Acelogger

Acelogger is a light and powerful logger with tracing and metrics logging. It is inspired by opentelemetry-js.

Design

Why make a new one?

opentelemetry, opentracing and other libraries, are hard to understand and use.

1. too many concepts. TracerProvider, Tracer, SpanProcessor, Span, Logger, Event, Metric, MetricProvider etc.

2. large code size

   1. @opentelemetry/tracing minimized 39.9kb
   2. @opentelemetry/api minimized 13.8kb
   3. @opentelemetry/web minimized 46.1kb
   4. acelogger minimized < 10kb

3. bad design

   1. circulation dependencies
   2. do not support tree shaking

Core Concepts

The logging, tracing and metrics will generate events which logged by logger, event have different alert level and event type.

1. tracer is just the factory class for span.
2. logger use tracer to create span and span context.
3. logger can create, record and export events.
4. define exporter with alert level, includes: debug, info, warn, error, fatal
5. exporter will sample the events
6. event type includes:
   1. log event, for message logging
   2. store, count and timing events, for metric reporting
   3. span start and span end events, for tracing

Usage

Install

$ npm install --save acelogger

Example

import ace, {
  ConsoleExporterWeb,
  LogLevel,
  CanonicalCode,
  isMetricEvent,
} from 'acelogger';

ace.logger.setAttributes({
  os: 'MacOS',
  osVersion: '13.0',
});

class MetricExporterWeb implements LoggerEventExporter {
  export(evts: LoggerEvent[]) {
    const metricEvents = evts.filter(isMetricEvent);
    console.log(metricEvents);
  }
}

// set event exporter, for mesage logging
ace.setExporter(LogLevel.Debug, new ConsoleExporterWeb());
// set event exporter, for metric reportings
ace.setExporter(LogLevel.Debug, new MetricExporterWeb());

// log info level message
ace.logger.info('test info');
ace.logger.storeMetrics({
  metrics: {
    memoryUsage: 0.1,
    cpuUsage: 0.5,
  },
});
ace.logger.event('button_click');

// creat a span logger
const spanLogger = ace.logger.startSpan('first.span', {
  parent: ace.tracer.createSpanContext(),
});

spanLogger.setAttributes({
  path: '/path/to',
});

spanLogger.info('test info');
spanLogger.event('button_click');

spanLogger.endSpan({
  status: CanonicalCode.OK,
});

Customize Logger

when logging in module, you can customize a scoped logger.

import globaleAce, {
  SimpleManager,
  LogLevel,
  ConsoleExporterWeb,
} from 'acelogger';
const manager = new SimpleManager();

manager.logger.setAttributes({
  app: globaleAce.logger.getAttributes().app,
  appVersion: globaleAce.logger.getAttributes().appVersion,
  lib: 'my-module@0.0.1',
});

// init logger exporter
manager.setExporter(LogLevel.Debug, new ConsoleExporterWeb());
manager.setBufferSize(0);

export { manager as ace };

Customize Exporter

you can customize a exporter

import ace, { TraceFlags, SimpleManager, LogLevel, ConsoleExporterWeb, isCountEvent } from 'acelogger';

// init logger exporter
manager.setExporter(LogLevel.Debug, {
  export(
    events: LoggerEvent[],
    resultCallback: (result: ExportResult) => void
  ): void {
    for (const evt of events) {
      if (evt.traceFlags === TraceFlags.SAMPLED && !isSimpled(evt)) {
        return;
      }
      if (evt.metrics) {
        logMetric(evt);
      } else if (isCountEvent(evt)) {
        logCount(evt)
      }
      logToFile(evt);
    }
  };
});

API

See Details

ChangeLog

2022-01-24 0.13.5

• feat: remove duration infomation in endSpan message

2022-01-14 0.13.4

• feat: set logStart default is true
• feat: add IDGenerator api

2022-01-13 0.13.3

• fix: default span id start with 0
• feat: add userStartTime to span start event

2021-10-18 0.13.2

• refactor: new exporter api (break change)

2021-10-18 0.12.1

• refactor: add some util for event name and metric name

2021-10-11 0.12.0

• feat: enhancement default traceId and spanId

2021-10-08 0.11.0

• feat: support set flush ready flag

2021-10-08 0.10.0

• feat: remove setBufferSize

2021-04-23 0.9.2

• feat: chage samplingRatio to samplingRate

2021-04-20 0.9.0

• feat: SimpleManager support customize flush delay time

2021-04-20 0.8.1

• feat: add samplingRatio for event and disable log start event by default

2021-04-19 0.8.0

• feat: startSpan add logStart param to disable start span event

2021-03-02 0.7.5

• fix: change __debug to __ace_debug

2021-01-03 0.7.4

• feat: support data option for Logger.startSpan
• fix: logger.error and fatal not support string as message

2020-12-12 0.7.3

• optimize: async flush events
• optimize: console expoter default only print warn, error, fatal logs

2020-11-18 0.7.2

• fix: use strict rule for function type

2020-11-18 0.7.1

• fix: storeMetrics support status

2020-11-18 0.7.0 Breaking Change

• refactor: LoggerEvent structure changed
• refactor: remove isCountEvent

2020-11-17 0.6.0 Breaking Change

• refactor: move setExporter & setBufferSize to Manager

2020-11-17 0.5.2

• feat: move spanId and traceId to LoggerEvent.data

2020-11-13 0.5.1

• update README.md

2020-11-12 0.5.0 Breaking Change

• remove api count, timing, store
• add storeMetrics, event api

2020-11-08 0.4.0

• remove some default attributes of LoggerEvent

2020-11-07 0.3.0

• add fatal for Logger
• Logger.count only record 1 time
• LoggerEvent add metrics property and data property will without metrics

2020-10-11 0.2.2

• add traceFlags for LoggerEvent, which can get sampled flag
• change endSpan message format, now have duration and customized message

2020-09-25 0.2.1

• refactor isMetricEvent

2020-09-24 0.2.0

• break change SimpleLogger api, to reduce duplicate logs

2020-09-24 0.1.1

• remove unsafe dependencies

2020-09-23 0.1.0

• refactor: new Manager api

2020-08-27 0.0.6

• fix: build with no files

2020-08-27 0.0.5

• fix: console logger name is undefined

2020-08-12 0.0.4

• remove span methods

2020-08-10 0.0.3

• new singleton api

2020-08-02 0.0.2

• fix opentelemetry-api do not support tree shaking problem

2020-08-02 0.0.1

• first version with logger and tracer