action.yml

name: benchdiff
description: Runs go benchmarks on HEAD and a base branch and reports the resulting benchstat output.

branding:
  icon: zap
  color: purple
inputs:
  benchdiff_args:
    description: |
      Arguments for the benchdiff command line.  This action will run the command line `benchdiff <benchdiff_args>`
      after making some adjustments to the arguments (listed below).

      If `--base-ref` isn't present in the arguments, then `--base-ref <default branch>` will be added.

      `--json` is always added because the action requires json formatted output.

      `--benchstat-output=markdown` is added when no other benchstat-output value is set because the reports look best
      with markdown formatting.

      Consider this example:
      ```
      --cpu=1,2 --warmup-count=1 --warmup-time=10ms --tolerance=50 --debug
      ```
      `--cpu=1,2` is important on actions because runners have only two cores available to them.

      `--warmup-count=1` and `warmup-time=10ms` cause benchdiff to do a quick warmup before starting the benchmarks.
      This is important on actions because the runners appear to have a small amount of cpu burst available. If you burn
      through that in the warmup, then it makes for a better cmoparison between the real runs.

      `--tolerance=50` means that a benchmark isn't considered degraded unless it's delta is greater than +50%. Action
      runners can have inconsistent performance within the same run. This helps mitigate a lot of false alarms.

      `--debug` causes benchdiff to output raw results to stderr (among other debug data). I like having this on just
      to see progress in the logs.

      See https://github.com/willabides/benchdiff for all available flags.

    default: ""
    required: false
  benchdiff_version:
    description: |
      Version of the benchdiff command to use.

      When a new version of this action is released, the default value will be updated to the latest version of
      benchdiff that isn't a breaking change from the previous default.
    default: 0.5.6
    required: false
  report_status:
    description: |
      Whether to report the status. Any value other than "true" is interpreted as false.

      I call this "status" because that's a better known term. What is actually created is a check-run.
    default: "true"
    required: false
  status_name:
    description: |
      Name to use in reporting status. This is the name of the check-run that is created.
    default: benchdiff
    required: false
  status_sha:
    description: Report status to this sha. Default is the head of your benchdiff run.
    default: ""
    required: false
  status_on_degraded:
    description: |
      Status to report for degraded results.

      Options are "success", "failure" and "neutral"
    default: "failure"
    required: false
  github_token:
    description: |
      Authentication token to use for reporting status.

      If you use a non-default token it needs to be a token for a GitHub App installation with permission to create a
      check-run.
    required: false
    default: ${{ github.token }}
outputs:
  benchstat_output:
    description: |
      Stdout from the benchdiff command.
    value: ${{ steps.run-benchdiff.outputs.benchstat_output }}
  bench_command:
    description: |
      Command used to run benchmarks. This is derived from the `benchdiff_args` input.
    value: ${{ steps.run-benchdiff.outputs.bench_command }}
  degraded_result:
    description:
      Whether any of the benchmarks degraded between base and head.
    value: ${{ steps.run-benchdiff.outputs.degraded_result }}
  head_sha:
    description: The git revision benchstat used as head.
    value: ${{ steps.run-benchdiff.outputs.head_sha }}
  base_sha:
    description: The git revision benchstat used as base.
    value: ${{ steps.run-benchdiff.outputs.base_sha }}
runs:
  using: composite
  steps:
    - id: linux-only
      shell: bash
      run: |
        if [ "${{ runner.os }}" != "Linux" ]; then
          echo This action only runs on Linux
          exit 1
        fi
    - id: install
      shell: bash
      run: |
        export ACTION_PATH='${{ github.action_path }}'
        export BENCHDIFF_DIR='${{ runner.temp }}/benchdiff'
        export BENCHDIFF_VERSION='${{ inputs.benchdiff_version }}'
        "$ACTION_PATH/src/install.sh"
    - id: run-benchdiff
      shell: bash
      run: |
        export ACTION_PATH='${{ github.action_path }}'
        export BENCHDIFF_ARGS='${{ inputs.benchdiff_args }}'
        export BENCHDIFF_DIR='${{ runner.temp }}/benchdiff'
        "$ACTION_PATH/src/run.sh"
    - id: report-status
      shell: bash
      run: |
        export ACTION_PATH='${{ github.action_path }}'
        export REPORT_STATUS='${{ inputs.report_status }}'
        export BENCH_COMMAND='${{ steps.run-benchdiff.outputs.bench_command }}'
        export BENCHSTAT_OUTPUT='${{ steps.run-benchdiff.outputs.benchstat_output }}'
        export DEGRADED_RESULT='${{ steps.run-benchdiff.outputs.degraded_result }}'
        export HEAD_SHA='${{ steps.run-benchdiff.outputs.head_sha }}'
        export BASE_SHA='${{ steps.run-benchdiff.outputs.base_sha }}'
        export STATUS_SHA='${{ inputs.status_sha }}'
        export GH_TOKEN='${{ inputs.github_token }}'
        export STATUS_NAME='${{ inputs.status_name }}'
        export STATUS_ON_DEGRADED='${{ inputs.status_on_degraded }}'
        "$ACTION_PATH/src/report-status.sh"