From e00de102d16bb86b840df37c14dc73b9fc6a4a02 Mon Sep 17 00:00:00 2001
From: Abhijeet Prasad <aprasad@sentry.io>
Date: Wed, 2 Nov 2022 12:30:50 +0100
Subject: [PATCH] feat(otel): Add base SentryPropagator class (#6109)

---
 packages/opentelemetry-node/src/constants.ts  |  3 ++
 packages/opentelemetry-node/src/index.ts      |  1 +
 packages/opentelemetry-node/src/propagator.ts | 29 +++++++++++++++++++
 .../test/propagator.test.ts                   | 10 +++++++
 4 files changed, 43 insertions(+)
 create mode 100644 packages/opentelemetry-node/src/constants.ts
 create mode 100644 packages/opentelemetry-node/src/propagator.ts
 create mode 100644 packages/opentelemetry-node/test/propagator.test.ts

diff --git a/packages/opentelemetry-node/src/constants.ts b/packages/opentelemetry-node/src/constants.ts
new file mode 100644
index 000000000000..5c179dc5335b
--- /dev/null
+++ b/packages/opentelemetry-node/src/constants.ts
@@ -0,0 +1,3 @@
+export const SENTRY_TRACE_HEADER = 'sentry-trace';
+
+export const SENTRY_BAGGAGE_HEADER = 'baggage';
diff --git a/packages/opentelemetry-node/src/index.ts b/packages/opentelemetry-node/src/index.ts
index 21b5f209d3a8..501c93432b44 100644
--- a/packages/opentelemetry-node/src/index.ts
+++ b/packages/opentelemetry-node/src/index.ts
@@ -1,3 +1,4 @@
 import '@sentry/tracing';
 
 export { SentrySpanProcessor } from './spanprocessor';
+export { SentryPropagator } from './propagator';
diff --git a/packages/opentelemetry-node/src/propagator.ts b/packages/opentelemetry-node/src/propagator.ts
new file mode 100644
index 000000000000..897cc8819e33
--- /dev/null
+++ b/packages/opentelemetry-node/src/propagator.ts
@@ -0,0 +1,29 @@
+import { Context, TextMapGetter, TextMapPropagator, TextMapSetter } from '@opentelemetry/api';
+
+import { SENTRY_BAGGAGE_HEADER, SENTRY_TRACE_HEADER } from './constants';
+
+/**
+ * Injects and extracts `sentry-trace` and `baggage` headers from carriers.
+ */
+export class SentryPropagator implements TextMapPropagator {
+  /**
+   * @inheritDoc
+   */
+  public inject(_context: Context, _carrier: unknown, _setter: TextMapSetter): void {
+    // no-op
+  }
+
+  /**
+   * @inheritDoc
+   */
+  public extract(context: Context, _carrier: unknown, _getter: TextMapGetter): Context {
+    return context;
+  }
+
+  /**
+   * @inheritDoc
+   */
+  public fields(): string[] {
+    return [SENTRY_TRACE_HEADER, SENTRY_BAGGAGE_HEADER];
+  }
+}
diff --git a/packages/opentelemetry-node/test/propagator.test.ts b/packages/opentelemetry-node/test/propagator.test.ts
new file mode 100644
index 000000000000..62311a586b6c
--- /dev/null
+++ b/packages/opentelemetry-node/test/propagator.test.ts
@@ -0,0 +1,10 @@
+import { SENTRY_BAGGAGE_HEADER, SENTRY_TRACE_HEADER } from '../src/constants';
+import { SentryPropagator } from '../src/propagator';
+
+describe('SentryPropagator', () => {
+  const propogator = new SentryPropagator();
+
+  it('returns fields set', () => {
+    expect(propogator.fields()).toEqual([SENTRY_TRACE_HEADER, SENTRY_BAGGAGE_HEADER]);
+  });
+});