├── .babelrc ├── src ├── index.js └── middleware.js ├── .gitignore ├── index.d.ts ├── Makefile ├── circle.yml ├── package.json ├── README.md ├── test └── server.js └── LICENSE /.babelrc: -------------------------------------------------------------------------------- 1 | { 2 | "presets": [ 3 | "latest" 4 | ] 5 | } 6 | -------------------------------------------------------------------------------- /src/index.js: -------------------------------------------------------------------------------- 1 | import middleware from "./middleware"; 2 | 3 | export default middleware; 4 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # osx / sshfs 2 | ._* 3 | .DS_Store 4 | 5 | # emacs / vim 6 | *~ 7 | \#*\# 8 | .\#* 9 | 10 | # dependencies 11 | node_modules 12 | -------------------------------------------------------------------------------- /index.d.ts: -------------------------------------------------------------------------------- 1 | declare module 'express-opentracing' { 2 | import { Tracer } from 'opentracing' 3 | import { RequestHandler } from 'express' 4 | export type MiddlewareOptions = { 5 | tracer: Tracer 6 | } 7 | export default function middleware(options: MiddlewareOptions): RequestHandler 8 | } 9 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | .PHONY: all test build 2 | SHELL := /bin/bash 3 | TESTS=$(shell cd test && ls *.js | sed s/\.js$$//) 4 | 5 | all: test build 6 | 7 | test: build $(TESTS) 8 | 9 | $(TESTS): 10 | NODE_ENV=test node_modules/mocha/bin/mocha -R spec --ignore-leaks --bail --timeout 60000 test/$@.js 11 | 12 | build: clean 13 | @npm run-script build 14 | @echo '✓ Transpile to es5, output to dist' 15 | 16 | clean: 17 | @rm -rf dist 18 | @echo '✓ Clean out dist directory' 19 | -------------------------------------------------------------------------------- /circle.yml: -------------------------------------------------------------------------------- 1 | machine: 2 | post: 3 | - cd $HOME && git clone --depth 1 -v git@github.com:clever/ci-scripts.git && cd ci-scripts && git show --oneline -s 4 | node: 5 | version: 6.2.2 6 | services: 7 | - docker 8 | dependencies: 9 | override: 10 | - npm install 11 | compile: 12 | override: 13 | - make build 14 | test: 15 | override: 16 | - make test 17 | deployment: 18 | all: 19 | branch: master 20 | owner: Clever 21 | commands: 22 | - $HOME/ci-scripts/circleci/npm-publish $NPM_TOKEN . 23 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "express-opentracing", 3 | "version": "0.1.1", 4 | "description": "opentracing middleware for express-js", 5 | "main": "dist/index.js", 6 | "types": "index.d.ts", 7 | "publishConfig": { 8 | "registry": "https://registry.npmjs.org" 9 | }, 10 | "scripts": { 11 | "test": "echo \"Error: no test specified\" && exit 1", 12 | "build": "./node_modules/.bin/babel src -d dist" 13 | }, 14 | "repository": { 15 | "type": "git", 16 | "url": "git+https://github.com/opentracing-contrib/javascript-express.git" 17 | }, 18 | "keywords": [ 19 | "tracing", 20 | "opentracing", 21 | "middleware" 22 | ], 23 | "author": "Clever", 24 | "license": "Apache-2.0", 25 | "bugs": { 26 | "url": "https://github.com/opentracing-contrib/javascript-express/issues" 27 | }, 28 | "homepage": "https://github.com/opentracing-contrib/javascript-express#readme", 29 | "dependencies": { 30 | "opentracing": "^0.14.0" 31 | }, 32 | "peerDependencies": { 33 | "opentracing": "^0.14.0" 34 | }, 35 | "devDependencies": { 36 | "babel-cli": "^6.18.0", 37 | "babel-preset-latest": "^6.16.0", 38 | "express": "4.x.x", 39 | "lightstep-tracer": "^0.20.3", 40 | "mocha": "^3.2.0", 41 | "request": "^2.79.0", 42 | "sinon": "^1.17.7", 43 | "underscore": "^1.8.3" 44 | } 45 | } 46 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # express-opentracing 2 | 3 | Middleware for [express](http://expressjs.com) to enable [opentracing](https://opentracing.io). 4 | Supports any opentracing tracer compatible with version 0.11.0 of the opentracing javascript library. 5 | 6 | ## Install 7 | ```sh 8 | npm install --save express-opentracing 9 | ``` 10 | 11 | ## Usage 12 | 13 | E.g., using LightStep as your tracer: 14 | 15 | ```js 16 | import * as express from "express"; 17 | import middleware from "express-opentracing"; 18 | import * as LightStep from "lightstep-tracer"; 19 | 20 | const lsTracer = LightStep.tracer({ 21 | access_token : 'foo', 22 | component_name : 'bar', 23 | }); 24 | 25 | const app = express(); 26 | app.use(middleware({tracer: lsTracer})); 27 | ``` 28 | 29 | To trace specific HTTP calls, or to exclude certain calls (e.g. hosted static content), modify `app.use(middleware())` above: 30 | 31 | ```js 32 | app.use((req, res, next) => { 33 | // exclude paths that start with '/css' or '/js' 34 | if (req.path.startsWith("/css") || req.path.startsWith('/js')) { 35 | return next() 36 | } 37 | // trace calls 38 | middleware({tracer: tracer})(req, res, next); 39 | }); 40 | ``` 41 | 42 | To use a span (e.g for logging) access the `req.span` object from your handler: 43 | 44 | ```js 45 | app.use((req, res, next) => { 46 | req.span.log({ event: 'handler_triggered' }) 47 | }) 48 | ``` 49 | 50 | ## Options 51 | The `middleware` function takes in an options object as its only argument. 52 | ```js 53 | const options = { 54 | tracer: [Tracer], // Defaults to the opentracing no-op tracer. 55 | } 56 | ``` 57 | -------------------------------------------------------------------------------- /src/middleware.js: -------------------------------------------------------------------------------- 1 | import * as opentracing from "opentracing"; 2 | import * as url from "url"; 3 | 4 | export default function middleware(options = {}) { 5 | const tracer = options.tracer || opentracing.globalTracer(); 6 | 7 | return (req, res, next) => { 8 | const wireCtx = tracer.extract(opentracing.FORMAT_HTTP_HEADERS, req.headers); 9 | const pathname = url.parse(req.url).pathname; 10 | const span = tracer.startSpan(pathname, {childOf: wireCtx}); 11 | span.logEvent("request_received"); 12 | 13 | // include some useful tags on the trace 14 | span.setTag("http.method", req.method); 15 | span.setTag("span.kind", "server"); 16 | span.setTag("http.url", req.url); 17 | 18 | // include trace ID in headers so that we can debug slow requests we see in 19 | // the browser by looking up the trace ID found in response headers 20 | const responseHeaders = {}; 21 | tracer.inject(span, opentracing.FORMAT_TEXT_MAP, responseHeaders); 22 | Object.keys(responseHeaders).forEach(key => res.setHeader(key, responseHeaders[key])); 23 | 24 | // add the span to the request object for handlers to use 25 | Object.assign(req, {span}); 26 | 27 | // finalize the span when the response is completed 28 | res.on('close', () => { 29 | span.logEvent("response_closed"); 30 | span.finish(); 31 | }); 32 | 33 | res.on('finish', () => { 34 | span.logEvent("response_finished"); 35 | // Route matching often happens after the middleware is run. Try changing the operation name 36 | // to the route matcher. 37 | const opName = (req.route && req.route.path) || pathname; 38 | span.setOperationName(opName); 39 | span.setTag("http.status_code", res.statusCode); 40 | if (res.statusCode >= 500) { 41 | span.setTag("error", true); 42 | span.setTag("sampling.priority", 1); 43 | } 44 | }); 45 | 46 | next(); 47 | }; 48 | } 49 | -------------------------------------------------------------------------------- /test/server.js: -------------------------------------------------------------------------------- 1 | const assert = require("assert"); 2 | const opentracing = require("opentracing"); 3 | const express = require("express"); 4 | const middleware = require("../dist/index.js").default; 5 | const request = require("request"); 6 | const LightStep = require("lightstep-tracer"); 7 | const sinon = require("sinon"); 8 | 9 | describe("e2e express app", () => { 10 | it("works with default tracer", (done) => { 11 | const app = express(); 12 | const tracer = opentracing.globalTracer(); 13 | app.use(middleware({})); 14 | const startSpanSpy = sinon.spy(tracer, "startSpan"); 15 | 16 | let reqSpanPresent = false; 17 | app.get("/", (req, res) => { 18 | if (req.span) { 19 | reqSpanPresent = true; 20 | } 21 | res.send("Hello World!") 22 | }); 23 | 24 | const server = app.listen(3000, (err) => { 25 | const opts = { 26 | url : "http://localhost:3000/", 27 | method: "GET", 28 | }; 29 | request(opts, (err, res, body) => { 30 | assert.ifError(err); 31 | assert.equal(res.statusCode, 200, body); 32 | assert(reqSpanPresent, "expected req.span to be set"); 33 | assert(startSpanSpy.calledOnce, "expected only one span"); 34 | // TODO: once lightstep supports opentracing 0.13.0, we can use 35 | // mocktracer and verify some more details on the span itself 36 | //const span = mockTracer._spans[0]; 37 | //assert.deepEqual(span._tags, { 38 | // "http.method": "GET", 39 | // "span.kind": "server", 40 | // "http.url": "/", 41 | // "http.status_code": 200, 42 | //}); 43 | //assert.equal(span._operationName, "/"); 44 | //assert.equal(span._logs.length, 2, "expected two logs in the span"); 45 | //const [startLog, finishLog] = span._logs; 46 | //assert.equal(startLog.fields.event, "request_received"); 47 | //assert.equal(finishLog.fields.event, "request_finished"); 48 | server.close(); 49 | done(); 50 | }); 51 | }); 52 | }); 53 | 54 | it("sets an error tag and sampling priority on 5XX responses", (done) => { 55 | const app = express(); 56 | app.use(middleware({})); 57 | let spanTags = null; 58 | app.get("/", (req, res) => { 59 | if (req.span) { 60 | req.span.setTag = sinon.spy(); 61 | res.on("finish", () => { 62 | spanTags = req.span.setTag.args 63 | }); 64 | } 65 | res.status(500).send("ruhroh!"); 66 | }); 67 | const server = app.listen(3000, (err) => { 68 | const opts = { 69 | url : "http://localhost:3000/", 70 | method: "GET", 71 | }; 72 | request(opts, (err, res, body) => { 73 | assert.ifError(err); 74 | assert.equal(res.statusCode, 500, body); 75 | assert.deepEqual(spanTags, [ 76 | ['http.status_code', 500], 77 | ['error', true], 78 | ['sampling.priority', 1 ] 79 | ]); 80 | server.close(); 81 | done(); 82 | }); 83 | }); 84 | }); 85 | 86 | it("works with latest lightstep tracer", (done) => { 87 | const lsTracer = new LightStep.Tracer({ 88 | access_token : 'foo', 89 | component_name : 'bar', 90 | }); 91 | const app = express(); 92 | app.use(middleware({tracer: lsTracer})); 93 | 94 | var reqSpanPresent = false; 95 | app.get("/", (req, res) => { 96 | if (req.span) { 97 | reqSpanPresent = true; 98 | } 99 | res.send("Hello World!") 100 | }); 101 | 102 | const server = app.listen(3000, (err) => { 103 | const opts = { 104 | url : "http://localhost:3000/", 105 | method: "GET", 106 | }; 107 | request(opts, (err, res, body) => { 108 | assert.ifError(err); 109 | assert.equal(res.statusCode, 200, body); 110 | assert(reqSpanPresent, "expected req.span to be set"); 111 | server.close(); 112 | done(); 113 | }); 114 | }); 115 | }); 116 | }); 117 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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