disk-usage-watch.yml

name: Disk usage watch

# Scheduled sentinel for #2743: `/var` on the homeserver (backs
# /var/lib/docker -- every CI container, image build, and Arcane stack)
# reached 96% full with no warning anywhere, and broke two
# Elasticsearch-backed CI legs (unavailable_shards_exception on primary
# allocation) in a way that looked like flake until someone happened to
# check `df`. `docker builder prune -af` reclaimed 179GB of buildkit cache
# with zero active entries, taking /var to 89%, after which the same test
# passed on the same host at the same commit.
#
# Runs ON the homeserver-backed fleet (not GitHub-hosted) because it has to
# measure that host's own filesystem directly -- no separate SSH credential
# or network path to the thing being measured, same reasoning
# ci-queue-watch.py's own header gives for keeping detection logic
# runnable and inspectable outside Actions.
#
# Deliberately a separate workflow/script from ci-queue-watch.py rather
# than folding into it: that script already gained an unrelated
# runner-capacity report in this same batch of fixes (#2744); piling a
# second, unrelated concern onto the same function from a second,
# independent change risked a needless merge collision between the two.

on:
  schedule:
    - cron: "*/30 * * * *"
  workflow_dispatch:
    inputs:
      warn_percent:
        description: Override the alarm threshold (percent)
        required: false
        default: "90"

# #3313: job-scoped, workflow level defaults to none -- see the same note in
# backup-staleness-watch.yml.
permissions: {}

concurrency:
  group: disk-usage-watch
  cancel-in-progress: false

jobs:
  sweep:
    # honeypot-homeserver (#3379): this job measures the homeserver itself,
    # so it must never land on a --build-only honeypot-ci executor elsewhere.
    runs-on: [self-hosted, linux, x64, honeypot-ci, honeypot-homeserver]
    timeout-minutes: 5
    permissions:
      issues: write
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          persist-credentials: false
      - name: Sweep /var usage on this host
        env:
          GH_TOKEN: ${{ github.token }}
          # #3314: through env, not ${{ }} inside the script -- a dispatch
          # input interpolated into `run:` is shell code.
          WARN_PERCENT: ${{ inputs.warn_percent || '90' }}
        run: |
          python3 scripts/disk-usage-watch.py \
            --path /var \
            --warn-percent "$WARN_PERCENT"