doc: changelog doc

cmd/poller/plugin/changelog/change_log_helper.go

@@ -56,27 +56,31 @@ func getChangeLogConfig(parentParams *node.Node, overwriteConfig []byte, logger
 	)
 	object := parentParams.GetChildS("object").GetContentS()
 
+	useDefault := true
+
 	if len(overwriteConfig) > 0 {
 		entry, err = preprocessOverwrite(object, overwriteConfig)
 		if err != nil {
 			logger.Warn().Err(err).Str("template", string(overwriteConfig)).Msg("failed to parse changelog dsl. Trying default")
 		} else {
-			return entry, nil
+			useDefault = false
 		}
 	}
 
-	err = yaml.Unmarshal([]byte(defaultChangeLogTemplate), &config)
-	if err != nil {
-		return Entry{}, err
+	if useDefault {
+		err = yaml.Unmarshal([]byte(defaultChangeLogTemplate), &config)
+		if err != nil {
+			return Entry{}, err
+		}
+		i := slices.IndexFunc(config.ChangeLogs, func(entry Entry) bool {
+			return entry.Object == object
+		})
+		if i == -1 {
+			return Entry{}, nil
+		}
+		entry = config.ChangeLogs[i]
 	}
 
-	i := slices.IndexFunc(config.ChangeLogs, func(entry Entry) bool {
-		return entry.Object == object
-	})
-	if i == -1 {
-		return Entry{}, nil
-	}
-	entry = config.ChangeLogs[i]
 	// populate publish_labels if they are empty
 	if entry.PublishLabels == nil {
 		if exportOption := parentParams.GetChildS("export_options"); exportOption != nil {

docs/plugins.md

@@ -631,4 +631,116 @@ compute_metric:
 # inode_used_percent = inode_files_used / inode_files_total * 100
 ```
 
-# ChangeLog
+# ChangeLog Plugin
+
+The ChangeLog plugin is a feature of Harvest, designed to detect and track changes related to the creation, modification, and deletion of an object. By default, it supports volume, svm, and node objects. However, its functionality can be extended to track changes in any other objects by making relevant changes in the template.
+
+Please note that the ChangeLog plugin requires the `uuid` label, which is unique, to be collected by the template. Without the `uuid` label, the plugin will not function.
+
+The ChangeLog feature only detects changes when Harvest is up and running. It does not detect any changes that occur when Harvest is down. Additionally, the plugin currently does not detect changes in metric values.
+
+## Enabling the Plugin
+
+The plugin can be enabled in the templates under the plugins section.
+
+For volume, svm, and node objects, you can enable the plugin with the following configuration:
+
+```yaml
+plugins:
+  - ChangeLog
+```
+
+For other objects, you need to specify the labels to track in the plugin configuration. These labels should be relevant to the object you want to track. If these labels are not specified in template, the plugin will not be able to track changes for the object.
+
+Here's an example of how to enable the plugin for an aggregate object:
+
+```yaml
+plugins:
+  - ChangeLog:
+      track:
+        - aggr
+        - node
+        - state
+```
+
+In the above configuration, the plugin will track changes in the `aggr`, `node`, and `state` labels for the aggregate object.
+
+## Default Tracking for svm, node, volume
+
+By default, the plugin tracks changes in the following labels for svm, node, and volume objects:
+
+- svm: svm, state, type, anti_ransomware_state
+- node: node, location, healthy
+- volume: node, volume, svm, style, type, aggr, state, status
+
+For any other objects, defaults are not available and need to be defined in the plugin.
+
+These default settings can be overwritten as needed in the relevant templates. For instance, if you want to track `junction_path` labels for Volume, you can overwrite this in the volume template.
+
+```yaml
+plugins:
+  - ChangeLog:
+      - track:
+        - node
+        - volume
+        - svm
+        - style
+        - type
+        - aggr
+        - state
+        - status
+        - junction_path
+```
+
+## Change Types and Metrics
+
+The ChangeLog plugin publishes a metric with various labels providing detailed information about the change when an object is created, modified, or deleted.
+
+### Object Creation
+
+When a new object is created, the ChangeLog plugin will publish a metric with the following labels:
+
+- The name of the ONTAP object that was changed (object)
+- The type of change that was made (op)
+- The timestamp when Harvest Poller captured the change (Metric Value)
+
+Example of metric shape for object creation:
+
+```
+change_log{aggr="umeng_aff300_aggr2", cluster="umeng-aff300-01-02", datacenter="u2", index="0", instance="localhost:12993", job="prometheus", node="umeng-aff300-01", object="volume", op="create", style="flexvol", svm="harvest", volume="harvest_demo"} 1698735558
+```
+
+### Object Modification
+
+When an existing object is modified, the ChangeLog plugin will publish a metric with the following labels:
+
+- The name of the ONTAP object that was changed (object)
+- The type of change that was made (op)
+- The property of the object which was modified (Track)
+- The new value of the object after the change was made (New Value)
+- The previous value of the object before the change was made (Old Value)
+- The timestamp when Harvest Poller captured the change (Metric Value)
+
+Example of metric shape for object modification:
+
+```
+change_log{aggr="umeng_aff300_aggr2", cluster="umeng-aff300-01-02", datacenter="u2", index="1", instance="localhost:12993", job="prometheus", new_value="offline", node="umeng-aff300-01", object="volume", old_value="online", op="update", style="flexvol", svm="harvest", track="state", volume="harvest_demo"} 1698735677
+```
+
+### Object Deletion
+
+When an object is deleted, the ChangeLog plugin will publish a metric with the following labels:
+
+- The name of the ONTAP object that was changed (object)
+- The type of change that was made (op)
+- The timestamp when Harvest Poller captured the change (Metric Value)
+
+Example of metric shape for object deletion:
+
+```
+change_log{aggr="umeng_aff300_aggr2", cluster="umeng-aff300-01-02", datacenter="u2", index="2", instance="localhost:12993", job="prometheus", node="umeng-aff300-01", object="volume", op="delete", style="flexvol", svm="harvest", volume="harvest_demo"} 1698735708
+```
+
+## Viewing the Metrics
+
+You can view the metrics published by the ChangeLog plugin in the `ChangeLog Monitor` dashboard in `Grafana`. This dashboard provides a visual representation of the changes tracked by the plugin for volume, svm, and node objects.