grafana: set custom home dashboard

Set a home dashboard with a little logo, link to the source files and
a plain list of dashboards.

Change-Id: Ifa9373695c1edb7de83b342948d46a816702ee10

playbooks/roles/grafana/files/home.json

@@ -0,0 +1,86 @@
+{
+  "links": [],
+  "panels": [
+    {
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 6,
+        "y": 0
+      },
+      "id": 5,
+      "options": {
+        "content": "<img src=\"https://opendev.org/assets/img/opendev.svg\"\nalt=\"OpenDev Logo\"\nstyle=\"height: 100px; background-color:LightGray; padding: 10px; border-radius: 15px; display:block; margin-left: auto; margin-right:auto\" />\n\nWelcome to OpenDev Grafana\n\nThe following dashboards are populated automatically.  Contributions are welcome in the [project-config](https://opendev.org/openstack/project-config/src/branch/master/grafana) repository.",
+        "mode": "markdown"
+      },
+      "pluginVersion": "8.4.3",
+      "title": "OpenDev Grafana",
+      "transparent": true,
+      "type": "text"
+    },
+    {
+      "gridPos": {
+        "h": 50,
+        "w": 18,
+        "x": 3,
+        "y": 8
+      },
+      "id": 3,
+      "links": [],
+      "options": {
+        "folderId": 0,
+        "maxItems": 50,
+        "query": "",
+        "showHeadings": false,
+        "showRecentlyViewed": false,
+        "showSearch": true,
+        "showStarred": false,
+        "tags": []
+      },
+      "pluginVersion": "8.4.3",
+      "tags": [],
+      "title": "Dashboards",
+      "transparent": true,
+      "type": "dashlist"
+    }
+  ],
+  "schemaVersion": 35,
+  "style": "dark",
+  "tags": [],
+  "templating": {
+    "list": []
+  },
+  "time": {
+    "from": "now-6h",
+    "to": "now"
+  },
+  "timepicker": {
+    "hidden": true,
+    "refresh_intervals": [
+      "5s",
+      "10s",
+      "30s",
+      "1m",
+      "5m",
+      "15m",
+      "30m",
+      "1h",
+      "2h",
+      "1d"
+    ],
+    "time_options": [
+      "5m",
+      "15m",
+      "1h",
+      "6h",
+      "12h",
+      "24h",
+      "2d",
+      "7d",
+      "30d"
+    ],
+    "type": "timepicker"
+  },
+  "timezone": "browser",
+  "title": "OpenDev Home"
+}

playbooks/roles/grafana/tasks/main.yaml

@@ -41,6 +41,22 @@
     group: root
     mode: 0644
 
+- name: Ensure home panel directory exists
+  file:
+    state: directory
+    path: /etc/grafana/home
+    owner: root
+    group: root
+    mode: 0755
+
+- name: Copy home panel
+  copy:
+    src: 'home.json'
+    dest: '/etc/grafana/home/home.json'
+    owner: root
+    group: root
+    mode: 0644
+
 - name: Write update script
   template:
     src: update-grafana-dashboards.sh.j2

playbooks/roles/grafana/templates/docker-compose.yaml.j2

@@ -13,5 +13,7 @@ services:
       GF_SECURITY_SECRET_KEY__FILE: '/etc/grafana/secrets/secret_key'
       GF_AUTH_ANONYMOUS_ENABLED: 'true'
       GF_USERS_ALLOW_SIGN_UP: 'false'
+      GF_DASHBOARDS_DEFAULT_HOME_DASHBOARD_PATH: '/etc/grafana/home/home.json'
     volumes:
-      - /etc/grafana/secrets:/etc/grafana/secrets
+      - /etc/grafana/secrets:/etc/grafana/secrets:ro
+      - /etc/grafana/home:/etc/grafana/home:ro