feat: push impact metrics (#742)

Author: sighphyre

.eslintrc

@@ -20,6 +20,7 @@
         "ignoreUrls": true
       }
     ],
+    "@typescript-eslint/no-unused-vars": ["error", { "argsIgnorePattern": "^_" }],
     "class-methods-use-this": "off"
   },
   "settings": {

src/impact-metrics/metric-client.ts

@@ -1,57 +1,5 @@
 import { Unleash } from '../unleash';
 
-function forwardMethods<T extends object>(target: T, source: T, methodNames: (keyof T)[]) {
-  for (const name of methodNames) {
-    // @ts-ignore
-    target[name] = (...args: any[]) => source[name](...args);
-  }
-}
-
-export class UnleashMetricClient {
-  private backingInstance: Unleash;
-
-  constructor(unleash: Unleash) {
-    this.backingInstance = unleash;
-    forwardMethods(this, this.backingInstance as any, [
-      'isEnabled',
-      'getVariant',
-      'forceGetVariant',
-      'getFeatureToggleDefinition',
-      'getFeatureToggleDefinitions',
-      'count',
-      'countVariant',
-      'flushMetrics',
-      'destroyWithFlush',
-      'on',
-      'start',
-      'destroy',
-      'isSynchronized',
-    ]);
-  }
-
-  isEnabled!: Unleash['isEnabled'];
-
-  getVariant!: Unleash['getVariant'];
-
-  forceGetVariant!: Unleash['forceGetVariant'];
-
-  getFeatureToggleDefinition!: Unleash['getFeatureToggleDefinition'];
-
-  getFeatureToggleDefinitions!: Unleash['getFeatureToggleDefinitions'];
-
-  count!: Unleash['count'];
-
-  countVariant!: Unleash['countVariant'];
-
-  flushMetrics!: Unleash['flushMetrics'];
-
-  destroyWithFlush!: Unleash['destroyWithFlush'];
-
-  on!: Unleash['on'];
-
-  start!: Unleash['start'];
-
-  destroy!: Unleash['destroy'];
-
-  isSynchronized!: Unleash['isSynchronized'];
+export class UnleashMetricClient extends Unleash {
+  // empty for now, we'll use this to add in the public API for metrics later
 }

src/impact-metrics/metric-types.ts

@@ -53,6 +53,8 @@ class CounterImpl implements Counter {
       value,
     }));
 
+    this.values.clear();
+
     return {
       name: this.opts.name,
       help: this.opts.help,
@@ -92,6 +94,8 @@ class GaugeImpl implements Gauge {
       value,
     }));
 
+    this.values.clear();
+
     return {
       name: this.opts.name,
       help: this.opts.help,
@@ -113,7 +117,12 @@ export interface Gauge {
   set(value: number, labels?: MetricLabels): void;
 }
 
-export class ImpactMetricRegistry {
+export interface ImpactMetricRegistry {
+  collect(): CollectedMetric[];
+  restore(metrics: CollectedMetric[]): void;
+}
+
+export class InMemoryMetricRegistry implements ImpactMetricRegistry {
   private counters = new Map<string, Counter & CollectibleMetric>();
 
   private gauges = new Map<string, Gauge & CollectibleMetric>();
@@ -137,7 +146,32 @@ export class ImpactMetricRegistry {
   collect(): CollectedMetric[] {
     const allCounters = [...this.counters.values()].map((c) => c.collect());
     const allGauges = [...this.gauges.values()].map((g) => g.collect());
-    return [...allCounters, ...allGauges];
+    const allMetrics = [...allCounters, ...allGauges];
+
+    const nonEmpty = allMetrics.filter((metric) => metric.samples.length > 0);
+    return nonEmpty.length > 0 ? nonEmpty : [];
+  }
+
+  restore(metrics: CollectedMetric[]): void {
+    for (const metric of metrics) {
+      switch (metric.type) {
+        case 'counter': {
+          const counter = this.counter({ name: metric.name, help: metric.help });
+          for (const sample of metric.samples) {
+            counter.inc(sample.value, sample.labels);
+          }
+          break;
+        }
+
+        case 'gauge': {
+          const gauge = this.gauge({ name: metric.name, help: metric.help });
+          for (const sample of metric.samples) {
+            gauge.set(sample.value, sample.labels);
+          }
+          break;
+        }
+      }
+    }
   }
 }
 

src/metric-client.ts

@@ -7,6 +7,7 @@ import { suffixSlash, resolveUrl } from './url-utils';
 import { UnleashEvents } from './events';
 import { getAppliedJitter } from './helpers';
 import { SUPPORTED_SPEC_VERSION } from './repository';
+import { CollectedMetric, ImpactMetricRegistry } from './impact-metrics/metric-types';
 
 export interface MetricsOptions {
   appName: string;
@@ -21,6 +22,7 @@ export interface MetricsOptions {
   customHeadersFunction?: CustomHeadersFunction;
   timeout?: number;
   httpOptions?: HttpOptions;
+  metricRegistry?: ImpactMetricRegistry;
 }
 
 interface VariantBucket {
@@ -66,6 +68,7 @@ interface BaseMetricsData {
 
 interface MetricsData extends BaseMetricsData {
   bucket: Bucket;
+  impactMetrics?: CollectedMetric[];
 }
 
 interface RegistrationData extends BaseMetricsData {
@@ -112,6 +115,8 @@ export default class Metrics extends EventEmitter {
 
   private platformData: PlatformData;
 
+  private metricRegistry?: ImpactMetricRegistry;
+
   constructor({
     appName,
     instanceId,
@@ -125,6 +130,7 @@ export default class Metrics extends EventEmitter {
     customHeadersFunction,
     timeout,
     httpOptions,
+    metricRegistry,
   }: MetricsOptions) {
     super();
     this.disabled = disableMetrics;
@@ -143,6 +149,7 @@ export default class Metrics extends EventEmitter {
     this.bucket = this.createBucket();
     this.httpOptions = httpOptions;
     this.platformData = this.getPlatformData();
+    this.metricRegistry = metricRegistry;
   }
 
   private getAppliedJitter(): number {
@@ -241,13 +248,16 @@ export default class Metrics extends EventEmitter {
     if (this.disabled) {
       return;
     }
-    if (this.bucketIsEmpty()) {
+    const impactMetrics = this.metricRegistry?.collect() || [];
+
+    if (this.bucketIsEmpty() && impactMetrics.length === 0) {
       this.resetBucket();
       this.startTimer();
+      this.metricRegistry?.restore(impactMetrics);
       return;
     }
     const url = resolveUrl(suffixSlash(this.url), './client/metrics');
-    const payload = this.createMetricsData();
+    const payload = this.createMetricsData(impactMetrics);
 
     const headers = this.customHeadersFunction ? await this.customHeadersFunction() : this.headers;
 
@@ -277,12 +287,14 @@ export default class Metrics extends EventEmitter {
           this.backoff(url, res.status);
         }
         this.restoreBucket(payload.bucket);
+        this.metricRegistry?.restore(impactMetrics);
       } else {
         this.emit(UnleashEvents.Sent, payload);
         this.reduceBackoff();
       }
     } catch (err) {
       this.restoreBucket(payload.bucket);
+      this.metricRegistry?.restore(impactMetrics);
       this.emit(UnleashEvents.Warn, err);
       this.startTimer();
     }
@@ -356,10 +368,11 @@ export default class Metrics extends EventEmitter {
     this.bucket = this.createBucket();
   }
 
-  createMetricsData(): MetricsData {
+  createMetricsData(impactMetrics: CollectedMetric[]): MetricsData {
     const bucket = { ...this.bucket, stop: new Date() };
     this.resetBucket();
-    return {
+
+    const base: MetricsData = {
       appName: this.appName,
       instanceId: this.instanceId,
       connectionId: this.connectionId,
@@ -369,6 +382,12 @@ export default class Metrics extends EventEmitter {
       yggdrasilVersion: null,
       specVersion: SUPPORTED_SPEC_VERSION,
     };
+
+    if (impactMetrics.length > 0) {
+      base.impactMetrics = impactMetrics;
+    }
+
+    return base;
   }
 
   private restoreBucket(bucket: Bucket): void {