Traceability NPM

Install

NOTE This lib needs to run on version >= 14.0.0 of Nodejs After the veersion 1.7 there is a BREAKING CHANGE!
Using Yarn
yarn install traceability
Using npm
npm install traceability

Example Code

Logging the trackId in all methods

File: index.js

import * as traceability from 'traceability'

const levelRoot = () =>{ const {cid} = traceability.ContextAsyncHooks.getTrackId({}) traceability.ContextAsyncHooks.setContext({cid}) traceability.Logger.info('levelRoot'); level1()

} const level1 = () =>{ traceability.Logger.info('level1'); level2(); }

const level2 = () =>{ traceability.Logger.info('level2'); }

levelRoot();

### Output

{"message":"levelRoot","level":"info","cid":"6b1552d0-0db5-4d7d-8551-567847703fa6","timestamp":"2021-05-03T16:21:01.523Z"} {"message":"level1","level":"info","cid":"6b1552d0-0db5-4d7d-8551-567847703fa6","timestamp":"2021-05-03T16:21:01.525Z"} {"message":"level2","level":"info","cid":"6b1552d0-0db5-4d7d-8551-567847703fa6","timestamp":"2021-05-03T16:21:01.525Z"}

> **NOTE:** We can observe the same trackId value for all output messages.

## Changing the wiston configuration
```js
import { ContextAsyncHooks, Logger, LoggerTraceability } from 'traceability';


const conf = LoggerTraceability.getLoggerOptions();
conf.silent = true;

LoggerTraceability.configure(conf);

Logger.info('levelRoot');

Using as a Express middleware

File express.js (see examples directory)
import express from 'express';
import { ContextAsyncHooks, Logger } from 'traceability';

const app = express(); const port = 3000;

ContextAsyncHooks.trackKey= ETrackKey'cid'

app.use(ContextAsyncHooks.getExpressMiddlewareTracking()); app.get('/', (req, res) => { Logger.info('Hello World with trackId on server side!'); res.send('Hello World!'); });

app.listen(port, () => { Logger.info(Example app listening at http://localhost:${port}); });

## Using as a Express middleware with traceparent propagator
> **File** express-traceparent.ts (see examples directory)
```js
import express from 'express';
import { ContextAsyncHooks, Logger } from 'traceability';


const app = express();
const port = 3000;

ContextAsyncHooks.trackKey= ETrackKey['cid']

app.use(ContextAsyncHooks.getExpressMiddlewareTracking({
  responseHeaderPropagator: 'traceparent'
}));
app.get('/', (req, res) => {
  Logger.info('Hello World with trackId on server side!');
  res.send('Hello World!');
});

app.listen(port, () => {
  Logger.info(`Example app listening at http://localhost:${port}`);
});

When traceparent is enabled, the library will automatically generate and propagate the traceparent header in all outgoing requests, following the W3C Trace Context format: traceparent: 00-<trace-id>-<span-id>-<trace-flags>

Running the code:

yarn ts-node ./express.ts

And after that we will see the following output:

{"message":"Example app listening at http://localhost:3000","level":"info","timestamp":"2021-04-10T19:01:33.337Z"}

Testing the route GET /

We will test the route usig curl cli.

To install curl on linux: sudo apt-get install curl

Now type the following command:

curl -i http://localhost:3000

-i option will show you the header.
The output will look something like:

On ClientSide:

HTTP/1.1 200 OK
X-Powered-By: Express
cid: 79a0e7f2-3e02-49aa-9368-582b9cce6002
Content-Type: text/html; charset=utf-8
Content-Length: 12
ETag: W/"c-Lve95gjOVATpfV8EL5X4nxwjKHE"
Date: Mon, 03 May 2021 17:00:06 GMT
Connection: keep-alive
Keep-Alive: timeout=5

Hello World!%

On ServerSide:

{"message":"Hello World with trackId on server side!","level":"info","cid":"6ecf583a-7509-4ce3-baef-1fcbe94adc5c","timestamp":"2021-05-03T16:57:32.116Z"}

NOTE: At the momennt, we can compare the cid values printed onn server side and on client side.

Using as a Nest middleware - Global Middleware

First of all, follow the First Steps accessing the link NESTJS Oficial Docs. After that, just modify the main.ts file as described bellow.

File main.ts (see examples directory)

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import traceability from 'traceability';

const middlewareTracking = traceability.ContextAsyncHooks.getExpressMiddlewareTracking();

async function bootstrap() { const app = await NestFactory.create(AppModule); app.use(middlewareTracking); await app.listen(3000); } bootstrap();

## Using methods from winston

Just destructure the necessary methods directly from traceability

```js
import {format, addColors} from 'traceability';

format and addColors comes from winston

Known issues

TypeError: async_hooks_1.AsyncLocalStorage is not a constructor:

this.asyncLocalStorage = new async_hooks_1.AsyncLocalStorage();

TypeError: async_hooks_1.AsyncLocalStorage is not a constructor
   at new ContextAsyncHooks

This lib uses LocalStorageAsyncHooks as a feature that is only available on Node >= 14.0.0
Then, to solve it, you must migrates your node to 14.0.0. Type: nvm use 14.16.1