name: cache-prune

# Keeps the repository's total cache size below a fixed limit, so that GitHub never
# rejects a save for being over the allowance.

on:
  schedule:
    - cron: "37 2 * * *" # every day at 02:37 UTC
  workflow_dispatch:
  workflow_call:

permissions:
  actions: write # to delete caches

concurrency:
  group: cache-prune

jobs:
  prune:
    runs-on: ubuntu-latest
    if: github.repository == 'go-gitea/gitea'
    env:
      GH_TOKEN: ${{ github.token }}
      GH_REPO: ${{ github.repository }}
    steps:
      # Deletes least recently used first, the order GitHub itself evicts in, which takes
      # superseded generations first as those stop being restored once a newer one exists.
      - name: delete caches over the size limit
        run: |
          caches=$(gh cache list --limit 1000 --sort last_accessed_at --order asc --json id,key,sizeInBytes)
          size=$(jq '[.[].sizeInBytes] | add // 0' <<< "$caches")
          echo "cache usage: $((size / 1000000)) MB"
          jq -r '.[] | "\(.id) \(.sizeInBytes) \(.key)"' <<< "$caches" |
            while [ "$size" -gt 6500000000 ] && read -r id bytes key; do
              echo "deleting $key"
              gh cache delete "$id"
              size=$((size - bytes))
            done