forked from crosbymichael/skydock
/
main.go
283 lines (241 loc) · 6.22 KB
/
main.go
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/*
Multihost
Multiple ports
*/
package main
import (
"encoding/json"
"errors"
"flag"
"fmt"
"github.com/skynetservices/skydns/client"
"github.com/skynetservices/skydns/msg"
"io"
"log"
"net/http"
"os"
"sync"
"time"
)
var (
pathToSocket string
domain string
environment string
skydnsUrl string
secret string
ttl int
beat int
numberOfHandlers int
skydns *client.Client
dockerClient *docker
running = make(map[string]struct{})
errNotTagged = errors.New("image not tagged")
)
func init() {
flag.StringVar(&pathToSocket, "s", "/var/run/docker.sock", "path to the docker unix socket")
flag.StringVar(&skydnsUrl, "skydns", "", "url to the skydns url")
flag.StringVar(&secret, "secret", "", "skydns secret")
flag.StringVar(&domain, "domain", "", "same domain passed to skydns")
flag.StringVar(&environment, "environment", "dev", "environment name where service is running")
flag.IntVar(&ttl, "ttl", 60, "default ttl to use when registering a service")
flag.IntVar(&beat, "beat", 0, "heartbeat interval")
flag.IntVar(&numberOfHandlers, "workers", 10, "number of concurrent workers")
flag.Parse()
if beat < 1 {
beat = ttl - (ttl / 4)
}
if skydnsUrl == "" {
skydnsUrl = "http://" + os.Getenv("SKYDNS_PORT_8080_TCP_ADDR") + ":8080"
}
if domain == "" {
log.Fatal("Must specify your skydns domain")
}
}
func heartbeat(uuid string) {
if _, exists := running[uuid]; exists {
return
}
// TODO: not safe for concurrent access
running[uuid] = struct{}{}
defer delete(running, uuid)
var (
errorCount int
err error
container *Container
)
for _ = range time.Tick(time.Duration(beat) * time.Second) {
if errorCount > 10 {
// if we encountered more than 10 errors just quit
log.Printf("Aborting heartbeat for %s after 10 errors\n", uuid)
return
}
if container, err = dockerClient.fetchContainer(uuid, ""); err != nil {
errorCount++
log.Println(err)
break
}
if !container.State.Running {
if err := removeService(uuid); err != nil {
log.Println(err)
}
return
}
// don't fill logs if we have a low beat
// may need to do something better here
if beat >= 30 {
log.Printf("Updating ttl for %s\n", container.Name)
}
if err := skydns.Update(uuid, uint32(ttl)); err != nil {
errorCount++
log.Println(err)
break
}
}
}
// restoreContainers loads all running containers and inserts
// them into skydns when skydock starts
func restoreContainers() error {
req, err := http.NewRequest("GET", fmt.Sprintf("/containers/json"), nil)
if err != nil {
return err
}
c, err := dockerClient.newConn()
if err != nil {
return err
}
defer c.Close()
resp, err := c.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode == http.StatusOK {
var (
containers []*Container
container *Container
)
if err = json.NewDecoder(resp.Body).Decode(&containers); err != nil {
return err
}
for _, cnt := range containers {
uuid := truncate(cnt.Id)
if container, err = dockerClient.fetchContainer(uuid, cnt.Image); err != nil {
if err != errNotTagged {
log.Printf("Failed to fetch %s for restore - %s\n", cnt.Id, err)
}
continue
}
if err := sendService(uuid, createService(container)); err != nil {
log.Printf("Failed to send %s to skydns for restore - %s\n", uuid, err)
}
}
}
return nil
}
// <uuid>.<host>.<region>.<version>.<service>.<environment>.skydns.local
func createService(container *Container) *msg.Service {
return &msg.Service{
Name: cleanImageImage(container.Image), // Service name
Version: removeSlash(container.Name), // Instance of the service
Host: container.NetworkSettings.IpAddress,
Environment: environment, // testing, prod, dev
TTL: uint32(ttl), // 60 seconds
Port: 80, // TODO: How to handle multiple ports
}
}
// sendService sends the uuid and service data to skydns
func sendService(uuid string, service *msg.Service) error {
log.Printf("Adding %s (%s)\n", uuid, service.Name)
if err := skydns.Add(uuid, service); err != nil {
return err
}
go heartbeat(uuid)
return nil
}
func removeService(uuid string) error {
log.Printf("Removing %s from skydns\n", uuid)
return skydns.Delete(uuid)
}
func addService(uuid, image string) error {
log.Printf("Adding %s for %s\n", uuid, image)
container, err := dockerClient.fetchContainer(uuid, image)
if err != nil {
if err != errNotTagged {
return err
}
return nil
}
if err := sendService(uuid, createService(container)); err != nil {
return err
}
return nil
}
func eventHandler(c chan *Event, group *sync.WaitGroup) {
group.Add(1)
defer group.Done()
for event := range c {
uuid := truncate(event.ContainerId)
switch event.Status {
case "die", "stop", "kill":
if err := removeService(uuid); err != nil {
log.Printf("Error deleting %s - %s\n", uuid, err)
}
case "start", "restart":
if err := addService(uuid, event.Image); err != nil {
log.Printf("Error adding %s - %s\n", uuid, err)
}
}
}
}
func main() {
var (
err error
eventChan = make(chan *Event, 100) // 100 event buffer
group = &sync.WaitGroup{}
)
if dockerClient, err = newClient(pathToSocket); err != nil {
log.Fatal(err)
}
if skydns, err = client.NewClient(skydnsUrl, secret, domain, 53); err != nil {
log.Fatal(err)
}
log.Println("Starting restore of running containers...")
if err := restoreContainers(); err != nil {
log.Fatal(err)
}
c, err := dockerClient.newConn()
if err != nil {
log.Fatal(err)
}
defer c.Close()
// Start event handlers
for i := 0; i < numberOfHandlers; i++ {
go eventHandler(eventChan, group)
}
req, err := http.NewRequest("GET", "/events", nil)
if err != nil {
log.Fatal(err)
}
resp, err := c.Do(req)
if err != nil {
log.Fatal(err)
}
defer resp.Body.Close()
log.Println("Starting run loop...")
d := json.NewDecoder(resp.Body)
for {
var event *Event
if err := d.Decode(&event); err != nil {
if err == io.EOF {
break
}
log.Printf("Error decoding json %s\n", err)
continue
}
eventChan <- event
}
// Close the event chan then wait for handlers to finish
close(eventChan)
group.Wait()
log.Println("Stopping cleanly via EOF")
}