chore: rename CorrelationContext to Baggage (#1687)

* chore: rename CorrelationContext to Baggage

* chore: lint

README.md

@@ -108,7 +108,7 @@ Last updated March 2020
 | Metrics             | Beta       | v0.3                 | Beta        |
 | Context             | Beta       | v0.3                 | Beta        |
 | Propagation         | Beta       | v0.3                 | Beta        |
-| Correlation Context | Alpha      | v0.3                 | Development |
+| Baggage             | Alpha      | v0.3                 | Development |
 | OpenTracing Bridge  | N/A        | v0.3                 | Beta        |
 | Resources           | N/A        | v0.3                 | Beta        |
 

packages/opentelemetry-api/src/correlation_context/CorrelationContext.ts → packages/opentelemetry-api/src/baggage/Baggage.ts

@@ -17,13 +17,13 @@
 import { EntryValue } from './EntryValue';
 
 /**
- * CorrelationContext represents collection of entries. Each key of
- * CorrelationContext is associated with exactly one value. CorrelationContext
+ * Baggage represents collection of entries. Each key of
+ * Baggage is associated with exactly one value. Baggage
  * is serializable, to facilitate propagating it not only inside the process
- * but also across process boundaries. CorrelationContext is used to annotate
+ * but also across process boundaries. Baggage is used to annotate
  * telemetry with the name:value pair Entry. Those values can be used to add
  * dimension to the metric or additional contest properties to logs and traces.
  */
-export interface CorrelationContext {
+export interface Baggage {
   [entryKey: string]: EntryValue;
 }

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

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import { NoopSpan, Span, SpanContext } from '../';
 import { Context, createContextKey } from '@opentelemetry/context-base';
+import { Baggage, NoopSpan, Span, SpanContext } from '../';
 
 /**
  * Active span key
@@ -32,6 +32,11 @@ const SUPPRESS_INSTRUMENTATION_KEY = createContextKey(
   'OpenTelemetry Context Key SUPPRESS_INSTRUMENTATION'
 );
 
+/**
+ * Baggage key
+ */
+const BAGGAGE_KEY = createContextKey('OpenTelemetry Baggage Key');
+
 /**
  * Return the active span if one exists
  *
@@ -107,3 +112,19 @@ export function unsuppressInstrumentation(context: Context): Context {
 export function isInstrumentationSuppressed(context: Context): boolean {
   return Boolean(context.getValue(SUPPRESS_INSTRUMENTATION_KEY));
 }
+
+/**
+ * @param {Context} Context that manage all context values
+ * @returns {Baggage} Extracted baggage from the context
+ */
+export function getBaggage(context: Context): Baggage | undefined {
+  return (context.getValue(BAGGAGE_KEY) as Baggage) || undefined;
+}
+
+/**
+ * @param {Context} Context that manage all context values
+ * @param {Baggage} baggage that will be set in the actual context
+ */
+export function setBaggage(context: Context, baggage: Baggage): Context {
+  return context.setValue(BAGGAGE_KEY, baggage);
+}

packages/opentelemetry-api/src/index.ts

@@ -20,8 +20,8 @@ export * from './common/Time';
 export * from './context/context';
 export * from './context/propagation/TextMapPropagator';
 export * from './context/propagation/NoopTextMapPropagator';
-export * from './correlation_context/CorrelationContext';
-export * from './correlation_context/EntryValue';
+export * from './baggage/Baggage';
+export * from './baggage/EntryValue';
 export * from './metrics/BatchObserverResult';
 export * from './metrics/BoundInstrument';
 export * from './metrics/Meter';

packages/opentelemetry-api/src/metrics/NoopMeter.ts

@@ -33,7 +33,7 @@ import {
   BoundCounter,
   BoundBaseObserver,
 } from './BoundInstrument';
-import { CorrelationContext } from '../correlation_context/CorrelationContext';
+import { Baggage } from '../baggage/Baggage';
 import { SpanContext } from '../trace/span_context';
 import { ObserverResult } from './ObserverResult';
 
@@ -198,11 +198,7 @@ export class NoopBoundCounter implements BoundCounter {
 }
 
 export class NoopBoundValueRecorder implements BoundValueRecorder {
-  record(
-    _value: number,
-    _correlationContext?: CorrelationContext,
-    _spanContext?: SpanContext
-  ): void {
+  record(_value: number, _baggage?: Baggage, _spanContext?: SpanContext): void {
     return;
   }
 }

packages/opentelemetry-api/src/trace/span_context.ts

@@ -18,7 +18,7 @@ import { TraceState } from './trace_state';
 
 /**
  * A SpanContext represents the portion of a {@link Span} which must be
- * serialized and propagated along side of a {@link CorrelationContext}.
+ * serialized and propagated along side of a {@link Baggage}.
  */
 export interface SpanContext {
   /**

packages/opentelemetry-core/README.md

@@ -15,7 +15,7 @@ This package provides default implementations of the OpenTelemetry API for trace
     - [Built-in Propagators](#built-in-propagators)
       - [HttpTraceContext Propagator](#httptracecontext-propagator)
       - [Composite Propagator](#composite-propagator)
-      - [Correlation Context Propagator](#correlation-context-propagator)
+      - [Baggage Propagator](#baggage-propagator)
     - [Built-in Sampler](#built-in-sampler)
       - [Always Sampler](#always-sampler)
       - [Never Sampler](#never-sampler)
@@ -51,16 +51,16 @@ const { CompositePropagator } = require("@opentelemetry/core");
 api.propagation.setGlobalPropagator(new CompositePropagator());
 ```
 
-#### Correlation Context Propagator
+#### Baggage Propagator
 
-Provides a text-based approach to propagate [correlation context](https://w3c.github.io/correlation-context/) to remote services using the [OpenTelemetry CorrelationContext Propagation](https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/correlationcontext/api.md#header-name) HTTP headers.
+Provides a text-based approach to propagate [baggage](https://w3c.github.io/baggage/) to remote services using the [OpenTelemetry Baggage Propagation](https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/baggage/api.md#baggage-propagation) HTTP headers.
 
 ```js
 const api = require("@opentelemetry/api");
-const { HttpCorrelationContext } = require("@opentelemetry/core");
+const { HttpBaggage } = require("@opentelemetry/core");
 
 /* Set Global Propagator */
-api.propagation.setGlobalPropagator(new HttpCorrelationContext());
+api.propagation.setGlobalPropagator(new HttpBaggage());
 ```
 
 ### Built-in Sampler

packages/opentelemetry-core/src/correlation-context/propagation/HttpCorrelationContext.ts → packages/opentelemetry-core/src/baggage/propagation/HttpBaggage.ts

@@ -15,23 +15,21 @@
  */
 
 import {
+  Baggage,
   Context,
-  CorrelationContext,
+  getBaggage,
+  setBaggage,
   TextMapGetter,
   TextMapPropagator,
   TextMapSetter,
 } from '@opentelemetry/api';
-import {
-  getCorrelationContext,
-  setCorrelationContext,
-} from '../correlation-context';
 
 const KEY_PAIR_SEPARATOR = '=';
 const PROPERTIES_SEPARATOR = ';';
 const ITEMS_SEPARATOR = ',';
 
-// Name of the http header used to propagate the correlation context
-export const CORRELATION_CONTEXT_HEADER = 'baggage';
+// Name of the http header used to propagate the baggage
+export const BAGGAGE_HEADER = 'baggage';
 // Maximum number of name-value pairs allowed by w3c spec
 export const MAX_NAME_VALUE_PAIRS = 180;
 // Maximum number of bytes per a single name-value pair allowed by w3c spec
@@ -44,23 +42,23 @@ type KeyPair = {
 };
 
 /**
- * Propagates {@link CorrelationContext} through Context format propagation.
+ * Propagates {@link Baggage} through Context format propagation.
  *
- * Based on the Correlation Context specification:
- * https://w3c.github.io/correlation-context/
+ * Based on the Baggage specification:
+ * https://w3c.github.io/baggage/
  */
-export class HttpCorrelationContext implements TextMapPropagator {
+export class HttpBaggage implements TextMapPropagator {
   inject(context: Context, carrier: unknown, setter: TextMapSetter) {
-    const correlationContext = getCorrelationContext(context);
-    if (!correlationContext) return;
-    const keyPairs = this._getKeyPairs(correlationContext)
+    const baggage = getBaggage(context);
+    if (!baggage) return;
+    const keyPairs = this._getKeyPairs(baggage)
       .filter((pair: string) => {
         return pair.length <= MAX_PER_NAME_VALUE_PAIRS;
       })
       .slice(0, MAX_NAME_VALUE_PAIRS);
     const headerValue = this._serializeKeyPairs(keyPairs);
     if (headerValue.length > 0) {
-      setter.set(carrier, CORRELATION_CONTEXT_HEADER, headerValue);
+      setter.set(carrier, BAGGAGE_HEADER, headerValue);
     }
   }
 
@@ -71,36 +69,31 @@ export class HttpCorrelationContext implements TextMapPropagator {
     }, '');
   }
 
-  private _getKeyPairs(correlationContext: CorrelationContext): string[] {
-    return Object.keys(correlationContext).map(
+  private _getKeyPairs(baggage: Baggage): string[] {
+    return Object.keys(baggage).map(
       (key: string) =>
-        `${encodeURIComponent(key)}=${encodeURIComponent(
-          correlationContext[key].value
-        )}`
+        `${encodeURIComponent(key)}=${encodeURIComponent(baggage[key].value)}`
     );
   }
 
   extract(context: Context, carrier: unknown, getter: TextMapGetter): Context {
-    const headerValue: string = getter.get(
-      carrier,
-      CORRELATION_CONTEXT_HEADER
-    ) as string;
+    const headerValue: string = getter.get(carrier, BAGGAGE_HEADER) as string;
     if (!headerValue) return context;
-    const correlationContext: CorrelationContext = {};
+    const baggage: Baggage = {};
     if (headerValue.length == 0) {
       return context;
     }
     const pairs = headerValue.split(ITEMS_SEPARATOR);
     pairs.forEach(entry => {
       const keyPair = this._parsePairKeyValue(entry);
       if (keyPair) {
-        correlationContext[keyPair.key] = { value: keyPair.value };
+        baggage[keyPair.key] = { value: keyPair.value };
       }
     });
-    if (Object.entries(correlationContext).length === 0) {
+    if (Object.entries(baggage).length === 0) {
       return context;
     }
-    return setCorrelationContext(context, correlationContext);
+    return setBaggage(context, baggage);
   }
 
   private _parsePairKeyValue(entry: string): KeyPair | undefined {
@@ -120,6 +113,6 @@ export class HttpCorrelationContext implements TextMapPropagator {
   }
 
   fields(): string[] {
-    return [CORRELATION_CONTEXT_HEADER];
+    return [BAGGAGE_HEADER];
   }
 }

packages/opentelemetry-core/src/index.ts

@@ -26,8 +26,7 @@ export * from './version';
 export * from './context/propagation/composite';
 export * from './context/propagation/HttpTraceContext';
 export * from './context/propagation/types';
-export * from './correlation-context/correlation-context';
-export * from './correlation-context/propagation/HttpCorrelationContext';
+export * from './baggage/propagation/HttpBaggage';
 export * from './platform';
 export * from './trace/NoRecordingSpan';
 export * from './trace/Plugin';