[processor/metricsgeneration] Add config validation for generated metric names

.chloggen/metricsgeneration_loop.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: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: metricsgenerationprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Generated metric name may not match metric being scaled
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37474]
+
+# (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: []

processor/metricsgenerationprocessor/config.go

@@ -161,6 +161,12 @@ func (config *Config) Validate() error {
 		if rule.Operation != "" && !rule.Operation.isValid() {
 			return fmt.Errorf("%q must be in %q", operationFieldName, operationTypeKeys())
 		}
+
+		if rule.Name == rule.Metric1 {
+			return fmt.Errorf("value of field %q may not match value of field %q", nameFieldName, metric1FieldName)
+		} else if rule.Name == rule.Metric2 {
+			return fmt.Errorf("value of field %q may not match value of field %q", nameFieldName, metric2FieldName)
+		}
 	}
 	return nil
 }

processor/metricsgenerationprocessor/config_test.go

@@ -75,6 +75,14 @@ func TestLoadConfig(t *testing.T) {
 			id:           component.NewIDWithName(metadata.Type, "invalid_operation"),
 			errorMessage: fmt.Sprintf("%q must be in %q", operationFieldName, operationTypeKeys()),
 		},
+		{
+			id:           component.NewIDWithName(metadata.Type, "matching_metric1"),
+			errorMessage: fmt.Sprintf("value of field %q may not match value of field %q", nameFieldName, metric1FieldName),
+		},
+		{
+			id:           component.NewIDWithName(metadata.Type, "matching_metric2"),
+			errorMessage: fmt.Sprintf("value of field %q may not match value of field %q", nameFieldName, metric2FieldName),
+		},
 	}
 
 	for _, tt := range tests {

processor/metricsgenerationprocessor/testdata/config.yaml

@@ -68,3 +68,19 @@ metricsgeneration/missing_type:
       metric1: metric1
       metric2: metric2
       operation: percent
+
+metricsgeneration/matching_metric1:
+  rules:
+    - name: new_metric
+      type: scale
+      metric1: new_metric
+      operation: multiply
+      scale_by: 100
+
+metricsgeneration/matching_metric2:
+  rules:
+    - name: new_metric
+      type: calculate
+      metric1: original
+      metric2: new_metric
+      operation: multiply