adding the ability to inject propagation registry to register custom propagators (#29)

Author: mchandramouli

.gitignore

@@ -4,6 +4,7 @@ logs
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+package-lock.json
 
 # Runtime data
 pids
@@ -65,4 +66,6 @@ src/proto_idl_codegen/
 dist/
 .idea/typescript-compiler.xml
 *.iml
+*.ipr
+*.iws
 ws2/

examples/index.js

@@ -19,7 +19,10 @@
 
 /// first do `npm install haystack-client` and replace '../dist/index' with 'haystack-client'
 const initTracer = require('../dist/index').initTracer;
-const SpanContext = require('../dist/index').SpanContext;
+const PropagationRegistry = require('../dist/index').PropagationRegistry;
+const TextMapPropagator = require('../dist/index').TextMapPropagator;
+const DefaultCodex = require('../dist/index').DefaultCodex;
+const PropagatorOpts = require('../dist/index').PropagatorOpts;
 
 const opentracing = require('opentracing');
 const MyLogger = require('./logger');
@@ -52,8 +55,14 @@ const config = {
     logger: logger
 };
 
+/// ability to use custom propagation headers if needed
+const propagation = PropagationRegistry.default()
+  .register(opentracing.FORMAT_HTTP_HEADERS,
+            new TextMapPropagator(new DefaultCodex(),
+                                  new PropagatorOpts('X-Trace-ID', 'X-Span-ID', 'X-Parent-ID')));
+
 /// initialize the tracer only once at the time of your service startup
-const tracer = initTracer(config);
+const tracer = initTracer(config, propagation);
 
 /// now create a span, for e.g. at the time of incoming REST call.
 /// Make sure to add SPAN_KIND tag. Possible values are 'server' or 'client'.
@@ -65,15 +74,15 @@ const tracer = initTracer(config);
 const serverSpan = tracer
     .startSpan('/foo', {
         childOf: tracer.extract(opentracing.FORMAT_HTTP_HEADERS, {
-            'Trace-ID': '1848fadd-fa16-4b3e-8ad1-6d73339bbee7',
-            'Span-ID': '7a7cc5bf-796e-4527-9b42-13ae5766c6fd',
-            'Parent-ID': 'e96de653-ad6e-4ad5-b437-e81fd9d2d61d'
+            'X-Trace-ID': '1848fadd-fa16-4b3e-8ad1-6d73339bbee7',
+            'X-Span-ID': '7a7cc5bf-796e-4527-9b42-13ae5766c6fd',
+            'X-Parent-ID': 'e96de653-ad6e-4ad5-b437-e81fd9d2d61d'
         }),
         tags: {
             'span.kind': 'server',
             'http.method': 'GET'
         }
-    })
+    });
 // you can add more tags on server span later in the workflow
 serverSpan.setTag(opentracing.Tags.ERROR, true);
 

src/index.ts

@@ -27,8 +27,12 @@ import { DispatcherConfig } from './dispatchers/dispatcher-config';
 import Configuration from './configuration';
 import { Logger } from './logger';
 import { TracerConfig } from './tracer-config';
+import PropagationRegistry from './propagators/propagation_registry';
+import { PropagatorOpts } from './propagators/propagator';
 
 import * as opentracing from 'opentracing';
+import TextMapPropagator from './propagators/textmap_propagator';
+import DefaultCodex from './propagators/default_codex';
 
 export {
     Configuration,
@@ -43,7 +47,11 @@ export {
     HttpCollectorDispatcher,
     DispatcherConfig,
     opentracing,
-    Logger
+    Logger,
+    PropagationRegistry,
+    PropagatorOpts,
+    TextMapPropagator,
+    DefaultCodex
 };
 
 module.exports = {
@@ -56,5 +64,9 @@ module.exports = {
     InMemoryDispatcher,
     FileDispatcher,
     AgentDispatcher,
-    opentracing
+    opentracing,
+    PropagationRegistry,
+    PropagatorOpts,
+    TextMapPropagator,
+    DefaultCodex
 };

src/propagators/propagation_registry.ts

@@ -15,19 +15,31 @@
  */
 
 import {Propagator} from './propagator';
+import TextMapPropagator from './textmap_propagator';
+import URLCodex from './url_codex';
+import * as opentracing from 'opentracing';
+import BinaryPropagator from './binary_propagator';
 
 export default class PropagationRegistry {
-    _propagators: any;
+    private _propagators: any;
 
     constructor() {
         this._propagators = {};
     }
 
-    register(format: string, propagator: Propagator): void {
+    register(format: string, propagator: Propagator): PropagationRegistry {
         this._propagators[format] = propagator;
+        return this;
     }
 
     propagator(format): Propagator {
         return this._propagators[format];
     }
+
+    static default(): PropagationRegistry {
+        return new PropagationRegistry()
+            .register(opentracing.FORMAT_TEXT_MAP, new TextMapPropagator())
+            .register(opentracing.FORMAT_BINARY, new BinaryPropagator())
+            .register(opentracing.FORMAT_HTTP_HEADERS, new TextMapPropagator(new URLCodex()));
+    }
 }

src/propagators/propagator.ts

@@ -17,10 +17,21 @@
 import SpanContext from '../span_context';
 
 export class PropagatorOpts {
-    _traceIdKey: string;
-    _spanIdKey: string;
-    _parentSpanIdKey: string;
-    _baggageKeyPrefix: string;
+    private _traceIdKey: string;
+    private _spanIdKey: string;
+    private _parentSpanIdKey: string;
+    private _baggageKeyPrefix: string;
+
+    constructor(traceIdKey: string = 'Trace-ID',
+                spanIdKey: string = 'Span-ID',
+                parentSpanIdKey: string = 'Parent-ID',
+                baggageKeyPrefix: string = 'Baggage-') {
+
+        this._traceIdKey = traceIdKey;
+        this._spanIdKey = spanIdKey;
+        this._parentSpanIdKey = parentSpanIdKey;
+        this._baggageKeyPrefix = baggageKeyPrefix;
+    }
 
     traceIdKey(): string {
         return this._traceIdKey || 'Trace-ID';

src/tracer-config.ts

@@ -25,4 +25,5 @@ export interface TracerConfig {
     commonTags?: { [key: string]: any };
     dispatcher?: DispatcherConfig;
     idGenerator?: Generator;
+    useDualSpanMode?: boolean;
 }

src/tracer.ts

@@ -21,15 +21,12 @@ import {Dispatcher} from './dispatchers/dispatcher';
 import Span from './span';
 import SpanContext from './span_context';
 import NoopDispatcher from './dispatchers/noop';
-import { Logger, NullLogger } from './logger';
+import {Logger, NullLogger} from './logger';
 import Utils from './utils';
 import PropagationRegistry from './propagators/propagation_registry';
-import TextMapPropagator from './propagators/textmap_propagator';
-import URLCodex from './propagators/url_codex';
 import StartSpanFields from './start_span_fields';
-import BinaryPropagator from './propagators/binary_propagator';
-import { TracerConfig } from './tracer-config';
-import { Generator, UUIDGenerator } from './generators';
+import {TracerConfig} from './tracer-config';
+import {Generator, UUIDGenerator} from './generators';
 
 export default class Tracer extends opentracing.Tracer {
     _serviceName: string;
@@ -45,16 +42,14 @@ export default class Tracer extends opentracing.Tracer {
                 commonTags: { [key: string]: any } = {},
                 logger: Logger = new NullLogger(),
                 idGenerator: Generator = new UUIDGenerator(),
-                useDualSpanMode: boolean = false) {
+                useDualSpanMode: boolean = false,
+                propagationRegistry: PropagationRegistry = PropagationRegistry.default()) {
         super();
         this._commonTags = commonTags || {};
         this._serviceName = serviceName;
         this._dispatcher = dispatcher;
         this._logger = logger;
-        this._registry = new PropagationRegistry();
-        this._registry.register(opentracing.FORMAT_TEXT_MAP, new TextMapPropagator());
-        this._registry.register(opentracing.FORMAT_BINARY, new BinaryPropagator());
-        this._registry.register(opentracing.FORMAT_HTTP_HEADERS, new TextMapPropagator(new URLCodex()));
+        this._registry = propagationRegistry;
         this._idGenerator = idGenerator;
         this._useDualSpanMode = useDualSpanMode;
     }
@@ -188,7 +183,8 @@ export default class Tracer extends opentracing.Tracer {
         return ctx;
     }
 
-    static initTracer(config: TracerConfig): opentracing.Tracer {
+    static initTracer(config: TracerConfig,
+                      propagationRegistry: PropagationRegistry = PropagationRegistry.default()): opentracing.Tracer {
         if (config.disable) {
             return new opentracing.Tracer();
         }
@@ -202,6 +198,7 @@ export default class Tracer extends opentracing.Tracer {
         if (config.logger) {
             config.logger.info(`Initializing Haystack Tracer with ${dispatcher.name()}`);
         }
-        return new Tracer(config.serviceName, dispatcher, config.commonTags, config.logger, config.idGenerator);
+        return new Tracer(config.serviceName, dispatcher, config.commonTags, config.logger,
+            config.idGenerator, config.useDualSpanMode, propagationRegistry);
     }
 }