app-cli services, app-cli-reconciler is the reloader name.

# service named app, returns back 3 results: app, app-cli & the reloader
>>> client.containers.list(filters={"name": "app"})
[<Container: 1d09419b95>, <Container: da4b6fd5ed>, <Container: bac16483c4>]

# exact match does not find grep like name
>>> client.containers.list(filters={"name": "^/app$"})
[]

# we target the docker-compose name now, target specific container
>>> client.containers.list(filters={"name": "^/app_app-cli_1$"})
[<Container: 1d09419b95>]

[apogiatzis]

Hey @dreamPathsProjekt !!

Thanks for your contribution addressing a significant limitation! It's very much appreciated.

The code changes look good to me! Would you mind updating the README as well to reflect the changes?

[dreamPathsProjekt]

Hey @dreamPathsProjekt !!

Thanks for your contribution addressing a significant limitation! It's very much appreciated.

The code changes look good to me! Would you mind updating the README as well to reflect the changes?

Not a problem. You mean examples for how to use multiple reloaders and how to use strict container names in RELOAD_CONTAINER?

[apogiatzis]

Yes :)

[dreamPathsProjekt]

Hey @apogiatzis Sorry to have responded this late. https://github.com/apogiatzis/docker-compose-livereloader/pull/13/commits/5abc46940f2249fb9ddcd957de235db5800ac804 addresses the documentation requests, by adding a more complicated example with reloaders routing and also servers as a good acceptance test, for the fixes proposed.

Note: Images used in all examples, are referencing dreampathsprojekt/livereloader which is the fork https://github.com/dreamPathsProjekt/docker-compose-livereloader version image containing the fixes. This is done, to be able initially to run all examples without issues.

• To run as PR review, run the scenarios with images as is dreampathsprojekt/livereloader containing the fixes to validate.
• You can confirm fixes have been applied by changing all docker-compose image repos under test/monitoring to apogiatzis/livereloader to verify faulty behaviour in previous image.
• After Review comments, I can do a final commit to edit docs and docker-compose files to the finally built image repo apogiatzis/livereloader preparing the PR to be merged. Or you can merge the PR and apply the changes afterwards, in a small PR yourself.

Thanks again and sorry for the wait.

[apogiatzis]

Hey @apogiatzis Sorry to have responded this late. 5abc469 addresses the documentation requests, by adding a more complicated example with reloaders routing and also servers as a good acceptance test, for the fixes proposed.

Note: Images used in all examples, are referencing dreampathsprojekt/livereloader which is the fork https://github.com/dreamPathsProjekt/docker-compose-livereloader version image containing the fixes. This is done, to be able initially to run all examples without issues.

• To run as PR review, run the scenarios with images as is dreampathsprojekt/livereloader containing the fixes to validate.
• You can confirm fixes have been applied by changing all docker-compose image repos under test/monitoring to apogiatzis/livereloader to verify faulty behaviour in previous image.
• After Review comments, I can do a final commit to edit docs and docker-compose files to the finally built image repo apogiatzis/livereloader preparing the PR to be merged. Or you can merge the PR and apply the changes afterwards, in a small PR yourself.

Thanks again and sorry for the wait.

This is great!!! Thank you very much for your contribution and response!

It looks and works great. Merging now.