first commit

.env

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+OTEL_SERVICE_NAME="my-app"
+OTEL_NODE_DISABLED_INSTRUMENTATIONS="fs"

.gitignore

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+node_modules/

.mocharc.json

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+{
+  "node-option": ["experimental-specifier-resolution=node", "loader=ts-node/esm"],
+  "timeout": 10000
+}

README.md

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+# Opetelemetry decorator
+
+This package provides a set of decorators to instrument your code.
+
+- _WithTracer_: Optionaly set the tracer name to for retrieving the tracer from the global tracer provider `trace.getTracer`
+- _WithSpan_: Wrap the decorated function with a new span using `tracer.startActiveSpan`
+- _SpanAttribute_: Will add the dedcorated parameter to the span attributes
+
+If you do not understand what is going on, please read the [OpenTelemetry documentation](https://opentelemetry.io/docs/instrumentation/js/).
+
+## Basic usage
+
+```ts
+@WithTracer(mypkg)
+export class MyClass {
+  constructor() {}
+
+  @WithSpan({
+    spanName: "customSpanName",
+    recordException: false,
+    setErrorStatusOnException: false,
+    setOkStatusOnSuccess: false,
+  })
+  public static async aStaticMethod(@SpanAttribute("arg1") arg: string, @SpanAttribute("arg2") arg2: number) {
+    console.log("inside aStaticMethod");
+    return arg + arg2;
+  }
+
+  @WithSpan()
+  public aMethod(arg: string, arg2: number) {
+    console.log("inside aMethod");
+    const span = arguments[arguments.length - 1] as Span;
+    span.setAttribute("custom.inner.attribute", arg + arg2);
+    return arg + arg2;
+  }
+}
+```
+
+## Testing
+
+Run jaeger all in one
+
+```bash
+docker run -d --name jaeger-aio \
+      -e COLLECTOR_ZIPKIN_HOST_PORT=:9411 \
+      -p 6831:6831/udp \
+      -p 6832:6832/udp \
+      -p 5778:5778 \
+      -p 16686:16686 \
+      -p 4317:4317 \
+      -p 4318:4318 \
+      -p 14250:14250 \
+      -p 14268:14268 \
+      -p 14269:14269 \
+      -p 9411:9411 \
+      jaegertracing/all-in-one:1.60
+```
+
+Run the example
+
+```bash
+node --inspect --loader ts-node/esm -r '@opentelemetry/auto-instrumentations-node/register' ./example.ts
+```

example.ts

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+import { diag, Span, SpanOptions, SpanStatusCode, trace } from "@opentelemetry/api";
+import { SpanAttribute, WithSpan, WithTracer } from "./src/lib.js";
+
+const mypkg = process.env.OTEL_SERVICE_NAME ?? "testing-otel-decorator";
+
+@WithTracer(mypkg)
+export class MyClass {
+  constructor() {}
+
+  @WithSpan()
+  public static async aStaticMethod(@SpanAttribute("arg1") arg: string, @SpanAttribute("arg2") arg2: number) {
+    console.log("inside aStaticMethod");
+    return arg + arg2;
+  }
+
+  @WithSpan()
+  public aMethod(arg: string, arg2: number) {
+    console.log("inside aMethod");
+    const span = arguments[arguments.length - 1] as Span;
+    span.setAttribute("custom.inner.attribute", arg + arg2);
+    return arg + arg2;
+  }
+
+  @WithSpan()
+  public async aAsyncMethod(@SpanAttribute("arg1") arg: string, @SpanAttribute("arg2") arg2: number) {
+    console.log("inside aAsyncMethod");
+    return new Promise((resolve) => {
+      setTimeout(() => {
+        resolve(arg + arg2);
+      }, 1000);
+    });
+  }
+
+  @WithSpan({ spanName: "customSpanName" })
+  public async anAsyncMethodWithError() {
+    console.log("inside anAsyncMethodWithError");
+    return new Promise((resolve, reject) => {
+      setTimeout(() => {
+        reject("or nah");
+        ("this a very bad error");
+      }, 5000);
+    });
+  }
+}
+
+trace.getTracer("main").startActiveSpan("mainSpan", async (span: Span) => {
+  try {
+    const myInstance = new MyClass();
+    console.log(`#### calling aAsyncMethod`);
+    const resultAsync = await myInstance.aAsyncMethod("test", 123);
+    console.log(`result ${resultAsync}`);
+    console.log(`#### calling aMethod`);
+    const r1 = myInstance.aMethod("test", 123);
+    console.log(`result ${r1}`);
+    console.log(`#### calling aStaticMethod`);
+    const r2 = await MyClass.aStaticMethod("test", 123);
+    console.log(`result ${r2}`);
+    const r3 = await myInstance.anAsyncMethodWithError();
+    console.log(`result ${r3}`);
+  } finally {
+    span.end();
+  }
+});