✨(grafana) add post deployment hooks support

Some dashboards may require to be modified once deployed by injecting
grafana database values in their source.

Those hooks are scripts distributed along with compiled dashboards and
will be executed in a side-car container so that it can access to the
temporary volume used to provision dashboards. This requires
post-deployment hooks scripts to be idempotent.

apps/grafana/CHANGELOG.md

@@ -8,6 +8,10 @@ Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to
 
 ## [Unreleased]
 
+### Added
+
+- Implement support for post-deployment hook scripts as sidecar containers
+
 ## [1.0.0] - 2021-12-03
 
 ### Added

apps/grafana/templates/services/app/deploy.yml.j2

@@ -93,6 +93,21 @@ spec:
             - name: grafana-provisioning-dashboards
               mountPath: /etc/grafana/provisioning/dashboards/dashboards.yml
               subPath: dashboards.yml
+{% if grafana_activate_hooks %}
+        - name: hooks
+          image: "{{ grafana_hooks_image_name }}:{{ grafana_hooks_image_tag }}"
+          imagePullPolicy: Always
+          command: {{ grafana_hooks_commands }}
+          envFrom:
+            - secretRef:
+                name: "{{ grafana_secret_name }}"
+            - configMapRef:
+                name: "grafana-app-dotenv-{{ deployment_stamp }}"
+          resources: {{ grafana_hooks_resources }}
+          volumeMounts:
+            - mountPath: /var/lib/grafana
+              name: grafana-resources
+{% endif %}
       securityContext:
         runAsUser: {{ grafana_container_uid }}
         runAsGroup: {{ grafana_container_gid }}

apps/grafana/vars/all/main.yml

@@ -33,6 +33,13 @@ grafana_dashboards_providers: []
 # Datasources providers
 # https://grafana.com/docs/grafana/latest/administration/provisioning/#data-sources
 grafana_datasources_providers: []
+# Hooks
+# If activated, hooks allow to modify provided dashboards or datasources
+# (post deployment).
+grafana_activate_hooks: false
+grafana_hooks_image_name: "fundocker/curl-jq"
+grafana_hooks_image_tag: latest
+grafana_hooks_commands: []
 
 # -- resources requests
 grafana_app_resources:
@@ -44,3 +51,8 @@ grafana_postgresql_resources:
   requests:
     cpu: 10m
     memory: 100Mi
+
+grafana_hooks_resources:
+  requests:
+    cpu: 10m
+    memory: 100Mi