# How to trace Socket Events using Elastic APM Tool

**URL:** <https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153>\
**Category:** APM\
**Tags:** nodejs\
**Created:** [August 7, 2020, 10:27am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153 "2020-08-07T10:27:06Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![sreedharbukya](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sreedharbukya/32/70451_2.png) [@sreedharbukya](https://discuss.elastic.co/u/sreedharbukya)\
**Post date:** [August 7, 2020, 10:27am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/1 "2020-08-07T10:27:06Z")

</div>

**Kibana version** :  
7.5.2  
**Elasticsearch version** :  
7.5.2  
**APM Server version** :  
7.5.2  
**Kibana 7.5.2**

**APM Agent language and version** :

elastic-apm-node : 3.6.1

# How do we capture the socket events?

I am using TypeScript version (3.9.6) for writing this functionality.

I tried to work around using custom Transaction to this way.

```auto
     apm.startTransaction("Socket Unknown", "request", "socket.io");
      

```

This call is always throwing me error ☹

```auto
TypeError: apm.startTransaction is not a function
    at /Users/sreedhar/projects/ABC/Example/build/index.js:71:9
    at Layer.handle [as handle_request] (/Users/sreedhar/projects/ABC/Example/node_modules/express/lib/router/layer.js:95:5)

    at next (/Users/sreedhar/projects/ABC/Example/node_modules/express/lib/router/

```

my sample code for health check:

```auto
import * as apm from 'elastic-apm-node/start'
const app = new ExampleServer().getApp(); // express app

app.use(bodyParser.json());

app.get("/health", (request , response) => {
    apm.startTransaction("Health Test");
    response.statusCode = 200;
    response.statusMessage = "OK";
    response.send(
        {
            "Health" : "OK",
            "ServiceName" : "VideoCallService"
        }
    )
});

```

```auto
  "dependencies": {
    "@sentry/integrations": "5.19.1",
    "@sentry/node": "5.19.1",
    "@types/node": "^14.0.23",
    "@types/socket.io": "^2.1.8",
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "elastic-apm-node": "^3.6.1",
    "express": "^4.17.1",
    "nodemon": "^2.0.4",
    "rimraf": "^3.0.2",
    "socket.io": "^2.3.0"
  },
  "devDependencies": {
    "@danmasta/mocha-sonar": "0.0.6",
    "@types/cors": "^2.8.6",
    "codecov": "^3.7.0",
    "cypress-multi-reporters": "^1.4.0",
    "mocha": "^8.0.1",
    "mocha-junit-reporter": "^2.0.0",
    "nyc": "^15.1.0",
    "tslib": "^2.0.0",
    "typescript": "^3.9.6",
    "ts-node": "^8.10.2",
    "supertest": "latest"
  }
}

```

All the settings are loaded with environment variables.

---

<div class="post-metadata">

**Author:** ![vigneshh](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/vigneshh/32/35767_2.png) [@vigneshh](https://discuss.elastic.co/u/vigneshh)\
**Post date:** [August 11, 2020, 9:24am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/2 "2020-08-11T09:24:59Z")

</div>

Hi @sreedharbukya,

Possible reason for that would be TypeScript is compiling the modules in a way that breaks the exported functions of the APM Node.js module. Could you share your tsconfig.json, that would help isolate the issue.

Thanks,  
Vignesh

---

<div class="post-metadata">

**Author:** ![sreedharbukya](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sreedharbukya/32/70451_2.png) [@sreedharbukya](https://discuss.elastic.co/u/sreedharbukya)\
**Post date:** [August 11, 2020, 9:55am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/3 "2020-08-11T09:55:07Z")

</div>

Here is tsconfig.json

```auto
{
  "compilerOptions": {
   "target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
    "module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
    "lib": ["es6"], /* Specify library files to be included in the compilation. */
    "allowJs": true, /* Allow javascript files to be compiled. */
    "outDir": "build", /* Redirect output structure to the directory. */
    "rootDir": "src", /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
    "strict": true, /* Enable all strict type-checking options. */
    "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
    "strictPropertyInitialization": false, /* Enable strict checking of property initialization in classes. */
    "esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    "resolveJsonModule": true, /* Include modules imported with '.json' extension */
    "skipLibCheck": true, /* Skip type checking of declaration files. */
    "forceConsistentCasingInFileNames": true, /* Disallow inconsistently-cased references to the same file. */
    "baseUrl": "./",
    "paths": {
      "tslib" : ["node_modules/tslib/tslib.d.ts"]
   }
  },
 "exclude": [
  "node_modules",
  "test"
 ]
}

```

tsconfig.production.json

```auto
{
  "extends": "./tsconfig",
  "compilerOptions": {
    "sourceMap": true,
    "inlineSources": true,
    "sourceRoot": "/",
    "noEmitHelpers": true,
    "importHelpers": true
  }
}

```

---

<div class="post-metadata">

**Author:** ![vigneshh](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/vigneshh/32/35767_2.png) [@vigneshh](https://discuss.elastic.co/u/vigneshh)\
**Post date:** [August 11, 2020, 10:24am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/4 "2020-08-11T10:24:24Z")

</div>

APM Node.js module uses the ES6 default exports to export the agent interface. Since the code is importing all the named module exports through `import * as apm` it wont be able to find the correct export.

You have to change the code in either of the following ways

```auto
import apm from 'elastic-apm-node' 

apm.startTransaction

// OR

import * as apm from 'elastic-apm-node'

apm.default.startTransaction // default exports

```

Let us know if it helps.

Thanks,  
Vignesh

---

<div class="post-metadata">

**Author:** ![sreedharbukya](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sreedharbukya/32/70451_2.png) [@sreedharbukya](https://discuss.elastic.co/u/sreedharbukya)\
**Post date:** [August 14, 2020, 3:01am UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/5 "2020-08-14T03:01:55Z")

</div>

Thanks @vigneshh, It did worked but in the following statement

```auto
 apm.startTransaction('SocketIO Unknown', 'request', 'socket.io');

```

But fails in following statement

```auto
 apm.startTransaction('SocketIO Unknown', 'request', 'socket.io', {
                    childOf: apm.currentTraceparent
                });

```

Second line of code throws the same Error which is reported above.

---

<div class="post-metadata">

**Author:** ![vigneshshanmugam](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/vigneshshanmugam/32/40324_2.png) [@vigneshshanmugam](https://discuss.elastic.co/u/vigneshshanmugam)\
**Post date:** [August 17, 2020, 6:34pm UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/6 "2020-08-17T18:34:36Z")

</div>

Apologies for the delay,

You have to use the [elastic-apm-node-opentracing](https://www.npmjs.com/package/elastic-apm-node-opentracing) package to use the Opentracing bridge.

Thanks,  
Vignesh

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [September 7, 2020, 2:34pm UTC](https://discuss.elastic.co/t/how-to-trace-socket-events-using-elastic-apm-tool/244153/7 "2020-09-07T14:34:40Z")

</div>

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