action.yml

name: "SyncerD"
description: "Sync Docker images between registries, or mirror git repositories between hosting providers."
author: "CloudDrove"
branding:
  icon: "package"
  color: "blue"

inputs:
  command:
    description: "Subcommand to run: sync (Docker registry sync) or git-sync (git repository mirroring)"
    required: false
    default: "sync"
  config:
    description: "Path to syncerd.yaml"
    required: false
    default: "syncerd.yaml"
  once:
    description: "Run once and exit (true/false)"
    required: false
    default: "true"
  dry-run:
    description: "Report what would be created, pushed, and pruned without writing anything. git-sync only."
    required: false
    default: "false"
  report:
    description: "Write a machine readable JSON report of the run to this path. Empty disables it."
    required: false
    default: ""
  metrics-file:
    description: "Write Prometheus textfile collector metrics for the last run to this path. Empty disables it."
    required: false
    default: ""
  log-format:
    description: "Log output format: text or json."
    required: false
    default: "text"

runs:
  using: "docker"
  # Marketplace best practice is to pin to a major tag, but v1 has not been
  # released yet (project is still 0.x). The release workflow's
  # type=semver,pattern=v{{major}} produces v0 for the current line; this
  # must move to v1 once a 1.0 release ships.
  image: "docker://ghcr.io/clouddrove/syncerd:v0"
  # args is a fixed list: it cannot branch on inputs.command at the shell
  # level, only per element via an expression. --dry-run exists on git-sync
  # only, so it cannot simply be appended: an unconditional --dry-run would
  # be an unknown flag on sync and break every existing image sync workflow.
  # The element below evaluates to "--dry-run=<value>" when command is
  # git-sync, and to an empty string otherwise. An empty string element is
  # still passed to the binary as its own argv entry, but neither command
  # has a positional-argument validator (cobra's default Args is
  # ArbitraryArgs), so it is silently ignored; confirmed by running the
  # built binary with a trailing empty-string argument and getting the
  # normal "at least one destination is required" error, not an argument
  # parsing error. This is a guarded invariant, not just a comment: see
  # TestCommandsTolerateEmptyPositionalArg in main_test.go. If that test
  # ever fails, this args list must change in the same commit, or an Args
  # validator added to either command will break every image sync workflow
  # the next time the Action image is published.
  #
  # Hyphenated input names (dry-run, metrics-file, log-format) must be read
  # with bracket syntax, inputs['name'], not inputs.name: the expression
  # parser reads the hyphen in dot notation as subtraction.
  #
  # The conditional expression below is asserted, with literal values, by
  # the "dry run expression resolves correctly" step in
  # .github/workflows/action-smoke.yml. If you change this expression,
  # update that step's literals to match, or the workflow will stop
  # guarding what it says it guards.
  args:
    - "${{ inputs.command }}"
    - "--config"
    - "${{ inputs.config }}"
    - "--once=${{ inputs.once }}"
    - "${{ inputs.command == 'git-sync' && format('--dry-run={0}', inputs['dry-run']) || '' }}"
    - "--report=${{ inputs.report }}"
    - "--metrics-file=${{ inputs['metrics-file'] }}"
    - "--log-format=${{ inputs['log-format'] }}"