Logging

FrankenPress writes structured logs to stdout/stderr. Any cluster-side shipper that tails container streams (Vector, Grafana Alloy, Promtail, Datadog Agent, Fluent Bit) picks them up without pod-level config. The platform stays backend-neutral; you choose the destination.

What’s emitted

Stream	Source	Format	When
stdout	Caddy access log	JSON, one line per request	Always (public server only)
stderr	PHP errors	Plain text	Always — `php.ini` `error_log = /dev/stderr`
stderr	WordPress debug log	Plain text	Only when `WP_ENV=staging` (routed to `php://stderr`)

The metrics server on FP_METRICS_PORT (default 9145) is not access-logged on purpose — Prometheus scrapes every ~15s would otherwise dominate the log stream. A Caddy access log line looks like:

{"level":"info","ts":1778097120.412,"logger":"http.log.access.log0","msg":"handled request","request":{"remote_ip":"10.244.0.5","method":"GET","host":"site.example.com","uri":"/2026/05/welcome/","headers":{"User-Agent":["Mozilla/5.0"]}},"bytes_read":0,"user_id":"","duration":0.0341,"size":18234,"status":200,"resp_headers":{"Content-Type":["text/html; charset=UTF-8"],"Cache-Status":["Souin; hit; ttl=287"]}}

The Cache-Status response header tells you whether Souin served from cache (hit) or fell through to PHP (miss).

Recommended: Vector DaemonSet

Vector is a vendor-neutral agent maintained by Datadog. A single DaemonSet ships to Loki, Datadog, both, or any other supported sink. This is the recommended path because it keeps the FrankenPress chart free of backend-specific glue.

Install the Vector Helm chart in DaemonSet mode

helm repo add vector https://helm.vector.dev
helm install vector vector/vector \
  --namespace observability --create-namespace \
  --set role=Agent \
  --values vector-values.yaml

Provide a `vector.yaml` config

The example below tails container logs cluster-wide, parses Caddy’s JSON access log, and ships to both Loki and Datadog. Drop whichever sink you don’t want.

vector-values.yaml

customConfig:
  data_dir: /vector-data-dir
  api:
    enabled: false

  sources:
    kubernetes:
      type: kubernetes_logs
      extra_label_selector: "app.kubernetes.io/name=site"

  transforms:
    parse_caddy_json:
      type: remap
      inputs: [kubernetes]
      source: |
        # Caddy emits JSON on stdout; PHP/WP errors are plain on stderr.
        if .stream == "stdout" {
          parsed, err = parse_json(.message)
          if err == null {
            . = merge!(., parsed)
            .source_type = "caddy_access"
          }
        } else {
          .source_type = "php_error"
        }

  sinks:
    # Grafana Loki (Grafana Cloud or self-hosted)
    loki:
      type: loki
      inputs: [parse_caddy_json]
      endpoint: https://logs-prod-XXX.grafana.net
      auth:
        strategy: basic
        user: "${LOKI_USER}"
        password: "${LOKI_API_KEY}"
      labels:
        namespace: '{{ kubernetes.pod_namespace }}'
        pod: '{{ kubernetes.pod_name }}'
        source: '{{ source_type }}'
      encoding:
        codec: json

    # Datadog Logs
    datadog:
      type: datadog_logs
      inputs: [parse_caddy_json]
      default_api_key: "${DATADOG_API_KEY}"
      site: datadoghq.com

Verify in your backend

Generate traffic against the site, then check Loki Explore (filter {source="caddy_access"}) or Datadog Logs (source:caddy_access). You should see one entry per request with status, duration, uri, and resp_headers fields.

Vector’s kubernetes_logs source automatically picks up app.kubernetes.io/name=site labels because the chart applies the standard Bitnami common labels. If you’ve overridden nameOverride, adjust the extra_label_selector.

Alternative: Grafana Alloy / Promtail (Loki only)

If you’re a Loki-only shop and already run Grafana Alloy (or its predecessor Promtail), no FrankenPress-specific config is needed. The default discovery.kubernetes + loki.source.kubernetes pipeline tails all pod logs in the cluster. Filter by namespace or by the app.kubernetes.io/name=site label in your Alloy config to scope to FrankenPress sites.

Alternative: Datadog Agent (autodiscovery)

If you run the Datadog Agent DaemonSet with log autodiscovery, set pod annotations on the FrankenPress release:

podAnnotations:
  ad.datadoghq.com/site.logs: |
    [{"source": "caddy", "service": "site"}]

The site segment of the annotation key is the container name in the deployment template (it’s not configurable). The Datadog Agent will auto-tag each line with source:caddy and service:site so its default Caddy log pipeline applies.

What’s not shipped

Subchart logs. The chart’s bundled mariadb, redis, and minio subcharts each write their own logs to their own pod stdout. A cluster-side shipper picks those up automatically — they’re not FrankenPress’s concern. Production deploys typically disable the subcharts and use external services (RDS, DragonflyDB Operator, AWS S3) whose logs live wherever that operator/service writes them.
wp-cron Job logs. The wpCron CronJob writes to its own pod stdout; a DaemonSet-mode shipper captures those lines too.
Prometheus scrape access logs. Suppressed on purpose (see above). If you want them, add a log block inside the :{$FP_METRICS_PORT} server in a forked Caddyfile — but you almost certainly don’t.

Failure modes

Symptom	Likely cause
Only startup chatter in stdout, no per-request lines	You’re on a `runtime` image older than the JSON-access-log change. Pull the latest tag and `helm upgrade`.
WP debug entries missing from logs in staging	`WP_DEBUG_LOG` was overridden to `true` (writes to disk); confirm it resolves to `php://stderr` in your `config/environments/staging.php`.
Vector / Alloy isn’t seeing the pod’s logs	Label selector mismatch — verify `app.kubernetes.io/name=site` is present on the pod (`kubectl get pod -o yaml	grep -A1 labels`).
Cache-Status header missing from access log lines	Souin only sets it on requests that flow through the `cache` directive. Logged-in / authenticated requests bypass cache by design and show no `Cache-Status`.

Getting started

Components

Operations

What’s emitted

Recommended: Vector DaemonSet

Alternative: Grafana Alloy / Promtail (Loki only)

Alternative: Datadog Agent (autodiscovery)

What’s not shipped

Failure modes

​What’s emitted

​Recommended: Vector DaemonSet

​Alternative: Grafana Alloy / Promtail (Loki only)

​Alternative: Datadog Agent (autodiscovery)

​What’s not shipped

​Failure modes

What’s emitted

Recommended: Vector DaemonSet

Alternative: Grafana Alloy / Promtail (Loki only)

Alternative: Datadog Agent (autodiscovery)

What’s not shipped

Failure modes