Fix discovery of data sources defined by dashboard variables

Because you can choose any data source with the corresponding chooser,
this will never be accurate. However, it will check if the _default_
data source defined within the variable definition actually exists.

grafana_wtf/core.py

@@ -9,7 +9,6 @@
 from collections import OrderedDict
 from concurrent.futures.thread import ThreadPoolExecutor
 from urllib.parse import parse_qs, urljoin, urlparse
-from tqdm.contrib.logging import tqdm_logging_redirect
 
 import colored
 import requests
@@ -18,6 +17,7 @@
 from grafana_client.client import GrafanaClientError, GrafanaUnauthorizedError
 from munch import Munch, munchify
 from tqdm import tqdm
+from tqdm.contrib.logging import tqdm_logging_redirect
 from urllib3.exceptions import InsecureRequestWarning
 
 from grafana_wtf.model import (
@@ -492,20 +492,35 @@ def __init__(self, engine: GrafanaWtf):
         self.index()
 
     def index(self):
-        self.index_dashboards()
         self.index_datasources()
+        self.index_dashboards()
+        self.index_crossref()
 
-    @staticmethod
-    def collect_datasource_items(element):
+    def collect_datasource_items(self, element):
         element = element or []
         items = []
         for node in element:
+            ds = None
+
+            # Directly defined datasources.
             if "datasource" in node and node["datasource"]:
                 ds = node.datasource
                 if isinstance(ds, Munch):
                     ds = dict(ds)
-                if ds not in items:
-                    items.append(ds)
+
+            # Datasources defined as variables.
+            if "type" in node and node["type"] == "datasource":
+                ds_name = node.get("current", {}).get("value")
+                datasource = self.datasource_by_name.get(ds_name, {})
+                ds = dict(
+                    type=datasource.get("type"),
+                    uid=datasource.get("uid"),
+                    name=datasource.get("name"),
+                    url=datasource.get("url"),
+                )
+
+            if ds is not None and ds not in items:
+                items.append(ds)
         return items
 
     def index_dashboards(self):
@@ -548,6 +563,7 @@ def index_datasources(self):
                 self.datasource_by_ident[datasource.uid] = datasource
                 self.datasource_by_uid[datasource.uid] = datasource
 
+    def index_crossref(self):
         for dashboard_uid, datasource_items in self.dashboard_datasource_index.items():
             datasource_item: DatasourceItem
             for datasource_item in datasource_items: