How-to: Add a Worker (Collector or Logger)

This guide explains how to extend DNS-collector by creating a custom worker (input collector or output logger) using the Pluggable Component Registry.

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1. Add Configuration

Add the configuration struct for your worker in pkgconfig/loggers.go or pkgconfig/collectors.go:

type ConfigLoggers struct {
    MyLogger struct {
        Enable bool   `yaml:"enable"`
        // add other custom parameters here
    } `yaml:"mylogger"`
}

Define the defaults in SetDefault():

func (c *ConfigLoggers) SetDefault() {
    c.MyLogger.Enable = false
}

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2. Implement the Worker

Create your worker file workers/mylogger.go (and unit tests workers/mylogger_test.go):

package workers

import (
    "github.com/dmachard/go-dnscollector/v3/dnsutils"
    "github.com/dmachard/go-dnscollector/v3/pkgconfig"
    "github.com/dmachard/go-logger"
)

type MyWorker struct {
    *GenericWorker
}

func NewMyWorker(config *pkgconfig.Config, console *logger.Logger, name string) *MyWorker {
    bufSize := config.Global.Worker.ChannelBufferSize
    s := &MyWorker{
        GenericWorker: NewGenericWorker(config, console, name, "mylogger", bufSize, pkgconfig.DefaultMonitor),
    }
    s.ReadConfig()
    return s
}

func (w *MyWorker) StartCollect() {
    w.LogInfo("starting data collection")
    defer w.CollectDone()

    // goroutine to process transformed DNS messages
    go w.StartLogging()

    // loop to process incoming messages
    for {
        select {
        case <-w.OnStop():
            w.StopLogger()
            return

        case _, opened := <-w.GetInputChannel():
            if !opened {
                w.LogInfo("run: input channel closed!")
                return
            }
        }
    }
}

func (w *MyWorker) StartLogging() {
    w.LogInfo("logging has started")
    defer w.LoggingDone()

    for {
        select {
        case <-w.OnLoggerStopped():
            return

        case batch, opened := <-w.GetOutputChannel():
            if !opened {
                w.LogInfo("process: output channel closed!")
                return
            }

            for _, dm := range batch.Messages {
                // Process/forward the DNS message
                w.CountEgressTraffic()
            }
            batch.Release()
        }
    }
}

---

3. Register via Component Registry

Register your worker directly in the same file using init().

For a Logger:

func init() {
    RegisterLogger("mylogger", func(c *pkgconfig.Config) bool { return c.Loggers.MyLogger.Enable }, func(c *pkgconfig.Config, l *logger.Logger, s string) Worker {
        return NewMyWorker(c, l, s)
    })
}

For a Collector:

func init() {
    RegisterCollector("mycollector", func(c *pkgconfig.Config) bool { return c.Collectors.MyCollector.Enable }, func(c *pkgconfig.Config, l *logger.Logger, s string) Worker {
        return NewMyCollector(nil, c, l, s)
    })
}

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4. Documentation & Tests

1. Add unit tests in workers/mylogger_test.go.
2. Add reference documentation in docs/platforms/ or docs/collectors/ and update README.md.