# Feedser GHSA Connector – Operations Runbook

_Last updated: 2025-10-16_

## 1. Overview
The GitHub Security Advisories (GHSA) connector pulls advisory metadata from the GitHub REST API `/security/advisories` endpoint. GitHub enforces both primary and secondary rate limits, so operators must monitor usage and configure retries to avoid throttling incidents.

## 2. Rate-limit telemetry
The connector now surfaces rate-limit headers on every fetch and exposes the following metrics via OpenTelemetry:

| Metric | Description | Tags |
|--------|-------------|------|
| `ghsa.ratelimit.limit` (histogram) | Samples the reported request quota at fetch time. | `phase` = `list` or `detail`, `resource` (e.g., `core`). |
| `ghsa.ratelimit.remaining` (histogram) | Remaining requests returned by `X-RateLimit-Remaining`. | `phase`, `resource`. |
| `ghsa.ratelimit.reset_seconds` (histogram) | Seconds until `X-RateLimit-Reset`. | `phase`, `resource`. |
| `ghsa.ratelimit.headroom_pct` (histogram) | Percentage of the quota still available (`remaining / limit * 100`). | `phase`, `resource`. |
| `ghsa.ratelimit.headroom_pct_current` (observable gauge) | Latest headroom percentage reported per resource. | `phase`, `resource`. |
| `ghsa.ratelimit.exhausted` (counter) | Incremented whenever GitHub returns a zero remaining quota and the connector delays before retrying. | `phase`. |

### Dashboards & alerts
- Plot `ghsa.ratelimit.remaining` as the latest value to watch the runway. Alert when the value stays below **`RateLimitWarningThreshold`** (default `500`) for more than 5 minutes.
- Use `ghsa.ratelimit.headroom_pct_current` to visualise remaining quota % — paging once it sits below **10 %** for longer than a single reset window helps avoid secondary limits.
- Raise a separate alert on `increase(ghsa.ratelimit.exhausted[15m]) > 0` to catch hard throttles.
- Overlay `ghsa.fetch.attempts` vs `ghsa.fetch.failures` to confirm retries are effective.

## 3. Logging signals
When `X-RateLimit-Remaining` falls below `RateLimitWarningThreshold`, the connector emits:
```
GHSA rate limit warning: remaining {Remaining}/{Limit} for {Phase} {Resource} (headroom {Headroom}%)
```
When GitHub reports zero remaining calls, the connector logs and sleeps for the reported `Retry-After`/`X-RateLimit-Reset` interval (falling back to `SecondaryRateLimitBackoff`).

After the quota recovers above the warning threshold the connector writes an informational log with the refreshed remaining/headroom, letting operators clear alerts quickly.

## 4. Configuration knobs (`feedser.yaml`)
```yaml
feedser:
  sources:
    ghsa:
      apiToken: "${GITHUB_PAT}"
      pageSize: 50
      requestDelay: "00:00:00.200"
      failureBackoff: "00:05:00"
      rateLimitWarningThreshold: 500    # warn below this many remaining calls
      secondaryRateLimitBackoff: "00:02:00"  # fallback delay when GitHub omits Retry-After
```

### Recommendations
- Increase `requestDelay` in air-gapped or burst-heavy deployments to smooth token consumption.
- Lower `rateLimitWarningThreshold` only if your dashboards already page on the new histogram; never set it negative.
- For bots using a low-privilege PAT, keep `secondaryRateLimitBackoff` at ≥60 seconds to respect GitHub’s secondary-limit guidance.

#### Default job schedule

| Job kind | Cron | Timeout | Lease |
|----------|------|---------|-------|
| `source:ghsa:fetch` | `1,11,21,31,41,51 * * * *` | 6 minutes | 4 minutes |
| `source:ghsa:parse` | `3,13,23,33,43,53 * * * *` | 5 minutes | 4 minutes |
| `source:ghsa:map` | `5,15,25,35,45,55 * * * *` | 5 minutes | 4 minutes |

These defaults spread GHSA stages across the hour so fetch completes before parse/map fire. Override them via `feedser.jobs.definitions[...]` when coordinating multiple connectors on the same runner.

## 5. Provisioning credentials

Feedser requires a GitHub personal access token (classic) with the **`read:org`** and **`security_events`** scopes to pull GHSA data. Store it as a secret and reference it via `feedser.sources.ghsa.apiToken`.

### Docker Compose (stack operators)
```yaml
services:
  feedser:
    environment:
      FEEDSER__SOURCES__GHSA__APITOKEN: /run/secrets/ghsa_pat
    secrets:
      - ghsa_pat

secrets:
  ghsa_pat:
    file: ./secrets/ghsa_pat.txt  # contains only the PAT value
```

### Helm values (cluster operators)
```yaml
feedser:
  extraEnv:
    - name: FEEDSER__SOURCES__GHSA__APITOKEN
      valueFrom:
        secretKeyRef:
          name: feedser-ghsa
          key: apiToken

extraSecrets:
  feedser-ghsa:
    apiToken: "<paste PAT here or source from external secret store>"
```

After rotating the PAT, restart the Feedser workers (or run `kubectl rollout restart deployment/feedser`) to ensure the configuration reloads.

When enabling GHSA the first time, run a staged backfill:

1. Trigger `source:ghsa:fetch` manually (CLI or API) outside of peak hours.
2. Watch `feedser.jobs.health` for the GHSA jobs until they report `healthy`.
3. Allow the scheduled cron cadence to resume once the initial backlog drains (typically < 30 minutes).

## 6. Runbook steps when throttled
1. Check `ghsa.ratelimit.exhausted` for the affected phase (`list` vs `detail`).
2. Confirm the connector is delaying—logs will show `GHSA rate limit exhausted...` with the chosen backoff.
3. If rate limits stay exhausted:
   - Verify no other jobs are sharing the PAT.
   - Temporarily reduce `MaxPagesPerFetch` or `PageSize` to shrink burst size.
   - Consider provisioning a dedicated PAT (GHSA permissions only) for Feedser.
4. After the quota resets, reset `rateLimitWarningThreshold`/`requestDelay` to their normal values and monitor the histograms for at least one hour.

## 7. Alert integration quick reference
- Prometheus: `ghsa_ratelimit_remaining_bucket` (from histogram) – use `histogram_quantile(0.99, ...)` to trend capacity.
- VictoriaMetrics: `LAST_over_time(ghsa_ratelimit_remaining_sum[5m])` for simple last-value graphs.
- Grafana: stack remaining + used to visualise total limit per resource.

## 8. Canonical metric fallback analytics
When GitHub omits CVSS vectors/scores, the connector now assigns a deterministic canonical metric id in the form `ghsa:severity/<level>` and publishes it to Merge so severity precedence still resolves against GHSA even without CVSS data.

- Metric: `ghsa.map.canonical_metric_fallbacks` (counter) with tags `severity`, `canonical_metric_id`, `reason=no_cvss`.
- Monitor the counter alongside Merge parity checks; a sudden spike suggests GitHub is shipping advisories without vectors and warrants cross-checking downstream exporters.
- Because the canonical id feeds Merge, parity dashboards should overlay this metric to confirm fallback advisories continue to merge ahead of downstream sources when GHSA supplies more recent data.
