Separate context propagation (OTEP 66) (open-telemetry#769)

* feat: separate context propagation

.circleci/config.yml

@@ -40,7 +40,7 @@ mysql_service: &mysql_service
     MYSQL_ROOT_PASSWORD: rootpw
 
 cache_1: &cache_1
-  key: npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+  key: npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
   paths:
     - ./node_modules
     - ./package-lock.json
@@ -60,7 +60,7 @@ cache_1: &cache_1
     - packages/opentelemetry-plugin-dns/node_modules
 
 cache_2: &cache_2
-  key: npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+  key: npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
   paths:
     - packages/opentelemetry-plugin-grpc/node_modules
     - packages/opentelemetry-plugin-http/node_modules
@@ -95,10 +95,10 @@ node_unit_tests: &node_unit_tests
           echo "CIRCLE_NODE_VERSION=${CIRCLE_NODE_VERSION}"
     - restore_cache:
         keys:
-          - npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+          - npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
     - restore_cache:
         keys:
-          - npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+          - npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
     - run:
         name: Install Root Dependencies
         command: npm install --ignore-scripts
@@ -135,10 +135,10 @@ browsers_unit_tests: &browsers_unit_tests
           echo "CIRCLE_NODE_VERSION=${CIRCLE_NODE_VERSION}"
     - restore_cache:
         keys:
-          - npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+          - npm-cache-01-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
     - restore_cache:
         keys:
-          - npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-FDF2088C
+          - npm-cache-02-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/checksums.txt" }}-F267A71D
     - run:
         name: Install Root Dependencies
         command: npm install --ignore-scripts
@@ -160,6 +160,8 @@ jobs:
   lint_&_docs:
     docker:
       - image: node:12
+        environment:
+          NPM_CONFIG_UNSAFE_PERM: true
     steps:
       - checkout
       - run:
@@ -171,6 +173,9 @@ jobs:
       - run:
           name: Check code style and linting
           command: npm run check
+      - run:
+          name: Install API dependencies
+          command: lerna bootstrap --scope @opentelemetry/api --include-filtered-dependencies
       - run:
           name: Docs tests
           command: npm run docs-test

packages/opentelemetry-api/package.json

@@ -45,6 +45,9 @@
   "publishConfig": {
     "access": "public"
   },
+  "dependencies": {
+    "@opentelemetry/scope-base": "^0.4.0"
+  },
   "devDependencies": {
     "@types/mocha": "^5.2.7",
     "@types/node": "^12.6.8",

packages/opentelemetry-api/src/context/propagation/HttpTextFormat.ts

@@ -14,40 +14,35 @@
  * limitations under the License.
  */
 
-import { SpanContext } from '../../trace/span_context';
+import { Context } from '@opentelemetry/scope-base';
 import { Carrier } from './carrier';
 
 /**
- * Injects and extracts a value as text into carriers that travel in-band
- * across process boundaries. Encoding is expected to conform to the HTTP
+ * Injects {@link Context} into and extracts it from carriers that travel
+ * in-band across process boundaries. Encoding is expected to conform to the HTTP
  * Header Field semantics. Values are often encoded as RPC/HTTP request headers.
  *
  * The carrier of propagated data on both the client (injector) and server
- * (extractor) side is usually an http request. Propagation is usually
- * implemented via library- specific request interceptors, where the
- * client-side injects values and the server-side extracts them.
+ * (extractor) side is usually an object such as http headers.
  */
 export interface HttpTextFormat {
   /**
-   * Injects the given {@link SpanContext} instance to transmit over the wire.
+   * Injects values from a given {@link Context} into a carrier.
    *
    * OpenTelemetry defines a common set of format values (BinaryFormat and
    * HTTPTextFormat), and each has an expected `carrier` type.
    *
-   * @param spanContext the SpanContext to transmit over the wire.
-   * @param format the format of the carrier.
+   * @param context the Context from which to extract values to transmit over the wire.
    * @param carrier the carrier of propagation fields, such as http request headers.
    */
-  inject(spanContext: SpanContext, format: string, carrier: Carrier): void;
+  inject(context: Context, carrier: Carrier): void;
 
   /**
-   * Returns a {@link SpanContext} instance extracted from `carrier` in the
-   * given format from upstream.
+   * Given a {@link Context} and a carrier, extract context values from a carrier and
+   * return a new context, created from the old context, with the extracted values.
    *
-   * @param format the format of the carrier.
+   * @param context the Context from which to extract values to transmit over the wire.
    * @param carrier the carrier of propagation fields, such as http request headers.
-   * @returns SpanContext The extracted SpanContext, or null if no such
-   *     SpanContext could be found in carrier.
    */
-  extract(format: string, carrier: Carrier): SpanContext | null;
+  extract(context: Context, carrier: Carrier): Context;
 }

packages/opentelemetry-api/src/context/propagation/NoopHttpTextFormat.ts

@@ -14,19 +14,19 @@
  * limitations under the License.
  */
 
-import { SpanContext } from '../../trace/span_context';
+import { Context } from '@opentelemetry/scope-base';
 import { Carrier } from './carrier';
 import { HttpTextFormat } from './HttpTextFormat';
 
 /**
  * No-op implementations of {@link HttpTextFormat}.
  */
 export class NoopHttpTextFormat implements HttpTextFormat {
-  // By default does nothing
-  inject(spanContext: SpanContext, format: string, carrier: Carrier): void {}
-  // By default does nothing
-  extract(format: string, carrier: Carrier): SpanContext | null {
-    return null;
+  /** Noop inject function does nothing */
+  inject(context: Context, carrier: Carrier): void {}
+  /** Noop extract function does nothing and returns the input context */
+  extract(context: Context, carrier: Carrier): Context {
+    return context;
   }
 }
 

packages/opentelemetry-api/src/index.ts

@@ -46,6 +46,8 @@ export * from './trace/NoopTracerProvider';
 export * from './metrics/NoopMeterProvider';
 export * from './metrics/NoopMeter';
 
+export { Context } from '@opentelemetry/scope-base';
+
 import { TraceAPI } from './api/trace';
 /** Entrypoint for trace API */
 export const trace = TraceAPI.getInstance();

packages/opentelemetry-api/test/noop-implementations/noop-tracer.test.ts

@@ -16,6 +16,7 @@
 
 import * as assert from 'assert';
 import { NoopTracer, NOOP_SPAN, SpanKind } from '../../src';
+import { Context } from '@opentelemetry/scope-base';
 
 describe('NoopTracer', () => {
   it('should not crash', () => {
@@ -38,8 +39,12 @@ describe('NoopTracer', () => {
     assert.deepStrictEqual(tracer.getCurrentSpan(), NOOP_SPAN);
     const httpTextFormat = tracer.getHttpTextFormat();
     assert.ok(httpTextFormat);
-    httpTextFormat.inject(spanContext, 'HttpTextFormat', {});
-    assert.deepStrictEqual(httpTextFormat.extract('HttpTextFormat', {}), null);
+
+    httpTextFormat.inject(Context.ROOT_CONTEXT, {});
+    assert.deepStrictEqual(
+      httpTextFormat.extract(Context.ROOT_CONTEXT, {}),
+      Context.ROOT_CONTEXT
+    );
 
     const binaryFormat = tracer.getBinaryFormat();
     assert.ok(binaryFormat);

packages/opentelemetry-core/package.json

@@ -79,6 +79,7 @@
   },
   "dependencies": {
     "@opentelemetry/api": "^0.4.0",
+    "@opentelemetry/scope-base": "^0.4.0",
     "semver": "^6.3.0"
   }
 }

packages/opentelemetry-core/src/context/context.ts

@@ -0,0 +1,83 @@
+/*!
+ * Copyright 2020, OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Span, SpanContext } from '@opentelemetry/api';
+import { Context } from '@opentelemetry/scope-base';
+
+const ACTIVE_SPAN_KEY = Context.createKey(
+  'OpenTelemetry Context Key ACTIVE_SPAN'
+);
+const EXTRACTED_SPAN_CONTEXT_KEY = Context.createKey(
+  'OpenTelemetry Context Key EXTRACTED_SPAN_CONTEXT'
+);
+
+/**
+ * Return the active span if one exists
+ *
+ * @param context context to get span from
+ */
+export function getActiveSpan(context: Context): Span | undefined {
+  return (context.getValue(ACTIVE_SPAN_KEY) as Span) || undefined;
+}
+
+/**
+ * Set the active span on a context
+ *
+ * @param context context to use as parent
+ * @param span span to set active
+ */
+export function setActiveSpan(context: Context, span: Span): Context {
+  return context.setValue(ACTIVE_SPAN_KEY, span);
+}
+
+/**
+ * Get the extracted span context from a context
+ *
+ * @param context context to get span context from
+ */
+export function getExtractedSpanContext(
+  context: Context
+): SpanContext | undefined {
+  return (
+    (context.getValue(EXTRACTED_SPAN_CONTEXT_KEY) as SpanContext) || undefined
+  );
+}
+
+/**
+ * Set the extracted span context on a context
+ *
+ * @param context context to set span context on
+ * @param spanContext span context to set
+ */
+export function setExtractedSpanContext(
+  context: Context,
+  spanContext: SpanContext
+): Context {
+  return context.setValue(EXTRACTED_SPAN_CONTEXT_KEY, spanContext);
+}
+
+/**
+ * Get the span context of the parent span if it exists,
+ * or the extracted span context if there is no active
+ * span.
+ *
+ * @param context context to get values from
+ */
+export function getParentSpanContext(
+  context: Context
+): SpanContext | undefined {
+  return getActiveSpan(context)?.context() || getExtractedSpanContext(context);
+}

packages/opentelemetry-core/src/context/propagation/B3Format.ts

@@ -16,10 +16,11 @@
 
 import {
   Carrier,
+  Context,
   HttpTextFormat,
-  SpanContext,
   TraceFlags,
 } from '@opentelemetry/api';
+import { getParentSpanContext, setExtractedSpanContext } from '../context';
 
 export const X_B3_TRACE_ID = 'x-b3-traceid';
 export const X_B3_SPAN_ID = 'x-b3-spanid';
@@ -41,7 +42,10 @@ function isValidSpanId(spanId: string): boolean {
  * Based on: https://github.com/openzipkin/b3-propagation
  */
 export class B3Format implements HttpTextFormat {
-  inject(spanContext: SpanContext, format: string, carrier: Carrier): void {
+  inject(context: Context, carrier: Carrier) {
+    const spanContext = getParentSpanContext(context);
+    if (!spanContext) return;
+
     if (
       isValidTraceId(spanContext.traceId) &&
       isValidSpanId(spanContext.spanId)
@@ -57,11 +61,11 @@ export class B3Format implements HttpTextFormat {
     }
   }
 
-  extract(format: string, carrier: Carrier): SpanContext | null {
+  extract(context: Context, carrier: Carrier): Context {
     const traceIdHeader = carrier[X_B3_TRACE_ID];
     const spanIdHeader = carrier[X_B3_SPAN_ID];
     const sampledHeader = carrier[X_B3_SAMPLED];
-    if (!traceIdHeader || !spanIdHeader) return null;
+    if (!traceIdHeader || !spanIdHeader) return context;
     const traceId = Array.isArray(traceIdHeader)
       ? traceIdHeader[0]
       : traceIdHeader;
@@ -71,15 +75,15 @@ export class B3Format implements HttpTextFormat {
       : sampledHeader;
 
     if (isValidTraceId(traceId) && isValidSpanId(spanId)) {
-      return {
+      return setExtractedSpanContext(context, {
         traceId,
         spanId,
         isRemote: true,
         traceFlags: isNaN(Number(options))
           ? TraceFlags.UNSAMPLED
           : Number(options),
-      };
+      });
     }
-    return null;
+    return context;
   }
 }

packages/opentelemetry-core/src/context/propagation/HttpTraceContext.ts

@@ -16,11 +16,13 @@
 
 import {
   Carrier,
+  Context,
   HttpTextFormat,
   SpanContext,
   TraceFlags,
 } from '@opentelemetry/api';
 import { TraceState } from '../../trace/TraceState';
+import { getParentSpanContext, setExtractedSpanContext } from '../context';
 
 export const TRACE_PARENT_HEADER = 'traceparent';
 export const TRACE_STATE_HEADER = 'tracestate';
@@ -61,7 +63,10 @@ export function parseTraceParent(traceParent: string): SpanContext | null {
  * https://www.w3.org/TR/trace-context/
  */
 export class HttpTraceContext implements HttpTextFormat {
-  inject(spanContext: SpanContext, format: string, carrier: Carrier) {
+  inject(context: Context, carrier: Carrier) {
+    const spanContext = getParentSpanContext(context);
+    if (!spanContext) return;
+
     const traceParent = `${VERSION}-${spanContext.traceId}-${
       spanContext.spanId
     }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
@@ -72,14 +77,14 @@ export class HttpTraceContext implements HttpTextFormat {
     }
   }
 
-  extract(format: string, carrier: Carrier): SpanContext | null {
+  extract(context: Context, carrier: Carrier): Context {
     const traceParentHeader = carrier[TRACE_PARENT_HEADER];
-    if (!traceParentHeader) return null;
+    if (!traceParentHeader) return context;
     const traceParent = Array.isArray(traceParentHeader)
       ? traceParentHeader[0]
       : traceParentHeader;
     const spanContext = parseTraceParent(traceParent);
-    if (!spanContext) return null;
+    if (!spanContext) return context;
 
     spanContext.isRemote = true;
 
@@ -92,6 +97,6 @@ export class HttpTraceContext implements HttpTextFormat {
         : traceStateHeader;
       spanContext.traceState = new TraceState(state as string);
     }
-    return spanContext;
+    return setExtractedSpanContext(context, spanContext);
   }
 }

packages/opentelemetry-core/src/index.ts

@@ -19,6 +19,7 @@ export * from './common/NoopLogger';
 export * from './common/time';
 export * from './common/types';
 export * from './version';
+export * from './context/context';
 export * from './context/propagation/B3Format';
 export * from './context/propagation/BinaryTraceContext';
 export * from './context/propagation/HttpTraceContext';