2026 OpenClaw Field Practice: Harbor Webhook, Remote Mac Image Prefetch, Summary Callbacks & Egress Allowlists

Goals. When Harbor records a relevant artifact event, your Mac should (1) authenticate the webhook, (2) derive one or more fully qualified image references, (3) prefetch them with bounded parallelism and disk safety, and (4) emit a short JSON summary to a fixed set of outbound hosts so operators see success or structured failure without opening Harbor’s UI.

Prerequisites. A Harbor project with webhook permissions, a TLS-terminated HTTPS entry that forwards to OpenClaw’s listener (often loopback plus reverse proxy), Docker Desktop or Colima with a logged-in daemon for your registry hostname, and a non-interactive service account (robot token or scoped credential) stored at mode 600 on the Mac. Align Node 22 LTS (or the major your OpenClaw release tests against) before installing OpenClaw—many teams still install Node via official curl installers or version managers, then install OpenClaw globally or via the project’s documented script.

Bring the gateway online with openclaw onboard and, when applicable, openclaw onboard --install-daemon so launchd owns restarts. Run openclaw doctor until you understand every warning, then add a cron or LaunchAgent curl probe against the documented health route from the same machine that will receive Harbor traffic. Finally, document an egress allowlist: Harbor ingress CIDRs, registry pull endpoints, and exactly one or two summary destinations (for example internal CI or a signed Slack-compatible webhook behind your API gateway).

Harbor emits JSON envelopes with a type string (for example PUSH_ARTIFACT, PULL_ARTIFACT, DELETE_ARTIFACT), an occur_at timestamp, an operator field, and an event_data object that carries repository and resource metadata. For prefetch you usually care about repository name, tag or digest, and sometimes artifact digest to deduplicate pulls. Keep a printed sample payload in your runbook so field names stay aligned with your Harbor minor version.

Verification checklist (copy into your PR template). (1) Read the raw HTTP body before JSON.parse. (2) Compare Harbor’s configured secret using constant-time equality—either a dedicated header your proxy injects after TLS termination or a shared bearer token Harbor sends per project settings. (3) Reject requests whose Content-Type is not application/json unless you explicitly support alternates. (4) Optionally enforce a freshness window on occur_at if replays worry you. (5) Log only repository plus digest after auth succeeds, never the secret. (6) If you add HMAC later, hash the same raw bytes Harbor signed, not a re-serialized object—proxies that pretty-print JSON are the usual culprit when verification “always fails.”

Once the handler extracts image references, call a small shell script rather than inlining endless docker pull lines—this keeps OpenClaw routes readable and lets operators tune knobs without redeploying TypeScript. Typical 2026 defaults for shared Mini hosts: two to four concurrent pulls, a per-pull wall clock between six and fifteen minutes depending on layer size, and an absolute stop when free disk drops below fifteen to twenty-five gigabytes on the Docker data volume.

Expose parameters as environment variables your LaunchAgent plist sets: PREFETCH_CONCURRENCY, PULL_TIMEOUT_SEC, MIN_FREE_GB, and optionally MAX_IMAGES_PER_EVENT to prevent a misconfigured webhook from queuing hundreds of repos. Use xargs -P or GNU parallel if installed, but stay consistent with macOS BSD xargs limits. After each batch, append a single JSON line to a log file OpenClaw tails for summaries.

#!/usr/bin/env bash
set -euo pipefail
: "${PREFETCH_CONCURRENCY:=3}"
: "${PULL_TIMEOUT_SEC:=600}"
: "${MIN_FREE_GB:=18}"
# macOS: df -g uses 1 GiB blocks (see man df on the runner)
avail_gib="$(df -g / | awk 'NR==2 {print $4}')"
if [ "${avail_gib:-0}" -lt "${MIN_FREE_GB}" ]; then
  printf '{"prefetch":"skipped","reason":"disk_low","avail_gib":%s}\n' "${avail_gib}"
  exit 0
fi
printf '%s\n' "$@" | xargs -n1 -P"${PREFETCH_CONCURRENCY}" -IREF docker pull REF
# Optional: wrap each pull with gtimeout "${PULL_TIMEOUT_SEC}" if GNU coreutils is installed

Replace the placeholder timeout comment with your preferred implementation (gtimeout from coreutils, a Python wrapper, or Docker’s own pull settings). Pair this script with the resilience ideas in OpenClaw Docker integration on remote Mac when CI and the gateway share one host.

Mount one HTTPS route per integration (for example /hooks/harbor/v1) so firewall rules stay narrow. Inside the handler, branch on verified type, enqueue prefetch work if the event matches your policy, and always build a failure summary template that downstream systems can parse without regex on prose.

{
  "source": "harbor-webhook",
  "event_type": "PUSH_ARTIFACT",
  "repository": "acme/base-images/nodejs",
  "digest": "sha256:…",
  "prefetch": { "ok": false, "failed_image": "reg.example/acme/base-images/nodejs:20", "exit_code": 1, "log_tail": "…last 400 chars…" },
  "host": "mac-ci-07",
  "duration_ms": 8420
}

POST this object only to hosts present in your allowlist configuration; reject unknown hostnames before DNS resolution when possible. Retry failures with two, four, and eight second sleeps and curl --max-time 25 (or equivalent) so a wedged summary endpoint does not block Harbor’s delivery thread—if Harbor’s timeout is aggressive, respond 202 Accepted quickly after validation and finish prefetch asynchronously when your design permits.

You now have a minimal, reproducible spine: verify Harbor’s raw JSON, prefetch with explicit concurrency and disk gates, route through OpenClaw with a typed summary JSON, and keep outbound callbacks on a short allowlist with bounded retries. That combination cuts CI noise and makes Apple Silicon runners predictable without turning the Mac into a generic open relay.

If you need a host that stays awake, keeps stable TLS, and survives reboots with the same launchd labels, rent a remote Mac from MacPull—public entry points only: home, purchase, help, and the technical blog index (no login required to browse).