Package Exports

@well-known-components/logger
@well-known-components/logger/dist/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@well-known-components/logger) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

logger component

Simple stdout & stderr logger component.

Config

`LOG_LEVEL` configuration

Using the LOG_LEVEL value provided by the IConfigComponent, the following scale is used to filter out the log levels based on the following scale:

"ALL" > "LOG" > "DEBUG" > "INFO" > "WARN" > "ERROR" > "OFF"

Eg:

const config: IConfigComponent = createConfigComponent({ ...process.env, LOG_LEVEL: 'INFO' })

const loggerComponent = createLogComponent({ config })
const logger = getLogger('Test')

logger.info('log some info') // This will be logged
logger.warn('log some warn') // This will be logged
logger.debug('log some debug') // This will NOT be logged

Logger enhancers can be configured

// Datadog enhancer
const tracer = require('dd-trace')
const formats = require('dd-trace/ext/formats')

// enhances the "extra" field of each log to add new data. in this case
// dd.trace_id and dd.span_id will be added
function enhancer(extra) {
  var enhancedObject = extra || {}
  const time = new Date().toISOString()

  const span = tracer.scope().active()
  if (span) {
    tracer.inject(span.context(), formats.LOG, enhancedObject)
  }
  return enhancedObject
}

// in initComponents(), pass the enhancer
const logs = createJsonLogComponent({}, enhancer)

The loggers generate metrics, use them like this:

// metrics.ts
import { validateMetricsDeclaration } from '@well-known-components/metrics'
import { metricDeclarations as logsMetricsDeclarations } from '@well-known-components/logger'

export const metricDeclarations = {
  // ...otherMetrics,
  ...logsMetricsDeclarations
}

// type assertions
validateMetricsDeclaration(metricDeclarations)

// in initComponents(), pass the metrics component to the component

const logs = createJsonLogComponent({ metrics })

@well-known-components/logger