Accept a string as extraInitContainers value for filebeat

filebeat/README.md

@@ -61,7 +61,7 @@ helm install --name filebeat elastic/filebeat --set imageTag=7.6.1
 | `filebeatConfig`         | Allows you to add any config files in `/usr/share/filebeat` such as `filebeat.yml`. See [values.yaml](https://github.com/elastic/helm-charts/tree/master/filebeat/values.yaml) for an example of the formatting with the default configuration.                                                                          | see [values.yaml](https://github.com/elastic/helm-charts/tree/master/filebeat/values.yaml)                                |
 | `extraContainers`        | List of additional init containers to be added at the Daemonset                                                                                                                                                                                                                                                          | `""`                                                                                                                      |
 | `extraEnvs`              | Extra [environment variables](https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/#using-environment-variables-inside-of-your-config) which will be appended to the `env:` definition for the container                                                                       | `[]`                                                                                                                      |
-| `extraInitContainers`    | List of additional init containers to be added at the Daemonset                                                                                                                                                                                                                                                          | `[]`                                                                                                                      |
+| `extraInitContainers`    | List of additional init containers to be added at the Daemonset. It also accepts a templatable string of additional containers to be passed to the `tpl` function                                                                                                                                                                                                                                                          | `[]`                    |
 | `extraVolumeMounts`      | List of additional volumeMounts to be mounted on the Daemonset                                                                                                                                                                                                                                                           | `[]`                                                                                                                      |
 | `extraVolumes`           | List of additional volumes to be mounted on the Daemonset                                                                                                                                                                                                                                                                | `[]`                                                                                                                      |
 | `envFrom`                | Templatable string of envFrom to be passed to the  [environment from variables](https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/#configure-all-key-value-pairs-in-a-configmap-as-container-environment-variables) which will be appended to the `envFrom:` definition for the container | `[]`                                                                                                                      |

filebeat/templates/daemonset.yaml

@@ -87,7 +87,17 @@ spec:
       {{- end }}
       {{- if .Values.extraInitContainers }}
       initContainers:
+      # All the other beats accept a string here while
+      # filebeat accepts a valid yaml array. We're keeping
+      # this as a backwards compatible change, while adding
+      # also a way to pass a string as other templates to
+      # make these implementations consistent.
+      # https://github.com/elastic/helm-charts/issues/490
+      {{- if eq "string" (printf "%T" .Values.extraInitContainers) }}
+{{ tpl .Values.extraInitContainers . | indent 8 }}
+      {{- else }}
 {{ toYaml .Values.extraInitContainers | indent 8 }}
+      {{- end }}
       {{- end }}
       containers:
       - name: "filebeat"

filebeat/tests/filebeat_test.py

@@ -74,7 +74,7 @@ def test_adding_a_extra_container():
     } in extraContainer
 
 
-def test_adding_init_containers():
+def test_adding_init_containers_as_yaml():
     config = """
 extraInitContainers:
 - name: dummy-init
@@ -90,6 +90,22 @@ def test_adding_init_containers():
     } in initContainers
 
 
+def test_adding_init_containers():
+    config = """
+extraInitContainers: |
+  - name: dummy-init
+    image: busybox
+    command: ['echo', 'hey']
+"""
+    r = helm_template(config)
+    initContainers = r["daemonset"][name]["spec"]["template"]["spec"]["initContainers"]
+    assert {
+        "name": "dummy-init",
+        "image": "busybox",
+        "command": ["echo", "hey"],
+    } in initContainers
+
+
 def test_adding_image_pull_secrets():
     config = """
 imagePullSecrets: