feat: adds option for performance metrics so they can be disabled, de…

…fault is enabled (nodeshift#20) * adds the exposePerformanceMetrics option
lholmquist · Apr 23, 2020 · 2437eca · 2437eca
1 parent b353a59
commit 2437eca
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Showing 3 changed files with 67 additions and 11 deletions.
diff --git a/README.md b/README.md
@@ -69,7 +69,8 @@ const options = {};
 new PrometheusMetrics(options)
 ```
 
-|Name      |Description                                               |Default                                                                                                |
-|----------|----------------------------------------------------------|-------------------------------------------------------------------------------------------------------|
-|`circuits`|A list or individual circuit breaker to create metrics for|No circuits                                                                                            |
-|`registry`|An existing registry to use for prometheus metrics        |`undefined` - The default prometheus registry will be used and default system metrics will be collected|
+|Name                      |Description                                                             |Default                                                                                                |
+|--------------------------|------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------|
+|`circuits`                |A list or individual circuit breaker to create metrics for              |No circuits                                                                                            |
+|`registry`                |An existing registry to use for prometheus metrics                      |`undefined` - The default prometheus registry will be used and default system metrics will be collected|
+|`exposePerformanceMetrics`|Measure the performance of breakers and report them through the registry|true                                                                                                   |
diff --git a/index.js b/index.js
@@ -14,19 +14,22 @@ class PrometheusMetrics {
   constructor (options = {}) {
     this._registry = options.registry || client.register;
     this._client = client;
+    this._options = options;
     this._counter = new this._client.Counter({
       name: `circuit`,
       help: `A count of all circuit' events`,
       registers: [this._registry],
       labelNames: ['name', 'event']
     });
 
-    this._summary = new this._client.Summary({
-      name: `circuit_perf`,
-      help: `A summary of all circuit's events`,
-      registers: [this._registry],
-      labelNames: ['name', 'event']
-    });
+    if (this.exposePerformanceMetrics()) {
+      this._summary = new this._client.Summary({
+        name: `circuit_perf`,
+        help: `A summary of all circuit's events`,
+        registers: [this._registry],
+        labelNames: ['name', 'event']
+      });
+    }
 
     if (!options.registry) {
       this.interval = this._client
@@ -38,6 +41,12 @@ class PrometheusMetrics {
     }
   }
 
+  exposePerformanceMetrics () {
+    return this._options === undefined ||
+      this._options.exposePerformanceMetrics === undefined ||
+      this._options.exposePerformanceMetrics;
+  }
+
   add (circuits) {
     if (!circuits) {
       return;
@@ -50,7 +59,8 @@ class PrometheusMetrics {
           this._counter.labels(circuit.name, eventName).inc();
         });
 
-        if (eventName === 'success' || eventName === 'failure') {
+        if (this.exposePerformanceMetrics() &&
+          (eventName === 'success' || eventName === 'failure')) {
           // not the timeout event because runtime == timeout
           circuit.on(eventName, (result, runTime) => {
             this._summary.labels(circuit.name, eventName).observe(runTime);

diff --git a/test/prometheus-test.js b/test/prometheus-test.js
@@ -274,3 +274,48 @@ test('Node.js specific metrics are enabled', t => {
   prometheus.clear();
   t.end();
 });
+
+test('Performance metrics are not created when disabled',
+  async t => {
+    t.plan(3);
+    const c1 = new CircuitBreaker(passFail, { name: 'fred' });
+    const prometheus = new PrometheusMetrics({
+      circuits: [c1],
+      exposePerformanceMetrics: false
+    });
+    await c1.fire(1);
+    t.equal(c1.name, 'fred');
+    t.ok(/circuit.*fred/.test(prometheus.metrics));
+    t.notOk(/circuit_perf.*fred/.test(prometheus.metrics));
+    prometheus.clear();
+    t.end();
+  });
+
+test('Performance metrics are created when not configured in options',
+  async t => {
+    t.plan(3);
+    const c1 = new CircuitBreaker(passFail, { name: 'fred' });
+    const prometheus = new PrometheusMetrics({ circuits: [c1] });
+    await c1.fire(1);
+    t.equal(c1.name, 'fred');
+    t.ok(/circuit.*fred/.test(prometheus.metrics));
+    t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
+    prometheus.clear();
+    t.end();
+  });
+
+test('Performance metrics are created when enabled in options',
+  async t => {
+    t.plan(3);
+    const c1 = new CircuitBreaker(passFail, { name: 'fred' });
+    const prometheus = new PrometheusMetrics({
+      circuits: [c1],
+      exposePerformanceMetrics: true
+    });
+    await c1.fire(1);
+    t.equal(c1.name, 'fred');
+    t.ok(/circuit.*fred/.test(prometheus.metrics));
+    t.ok(/circuit_perf.*fred/.test(prometheus.metrics));
+    prometheus.clear();
+    t.end();
+  });