add changelog and move comment

Author: spiffyy99

.chloggen/splunk_enforce_metrics_naming_regex.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: internal/splunk
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a regex to enforce metrics naming for Splunk events fields based on metrics documentation.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34275]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

internal/splunk/common.go

@@ -67,6 +67,9 @@ func (e *Event) IsMetric() bool {
 // checks if the field name matches the requirements for a metric datapoint field,
 // and returns the metric name and a bool indicating whether the field is a metric.
 func getMetricNameFromField(fieldName string) (string, bool) {
+	// only consider metric name if it fits regex criteria.
+	// use matches[1] since first element contains entire string.
+	// first subgroup will be the actual metric name.
 	if matches := metricNameRegexp.FindStringSubmatch(fieldName); len(matches) > 1 {
 		return matches[1], !strings.Contains(matches[1], "metric_name")
 	}
@@ -81,9 +84,6 @@ func (e *Event) GetMetricValues() map[string]any {
 
 	values := map[string]any{}
 	for k, v := range e.Fields {
-		// only consider metric name if it fits regex criteria.
-		// use matches[1] since first element contains entire string.
-		// first subgroup will be the actual metric name.
 		if metricName, ok := getMetricNameFromField(k); ok {
 			values[metricName] = v
 		}