# Wiring a Gitea runner into clawstor

One-time per-runner setup, then workflows opt in with

```yaml
- uses: ./.gitea/actions/cargo-cache
```

## Prerequisites on the runner host

1. A running clawstor cluster daemon on the host. See
   `systemd/clawstor-cluster.service`.
2. The runner uses `runs-on: ubuntu-latest:host` (or equivalent host
   runner label). Container-only runners need to bind-mount the CLI
   + tls dir into the job container; that's a future extension.

## Provisioning claw-cargo for the runner user

Run these on the runner host as an operator with sudo. The runner
user (act_runner on stock Gitea Actions installs) needs the CLI on
`PATH`, a leaf cert signed by the fleet CA, and a
`~/.config/claw-cargo/config.toml` pointing at the local daemon.

```sh
# 1. Sign a leaf cert for this runner. `--node` becomes the SAN.
claw-store fleet-ca-sign \
  --ca-dir /path/to/fleet-ca \
  --node act-runner-$(hostname -s) \
  --out-dir /tmp/act-runner-tls

# 2. Install the CLI + TLS material where act_runner can read them.
sudo install -m 755 /path/to/claw-cargo /usr/local/bin/claw-cargo

sudo install -d -o act_runner -g act_runner -m 700 \
  /var/lib/act_runner/.config/claw-cargo \
  /var/lib/act_runner/clawstor-tls

sudo install -o act_runner -g act_runner -m 644 \
  /tmp/act-runner-tls/ca.crt /var/lib/act_runner/clawstor-tls/ca.crt
sudo install -o act_runner -g act_runner -m 644 \
  /tmp/act-runner-tls/node.crt /var/lib/act_runner/clawstor-tls/node.crt
sudo install -o act_runner -g act_runner -m 600 \
  /tmp/act-runner-tls/node.key /var/lib/act_runner/clawstor-tls/node.key

# 3. Write the runner's claw-cargo config. `peer.name` MUST match the
#    daemon's cert SAN. `peer.addr` is where act_runner reaches the
#    daemon — 127.0.0.1:7702 for host-mode runners.
sudo tee /var/lib/act_runner/.config/claw-cargo/config.toml >/dev/null <<'EOF'
[peer]
name = "tank"                       # <-- match this to your host
addr = "127.0.0.1:7702"
tls_dir = "/var/lib/act_runner/clawstor-tls"

[build]
profile = "dev"
EOF
sudo chown act_runner:act_runner /var/lib/act_runner/.config/claw-cargo/config.toml
sudo chmod 600 /var/lib/act_runner/.config/claw-cargo/config.toml

# 4. Smoke test as the runner user.
sudo -u act_runner claw-cargo peer-metrics \
  --peer tank --peer-addr 127.0.0.1:7702 \
  --tls-dir /var/lib/act_runner/clawstor-tls
```

## Runner label

Every provisioned runner gets a dedicated label so workflows only
land on hosts that actually have `claw-cargo` installed. Add to
`/etc/act_runner/config.yaml`:

```yaml
runner:
  labels:
    - "clawstor-cache:host"   # add this line
    - "ubuntu-latest:host"    # keep any existing labels
```

Then `sudo systemctl restart act_runner.service` so the label
re-registers.

## Using the action in a workflow

Field finding: `ubuntu-latest` on Gitea Actions routes to
container mode by default (even with the `:host` suffix on the
runner label). Container mode hides `/usr/local/bin/claw-cargo` and
the per-runner tls_dir. Use the dedicated label instead:

```yaml
jobs:
  build:
    runs-on: clawstor-cache        # dedicated host runner
    steps:
      - uses: actions/checkout@v4
      - uses: ./.gitea/actions/cargo-cache
        with:
          workspace: .
          # Read-only from forks so a malicious PR can't poison the cache.
          no-upload: ${{ github.event_name == 'pull_request' && 'true' || 'false' }}
```

Outputs available on the step: `cache-outcome` (HIT | MISS |
POPULATED | SKIPPED), `fingerprint`, `elapsed-seconds`.

### Ref-tracking (Phase 7f)

For the nightly `cluster-ref-sweep` timer to identify stale cache
entries, `claw-cargo build` needs to record which `(repo, git-ref)`
produced each fingerprint. Set these in the workflow env:

```yaml
jobs:
  build:
    runs-on: clawstor-cache
    env:
      CLAWSTOR_REPO: ${{ gitea.repository }}
      CLAWSTOR_GIT_REF: ${{ gitea.ref_name }}
      CLAWSTOR_DATA_DIR: /var/lib/claw-store/data
    steps:
      - uses: actions/checkout@v4
      - uses: ./.gitea/actions/cargo-cache
```

`claw-cargo` reads these via clap `env=` fallbacks — no flag
plumbing needed. If unset, the build still works, but the
fingerprint won't gain a ref-tracking annotation and won't be
eligible for automatic stale-cache reaping.

## What to expect

- **First push on main** → cache MISS → the runner rebuilds cold,
  captures + uploads the target dir. Wall clock ≈ cold-build time.
- **Second push touching just workspace crates** → cache HIT → deps
  restored from the daemon, cargo only rebuilds changed workspace
  crates. Ratio measured on real workloads:

  | Runner | Cold | Warm HIT | Speedup |
  |---|---|---|---|
  | Pi 5 (4 core, 8 GB, SSD) | 7m 54s | 2m 50s | **2.79× wall, 5m 4s saved** |
  | Tank (48 core Threadripper) | 59s | 27s | 2.18× wall |

## Troubleshooting

- `claw-cargo not on PATH` → step 2 missed.
- `missing $HOME/.config/claw-cargo/config.toml` → step 3 missed.
- `Error: dialing 127.0.0.1:7702 for name tank` → daemon isn't running
  or `bind_lan` still points at the fabric-only address. Change to
  `0.0.0.0:7701` and restart.
- `rustc release drift: local_rustc=X peer_rustc=Y` → your
  workspace's `rust-toolchain.toml` doesn't match the runner's
  system rustc. The cache will still be valid but siloed per rustc.
  Fix by pinning `rust-toolchain.toml`.