dockerClient.go

package main

import (
	"fmt"
	"strconv"
	"time"

	"github.com/fsouza/go-dockerclient"
	"github.com/samuel/go-zookeeper/zk"
)

func main() {
	dkrClient, err := docker.NewClientFromEnv()
	handleError(err)
	zkConn, _, err := zk.Connect([]string{"127.0.0.1:2181"}, time.Second)
	handleError(err)
	time.Sleep(time.Second)
	prevcontainers := 0

	for {
		containers, err := dkrClient.ListContainers(docker.ListContainersOptions{All: false, Filters: map[string][]string{"name": {"pushpin1"}, "status": {"running"}}})
		handleError(err)
		if len(containers) == prevcontainers {
			continue
		} else {
			if len(containers) == 1 {
				_, err := zkConn.Create("/pushpin/server", []byte("localhost:"+strconv.FormatInt(containers[0].Ports[0].PrivatePort, 10)), zk.FlagEphemeral, zk.WorldACL(zk.PermAll))
				handleError(err)
				fmt.Println("[zookeeper] : Registered pushpin server")
			} else {
				err := zkConn.Delete("/pushpin/server", -1)
				handleError(err)
				fmt.Println("[zookeeper] : Deleted pushpin server")
			}
		}
		prevcontainers = len(containers)
	}

}

//handleError stops the program execution
func handleError(err error) {
	if err != nil {
		panic(err)
	}
}