Add 'extraContainers' parameter (#697)

### Description of the change

Adds an 'extraContainers' parameter.

### Benefits

Users will be able to run sidecar containers as required by their environment.

### Possible drawbacks

N/A

### Applicable issues

- Fixes #696

### Checklist

- [X] Parameters are documented in the `values.yaml` and added to the `README.md` using [readme-generator-for-helm](https://github.com/bitnami-labs/readme-generator-for-helm)

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/697
Reviewed-by: justusbunsi <justusbunsi@noreply.gitea.com>
Co-authored-by: rossigee <rossigee@noreply.gitea.com>
Co-committed-by: rossigee <rossigee@noreply.gitea.com>

README.md

@@ -980,6 +980,7 @@ To comply with the Gitea helm chart definition of the digest parameter, a "custo
 | `persistence.storageClass`                        | Name of the storage class to use                                                                      | `nil`                  |
 | `persistence.subPath`                             | Subdirectory of the volume to mount at                                                                | `nil`                  |
 | `persistence.volumeName`                          | Name of persistent volume in PVC                                                                      | `""`                   |
+| `extraContainers`                                 | Additional sidecar containers to run in the pod                                                       | `[]`                   |
 | `extraVolumes`                                    | Additional volumes to mount to the Gitea deployment                                                   | `[]`                   |
 | `extraContainerVolumeMounts`                      | Mounts that are only mapped into the Gitea runtime/main container, to e.g. override custom templates. | `[]`                   |
 | `extraInitVolumeMounts`                           | Mounts that are only mapped into the init-containers. Can be used for additional preconfiguration.    | `[]`                   |

templates/gitea/deployment.yaml

@@ -340,6 +340,9 @@ spec:
               subPath: {{ .Values.persistence.subPath }}
               {{- end }}
             {{- include "gitea.container-additional-mounts" . | nindent 12 }}
+        {{- if .Values.extraContainers }}
+        {{- toYaml .Values.extraContainers | nindent 8 }}
+        {{- end }}
       {{- with .Values.global.hostAliases }}
       hostAliases:
         {{- toYaml . | nindent 8 }}

unittests/deployment/sidecar-container.yaml

@@ -0,0 +1,21 @@
+suite: sidecar container
+release:
+  name: gitea-unittests
+  namespace: testing
+templates:
+  - templates/gitea/deployment.yaml
+  - templates/gitea/config.yaml
+tests:
+  - it: supports adding a sidecar container
+    template: templates/gitea/deployment.yaml
+    set:
+      extraContainers:
+        - name: sidecar-bob
+          image: busybox
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[1].name
+          value: "sidecar-bob"
+      - equal:
+          path: spec.template.spec.containers[1].image
+          value: "busybox"

values.yaml

@@ -283,6 +283,12 @@ persistence:
   annotations:
     helm.sh/resource-policy: keep
 
+## @param extraContainers Additional sidecar containers to run in the pod
+extraContainers: []
+#  - name: sidecar-bob
+#    image: busybox
+#    command: [/bin/sh, -c, 'echo "Hello world"; sleep 86400']
+
 ## @param extraVolumes Additional volumes to mount to the Gitea deployment
 extraVolumes: []
 # - name: postgres-ssl-vol