README.md

Logstash hook for logrus

Use this hook to send the logs to Logstash.

Improved with better callframe override abilities and better support for elasticsearch index patterns by merging additional fields into key=val format and store them into fields field in elasticsearch document.

Usage

Logstash configuration

Send to Elasticsearch Cluster

input {
    tcp {
        port => 8911 # Select a free and opening port
        codec => json
        tcp_keep_alive => true # optional: keep the connection alive
    }
}

output {
    elasticsearch {
        hosts => ["https://localhost:9200"]
        ssl => true
        cacert => "" # optional: path to elasticsearch host CA certificates, such as /etc/logstash/certs/ca.crt
        api_key => "" # Kibana generated API key, if you dont have API key configurated, use username and password instead
        index => "" # optional: Specify the index you wish to send to
    }
}

Directly print in console

input {
    tcp {
        port => 8911 # Select a free and opening port
        codec => json
        tcp_keep_alive => true # optional: keep the connection alive
    }
}

output {
    stdout {
        codec => rubydebug
    }
}

Golang code references

General usage

package main

import (
        "net"

        "github.com/sirupsen/logrus"
        logrustash "github.com/nekomeowww/logrus-logstash-hook"
)

func main() {
        // new logrus instance
        logger := logrus.New()

        // these fields will be at the top-level fields of documents
        predefinedFields := logrus.Fields{"type": "myappName"}

        // create a hook to send logs to Logstash
        hook, err := logrustash.New("tcp", "logstash.mycompany.net:8911", logrustash.DefaultFormatter(predefinedFields))
        if err != nil {
                log.Fatal(err)
        }

        // add this hook to the logger
        logger.Hooks.Add(hook)

        // this package will merge the non-pre-defined fields into key=val format,
        // and store them into fields field of the document for better elasticsearch compatibility,
        // may also reduce the time to deal with the elasticsearch index template
        laterAddedFields := logrus.Fields{"exampleFields", "fields"}

        // then just use as normal logrus
        logger.WithFields(laterAddedFields).Info("Hello World!")
}

This is how it will look like:

{
    "@timestamp" => "2016-02-29T16:57:23.000Z",
      "@version" => "1",
         "level" => "info",
       "message" => "Hello World!",
        "fields" => "exampleFields=fields", # merged fields
          "host" => "172.17.0.1",
          "port" => 45199,
          "type" => "myappName"
}

With caller information

package main

import (
        "net"
        "runtime"

        "github.com/sirupsen/logrus"
        logrustash "github.com/nekomeowww/logrus-logstash-hook"


)

var Log *logrus.Logger

func setCaller(entry *logrus.Entry) {
        // get the caller context
        pc, file, line, _ := runtime.Caller(1)

        // transform pc pointer to *runtime.Func
        funcDetail := runtime.FuncForPC(pc)
        var funcName string
        if funcDetail != nil {
                // get the function name
                funcName = funcDetail.Name()
        }

        // set the caller context into entry.Context
        entry.Context = context.WithValue(context.Background(), logrustash.ContextKeyRuntimeCaller, &runtime.Frame{
                File:     file,
                Line:     line,
                Function: funcName,
        })
}

func Info(args ...interface{}) {
        entry := logrus.NewEntry(Log)
        setCaller(entry, 1)
        entry.Info(args...)
}

func main() {
        // new logrus instance
        Log = logrus.New()
        // set ReportCaller to true to get the callframe
        Log.SetReportCaller(true)

        // these fields will be at the top-level fields of documents
        predefinedFields := logrus.Fields{"type": "myappName"}

        // create a hook to send logs to Logstash
        hook, err := logrustash.New("tcp", "logstash.mycompany.net:8911", logrustash.DefaultFormatter(predefinedFields))
        if err != nil {
                log.Fatal(err)
        }

        // add this hook to the logger
        Log.Hooks.Add(hook)

        // then just use as normal logrus
        Info("Hello World!")
}

{
    "@timestamp" => 2022-07-15T09:22:34Z,
      "@version" => "1",
          "file" => "<path/to/code>:1",
      "function" => "main",
         "level" => "info",
       "message" => "Hello World",
          "type" => "log"
}

Original Creator

Boaz Shuster

Maintainers

Name	Github
Ayaka Neko	@nekomeowww

License

MIT.