Merge ~rgildein/charm-telegraf:lp2009613 into charm-telegraf:master

[Robert Gildein]

functional test fix + dropped Xenial

Dropped the Xenial series and providing a small fix for bundles in
functional tests. Added some things from the bs templates to make
the func test smoother.

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

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

[🤖 prod-jenkaas-bootstack (prod-jenkaas-bootstack)]

PASSED: Continuous integration, rev:1ec40b3cb0e74ea1aff7ecec1332f56820eb83b6
https://jenkins.canonical.com/bootstack/job/lp-charm-telegraf-ci/7/
Executed test runs:
    SUCCESS: https://jenkins.canonical.com/bootstack/job/lp-charm-test-functest/277/
    None: https://jenkins.canonical.com/bootstack/job/lp-update-mp/107/

Click here to trigger a rebuild:
https://jenkins.canonical.com/bootstack/job/lp-charm-telegraf-ci/7//rebuild

review: Approve (continuous-integration)

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

Change successfully merged at revision 0b467d14b7fe63a18eeaeb44b77f1f4409e7b482

diff --git a/charmcraft.yaml b/charmcraft.yaml
index e814176..559f214 100644
--- a/charmcraft.yaml
+++ b/charmcraft.yaml
@@ -10,9 +10,11 @@ parts:
   charm:
     source: src
     plugin: reactive
-    build-snaps: [ charm/2.x/stable ] # charmcraft has incompatibility issue
-                                      # with the latest charm snap. Pining the
-                                      # version to 2.x/stable as a temporary fix
+    # Using charm/3.x/stable will cause the charm unable to install on 18.04
+    # with the following error: "pip requires Python '>=3.7' but the running
+    # Python is 3.6.9". This is because charm/3.x/stable start using system
+    # installation of python instead of a python snap.
+    build-snaps: [charm/2.x/stable]
 
 bases:
   - build-on:
diff --git a/src/metadata.yaml b/src/metadata.yaml
index 0b9ad39..bbf02e7 100644
--- a/src/metadata.yaml
+++ b/src/metadata.yaml
@@ -28,8 +28,8 @@ description: >
   plugins are designed to be easy to contribute, we'll eagerly accept
   pull requests and will manage the set of plugins that Telegraf supports.
   See the contributing guide for instructions on writing new plugins.
-# NOTE (rgildein): This is a temporary fix until the issue is resolved.
-# https://github.com/juju/charm-tools/issues/615
+# Series are needed here only because we use charm/2.x/stable, whose linter will fail
+# if it doesn't find series here. Bases in charmcraft.yaml are used instead of series.
 series: []
 subordinate: true
 requires:
diff --git a/src/reactive/telegraf.py b/src/reactive/telegraf.py
index b335f62..8f88df8 100644
--- a/src/reactive/telegraf.py
+++ b/src/reactive/telegraf.py
@@ -1023,7 +1023,6 @@ def upgrade_charm():
     clear_flag("telegraf.configured")
     clear_flag("telegraf.apt.configured")
     clear_flag("telegraf.snap.configured")
-    clear_flag("grafana.configured")
 
 
 @when("config.changed")
@@ -1075,7 +1074,6 @@ def handle_config_changes():
     clear_flag("telegraf.apt.configured")
     clear_flag("telegraf.snap.configured")
     clear_flag("telegraf.nagios-setup.complete")
-    clear_flag("grafana.configured")
 
 
 @when("telegraf.configured")
@@ -1961,7 +1959,6 @@ def prometheus_client_departed():
     "endpoint.dashboards.joined",
     "leadership.is_leader",
 )
-@when_not("grafana.configured")
 def register_grafana_dashboards():
     grafana = endpoint_from_flag("endpoint.dashboards.joined")
     grafana_dashboard_config = GRAFANA_DASHBOARD_CONFIG.copy()
@@ -1996,8 +1993,6 @@ def register_grafana_dashboards():
             grafana.register_dashboard(name=dashboard_name, dashboard=dashboard_dict)
             hookenv.log('Grafana dashboard "{}" registered.'.format(dashboard_name))
 
-    set_flag("grafana.configured")
-
 
 def _load_grafana_dashboard(dashboard_data, dashboard_filter):
     related_prometheus_app = None
@@ -2044,11 +2039,6 @@ def render_custom(source, render_context, **parameters):
     return template.render(render_context)
 
 
-@when("endpoint.dashboards.departed", "grafana.configured")
-def unregister_grafana_dashboard():
-    clear_flag("grafana.configured")
-
-
 @when("endpoint.dashboards.failed", "leadership.is_leader")
 def grafana_dashboard_import_failed():
     grafana = endpoint_from_flag("endpoint.dashboards.failed")
@@ -2059,7 +2049,6 @@ def grafana_dashboard_import_failed():
             ),
             level=hookenv.ERROR,
         )
-    clear_flag("grafana.configured")
 
 
 @when("telegraf.needs_reload")
diff --git a/src/tests/unit/test_telegraf.py b/src/tests/unit/test_telegraf.py
index 5f59a91..512f5c4 100644
--- a/src/tests/unit/test_telegraf.py
+++ b/src/tests/unit/test_telegraf.py
@@ -1627,9 +1627,8 @@ def test_upgrade_charm(mocker):
     clear_flag.assert_any_call("plugins.foo.configured")
     clear_flag.assert_any_call("plugins.bar.configured")
     clear_flag.assert_any_call("extra_plugins.configured")
-    clear_flag.assert_any_call("grafana.configured")
     clear_flag.assert_any_call("prometheus-client.relation.configured")
-    assert clear_flag.call_count == 8
+    assert clear_flag.call_count == 7
 
 
 def test_upgrade_charm_prometheus_client(mocker, monkeypatch, config):
@@ -1738,17 +1737,19 @@ class TestTelegrafNagios:
 
 
 class TestGrafanaDashboard:
+    @patch("reactive.telegraf.endpoint_from_flag")
+    def test_register_grafana_dashboard_n(self, mock_endpoint_from_flag):
+        ...
+
     @patch("reactive.telegraf.render_custom")
     @patch("reactive.telegraf.endpoint_from_flag")
     @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,
         mock_endpoint_from_flag,
         mock_render,
@@ -1816,18 +1817,11 @@ class TestGrafanaDashboard:
             mock_register_dashboards_calls, any_order=True
         )
         mock_render.assert_has_calls(mock_render_calls, any_order=True)
-        mock_set_flag.assert_called_once_with("grafana.configured")
-
-    @patch("reactive.telegraf.clear_flag")
-    def test_unregister_grafana_dashboard(self, mock_clear_flag):
-        telegraf.unregister_grafana_dashboard()
-        mock_clear_flag.assert_called_with("grafana.configured")
 
     @patch("reactive.telegraf.endpoint_from_flag")
-    @patch("reactive.telegraf.clear_flag")
     @patch("reactive.telegraf.hookenv")
     def test_grafana_dashboard_import_failed(
-        self, mock_hookenv, mock_clear_flag, mock_endpoint_from_flag
+        self, mock_hookenv, mock_endpoint_from_flag
     ):
         test_failed_imports = [
             MagicMock(name="import1", reason="some_reason1"),
@@ -1841,7 +1835,6 @@ class TestGrafanaDashboard:
         telegraf.grafana_dashboard_import_failed()
 
         assert mock_hookenv.log.call_count == 2
-        mock_clear_flag.assert_called_once_with("grafana.configured")
 
 
 @pytest.mark.parametrize("install_method", ["deb", "snap"])