This module provides an useful helper to save structured logs in the stdout.
npm install @condor-labs/loggerThis module provides a useful helper to save structured logs in the stdout. Versions greater or equal to 2.x of this module are recommended for Back-end applications and not for Web clients. See CHANGELOG for further information.
Structured logs are really important to process them in Splunk.
Starting from version 3.x.x, the minimum supported version of Node.js is v14.16.x.
To use the library you just need to follow the following steps:
1. Install the library with npm
``shell`
npm install @condor-labs/logger
2. Import the library:
`js`
const logger = require("@condor-labs/logger");
index.js
`js`
try {
const logger = require('@condor-labs/logger');
console.log('-------------------');
logger.debug({ y: 1, z: 2 });
console.log('-------------------');
logger.info({ a: 1, b: 2 });
console.log('-------------------');
logger.warn('My text...');
console.log('-------------------');
logger.error(Error("my error"));
console.log('-------------------');
logger.error('THIS IS SIMPLE TEXT', {name: "my name", country:"Colombia"}, Error("This is an error"));
console.log('-------------------');
const arr = [{}, 1, 2];
arr[0].arr = arr;
// ⛔️ TypeError: Converting circular structure to JSON
logger.fatal(arr);
} catch (error) {
console.error(error);
}
Error objects are _special_ objects that needs extra handling. We recommend to logs errors instances in this way:
`js
const logger = require('@condor-labs/logger');
const veryImportantData = { key: '1A2B3C', client: 'my_client' };
try {
// Runs my code and throws an error
throw new Error('Unauthorized');
} catch (error) {
// OK
logger.error('ERROR_DURING_AUTHORIZATION', error, { veryImportantData });
// NOT RECOMMENDED
logger.error('ERROR_DURING_AUTHORIZATION', { error, veryImportantData });
}
`
Output (this output is formatted for reading purposes. In runtime, it will be printed as one-line JSON):
`js
/*
OK:
{
"level": "ERROR",
"time": 1676986542037,
"pid": 29461,
"hostname": "MyPC.local",
"arg1": "ERROR_DURING_AUTHORIZATION",
"arg2": {
"message": "Unauthorized",
"stack": "Error: Unauthorized
at Object.
at Module._compile (node:internal/modules/cjs/loader:1155:14)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1209:10)
at Module.load (node:internal/modules/cjs/loader:1033:32)
at Function.Module._load (node:internal/modules/cjs/loader:868:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:22:47"
},
"arg3": { "veryImportantData": { "key": "1A2B3C", "client": "my_client" } }
}
NOT RECOMMENDED WAY:
{
"level": "ERROR",
"time": 1676986691805,
"pid": 29631,
"hostname": "MyPC.local",
"arg1": "ERROR_DURING_AUTHORIZATION",
"arg2": {
"error": {},
"veryImportantData": { "key": "1A2B3C", "client": "my_client" }
}
}
*/
`
Notice that error in arg2 is printed as an empty object.
to show the debug messages (` logger.debug({ y: 1, z: 2 });`) otherwise those message won't appear in console.
* Import loggerMiddleware from the logger and set it as middleware of your ExpressJS server:
`js
const logger = require('@condor-labs/logger');
const { loggerMiddleware } = logger;
...
app.use(loggerMiddleware());
` module for ExpressJS-based servers. Check the docs for further information.How to Publish
$3
Once your contribution is done in the files of folder
src/logger/, run npm run build. This will generate a transpilated version of your changes on folder lib/, that contains the file exported as the logger library. then, move to the next step to publish.$3
You will need to update the
package.json file placed in the root folder.identify the property
version and increase the right number in plus one.$3
`sh
npm login
[Enter username]
[Enter password]
[Enter email]
`If all is ok the console will show you something like this :
$3
sh
npm publish --access public
`Ref: https://docs.npmjs.com/getting-started/publishing-npm-packages
Note: you will need to have a NPM account, if you don't have one create one here: https://www.npmjs.com/signup
The original author and current lead maintainer of this module is the @condor-labs development team.
More about Condor Labs Here.