Merge pull request #484 from JulienFauvel/fix/metric-annotation-wrong…

…ly-typed

fix: fix/metric annotation wrongly typed

src/metrics/decorators/index.ts

@@ -1,4 +1,2 @@
 export * from './common';
-export * from './counter';
-export * from './histogram';
-export * from './observable';
+export * from './param';

src/metrics/decorators/param.ts

@@ -0,0 +1,49 @@
+import { createParamDecorator } from '@nestjs/common';
+import { OtelMetricOptions } from '../../interfaces/metric-options.interface';
+import {
+  getOrCreateCounter,
+  getOrCreateHistogram,
+  getOrCreateObservableCounter,
+  getOrCreateObservableGauge,
+  getOrCreateObservableUpDownCounter,
+} from '../metric-data';
+
+export type MetricParamDecorator = (
+  name: string,
+  options?: OtelMetricOptions
+) => ParameterDecorator;
+
+function createMetricParamDecorator<T>(
+  type: string,
+  getOrCreateMetric: (name: string, options?: OtelMetricOptions) => T
+): MetricParamDecorator {
+  return (name: string, options?: OtelMetricOptions): ParameterDecorator => {
+    return createParamDecorator(() => {
+      if (!name || name.length === 0) {
+        throw new Error(`${type} need a name argument`);
+      }
+      return getOrCreateMetric(name, options);
+    })();
+  };
+}
+
+export const OtelCounter = createMetricParamDecorator('OtelCounter', getOrCreateCounter);
+export const OtelUpDownCounter = createMetricParamDecorator(
+  'OtelUpDownCounter',
+  getOrCreateCounter
+);
+
+export const OtelHistogram = createMetricParamDecorator('OtelHistogram', getOrCreateHistogram);
+
+export const OtelObservableGauge = createMetricParamDecorator(
+  'OtelObservableGauge',
+  getOrCreateObservableGauge
+);
+export const OtelObservableCounter = createMetricParamDecorator(
+  'OtelObservableCounter',
+  getOrCreateObservableCounter
+);
+export const OtelObservableUpDownCounter = createMetricParamDecorator(
+  'OtelObservableUpDownCounter',
+  getOrCreateObservableUpDownCounter
+);

tests/e2e/metrics/decorators/common.spec.ts

@@ -15,8 +15,9 @@ describe('Common Decorators', () => {
 
   beforeEach(done => {
     exporter = new PrometheusExporter({}, () => {
-      meterProvider = new MeterProvider();
-      meterProvider.addMetricReader(exporter);
+      meterProvider = new MeterProvider({
+        readers: [exporter],
+      });
       metrics.setGlobalMeterProvider(meterProvider);
       done();
     });
@@ -34,7 +35,7 @@ describe('Common Decorators', () => {
     }
   });
 
-  describe('Instance counter & Method counter', () => {
+  describe('Instance counter, method counter & param counter', () => {
     it('creates an instance counter and increase counter when new instance is created', async () => {
       const testingModule = await Test.createTestingModule({
         imports: [
@@ -61,6 +62,9 @@ describe('Common Decorators', () => {
 
       expect(/app_AppController_instances_total 1/.test(text)).toBeTruthy();
       expect(/app_AppController_example_calls_total 1/.test(text)).toBeTruthy();
+
+      expect(/# HELP example_counter_total An example counter/.test(text)).toBeTruthy();
+      expect(/example_counter_total 1/.test(text)).toBeTruthy();
     });
   });
 });

tests/fixture-app/app.controller.ts

@@ -1,5 +1,7 @@
 import { Get, Controller } from '@nestjs/common';
+import { Counter } from '@opentelemetry/api';
 import { OtelInstanceCounter, OtelMethodCounter } from '../../src/metrics/decorators/common';
+import { OtelCounter } from '../../src/metrics/decorators/param';
 
 @OtelInstanceCounter()
 @Controller('example')
@@ -11,7 +13,8 @@ export class AppController {
 
   @Get(':id')
   @OtelMethodCounter()
-  example() {
+  example(@OtelCounter('example_counter', { description: 'An example counter' }) counter: Counter) {
+    counter.add(1);
     return 'example';
   }
 }