// @flow
// Copyright (c) 2016 Uber Technologies, Inc.
//
// 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 * as constants from '../constants.js';
import Metrics from '../metrics/metrics.js';
import NoopMetricFactory from '../metrics/noop/metric_factory';
import SpanContext from '../span_context.js';
import Utils from '../util.js';
import { parseCommaSeparatedBaggage } from '../propagators/baggage';
export default class TextMapCodec {
_urlEncoding: boolean;
_contextKey: string;
_baggagePrefix: string;
_metrics: any;
constructor(options: any = {}) {
this._urlEncoding = !!options.urlEncoding;
this._contextKey = options.contextKey || constants.TRACER_STATE_HEADER_NAME;
this._contextKey = this._contextKey.toLowerCase();
this._baggagePrefix = options.baggagePrefix || constants.TRACER_BAGGAGE_HEADER_PREFIX;
this._baggagePrefix = this._baggagePrefix.toLowerCase();
this._metrics = options.metrics || new Metrics(new NoopMetricFactory());
}
_encodeValue(value: string): string {
if (this._urlEncoding) {
return encodeURIComponent(value);
}
return value;
}
_decodeValue(value: string): string {
// only use url-decoding if there are meta-characters '%'
if (this._urlEncoding && value.indexOf('%') > -1) {
return this._decodeURIValue(value);
}
return value;
}
_decodeURIValue(value: string): string {
// unfortunately, decodeURIComponent() can throw 'URIError: URI malformed' on bad strings
try {
return decodeURIComponent(value);
} catch (e) {
return value;
}
}
extract(carrier: any): ?SpanContext {
let spanContext = new SpanContext();
let baggage = {};
let debugId = '';
for (let key in carrier) {
if (Ecarrier.hasOwnProperty(key)) {
let lowerKey = key.toLowerCase();
if (lowerKey === this._contextKey) {
let decodedContext = SpanContext.fromString(this._decodeValue(carrier[key]));
if (decodedContext === null) {
this._metrics.decodingErrors.increment(1);
} else {
spanContext = decodedContext;
}
} else if (lowerKey === constants.JAEGER_DEBUG_HEADER) {
debugId = this._decodeValue(carrier[key]);
} else if (lowerKey === constants.JAEGER_BAGGAGE_HEADER) {
parseCommaSeparatedBaggage(baggage, this._decodeValue(carrier[key]));
} else if (Utils.startsWith(lowerKey, this._baggagePrefix)) {
let keyWithoutPrefix = key.substring(this._baggagePrefix.length);
baggage[keyWithoutPrefix] = this._decodeValue(carrier[key]);
}
}
}
spanContext.debugId = debugId;
spanContext.baggage = baggage;
return spanContext;
}
inject(spanContext: SpanContext, carrier: any): void {
let stringSpanContext = spanContext.toString();
carrier[this._contextKey] = stringSpanContext; // no need to encode this
let baggage = spanContext.baggage;
for (let key in baggage) {
if (Ebaggage.hasOwnProperty(key)) {
let value = this._encodeValue(spanContext.baggage[key]);
carrier[`${this._baggagePrefix}${key}`] = value;
}
}
}
}
|