Merge ~xavpaice/charm-telegraf:bug/1919937-digest into charm-telegraf:master

[Xav Paice]

add dashboard digest to dashboard request

Adds a digest key to the dashboard dict, so that the Grafana charm can detect when the dashboard has been updated.

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[James Troup (elmo)]

LGTM

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 86e4ac2f59661b3c40d2d9f351bf98446dbad738

diff --git a/src/reactive/telegraf.py b/src/reactive/telegraf.py
index c5406ba..4c06424 100644
--- a/src/reactive/telegraf.py
+++ b/src/reactive/telegraf.py
@@ -16,6 +16,7 @@
 
 import base64
 import binascii
+import hashlib
 import io
 import ipaddress
 import json
@@ -1488,14 +1489,16 @@ def prometheus_client_departed():
 @when(
     "plugins.prometheus-client.configured",
     "endpoint.dashboards.joined",
-    "leadership.is_leader"
+    "leadership.is_leader",
 )
 @when_not("grafana.configured")
 def register_grafana_dashboard():
     grafana = endpoint_from_flag("endpoint.dashboards.joined")
     hookenv.log("Loading grafana dashboard", level=hookenv.DEBUG)
     dashboard = _load_grafana_dashboard()
+    digest = hashlib.md5(dashboard.encode("utf8")).hexdigest()
     dashboard_dict = json.loads(dashboard)
+    dashboard_dict["digest"] = digest
     hookenv.log(
         "Rendered dashboard dict:\n{}".format(dashboard_dict), level=hookenv.DEBUG
     )
diff --git a/src/tests/unit/test_telegraf.py b/src/tests/unit/test_telegraf.py
index a82a337..1f9372f 100644
--- a/src/tests/unit/test_telegraf.py
+++ b/src/tests/unit/test_telegraf.py
@@ -1450,8 +1450,10 @@ class TestGrafanaDashboard:
     @patch("reactive.telegraf.hookenv")
     @patch("reactive.telegraf.set_flag")
     @patch("reactive.telegraf.json")
+    @patch("hashlib.md5")
     def test_register_grafana_dashboard(
         self,
+        mock_md5,
         mock_json,
         mock_set_flag,
         mock_hookenv,
@@ -1471,6 +1473,7 @@ class TestGrafanaDashboard:
         mock_dashboard_dict = MagicMock()
         mock_rendered_content = MagicMock()
 
+        mock_md5.return_value = MagicMock()
         mock_endpoint_from_flag.return_value = mock_grafana
         mock_hookenv.config.return_value = fake_config
         mock_json.loads.return_value = mock_dashboard_dict