fix: Minor fixes (#1075)

A batch of small, self-contained fixes and docs/example additions.

Fixes #625 - align the example config's `force_pull` with the actual default (`false`)
Fixes #804 - return an error instead of discarding `os.UserHomeDir()` when defaulting `cache.dir`/`host.workdir_parent`
Fixes #571 - send a `gitea-runner/<version>` User-Agent on API requests
Fixes #650 - detect an `Unauthenticated` fetch response and exit the daemon with an error instead of retrying forever
Fixes #766 - add `exec --eventpath` to supply a JSON event payload file
Fixes #256 - add a `bug-report` subcommand that prints version/Go/OS-arch/CPU info
Fixes #617 - add `runner.set_act_env` (default `true`) to optionally omit the `ACT=true` env var
Fixes #635 - record a failure result (and guard a nil reusable-workflow caller) when the job `if`-expression fails to evaluate
Fixes #1005 - remove README docs for config env-var overrides that were already removed from the code
Fixes #448 - clarify in `exec --job` help that `--workflows` may be needed to disambiguate
Fixes #209 - note that `host`-labelled runners still need Docker for `docker://` actions and service containers
Fixes #757 - add a systemd service example with automatic restart
Fixes #474 - add a Kubernetes StatefulSet example that persists the `.runner` registration across reschedules
Fixes #776 - build the basic (non-dind) docker image for `linux/riscv64`
Fixes #628 - build the basic (non-dind) docker image for `linux/s390x`Reviewed-on: https://gitea.com/gitea/runner/pulls/1075
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>

examples/kubernetes/statefulset-dind.yaml

@@ -0,0 +1,79 @@
+# StatefulSet variant of the dind example.
+#
+# Unlike the Deployment, a StatefulSet gives each replica a stable identity and,
+# via volumeClaimTemplates, its own persistent volume. That means every runner
+# pod keeps its own `.runner` registration file across restarts and reschedules,
+# so it re-attaches to the server instead of trying to register again.
+apiVersion: v1
+data:
+  # The registration token can be obtained from the web UI, API or command-line.
+  # You can also set a pre-defined global runner registration token for the Gitea instance via
+  # `GITEA_RUNNER_REGISTRATION_TOKEN`/`GITEA_RUNNER_REGISTRATION_TOKEN_FILE` environment variable.
+  token: << base64 encoded registration token >>
+kind: Secret
+metadata:
+  name: runner-secret
+type: Opaque
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  labels:
+    app: runner
+  name: runner
+spec:
+  serviceName: runner
+  replicas: 1
+  selector:
+    matchLabels:
+      app: runner
+  template:
+    metadata:
+      labels:
+        app: runner
+    spec:
+      restartPolicy: Always
+      volumes:
+      - name: docker-socket
+        emptyDir: {}
+      initContainers:
+      - name: docker
+        image: docker:28.2.2-dind
+        securityContext:
+          privileged: true
+        volumeMounts:
+        - name: docker-socket
+          mountPath: /var/run
+        startupProbe:
+          exec:
+            command: ["/usr/bin/test", "-S", "/var/run/docker.sock"]
+        livenessProbe:
+          exec:
+            command: ["/usr/bin/test", "-S", "/var/run/docker.sock"]
+        restartPolicy: Always
+      containers:
+      - name: runner
+        image: gitea/runner:nightly
+        env:
+        - name: GITEA_INSTANCE_URL
+          value: http://gitea-http.gitea.svc.cluster.local:3000
+        - name: GITEA_RUNNER_REGISTRATION_TOKEN
+          valueFrom:
+            secretKeyRef:
+              name: runner-secret
+              key: token
+        volumeMounts:
+        - name: runner-data
+          mountPath: /data
+        - name: docker-socket
+          mountPath: /var/run
+  volumeClaimTemplates:
+  - metadata:
+      name: runner-data
+    spec:
+      accessModes:
+      - ReadWriteOnce
+      resources:
+        requests:
+          storage: 1Gi
+      storageClassName: standard