// @flow
// Copyright (c) 2017 The Jaeger 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 * 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';
const ZIPKIN_PARENTSPAN_HEADER = 'x-b3-parentspanid';
const ZIPKIN_SPAN_HEADER = 'x-b3-spanid';
const ZIPKIN_TRACE_HEADER = 'x-b3-traceid';
const ZIPKIN_SAMPLED_HEADER = 'x-b3-sampled';
const ZIPKIN_FLAGS_HEADER = 'x-b3-flags';
export default class ZipkinB3TextMapCodec {
_urlEncoding: boolean;
_baggagePrefix: string;
_metrics: any;
constructor(options: any = {}) {
this._urlEncoding = !!options.urlEncoding;
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 (Ethis._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;
}
_isValidZipkinId(value: string): boolean {
// Validates a zipkin trace/spanID by attempting to parse it as a
// string of hex digits. This "validation" is not entirely rigorous,
// but equivalent to what is performed in the TextMapCodec.
//
// Note: due to the way parseInt works, this does not guarantee that
// the string is composed *entirely* of hex digits.
//
// > If parseInt encounters a character that is not a numeral in the
// > specified radix, it ignores it and all succeeding characters and
// > returns the integer value parsed up to that point.
//
// Note: The Number type in JS cannot represent the full range of 64bit
// unsigned ints, so using parseInt() on strings representing 64bit hex
// numbers only returns an approximation of the actual value.
// Fortunately, we do not depend on the returned value, we are only
// using it to validate that the string is a valid hex number (which is
// faster than doing it manually). We cannot use
// Int64(numberValue).toBuffer() because it throws exceptions on bad
// strings.
if (!value) {
return true;
}
return !isNaN(parseInt(value, 16));
}
_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 baggage = {};
let flags = 0;
let debugId = '';
let parentId = '';
let spanId = '';
let traceId = '';
for (let key in carrier) {
if (Ecarrier.hasOwnProperty(key)) {
let lowerKey = key.toLowerCase();
switch (lowerKey) {
case ZIPKIN_PARENTSPAN_HEADER:
parentId = this._decodeValue(carrier[ZIPKIN_PARENTSPAN_HEADER]);
break;
case ZIPKIN_SPAN_HEADER:
spanId = this._decodeValue(carrier[ZIPKIN_SPAN_HEADER]);
break;
case ZIPKIN_TRACE_HEADER:
traceId = this._decodeValue(carrier[ZIPKIN_TRACE_HEADER]);
break;
case ZIPKIN_SAMPLED_HEADER:
flags = flags | constants.SAMPLED_MASK;
break;
case ZIPKIN_FLAGS_HEADER:
// Per https://github.com/openzipkin/b3-propagation
// "Debug is encoded as X-B3-Flags: 1"
// and
// "Debug implies Sampled."
if (carrier[key] === '1') {
flags = flags | constants.SAMPLED_MASK | constants.DEBUG_MASK;
}
break;
case constants.JAEGER_DEBUG_HEADER:
debugId = this._decodeValue(carrier[constants.JAEGER_DEBUG_HEADER]);
break;
case constants.JAEGER_BAGGAGE_HEADER:
parseCommaSeparatedBaggage(baggage, this._decodeValue(carrier[key]));
break;
default:
if (Utils.startsWith(lowerKey, this._baggagePrefix)) {
let keyWithoutPrefix = key.substring(this._baggagePrefix.length);
baggage[keyWithoutPrefix] = this._decodeValue(carrier[key]);
}
}
}
}
if (
!this._isValidZipkinId(traceId) ||
!this._isValidZipkinId(spanId) ||
!this._isValidZipkinId(parentId)
) {
// Use a context devoid of trace/span/parentSpan IDs (to be
// consistent with the default codec behavior), and increment a
// metric
traceId = spanId = parentId = '';
this._metrics.decodingErrors.increment(1);
}
return SpanContext.withStringIds(traceId, spanId, parentId, flags, baggage, debugId);
}
inject(spanContext: SpanContext, carrier: any): void {
carrier[ZIPKIN_TRACE_HEADER] = spanContext.traceIdStr;
carrier[ZIPKIN_PARENTSPAN_HEADER] = spanContext.parentIdStr;
carrier[ZIPKIN_SPAN_HEADER] = spanContext.spanIdStr;
if (spanContext.isDebug()) {
carrier[ZIPKIN_FLAGS_HEADER] = '1';
} else {
// Only set the zipkin sampled header if we're NOT using debug.
// Per https://github.com/openzipkin/b3-propagation
// "Since Debug implies Sampled, so don't also send "X-B3-Sampled: 1"
carrier[ZIPKIN_SAMPLED_HEADER] = spanContext.isSampled() ? '1' : '0';
}
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;
}
}
}
}
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