dinghy

Dinghy implements leader election using part of the raft protocol. It might be useful if you have several workers but only want one of them at a time doing things.

package main

import (
    "flag"
    "fmt"
    "log"
    "net/http"
    "os"
    "strings"

    "github.com/upsight/dinghy"
)

func main() {
    addr := flag.String("addr", "localhost:8899", "The address to listen on.")
    nodesList := flag.String("nodes", "localhost:8898,localhost:8897", "Comma separated list of host:port")
    flag.Parse()

    nodes := strings.Split(*nodesList, ",")
    nodes = append(nodes, *addr)

    onLeader := func() error {
        fmt.Println("leader")
        return nil
    }
    onFollower := func() error {
        fmt.Println("me follower")
        return nil
    }

    din, err := dinghy.New(
        *addr,
        nodes,
        onLeader,
        onFollower,
        &dinghy.LogLogger{Logger: log.New(os.Stderr, "logger: ", log.Lshortfile)},
        dinghy.DefaultElectionTickRange,
        dinghy.DefaultHeartbeatTickRange,
    )
    if err != nil {
        log.Fatal(err)
    }
    for _, route := range din.Routes() {
        http.HandleFunc(route.Path, route.Handler)
    }
    go func() {
        if err := din.Start(); err != nil {
            log.Fatal(err)
        }
    }()
    log.Fatal(http.ListenAndServe(*addr, nil))
}