Make Stackdriver propagation module consistent with other propagations interface (#436)

* Make Stackdriver propagation module consistent with other propagations

* fix review comments

1. Use replace instead of split-join
2. Add helperGetter function

Author: mayurkale22

packages/opencensus-propagation-stackdriver/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@opencensus/propagation-stackdriver",
   "version": "0.0.9",
-  "description": "",
+  "description": "Opencensus propagation package for Stackdriver format.",
   "main": "build/src/index.js",
   "types": "build/src/index.d.ts",
   "repository": "census-instrumentation/opencensus-node",
@@ -38,6 +38,7 @@
     "typescript": "~3.2.0"
   },
   "dependencies": {
+    "@opencensus/core": "^0.0.9",
     "hex2dec": "^1.0.1",
     "uuid": "^3.2.1"
   },

packages/opencensus-propagation-stackdriver/src/index.ts

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+export * from './stackdriver-format';
+
 import * as v1API from './v1';
 
 export interface SpanContext {
@@ -46,6 +48,11 @@ export interface Propagation {
   generate(): SpanContext;
 }
 
+/**
+ * @deprecated since version 0.0.10 - use {@link StackdriverFormat} instead
+ * All other propagation exports a class constructor, while Stackdriver v1
+ * propagation exports an implementation of Propagation.
+ */
 export const v1: Propagation = {
   extract: v1API.extract,
   inject: v1API.inject,

packages/opencensus-propagation-stackdriver/src/stackdriver-format.ts

@@ -0,0 +1,103 @@
+/**
+ * Copyright 2019 OpenCensus 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
+ *
+ *      http://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.
+ */
+
+/**
+ * This file implements propagation for the Stackdriver Trace v1 Trace Context
+ * format.
+ *
+ * The header specification is:
+ * "X-Cloud-Trace-Context: TRACE_ID/SPAN_ID;o=TRACE_TRUE"
+ * Where:
+ *  {TRACE_ID} is a 32-character hexadecimal value representing a 128-bit
+ *    number. It should be unique between your requests, unless you
+ *    intentionally want to bundle the requests together.
+ *  {SPAN_ID} is the decimal representation of the (unsigned) span ID. It
+ *    should be 0 for the first span in your trace. For subsequent requests,
+ *    set SPAN_ID to the span ID of the parent request.
+ *  {TRACE_TRUE} must be 1 to trace request. Specify 0 to not trace the request.
+ */
+
+import * as crypto from 'crypto';
+import {decToHex, hexToDec} from 'hex2dec';
+import * as uuid from 'uuid';
+import {HeaderGetter, HeaderSetter, Propagation, SpanContext} from './index';
+
+/** Header that carries span context across Google infrastructure. */
+export const TRACE_CONTEXT_HEADER_NAME = 'x-cloud-trace-context';
+const SPAN_ID_RANDOM_BYTES = 8;
+const TRACE_TRUE = 0x1;
+
+/** Propagates span context through Stackdriver Format propagation. */
+export class StackdriverFormat implements Propagation {
+  /**
+   * Gets the span context from a request headers. If there is no span context
+   * in the headers, null is returned.
+   * @param getter
+   */
+  extract(getter: HeaderGetter): SpanContext|null {
+    const traceContextHeader = getter.getHeader(TRACE_CONTEXT_HEADER_NAME);
+    if (typeof traceContextHeader !== 'string') {
+      return null;
+    }
+    const matches =
+        traceContextHeader.match(/^([0-9a-fA-F]+)(?:\/([0-9]+))(?:;o=(.*))?/);
+    if (!matches || matches.length !== 4 || matches[0] !== traceContextHeader ||
+        (matches[2] && isNaN(Number(matches[2])))) {
+      return null;
+    }
+    return {
+      traceId: matches[1],
+      // strip 0x prefix from hex output from decToHex, and and pad so it's
+      // always a length-16 hex string
+      spanId: `0000000000000000${decToHex(matches[2]).slice(2)}`.slice(-16),
+      options: isNaN(Number(matches[3])) ? TRACE_TRUE : Number(matches[3])
+    };
+  }
+
+  /**
+   * Adds a span context in a request headers.
+   * @param setter
+   * @param spanContext
+   */
+  inject(setter: HeaderSetter, spanContext: SpanContext): void {
+    let header = `${spanContext.traceId}/${hexToDec(spanContext.spanId)}`;
+    if (spanContext.options) {
+      header += `;o=${spanContext.options}`;
+    }
+
+    setter.setHeader(TRACE_CONTEXT_HEADER_NAME, header);
+  }
+
+  /** Generate SpanContexts */
+  generate(): SpanContext {
+    return {
+      traceId: uuid.v4().replace(/-/g, ''),
+      spanId: spanRandomBuffer().toString('hex'),
+      options: TRACE_TRUE
+    };
+  }
+}
+
+// Use the faster crypto.randomFillSync when available (Node 7+) falling back to
+// using crypto.randomBytes.
+// TODO(ofrobots): Use alternate logic for the browser where crypto and Buffer
+//    are not available.
+const spanIdBuffer = Buffer.alloc(SPAN_ID_RANDOM_BYTES);
+const randomFillSync = crypto.randomFillSync;
+const randomBytes = crypto.randomBytes;
+const spanRandomBuffer = randomFillSync ?
+    () => randomFillSync(spanIdBuffer) :
+    () => randomBytes(SPAN_ID_RANDOM_BYTES);

packages/opencensus-propagation-stackdriver/src/v1.ts

@@ -23,7 +23,6 @@
 import * as crypto from 'crypto';
 import {decToHex, hexToDec} from 'hex2dec';
 import * as uuid from 'uuid';
-
 import {HeaderGetter, HeaderSetter, SpanContext} from './index';
 
 const TRACE_CONTEXT_HEADER_NAME = 'x-cloud-trace-context';

packages/opencensus-propagation-stackdriver/test/test-stackdriver-format.ts

@@ -0,0 +1,129 @@
+/**
+ * Copyright 2019 OpenCensus 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
+ *
+ *      http://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 {HeaderGetter, HeaderSetter} from '@opencensus/core';
+import * as assert from 'assert';
+import {StackdriverFormat, TRACE_CONTEXT_HEADER_NAME} from '../src';
+
+const stackdriverFormat = new StackdriverFormat();
+
+function helperGetter(value: string|string[]|undefined) {
+  const headers: {[key: string]: string|string[]|undefined} = {};
+  headers[TRACE_CONTEXT_HEADER_NAME] = value;
+  const getter: HeaderGetter = {
+    getHeader(name: string) {
+      return headers[name];
+    }
+  };
+  return getter;
+}
+
+describe('StackdriverPropagation', () => {
+  describe('extract()', () => {
+    it('should extract context of a sampled span from headers', () => {
+      const getter = helperGetter('123456/667;o=1');
+      assert.deepEqual(
+          stackdriverFormat.extract(getter),
+          {traceId: '123456', spanId: '000000000000029b', options: 1});
+    });
+
+    it('should extract context of a span from headers when TRACE_TRUE set to 0',
+       () => {
+         const getter =
+             helperGetter('123456/123456123456123456123456123456123456;o=0');
+         assert.deepEqual(
+             stackdriverFormat.extract(getter),
+             {traceId: '123456', spanId: 'a89bb45f10f2f240', options: 0});
+       });
+
+    it('should extract context of a span from headers when option is undefined',
+       () => {
+         const getter = helperGetter('cafef00d/123');
+         assert.deepEqual(
+             stackdriverFormat.extract(getter),
+             {traceId: 'cafef00d', spanId: '000000000000007b', options: 1});
+       });
+
+    const inputs = [
+      '', undefined, '123456', '123456;o=1', 'o=1;123456', '123;456;o=1',
+      '123/o=1;456', '123/abc/o=1', 'cafefood/667;o=1'
+    ];
+    inputs.forEach(s => {
+      it(`should reject ${s}`, () => {
+        const getter = helperGetter(s);
+        const result = stackdriverFormat.extract(getter);
+        assert.ok(!result);
+      });
+    });
+  });
+
+  describe('inject', () => {
+    it('should inject a context of a sampled span', () => {
+      const spanContext = stackdriverFormat.generate();
+      const headers: {[key: string]: string|string[]|undefined} = {};
+      const setter: HeaderSetter = {
+        setHeader(name: string, value: string) {
+          headers[name] = value;
+        }
+      };
+      const getter: HeaderGetter = {
+        getHeader(name: string) {
+          return headers[name];
+        }
+      };
+
+      stackdriverFormat.inject(setter, spanContext);
+      assert.deepEqual(stackdriverFormat.extract(getter), spanContext);
+    });
+
+    it('should not inject empty spancontext', () => {
+      const emptySpanContext = {traceId: '', spanId: ''};
+      const headers: {[key: string]: string|string[]|undefined} = {};
+      const setter: HeaderSetter = {
+        setHeader(name: string, value: string) {
+          headers[name] = value;
+        }
+      };
+      const getter: HeaderGetter = {
+        getHeader(name: string) {
+          return headers[name];
+        }
+      };
+
+      stackdriverFormat.inject(setter, emptySpanContext);
+      assert.deepEqual(stackdriverFormat.extract(getter), null);
+    });
+  });
+
+  describe('generate', () => {
+    const TIMES = 20;
+
+    // Generate some span contexts.
+    const GENERATED = Array.from({length: TIMES})
+                          .fill(0)
+                          .map(_ => stackdriverFormat.generate());
+
+    it('should generate unique traceIds', () => {
+      const traceIds = GENERATED.map(c => c.traceId);
+      assert.strictEqual((new Set(traceIds)).size, TIMES);
+    });
+
+    it('should generate unique spanIds', () => {
+      const spanIds = GENERATED.map(c => c.spanId);
+      assert.strictEqual((new Set(spanIds)).size, TIMES);
+    });
+  });
+});

packages/opencensus-propagation-stackdriver/test/test-v1.ts

@@ -15,9 +15,7 @@
  */
 
 import * as assert from 'assert';
-import * as mocha from 'mocha';
 import {inspect} from 'util';
-
 import {SpanContext} from '../src/index';
 import {extract, generate, inject, parseContextFromHeader, serializeSpanContext} from '../src/v1';
 

packages/opencensus-propagation-stackdriver/tsconfig.json

@@ -2,7 +2,12 @@
   "extends": "./node_modules/gts/tsconfig-google.json",
   "compilerOptions": {
     "rootDir": ".",
-    "outDir": "build"
+    "outDir": "build",
+    "pretty": true,
+    "module": "commonjs",
+    "target": "es6",
+    "strictNullChecks": true,
+    "noUnusedLocals": true
   },
   "include": [
     "src/*.ts",