WIP: Docker support

[Taxel]

As per note of @glensc in #88 this is now a pull request.

The following changes have been made:

• I rebased the branch on my changes in Update to use guids from python-plexapi to fix Plexmovieagent breakage #87, if we wait for the official python-plexapi package to get updated this will have to be redone
• I changed the file structure: With configuration, cache, logs, and source code in one directory the project felt unorganized, so I should have probably done this before even making the project open source.
• The docker image is based on @twolaw 's Dockerfile. The main differences are, that I am using a multistep build (unnecessarily I might add, this does not really make the resulting image much smaller, but it was fun to play around with) and that the script does not run once by default but on a cronjob, so the container can be configured and then left running forever. One can, however, pass the environment variable "RUN_ONCE" with a non-empty value and the script will only be run once, after which the container shuts down. Changing the cron schedule is also done via an environment var: CRON_SCHEDULE
• Running this in Docker also means that via volume mounts and multiple containers, one can use different configs for multiple users and/or Plex servers, solving Allow custom envfile path to be used #70 indirectly (only in Docker, of course. Not when running this with Python. Since I extracted all the filepaths to config.py this should be trivial to implement, though)

What might be the most controversial change, is that I am rerouting the log outputs to stdout if the terminal is non-interactive. I use it to detect if the script is running in a container since Docker containers should output to stdout/stderr and let Docker take care of the logging. Do you agree the script should no longer write to lastRun.log if it is running in a container and is the sys.isatty(0) check okay or should I add an argument like python3 main.py --log-to-stdout so this is easier to control?

Since the file structure changes alone constitute some manual work when upgrading from an older version of PlexTraktSync, I also propose we create a release 0.9.0 before merging the pull request for this once the feature is complete and then release 1.0.0 along with the docker image (I'd like to try Github Packages as the image registry and create a Github action that automatically builds, tags and pushes each new release in the future)

[glensc]

[[ is bashism, but /bin/sh is the interpreter.

[glensc]

you don't need a subshell, there's nothing else after python command, so no need to subshell cd'ing

in fact. you should use exec to release memory from shell process:

Suggested change

	(cd ./src && python3 ./main.py)
	cd ./src && exec python3 ./main.py

and perhaps just use set -e instead of &&

Suggested change

	(cd ./src && python3 ./main.py)
	see -e
	cd ./src
	exec python3 ./main.py

[glensc]

you did cd in plex_track_sync.sh, but not here. is the cd needed or not?

[glensc]

| sort - | uniq - can be replaced with | sort -u

but check it first, you may have crippled sort in your image, i.e one from (older) busybox

[glensc]

if this crond is last command in the script, prepend with exec, so that:

1. memory is released from shell
2. signals get routed to main process, not shell (which typically ignores them)

[simonc56]

I ran docker-compose up -d and the image built fine (on arm: 75MB, mine was 58MB).
But the container is created without /var/config/ folder so the entry.sh can"t go further than :

config.json does not exist. copying it.
cp: can't create '/var/config/config.json': No such file or directory
Running the script every 2 hours (CRON_SCHEDULE='0 */2 * * *'). Set environment var 'CRON_SCHEDULE' to a valid cron expression to configure this
If you want to run the script only once, specify the environment var 'RUN_ONCE=1'
Traceback (most recent call last):
  File "/var/src/main.py", line 3, in <module>
    from config import CONFIG, CONFIG_DIR, LOG_DIR, CACHE_DIR
  File "/var/src/config.py", line 11, in <module>
    with open(config_file, 'r') as fp:
FileNotFoundError: [Errno 2] No such file or directory: '/var/src/../config/config.json'

Is the volume map for config/ missing in docker-compose.yml ?
Did I do something wrong ?

edit: after adding ./config:/var/config it's working good. I understand docker-compose.yml is in WIP status.

[SJ50]

@twolaw you need to mount “src” and “config” folder.

./src:/var/src
./config:/var/config