[Feature request] Add rootless docker support

[thiagocrepaldi]

I am using this action and love it. One issue that I have at work is that we are using rootless mode in which docker daemon is executed by the user and not by root.

Somehow, because this action uses

runs:
  using: 'docker'
  image: 'Dockerfile'

to invoke docker, the resulting docker call will be something like /usr/bin/docker run --name cbc94a5e31a432d984f5c9c68f20aee_b5c4a7 --label 015029 --workdir /github/workspace --rm -e "INPUT_DOCS-FOLDER" -e "INPUT_BUILD-COMMAND" -e "INPUT_PRE-BUILD-COMMAND" -e "HOME" -e "GITHUB_JOB" -e "GITHUB_REF" -e "GITHUB_SHA" -e "GITHUB_REPOSITORY" -e "GITHUB_REPOSITORY_OWNER" -e "GITHUB_REPOSITORY_OWNER_ID" -e "GITHUB_RUN_ID" -e "GITHUB_RUN_NUMBER" -e "GITHUB_RETENTION_DAYS" -e "GITHUB_RUN_ATTEMPT" -e "GITHUB_REPOSITORY_ID" -e "GITHUB_ACTOR_ID" -e "GITHUB_ACTOR" -e "GITHUB_TRIGGERING_ACTOR" -e "GITHUB_WORKFLOW" -e "GITHUB_HEAD_REF" -e "GITHUB_BASE_REF" -e "GITHUB_EVENT_NAME" -e "GITHUB_SERVER_URL" -e "GITHUB_API_URL" -e "GITHUB_GRAPHQL_URL" -e "GITHUB_REF_NAME" -e "GITHUB_REF_PROTECTED" -e "GITHUB_REF_TYPE" -e "GITHUB_WORKFLOW_REF" -e "GITHUB_WORKFLOW_SHA" -e "GITHUB_WORKSPACE" -e "GITHUB_ACTION" -e "GITHUB_EVENT_PATH" -e "GITHUB_ACTION_REPOSITORY" -e "GITHUB_ACTION_REF" -e "GITHUB_PATH" -e "GITHUB_ENV" -e "GITHUB_STEP_SUMMARY" -e "GITHUB_STATE" -e "GITHUB_OUTPUT" -e "RUNNER_OS" -e "RUNNER_ARCH" -e "RUNNER_NAME" -e "RUNNER_ENVIRONMENT" -e "RUNNER_TOOL_CACHE" -e "RUNNER_TEMP" -e "RUNNER_WORKSPACE" -e "ACTIONS_RUNTIME_URL" -e "ACTIONS_RUNTIME_TOKEN" -e "ACTIONS_CACHE_URL" -e "ACTIONS_ID_TOKEN_REQUEST_URL" -e "ACTIONS_ID_TOKEN_REQUEST_TOKEN" -e GITHUB_ACTIONS=true -e CI=true -v "/var/run/docker.sock":"/var/run/docker.sock" -v "/scratch/actions-runner/_work/_temp/_github_home":"/github/home" -v "/scratch/actions-runner/_work/_temp/_github_workflow":"/github/workflow" -v "/scratch/actions-runner/_work/_temp/_runner_file_commands":"/github/file_commands" -v "/scratch/actions-runner/_work/quark-examples/quark-examples":"/github/workspace" 015029:4cbc94a5e31a432d984f5c9c68f20aee

and the key part is the docker run argument -v "/var/run/docker.sock":"/var/run/docker.sock" which essentially maps the root docker PID instead of the user (rootless) docker PID at unix://$XDG_RUNTIME_DIR/docker.sock. My environment already sets

    docker context use rootless
    export DOCKER_HOST="unix://$XDG_RUNTIME_DIR/docker.sock"

but it is superseeded by the docker run -v "/var/run/docker.sock":"/var/run/docker.sock" argument.

Thus, my feature request is to refactor sphinx-action/action.yml to not use

runs:
  using: 'docker'
  image: 'Dockerfile'

but something else, such as

run: docker run ....

which allows rootless mode to work properly

Rootless mode support fixes #62, for example and is a lot safer to execute on critical environments in the case someone hacks into docker daemon

[thiagocrepaldi]

actions/runner#1754 is the actual root cause of this failure, but actions/runner team is not responsive in fixing this, so maybe this could be work arounded by not using the runs: syntax

[thiagocrepaldi]

https://github.com/rickstaa/action-sphinx-composite actually uses the same source code, but without a docker, which also works :)