metadata: add configuration_options for varnish and add validation (#565

)

* metadata: add configuration_options for varnish and add validation

Signed-off-by: Ridwan Sharif <[email protected]>

* metadata: add supported_app_version for varnish

Signed-off-by: Ridwan Sharif <[email protected]>

integration_test/third_party_apps_data/applications/varnish/metadata.yaml

@@ -1,5 +1,15 @@
 short_name: varnish
 long_name: Varnish HTTP Cache
+description: |-
+  The Varnish integration collects cache and session metrics.
+  It monitors the number of objects entering and exiting the cache,
+  as well as the number of sessions and backend connections.
+  The integration also collects Varnish access logs and parses them
+  into a standardized json payload.
+
+  For more information about Varnish, see
+  [Varnish HTTP Cache](https://varnish-cache.org/).
+supported_app_version: ["6.x", "7.0.x"]
 expected_metrics:
 - type: workload.googleapis.com/varnish.backend.connection.count
   value_type: INT64
@@ -63,4 +73,19 @@ expected_metrics:
   monitored_resource: gce_instance
   labels:
     operation: .*
-expected_logs:
+configuration_options:
+  metrics:
+  - type: varnish
+    fields:
+    - name: type
+      default: null
+      description: This value must be varnish.
+    - name: cache_dir
+      default: null
+      description: This specifies the cache dir instance name to use when collecting metrics. If not specified, this will default to the host. 
+    - name: exec_dir
+      default: null
+      description: The directory where the varnishadm and varnishstat executables are located. If not provided, will default to relying on the executables being in the user's PATH.
+    - name: collection_interval
+      default: 60s
+      description: A time.Duration value, such as 30s or 5m.