zkwatcher

ZKWatcher

ZKWatcher provides an easy way to recursively watch a zookeeper path and get meaningful events out of it.

Dependencies

The only dependency is the samuel's zookeeper driver: github.com/samuel/go-zookeeper/zk. If you have godep, you can use it directly, otherwise, you might need to download the driver: go get -d.

Usage

Example

package main

import (
	"fmt"
	"log"
	"time"

	"github.com/agrarianlabs/zkwatcher"
	"github.com/samuel/go-zookeeper/zk"
)

func main() {
	conn, _, err := zk.Connect([]string{"zookeeper host addr"}, 10*time.Second)
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	watcher := zkwatcher.NewWatcher(conn)
	defer func() { _ = watcher.Close() }()

	// Make sure the path exists before starting the watcher.
	if err := watcher.Watch("/path/to/watch"); err != nil {
		log.Println(err)
		return
	}

	for event := range watcher.C {
		if event.Error != nil {
			log.Println(err)
			return
		}
		fmt.Printf("%s on %s\n", event.Type, event.Path)
	}
}

Tests

The tests are only integration tests and relies on a running zookeeper. The tests will create random roots prefixed with zkwatchertest_. Even in case of failure, those should be removed.

With Docker

If you have Docker, make sure you have the DOCKER_IP variable defined and run:

make test

or with custom test options:

make test OPTS='-short -v -cover'

Without Docker

If you don't have Docker, you can spin up a Zookeeper on your own and then run:

go test -v -tags integration -zk-host $YOUR_ZK_TARGET .

or if you have godep:

godep go test -v -cover -tags integration -zk-host $YOUR_ZK_TARGET .