EasyLogger

A simple and easy to use logger for Node.js applications. It has a default StdoutLogAdapter and a default RemoteAPIAdapter. You can also create your own custom adapters.

The RemoteAPIAdapter is a simple HTTPS POST request to a custom endpoint. You can use it to send the logs to a custom log server.

You can disable the default adapters, and configure the RemoteAPIAdapter to send the logs every X seconds and to print the telemetry logs to the console.

The RemoteAPIAdapter will send the logs in batches. You can configure the time interval to send the logs to the remote API.

👩🏻‍💻 How to use

Import the EasyLogger and build an instance object:

const logger = EasyLogger()

Then you can use the info, error or dangerous methods as follow:

const repetitiveData = {
  applicationService: 'generatePDFFile',
  ...otherRepetitiveData
}

// This will be attached to every log.
// Keep in mind that this data will be attached to every log, so it's better to keep it small.
// Also, this data will be overwritten by the data you pass in every log call, so be careful with the keys you use.
const log = logger({
  ...repetitiveData
})

log.info({
  message: 'Coverage checking started',
  data: repetitiveData
})

log.info('You can pass a message only for the log.info method') // this will be threated as the message

log.error(new Error('Something went wrong'), {
  message: 'An error occurred',
  data: repetitiveData
})

log.dangerous({
  message: 'A very problematic error has ocurred',
  data: repetitiveData
}, new Error('Something went wrong'))

🔧 Config

You can attach some useful and generic metadata in the config. There are some options to configure the behavior of the logger.

• You can disable the default internal log adapters and use only custom adapters
• You can disable the default remote API adapter and use only the default StdoutLogAdapter
• You can decide the time interval to send the logs to the remote API
• You can choose to print the telemetry logs to the console

const logger = EasyLogger({
  microserviceName: 'PDF-files-generator',
  host: 'MainServer',
  useDefaultStdOut: true,
  useDefaultRemoteAPI: false, 
  customLogAdapters: [MyCustomAdapter],
  telemetryTimeoutInSecs: 8_000, // 10 seconds by default
  enableTelemetryMessages: true, // false by default
  telemetryEndpointUrl: 'https://my-custom-log-server.com',
})

If you want to use the default remote API adapter, you will need to pass the telemetryEndpointUrl param in the config.

⚙️ Custom adapters

The logger is based on adapters. It has 2 default available adapters:

• StdoutLogAdapter: to print the logs to the console
• RemoteAPIAdapter: to send the logs to a custom HTTPS endpoint

You can also create your own custom adapter. You just need to create a function that returns an object with a log method. The log method will receive the log data and will be executed every time you call the logger methods.

Because the logData receive the level, you can use it to decide how to handle the log. For example, you can use the level to filter the logs and send only the error logs to a custom adapter.

const MyCustomAdapter = (config) => {
  const log = (logData) => {
    if (logData.level === 'info') {
      console.table([{
        serviceName: config.serviceName,
        level: logData.level,
        data: logData.data,
        message: logData.message,
        errorData: logData.errorData
      }])
    }

    if (logData.level === 'error') {
      console.error('An error occurred', logData.errorData)
    }
  }

  return { log }
}

const logger = EasyLogger({
  customLogAdapters: [MyCustomAdapter]
})

📖 Config options

Option	Type	Description
microserviceName	string	The name of the microservice
host	string	The host of the microservice
useDefaultStdOut	boolean	Enable or disable the default StdoutLogAdapter
useDefaultRemoteAPI	boolean	Enable or disable the default RemoteAPIAdapter
customLogAdapters	array	An array of custom log adapters. You can use as many as you need and all of them will be executed.

📖 Custom adapter config data options

Option	Type	Description
serviceName	string	The name of the microservice
level	string	The log level
data	object	The data to be logged
message	string	The message to be logged
errorData	object	The error data to be logged

📖 Custom adapter Log function param options

Option	Type	Description
level	'info', 'error', 'dangerous'	The log level
data	object	The data to be logged
message	string	The message to be logged
errorData	object	The error data to be logged