fixup! fixup! fixup! fixup! fixup! fixup! fixup! fix: fallback to gauge for protofmt-based negotiations

Author: rexagod

pkg/customresourcestate/config.go

@@ -222,6 +222,7 @@ func configOverrides(config *Metrics) {
 		for j := range config.Spec.Resources[i].Metrics {
 
 			// Override the metric type to lowercase, so the internals have a single source of truth for metric type definitions.
+			// This is done as a convenience measure for users, so they don't have to remember the exact casing.
 			config.Spec.Resources[i].Metrics[j].Each.Type = metric.Type(strings.ToLower(string(config.Spec.Resources[i].Metrics[j].Each.Type)))
 		}
 	}

pkg/customresourcestate/config_test.go

@@ -32,6 +32,7 @@ var testData string
 func Test_Metrics_deserialization(t *testing.T) {
 	var m Metrics
 	assert.NoError(t, yaml.NewDecoder(strings.NewReader(testData)).Decode(&m))
+	configOverrides(&m)
 	assert.Equal(t, "active_count", m.Spec.Resources[0].Metrics[0].Name)
 
 	t.Run("can create resource factory", func(t *testing.T) {

pkg/customresourcestate/registry_factory.go

@@ -152,7 +152,7 @@ type compiledMetric interface {
 
 // newCompiledMetric returns a compiledMetric depending on the given metric type.
 func newCompiledMetric(m Metric) (compiledMetric, error) {
-	switch metric.Type(strings.ToLower(string(m.Type))) {
+	switch m.Type {
 	case metric.Gauge:
 		if m.Gauge == nil {
 			return nil, errors.New("expected each.gauge to not be nil")

pkg/metric/metric.go

@@ -40,11 +40,6 @@ var (
 // Type represents the type of the metric. See https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#metric-types.
 type Type string
 
-// String returns the string representation of the metric type.
-func (t Type) String() string {
-	return string(t)
-}
-
 // Supported metric types.
 var (
 

pkg/metric_generator/generator.go

@@ -90,7 +90,7 @@ func (g *FamilyGenerator) generateHeader() string {
 	header.WriteString("# TYPE ")
 	header.WriteString(g.Name)
 	header.WriteByte(' ')
-	header.WriteString(g.Type.String())
+	header.WriteString(string(g.Type))
 
 	return header.String()
 }

pkg/metrics_store/metrics_writer.go

@@ -92,12 +92,8 @@ func SanitizeHeaders(contentType string, writers MetricsWriterList) MetricsWrite
 	var lastHeader string
 	for _, writer := range writers {
 		if len(writer.stores) > 0 {
-			for i, header := range writer.stores[0].headers {
-
-				// Nothing to sanitize.
-				if len(header) == 0 {
-					continue
-				}
+			for i := 0; i < len(writer.stores[0].headers); {
+				header := writer.stores[0].headers[i]
 
 				// Removes duplicate headers from the given MetricsWriterList for the same family (generated through CRS).
 				// These are expected to be consecutive since G** resolution generates groups of similar metrics with same headers before moving onto the next G** spec in the CRS configuration.
@@ -106,8 +102,8 @@ func SanitizeHeaders(contentType string, writers MetricsWriterList) MetricsWrite
 
 					// If the requested content type was proto-based, replace "info" and "statesets" with "gauge", as they are not recognized by Prometheus' protobuf machinery.
 					if strings.HasPrefix(contentType, expfmt.ProtoType) {
-						infoTypeString := metric.Info.String()
-						stateSetTypeString := metric.StateSet.String()
+						infoTypeString := string(metric.Info)
+						stateSetTypeString := string(metric.StateSet)
 						if strings.HasSuffix(header, infoTypeString) {
 							header = header[:len(header)-len(infoTypeString)] + string(metric.Gauge)
 							writer.stores[0].headers[i] = header
@@ -121,22 +117,17 @@ func SanitizeHeaders(contentType string, writers MetricsWriterList) MetricsWrite
 
 				// Nullify duplicate headers after the sanitization to not miss out on any new candidates.
 				if header == lastHeader {
-					writer.stores[0].headers[i] = ""
+					writer.stores[0].headers = append(writer.stores[0].headers[:i], writer.stores[0].headers[i+1:]...)
+
+					// Do not increment the index, as the next header is now at the current index.
+					continue
 				}
 
 				// Update the last header.
 				lastHeader = header
-			}
-		}
-	}
 
-	// Remove all empty headers.
-	for _, writer := range writers {
-		if len(writer.stores) > 0 {
-			for i := len(writer.stores[0].headers) - 1; i >= 0; i-- {
-				if writer.stores[0].headers[i] == "" {
-					writer.stores[0].headers = append(writer.stores[0].headers[:i], writer.stores[0].headers[i+1:]...)
-				}
+				// Move to the next header.
+				i++
 			}
 		}
 	}

pkg/metricshandler/metrics_handler.go

@@ -178,8 +178,8 @@ func (m *MetricsHandler) Run(ctx context.Context) error {
 	return ctx.Err()
 }
 
-// ServeHTTP implements the http.Handler interface. It writes all generated
-// metrics to the response body.
+// ServeHTTP implements the http.Handler interface. It writes all generated metrics to the response body.
+// Note that all operations defined within this procedure are performed at every request.
 func (m *MetricsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	m.mtx.RLock()
 	defer m.mtx.RUnlock()