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| // @flow
// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
import assert from 'assert';
import * as constants from './constants';
import DefaultContext from './default_context';
import Span from './span';
import SpanContext from './span_context';
import Utils from './util';
import opentracing from 'opentracing';
import Tracer from './tracer';
import TextMapCodec from './propagators/text_map_codec';
let TCHANNEL_TRACING_PREFIX = '$tracing$';
export default class TChannelBridge {
_tracer: Tracer;
_codec: TextMapCodec;
_contextFactory: Function;
_getSpan: Function;
_setSpan: Function;
/**
* @param {Object} [tracer] - Jaeger Tracer
* @param {Object} [options] - options
* @param {Function} [options.contextFactory] - function used to create new Context object instead of DefaultContext
* @param {Function} [options.getSpan] - function(ctx): Span - used to read Span from Context object; default is ctx.getSpan()
* @param {Function} [options.setSpan] - function(ctx, span): void - used to set Span on the Context object; default is ctx.setSpan(span)
*/
constructor(tracer: Tracer, options: any = {}) {
this._tracer = tracer;
assert.equal('object', typeof(options), 'options must be an object');
this._codec = new TextMapCodec({
urlEncoding: false,
contextKey: TCHANNEL_TRACING_PREFIX + constants.TRACER_STATE_HEADER_NAME,
baggagePrefix: TCHANNEL_TRACING_PREFIX + constants.TRACER_BAGGAGE_HEADER_PREFIX
});
this._contextFactory = options.contextFactory || function() { return new DefaultContext(); };
this._getSpan = options.getSpan || function(ctx) { return ctx.getSpan(); };
this._setSpan = options.setSpan || function(ctx, span) { return ctx.setSpan(span); };
}
_tchannelCallbackWrapper(span: Span, callback: Function, err: any, res: any) {
if (Ierr) {
span.setTag(opentracing.Tags.ERROR, true);
span.log('error_msg', err);
}
span.finish();
return callback(err, res);
}
/**
* Wraps a tchannel handler, and takes a context in order to populate the incoming context
* with a span.
*
* @param {Function} [handlerFunc] - a tchannel handler function that responds to an incoming request.
* @param {Object} [options] - options to be passed to a span on creation.
* @returns {Function} - a function that wrapps the handler in order to automatically populate
* a the handler's context with a span.
**/
tracedHandler(handlerFunc: any, options: any = {}): Function {
return (perProcessOptions, request, headers, body, callback) => {
let context: Context = this._contextFactory();
let operationName: string = options.operationName || request.arg1;
let span: Span = this._extractSpan(operationName, headers);
// set tags
span.setTag(opentracing.Tags.PEER_SERVICE, request.callerName);
let hostPort: Array<string> = request.remoteAddr.split(':');
if (EhostPort.length == 2) {
span.setTag(opentracing.Tags.PEER_PORT, parseInt(hostPort[1]));
}
if (Erequest.headers && request.headers.as) {
span.setTag('as', request.headers.as);
}
this._setSpan(context, span);
// remove headers prefixed with $tracing$
let headerKeys: Array<string> = Object.keys(headers);
for (let i = 0; i < headerKeys.length; i++) {
let key = headerKeys[i];
if (Eheaders.hasOwnProperty(key) && Utils.startsWith(key, TCHANNEL_TRACING_PREFIX)) {
delete headers[key];
}
}
let wrappingCallback: Function = this._tchannelCallbackWrapper.bind(null, span, callback);
request.context = context;
handlerFunc(perProcessOptions, request, headers, body, wrappingCallback);
};
}
_wrapTChannelSend(wrappedSend: Function, channel: any, req: any, endpoint: string, headers: any, body: any, callback: Function) {
headers = headers || {};
let context: Context = req.context || this._contextFactory();
let childOf: Span = this._getSpan(context);
let clientSpan = this._tracer.startSpan(endpoint, {
childOf: childOf // ok if null, will start a new trace
});
clientSpan.setTag(opentracing.Tags.PEER_SERVICE, req.serviceName);
clientSpan.setTag(opentracing.Tags.SPAN_KIND, opentracing.Tags.SPAN_KIND_RPC_CLIENT);
this.inject(clientSpan.context(), headers);
// wrap callback so that span can be finished as soon as the response is received
let wrappingCallback: Function = this._tchannelCallbackWrapper.bind(null, clientSpan, callback);
return wrappedSend.call(channel, req, endpoint, headers, body, wrappingCallback);
}
_wrapTChannelRequest(channel: any, wrappedRequestMethod: any, requestOptions: any) {
// We set the parent to a span with trace_id zero, so that tchannel's
// outgoing tracing frame also has a trace id of zero.
// This forces other tchannel implementations to rely on the headers for the trace context.
requestOptions.parent = { span: TChannelBridge.makeFakeTChannelParentSpan() };
let tchannelRequest: any = wrappedRequestMethod.call(channel, requestOptions);
tchannelRequest.context = requestOptions.context;
return tchannelRequest;
}
/**
* Encode given span context as tchannel headers and store into the headers dictionary.
* @param {Object} spanContext - Jaeger SpanContext.
* @returns {Object} headers - a dictionary with TChannel application headers.
*/
inject(spanContext: any, headers: any) {
this._codec.inject(spanContext, headers);
}
/**
* A function that wraps a json, or thrift encoded channel, in order to populate
* the outgoing headers with trace context, and baggage information.
*
* @param {Object} channel - the encoded channel to be wrapped for tracing.
* @returns {Object} channel - the trace wrapped channel.
* */
tracedChannel(channel: any): any {
let wrappedSend = channel.send;
let wrappedRequestMethod = channel.channel.request;
// We are patching the top level channel request method, not the encoded request method.
channel.channel.request = this._wrapTChannelRequest.bind(this, channel.channel, wrappedRequestMethod);
channel.send = this._wrapTChannelSend.bind(this, wrappedSend, channel);
return channel;
}
static makeFakeTChannelParentSpan(): any {
return {
id: [0, 0],
traceid: [0, 0],
parentid: [0, 0],
flags: 0
};
}
_extractSpan(operationName: string, headers: any): Span {
let traceContext: ?SpanContext = this._codec.extract(headers);
let tags: any = {};
tags[opentracing.Tags.SPAN_KIND] = opentracing.Tags.SPAN_KIND_RPC_SERVER;
let options: any = {
childOf: traceContext,
tags: tags
}
let span: Span = this._tracer.startSpan(operationName, options);
return span;
}
}
|