Adds type definitions for 'jaeger-client' (#35796)

Adds type definitions and tests
Adds package configuration for external types
Adds tsconfig and tslint config
Adds target Typescript version header to support 'opentracing' external types

types/jaeger-client/index.d.ts

@@ -0,0 +1,90 @@
+// Type definitions for jaeger-client 3.15
+// Project: https://github.com/jaegertracing/jaeger-client-node#readme
+// Definitions by: jgeth <https://github.com/jgeth>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.1
+
+// opentracing requires typescript version ^2.1
+import * as opentracing from "opentracing";
+import * as prometheus from "prom-client";
+
+// Counter tracks the number of times an event has occurred
+export interface Counter {
+    // Adds the given value to the counter.
+    increment(delta: number): void;
+}
+
+// Gauge returns instantaneous measurements of something as an int64 value
+export interface Gauge {
+    // Update the gauge to the value passed in.
+    update(value: number): void;
+}
+
+export interface Logger {
+    info(msg: string): void;
+    error(msg: string): void;
+}
+
+export interface MetricsFactory {
+    createCounter(name: string, tags: any): Counter;
+    createTimer(name: string, tags: any): Timer;
+    createGauge(name: string, tags: any): Gauge;
+}
+
+export interface Reporter {
+    // TODO: use span type opentracing.Span from package 'opentracing' which fails DTS linting on import 2019-05-28 jgeth
+    report(span: opentracing.Span): void;
+    close(callback?: () => void): void;
+    setProcess(serviceName: string, tags: any): void;
+}
+
+export interface ReporterConfig {
+    logSpans?: boolean;
+    agentHost?: string;
+    agentPort?: number;
+    flushIntervalMs?: number;
+}
+
+export interface SamplerConfig {
+    type: string;
+    param: number;
+    host?: string;
+    port?: number;
+    refreshIntervalMs?: number;
+}
+
+// Timer tracks how long an operation took and also computes percentiles.
+export interface Timer {
+    // Records the time passed in.
+    record(value: number): void;
+}
+
+export interface TracingConfig {
+    serviceName?: string;
+    disable?: boolean;
+    sampler?: SamplerConfig;
+    reporter?: ReporterConfig;
+}
+
+export interface TracingOptions {
+    reporter?: Reporter;
+    metrics?: PrometheusMetricsFactory;
+    logger?: Logger;
+    tags?: any;
+}
+
+export function initTracer(
+    tracingConfig: TracingConfig,
+    tracingOptions: TracingOptions
+): opentracing.Tracer;
+
+export function initTracerFromEnv(
+    tracingConfig: TracingConfig,
+    tracingOptions: TracingOptions
+): opentracing.Tracer;
+
+export class PrometheusMetricsFactory {
+    constructor(client: typeof prometheus, serviceName: string);
+    createCounter(name: string, tags: {}): Counter;
+    createGauge(name: string, tags: {}): Gauge;
+}

types/jaeger-client/jaeger-client-tests.ts

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+import * as jaegerClient from "jaeger-client";
+import * as promClient from "prom-client";
+
+const tracingConfig: jaegerClient.TracingConfig = {};
+const tracingOptions: jaegerClient.TracingOptions = {};
+
+jaegerClient.initTracer(tracingConfig, tracingOptions);
+jaegerClient.initTracerFromEnv(tracingConfig, tracingOptions);
+
+const metrics = new jaegerClient.PrometheusMetricsFactory(promClient, "foo");

types/jaeger-client/package.json

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+{
+    "private": true,
+    "dependencies": {
+        "opentracing": "~0.14.3",
+        "prom-client": "~11.3.0"
+    }
+}

types/jaeger-client/tsconfig.json

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+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": ["es6"],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictFunctionTypes": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": ["../"],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": ["index.d.ts", "jaeger-client-tests.ts"]
+}

types/jaeger-client/tslint.json

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+{ "extends": "dtslint/dt.json" }