forked from rayleyva/docksul
/
docksul.go
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/
docksul.go
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package main
import (
"flag"
"log"
"os"
"path"
"strconv"
"strings"
"sync"
"github.com/armon/consul-api"
"github.com/cenkalti/backoff"
dockerapi "github.com/fsouza/go-dockerclient"
)
func getopt(name, def string) string {
if env := os.Getenv(name); env != "" {
return env
}
return def
}
func assert(err error) {
if err != nil {
log.Fatal("docksul:", err)
}
}
func containerServiceData(container *dockerapi.Container, prefix, key, dfault string) string {
if prefix != "" {
key = "SERVICE_" + prefix + "_" + key
} else {
key = "SERVICE_" + key
}
for _, env := range container.Config.Env {
kv := strings.SplitN(env, "=", 2)
if strings.ToLower(kv[0]) == strings.ToLower(key) {
return kv[1]
}
}
return dfault
}
type Bridge struct {
sync.Mutex
docker *dockerapi.Client
consul *consulapi.Client
nodeName string
services map[string][]*consulapi.AgentServiceRegistration
}
func (b *Bridge) buildService(container *dockerapi.Container, hostPort, exposedPort, portType string, multiService bool) *consulapi.AgentServiceRegistration {
var keyPrefix, defaultName string
defaultName = path.Base(container.Config.Image)
if multiService {
keyPrefix = exposedPort
defaultName = defaultName + "-" + exposedPort
}
service := new(consulapi.AgentServiceRegistration)
service.ID = b.nodeName + "/" + container.Name[1:] + ":" + exposedPort
service.Name = containerServiceData(container, keyPrefix, "name", defaultName)
p, _ := strconv.Atoi(hostPort)
service.Port = p
service.Tags = make([]string, 0)
if portType == "udp" {
service.ID = service.ID + "/udp"
service.Tags = append(service.Tags, "udp")
}
tags := containerServiceData(container, keyPrefix, "tags", "")
if tags != "" {
service.Tags = append(service.Tags, strings.Split(tags, ",")...)
}
return service
}
func (b *Bridge) Add(containerId string) {
b.Lock()
defer b.Unlock()
container, err := b.docker.InspectContainer(containerId)
if err != nil {
log.Println("docksul: unable to inspect container:", containerId, err)
return
}
portDefs := make([][]string, 0)
for port, published := range container.NetworkSettings.Ports {
if len(published) > 0 {
p := strings.Split(string(port), "/")
portDefs = append(portDefs, []string{published[0].HostPort, p[0], p[1]})
}
}
multiservice := len(portDefs) > 1
for _, port := range portDefs {
service := b.buildService(container, port[0], port[1], port[2], multiservice)
err := backoff.Retry(func() error {
return b.consul.Agent().ServiceRegister(service)
}, backoff.NewExponentialBackoff())
if err != nil {
log.Println("docksul: unable to register service:", service, err)
continue
}
b.services[container.ID] = append(b.services[container.ID], service)
log.Println("docksul: added:", container.ID[:12], service.ID)
}
}
func (b *Bridge) Remove(containerId string) {
b.Lock()
defer b.Unlock()
for _, service := range b.services[containerId] {
err := backoff.Retry(func() error {
return b.consul.Agent().ServiceDeregister(service.ID)
}, backoff.NewExponentialBackoff())
if err != nil {
log.Println("docksul: unable to deregister service:", service.ID, err)
continue
}
log.Println("docksul: removed:", containerId[:12], service.ID)
}
delete(b.services, containerId)
}
func main() {
flag.Parse()
consulConfig := consulapi.DefaultConfig()
if flag.Arg(0) != "" {
consulConfig.Address = flag.Arg(0)
}
consul, err := consulapi.NewClient(consulConfig)
assert(err)
docker, err := dockerapi.NewClient(getopt("DOCKER_HOST", "unix:///var/run/docker.sock"))
assert(err)
log.Println("docksul: Getting Consul nodename...")
var nodeName string
err = backoff.Retry(func() (e error) {
nodeName, e = consul.Agent().NodeName()
if e != nil {
log.Println(e)
}
return
}, backoff.NewExponentialBackoff())
assert(err)
bridge := &Bridge{
docker: docker,
consul: consul,
nodeName: nodeName,
services: make(map[string][]*consulapi.AgentServiceRegistration),
}
containers, err := docker.ListContainers(dockerapi.ListContainersOptions{})
assert(err)
for _, listing := range containers {
bridge.Add(listing.ID[:12])
}
events := make(chan *dockerapi.APIEvents)
assert(docker.AddEventListener(events))
log.Println("docksul: Listening for Docker events...")
for msg := range events {
switch msg.Status {
case "start":
go bridge.Add(msg.ID)
case "die":
go bridge.Remove(msg.ID)
}
}
log.Fatal("docksul: docker event loop closed") // todo: reconnect?
}