loopback-log-extension
v1.0.14
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loopback log extension
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loopback-log-extension
log extension for LoopBack 4
Install npm i loopback-log-extension --save
or yarn add loopback-log-extension
Overview
This repository shows you how to use @loopback/cli to write a complex logging extension that requires a Component, Decorator, and a Mixin.
To use this extension you can add the LogMixin
to your Application which will
provide you a function to set the Application wide log level as well as
automatically load the LogComponent
. Only Controller methods configured at or
above the logLevel will be logged.
You may alternatively load LogComponent
yourself and set the log level using
the appropriate binding keys manually if you don't wish to use the LogMixin
.
Possible levels are: DEBUG < INFO < WARN < ERROR < OFF
Possible levels are represented as numbers but users can use
LOG_LEVEL.${level}
to specify the value instead of using numbers.
A decorator enables you to set the log level for Controller methods, at or above which it should be logged.
Usage
1. Create datasource to save token
Sample:
datasources/token.datasource.config.json
file
{
"name": "token",
"connector": "memory",
"localStorage": "",
"file": "../../data/token.json"
}
datasources/token.datasource.ts
file
import {
inject,
lifeCycleObserver,
LifeCycleObserver,
ValueOrPromise,
} from '@loopback/core';
import { juggler } from '@loopback/repository';
import config from './token.datasource.config.json';
import * as path from 'path'
interface TokenDataSourceInterFace {
name: string
connector: string
localStorage: string
file: string
}
@lifeCycleObserver('datasource')
export class TokenDataSource extends juggler.DataSource
implements LifeCycleObserver {
static dataSourceName = 'token';
constructor(
@inject('datasources.config.token', { optional: true })
dsConfig: TokenDataSourceInterFace = config,
) {
const newPath = path.join(__dirname, dsConfig.file)
dsConfig.file = newPath
super(dsConfig);
}
/**
* Start the datasource when application is started
*/
start(): ValueOrPromise<void> {
// Add your logic here to be invoked when the application is started
}
/**
* Disconnect the datasource when application is stopped. This allows the
* application to be shut down gracefully.
*/
stop(): ValueOrPromise<void> {
return super.disconnect();
}
}
2. Create Token Repository
repositories/token.repository.ts
file
import { DefaultCrudRepository } from '@loopback/repository';
import { Token, TokenRelations } from 'loopback-elog-extention';
import { TokenDataSource } from '../datasources';
import { inject } from '@loopback/core';
export class TokenRepository extends DefaultCrudRepository<
Token,
typeof Token.prototype.id,
TokenRelations
> {
constructor(@inject('datasources.token') dataSource: TokenDataSource) {
super(Token, dataSource);
}
}
In application.ts
file
import {LogMixin, LOG_BINDINGS} from 'loopback-log-extension';
import { TokenRepository } from './repositories';
// Other imports ...
class LogApp extends LogMixin(BootMixin(RestApplication)) {
constructor(options?: ApplicationConfig) {
super(options);
this.projectRoot = __dirname;
this.configure(LOG_BINDINGS.COMPONENT).to({
enableElog: true
})
this.configure(LOG_BINDINGS.LOGGER).to({
url: '${url_elog}',
username: '${elog_username}',
password: '${elog_password}',
appCode: '${elog_appcode}',
tokenRepo: TokenRepository
})
}
}
In controllers/my.controller.ts
file
...
import {
LOG_LEVEL,
LOG_BINDINGS,
ElogService,
log
} from 'loopback-elog-extention';
class MyController {
constructor(
@inject(LOG_BINDINGS.LOGGER)
private logger: ElogService
) { }
@log({
level: LOG_LEVEL.WARN,
description: 'description for log',
fn: {
code: 'function code',
name: 'function name'
},
// function parse request param for save to log
parseInfo: () => {},
// function parse result of method to get status of request and result code
parseResult: result => { //result of method
return {
status: result.status,
resultCode: result.responseCode
}
}
})
@get('/')
hello() {
...
this.logger.addTimeLine('test,', true, 'abc.txt', 'abc')
...
return {
status: true,
resultCode: 'I001'
};
}
}
In sequence.ts
file
...
import { LOG_BINDINGS, LogFn } from './loopback-elog-extention'
export class MySequence implements SequenceHandler {
constructor(
...
@inject(LOG_BINDINGS.LOG_ACTION)
protected log: LogFn
) { }
async handle(context: RequestContext) {
try {
const { request, response } = context;
const route = this.findRoute(request);
const args = await this.parseParams(request, route);
const result = await this.invoke(route, args);
this.send(response, result);
this.log(request, args[0], result, true)
} catch (err) {
this.reject(context, err);
this.log(context.request, context.request.body, err, false)
}
}
}