Normalize Prometheus metric name and label keys and values.

Add env variable toggle to selectively disable service label.

Bug: T247820

lib/heapwatch.js

@@ -56,7 +56,7 @@ class HeapWatch {
                             prometheus: {
                                 name: `nodejs_gc_${gcType}_duration_seconds`,
                                 help: 'garbage collection pause duration seconds',
-                                staticLabels: { service: this.metrics.getServiceName() },
+                                staticLabels: this.metrics.getServiceLabel(),
                                 buckets: [5e-4, 1e-3, 5e-3, 10e-3, 15e-3, 30e-3, 50e-3]
                             }
                         }).observe(totalGCTime * 1e-9); // nanoseconds to seconds
@@ -78,7 +78,7 @@ class HeapWatch {
             prometheus: {
                 name: 'nodejs_process_heap_rss_bytes',
                 help: 'process heap usage',
-                staticLabels: { service: this.metrics.getServiceName() }
+                staticLabels: this.metrics.getServiceLabel()
             }
         }).set(usage.rss);
         this.metrics.makeMetric({
@@ -87,7 +87,7 @@ class HeapWatch {
             prometheus: {
                 name: 'nodejs_process_heap_used_bytes',
                 help: 'process heap usage',
-                staticLabels: { service: this.metrics.getServiceName() }
+                staticLabels: this.metrics.getServiceLabel()
             }
         }).set(usage.heapUsed);
         this.metrics.makeMetric({
@@ -96,7 +96,7 @@ class HeapWatch {
             prometheus: {
                 name: 'nodejs_process_heap_total_bytes',
                 help: 'process heap usage',
-                staticLabels: { service: this.metrics.getServiceName() }
+                staticLabels: this.metrics.getServiceLabel()
             }
         }).set(usage.heapTotal);
         if (usage.heapUsed > this.limit) {

lib/metrics/index.js

@@ -53,6 +53,16 @@ class Metrics {
         return this.serviceName;
     }
 
+    // T247820: Selectively disable service label based on environment variable.
+    // Intended for production use case where the service label will be set
+    // by the Prometheus server.
+    getServiceLabel() {
+        if (process.env.METRICS_SERVICE_LABEL_ENABLED === 'false') {
+            return {};
+        }
+        return { service: this.serviceName };
+    }
+
     fetchClient(name) {
         return this.clients.find((client) => {
             return client.constructor.name === name;

lib/metrics/prometheus.js

@@ -17,6 +17,9 @@ class PrometheusMetric {
                 });
             }
         }
+        options.prometheus.name = this._normalize(options.prometheus.name);
+        options.prometheus.labelNames = options.prometheus.labelNames || [];
+        options.prometheus.labelNames = options.prometheus.labelNames.map(this._normalize);
         this.metric = new this.client[options.type]({
             name: options.prometheus.name,
             help: options.prometheus.help,
@@ -34,23 +37,33 @@ class PrometheusMetric {
         }
     }
 
+    _normalize(str) {
+        return String(str).replace( /\W/g, '_' ) // replace non-alphanumerics
+            .replace( /_+/g, '_' ) // dedupe underscores
+            .replace( /(^_+|_+$)/g, '' ); // trim leading and trailing underscores
+    }
+
     increment(amount, labels) {
         this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.metric.labels.apply(this.metric, labels).inc(amount);
     }
 
     decrement(amount, labels) {
         this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.metric.labels.apply(this.metric, labels).dec(amount);
     }
 
     observe(value, labels) {
         this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.metric.labels.apply(this.metric, labels).observe(value);
     }
 
     gauge(amount, labels) {
         this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         if (amount < 0) {
             this.metric.labels.apply(this.metric, labels).dec(Math.abs(amount));
         } else {
@@ -60,14 +73,19 @@ class PrometheusMetric {
 
     set(value, labels) {
         this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.metric.labels.apply(this.metric, labels).set(value);
     }
 
     timing(value, labels) {
+        this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.set(value, labels);
     }
 
     endTiming(startTime, labels) {
+        this._handleStaticLabels(labels);
+        labels = labels.map(this._normalize);
         this.timing(Date.now() - startTime, labels);
     }
 }

test/utils/simple_server.js

@@ -21,7 +21,7 @@ module.exports = (options) => {
             type: 'Counter',
             name: 'simple_server.hitcount.total',
             prometheus: {
-                name: 'hitcount_total',
+                name: 'hitcount total',
                 help: 'a hit counter'
             }
         }).increment();