@cumulus/logger v18.2.1

@cumulus/logger

A logging library for use on the Cumulus project.

The @cumulus/logger library exports a Logger class, which generates JSON-formated log events.

Log events always have the following keys:

• level (string) - the priority level of the message
• message (string) - the message itself
• sender (string) - the resource that created the message
• timestamp (string) - an ISO-8601 timestamp

Log events may have the following options keys:

• executions (string)
• version (string)

Log events may also contain user-specified keys.

Example log event:

{
  "level": "info",
  "message": "hello world",
  "sender": "greetingFunction",
  "timestamp": "2018-10-19T19:12:47.501Z"
}

Install

$ npm install @cumulus/logger

Usage

const Logger = require('@cumulus/logger');

const log = new Logger({ sender: 'example' });

log.info('hello, world');

API

new Logger({ sender, executions, version })

sender

Type: string

The sender of the log event. Typically a Lambda Function Name or ECS Task Name. Defaults to "unknown".

executions

Type: string

An optional description of the executions.

version

Type: string

An optional version.

log.debug(...messageArgs)

Writes a log event to stdout with level set to "debug".

args

Type: ...any

See console.log().

log.error(...messageArgs)

Writes a log event to stderr with level set to "error".

args

Type: ...any

See console.log().

error

Type: Error

If the last argument is an Error then the following additional properties will be set on the log event:

• error (Object)
  • name (string)
  • message (string)
  • stack (Array\<string>) - the lines of the stack trace

log.fatal(...messageArgs)

Writes a log event to stdout with level set to "fatal".

args

Type: ...any

See console.log().

log.info(...messageArgs)

Writes a log event to stdout with level set to "info".

args

Type: ...any

See console.log().

log.infoWithAdditionalKeys(additionalKeys, ...messageArgs)

Writes a log event to stdout with level set to "info". In addition to the standard keys, additional keys will be added to the event. If an additional key is specified with the same name as a standard key, the value standard key will be displayed.

additionalKeys

Type: Object

Additional key/value pairs to be added to the event.

args

Type: ...any

See console.log().

log.trace(...messageArgs)

Writes a log event to stdout with level set to "trace".

args

Type: ...any

See console.log().

log.warn(...messageArgs)

Writes a log event to stdout with level set to "debug".

args

Type: ...any

See console.log().

What is Cumulus?

Cumulus is a cloud-based data ingest, archive, distribution and management prototype for NASA's future Earth science data streams.

Cumulus Documentation

Contributing

See Cumulus README