[![TypeScript version][ts-badge]][typescript-38]
[![Node.js version][nodejs-badge]][nodejs]
[![APLv2][license-badge]][LICENSE]

Install

> NOTE This lib needs to run on version >= 14.0.0 of Nodejs
> After the veersion 1.7 there is a BREAKING CHANGE!

$3

``
yarn install traceability
`

$3

`
npm install traceability
`

Example Code

Logging the trackId in all methods

> File: index.js
`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();
`


$3


`
{"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)
`js
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---

$3


`
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"}
`

$3

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)
`js
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

License

See the LICENSE file for details.

[ts-badge]: https://img.shields.io/badge/TypeScript-3.8-blue.svg
[nodejs-badge]: https://img.shields.io/badge/Node.js-%3E=%2014.16-blue.svg
[nodejs]: https://nodejs.org/dist/latest-v14.x/docs/api/
[typescript]: https://www.typescriptlang.org/
[typescript-38]: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html
[license-badge]: https://img.shields.io/badge/license-APLv2-blue.svg
[license]: https://raw.githubusercontent.com/almerindo/traceability/main/LICENSE

[jest]: https://facebook.github.io/jest/
[eslint]: https://github.com/eslint/eslint
[wiki-js-tests]: https://github.com/...
[prettier]: https://prettier.io