name: Setup and Cache Golang

# clone of: https://github.com/magnetikonline/action-golang-cache/blob/main/action.yaml
#
# action-golang-cache runs an optimistic restore key prefix `${{runner.os}}-golang`.
# This causes the cache@v3 to restore from any preexisting module cache in the main
# branch, whether or not that the go.sum in that cache differs from the current branch's
# go.sum.  IE: once a cache exists for the main branch, we will always re-use it.
#
# Problem is, the cache identifies that as a 'cache hit', and as a result it refuses to
# store any differences we downloaded or removed using the current go.sum.  IE: once
# established, it always re-uses the old cache, and never updates it.
# 
# This version will only match on exact caches, and will run `go mod download` on any
# cache miss.  In a workflow with chained jobs, this action should be run prior to any
# jobs that build binaries (testing, linting, etc).  Downstream jobs should still use
# the magnetikonline action, since some cache restoration is better than none.

inputs:
  go-version:
    description: Desired Golang version to use.
  go-version-file:
    description: Path to go.mod file, determines Golang version to use. Used in place of `go-version` input.
  cache-key-suffix:
    description: Optional cache key suffix.
    default:

runs:
  using: composite
  steps:
    - name: Setup Golang
      uses: actions/setup-go@v3
      with:
        go-version: ${{ inputs.go-version }}
        go-version-file: ${{ inputs.go-version-file }}

    - name: Determine Golang cache paths
      id: golang-path
      run: |
        echo "::set-output name=build::$(go env GOCACHE)"
        echo "::set-output name=module::$(go env GOMODCACHE)"
      shell: bash

    - name: Setup Golang cache
      id: cache
      uses: actions/cache@v3
      with:
        path: |
          ${{ steps.golang-path.outputs.build }}
          ${{ steps.golang-path.outputs.module }}
        key: ${{ runner.os }}-golang${{ inputs.cache-key-suffix }}-${{ hashFiles('src/go.sum') }}
    
    - name: Module Download and Test Compilation, for future caching
      working-directory: src
      if: steps.cache.outputs.cache-hit != 'true'
      # cover all the bases, just to be make sure we loaded everything we'll use
      run: |
        go mod download -x
        go build -o compile
        go test -v -c -o compile_test
      shell: bash