chore: add typing to propagator carrier

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

@@ -15,6 +15,7 @@
  */
 
 import { SpanContext } from '../../trace/span_context';
+import { Carrier } from './carrier';
 
 /**
  * Injects and extracts a value as text into carriers that travel in-band
@@ -35,18 +36,18 @@ export interface HttpTextFormat {
    *
    * @param spanContext the SpanContext to transmit over the wire.
    * @param format the format of the carrier.
-   * @param carrier the carrier of propagation fields, such as an http request.
+   * @param carrier the carrier of propagation fields, such as http request headers.
    */
-  inject(spanContext: SpanContext, format: string, carrier: unknown): void;
+  inject(spanContext: SpanContext, format: string, carrier: Carrier): void;
 
   /**
    * Returns a {@link SpanContext} instance extracted from `carrier` in the
    * given format from upstream.
    *
    * @param format the format of the carrier.
-   * @param carrier the carrier of propagation fields, such as an http request.
+   * @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: unknown): SpanContext | null;
+  extract(format: string, carrier: Carrier): SpanContext | null;
 }

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

@@ -15,16 +15,17 @@
  */
 
 import { SpanContext } from '../../trace/span_context';
+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: unknown): void {}
+  inject(spanContext: SpanContext, format: string, carrier: Carrier): void {}
   // By default does nothing
-  extract(format: string, carrier: unknown): SpanContext | null {
+  extract(format: string, carrier: Carrier): SpanContext | null {
     return null;
   }
 }

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

@@ -0,0 +1,19 @@
+/*!
+ * 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.
+ */
+
+export type Carrier = {
+  [key: string]: unknown;
+};

packages/opentelemetry-api/src/index.ts

@@ -17,6 +17,7 @@
 export * from './common/Logger';
 export * from './common/Time';
 export * from './context/propagation/BinaryFormat';
+export * from './context/propagation/carrier';
 export * from './context/propagation/HttpTextFormat';
 export * from './distributed_context/DistributedContext';
 export * from './distributed_context/EntryValue';

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

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-import { SpanContext, HttpTextFormat, TraceFlags } from '@opentelemetry/api';
+import {
+  Carrier,
+  HttpTextFormat,
+  SpanContext,
+  TraceFlags,
+} from '@opentelemetry/api';
 
 export const X_B3_TRACE_ID = 'x-b3-traceid';
 export const X_B3_SPAN_ID = 'x-b3-spanid';
@@ -36,11 +41,7 @@ function isValidSpanId(spanId: string): boolean {
  * Based on: https://github.com/openzipkin/b3-propagation
  */
 export class B3Format implements HttpTextFormat {
-  inject(
-    spanContext: SpanContext,
-    format: string,
-    carrier: { [key: string]: unknown }
-  ): void {
+  inject(spanContext: SpanContext, format: string, carrier: Carrier): void {
     if (
       isValidTraceId(spanContext.traceId) &&
       isValidSpanId(spanContext.spanId)
@@ -56,10 +57,7 @@ export class B3Format implements HttpTextFormat {
     }
   }
 
-  extract(
-    format: string,
-    carrier: { [key: string]: unknown }
-  ): SpanContext | null {
+  extract(format: string, carrier: Carrier): SpanContext | null {
     const traceIdHeader = carrier[X_B3_TRACE_ID];
     const spanIdHeader = carrier[X_B3_SPAN_ID];
     const sampledHeader = carrier[X_B3_SAMPLED];

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

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-import { HttpTextFormat, SpanContext, TraceFlags } from '@opentelemetry/api';
+import {
+  Carrier,
+  HttpTextFormat,
+  SpanContext,
+  TraceFlags,
+} from '@opentelemetry/api';
 import { TraceState } from '../../trace/TraceState';
 
 export const TRACE_PARENT_HEADER = 'traceparent';
@@ -56,11 +61,7 @@ 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: { [key: string]: unknown }
-  ) {
+  inject(spanContext: SpanContext, format: string, carrier: Carrier) {
     const traceParent = `${VERSION}-${spanContext.traceId}-${
       spanContext.spanId
     }-0${Number(spanContext.traceFlags || TraceFlags.UNSAMPLED).toString(16)}`;
@@ -71,10 +72,7 @@ export class HttpTraceContext implements HttpTextFormat {
     }
   }
 
-  extract(
-    format: string,
-    carrier: { [key: string]: unknown }
-  ): SpanContext | null {
+  extract(format: string, carrier: Carrier): SpanContext | null {
     const traceParentHeader = carrier[TRACE_PARENT_HEADER];
     if (!traceParentHeader) return null;
     const traceParent = Array.isArray(traceParentHeader)

packages/opentelemetry-plugin-http/src/http.ts

@@ -407,7 +407,7 @@ export class HttpPlugin extends BasePlugin<Http> {
       const span = plugin._startHttpSpan(operationName, spanOptions);
       plugin._tracer
         .getHttpTextFormat()
-        .inject(span.context(), Format.HTTP, options.headers);
+        .inject(span.context(), Format.HTTP, options.headers!);
 
       const request: ClientRequest = plugin._safeExecute(
         span,

packages/opentelemetry-propagator-jaeger/src/JaegerHttpTraceFormat.ts

@@ -14,7 +14,12 @@
  * limitations under the License.
  */
 
-import { SpanContext, HttpTextFormat, TraceFlags } from '@opentelemetry/api';
+import {
+  SpanContext,
+  HttpTextFormat,
+  TraceFlags,
+  Carrier,
+} from '@opentelemetry/api';
 
 export const UBER_TRACE_ID_HEADER = 'uber-trace-id';
 
@@ -46,13 +51,9 @@ export class JaegerHttpTraceFormat implements HttpTextFormat {
   /**
    * @param {SpanContext} spanContext - context from which we take information to inject in carrier.
    * @param {string} format - unused.
-   * @param { [key: string]: unknown } carrier - a carrier to which span information will be injected.
+   * @param {Carrier} carrier - a carrier to which span information will be injected.
    **/
-  inject(
-    spanContext: SpanContext,
-    format: string,
-    carrier: { [key: string]: unknown }
-  ) {
+  inject(spanContext: SpanContext, format: string, carrier: Carrier) {
     const traceFlags = `0${(
       spanContext.traceFlags || TraceFlags.UNSAMPLED
     ).toString(16)}`;
@@ -64,13 +65,10 @@ export class JaegerHttpTraceFormat implements HttpTextFormat {
 
   /**
    * @param {string} format - unused.
-   * @param { [key: string]: unknown } carrier - a carrier from which span context will be constructed.
+   * @param {Carrier} carrier - a carrier from which span context will be constructed.
    * @return {SpanContext} - returns a span context extracted from carrier.
    **/
-  extract(
-    format: string,
-    carrier: { [key: string]: unknown }
-  ): SpanContext | null {
+  extract(format: string, carrier: Carrier): SpanContext | null {
     const uberTraceIdHeader = carrier[this._jaegerTraceHeader];
     if (!uberTraceIdHeader) return null;
     const uberTraceId = Array.isArray(uberTraceIdHeader)

packages/opentelemetry-shim-opentracing/src/shim.ts

@@ -120,7 +120,7 @@ export class TracerShim extends opentracing.Tracer {
   _inject(
     spanContext: opentracing.SpanContext,
     format: string,
-    carrier: unknown
+    carrier: types.Carrier
   ): void {
     const opentelemSpanContext: types.SpanContext = (spanContext as SpanContextShim).getSpanContext();
     switch (format) {
@@ -141,7 +141,10 @@ export class TracerShim extends opentracing.Tracer {
     }
   }
 
-  _extract(format: string, carrier: unknown): opentracing.SpanContext | null {
+  _extract(
+    format: string,
+    carrier: types.Carrier
+  ): opentracing.SpanContext | null {
     switch (format) {
       // tslint:disable-next-line:no-switch-case-fall-through
       case opentracing.FORMAT_HTTP_HEADERS: