Improve error reporting on invalid Grafana URLs, or invalid endpoints

- Rework "health" method (now a property) to raise exception on errors
- Report Grafana version on startup
- Improve error messages
- Add software tests evaluating connectivity error handling

Author: amotl

CHANGES.rst

@@ -14,6 +14,8 @@ in progress
 - Removed support for Python 3.7
 - SQLite cache: Use ``requests_cache.CachedSession`` for better concurrency
   behaviour. Thanks, @JensRichnow and @JWCook.
+- Improve error reporting and exit behavior when connecting to Grafana
+  instance fails. Thanks, @interfan7.
 
 2024-03-07 0.18.0
 =================

grafana_wtf/commands.py

@@ -228,13 +228,16 @@ def run():
             'No Grafana URL given. Please use "--grafana-url" option or environment variable "GRAFANA_URL".'
         )
 
-    log.info(f"Using Grafana at {grafana_url}")
+    log.info(f"Grafana location: {grafana_url}")
 
     engine = GrafanaWtf(grafana_url, grafana_token)
+
     engine.enable_cache(expire_after=cache_ttl, drop_cache=options["drop-cache"])
     engine.enable_concurrency(int(options["concurrency"]))
     engine.setup()
 
+    log.info(f"Grafana version: {engine.version}")
+
     if options.replace:
         engine.clear_cache()
 

grafana_wtf/core.py

@@ -37,7 +37,7 @@
 class GrafanaEngine:
     session = niquests.Session()
 
-    def __init__(self, grafana_url, grafana_token):
+    def __init__(self, grafana_url, grafana_token=None):
         self.grafana_url = grafana_url
         self.grafana_token = grafana_token
 
@@ -263,15 +263,10 @@ async def execute_parallel(self):
 
 class GrafanaWtf(GrafanaEngine):
     def info(self):
-        try:
-            health = self.grafana.client.GET("/health")
-        except Exception as ex:
-            log.error(f"Request to /health endpoint failed: {ex}")
-            health = {}
 
         response = OrderedDict(
             grafana=OrderedDict(
-                version=health.get("version"),
+                version=self.version,
                 url=self.grafana_url,
             ),
             statistics=OrderedDict(),
@@ -315,15 +310,29 @@ def info(self):
 
         return response
 
-    def version(self):
+    @property
+    def health(self):
+        response = None
+        error = None
+        error_template = f"The request to {self.grafana_url.rstrip('/')}/api/health failed"
         try:
-            health = self.grafana.client.GET("/health")
+            response = self.grafana.client.GET("/health")
+            if not isinstance(response, dict):
+                error = f"{error_template}: Invalid response, content was: {response}"
+
         except Exception as ex:
-            log.error(f"Request to /health endpoint failed: {ex}")
-            health = {}
+            error = f"{error_template}: {ex}"
 
-        version = health.get("version")
-        return version
+        if error:
+            log.critical(error)
+            raise ConnectionError(error)
+
+        if response:
+            return Munch(response)
+
+    @property
+    def version(self):
+        return self.health.get("version")
 
     def dashboard_details(self):
         for dashboard in self.data.dashboards:

tests/conftest.py

@@ -321,7 +321,7 @@ def grafana_version(docker_grafana):
     """
     engine = GrafanaWtf(grafana_url=docker_grafana, grafana_token=None)
     engine.setup()
-    grafana_version = engine.version()
+    grafana_version = engine.version
     return grafana_version
 
 

tests/test_core.py

@@ -1,8 +1,9 @@
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
+import pytest
 from munch import Munch
 
-from grafana_wtf.core import Indexer
+from grafana_wtf.core import Indexer, GrafanaWtf
 
 
 def test_collect_datasource_items_variable_all():
@@ -35,3 +36,37 @@ def test_collect_datasource_items_variable_all():
     indexer = Indexer(engine=engine_mock)
     result = indexer.collect_datasource_items([node])
     assert result == []
+
+
+def test_connect_success():
+    wtf = GrafanaWtf("https://play.grafana.org")
+    wtf.setup()
+    health = wtf.health
+    assert "commit" in health
+    assert "version" in health
+    assert health.database == "ok"
+
+
+def test_connect_failure():
+    wtf = GrafanaWtf("http://localhost:1234")
+    wtf.setup()
+    with pytest.raises(ConnectionError) as ex:
+        _ = wtf.health
+    assert ex.match("The request to http://localhost:1234/api/health failed")
+
+
+@patch("grafana_client.client.GrafanaClient.__getattr__")
+def test_connect_version(mock_get):
+    mock_get.return_value = Mock()
+    mock_get.return_value.return_value = {"commit": "14e988bd22", "database": "ok", "version": "9.0.1"}
+    wtf = GrafanaWtf("http://localhost:1234")
+    wtf.setup()
+    assert wtf.version == "9.0.1"
+
+
+def test_connect_non_json_response():
+    wtf = GrafanaWtf("https://example.org/")
+    wtf.setup()
+    with pytest.raises(ConnectionError) as ex:
+        _ = wtf.health
+    assert ex.match("The request to https://example.org/api/health failed: Client Error 404")