/
pool.go
209 lines (167 loc) · 3.68 KB
/
pool.go
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package main
import (
"fmt"
"log"
"sync"
"time"
docker "github.com/fsouza/go-dockerclient"
)
var pools map[string]*Pool
type Pool struct {
Config *Config
Client *docker.Client
Containers map[string]*docker.Container
Image string
Capacity int
Standby int
sync.Mutex
}
func findImage(client *docker.Client, image string) (*docker.APIImages, error) {
images, err := client.ListImages(docker.ListImagesOptions{})
if err != nil {
return nil, err
}
for _, img := range images {
for _, t := range img.RepoTags {
if t == image {
return &img, nil
}
}
}
return nil, fmt.Errorf("invalid image:", image)
}
func NewPool(config *Config, client *docker.Client, image string, capacity int, standby int) (*Pool, error) {
_, err := findImage(client, image)
if err != nil {
return nil, err
}
if standby <= 60 {
standby = 86400
}
pool := &Pool{
Config: config,
Client: client,
Containers: map[string]*docker.Container{},
Image: image,
Capacity: capacity,
Standby: standby,
}
return pool, nil
}
func (pool *Pool) Exists(id string) bool {
return pool.Containers[id] != nil
}
func (pool *Pool) Load() error {
pool.Lock()
defer pool.Unlock()
containers, err := pool.Client.ListContainers(docker.ListContainersOptions{All: true})
if err != nil {
return err
}
for _, c := range containers {
if c.Image == pool.Image && c.Labels["id"] != "" {
pool.Containers[c.ID] = &docker.Container{
ID: c.ID,
Config: &docker.Config{
Labels: c.Labels,
},
}
}
}
return nil
}
func (pool *Pool) Add() error {
container, err := CreateContainer(pool.Client, pool.Config, pool.Image, pool.Standby, "")
if err != nil {
return err
}
if err = pool.Client.StartContainer(container.ID, nil); err != nil {
return err
}
pool.Lock()
defer pool.Unlock()
pool.Containers[container.ID] = container
return nil
}
func (pool *Pool) Fill() {
num := pool.Capacity - len(pool.Containers)
// Pool is full
if num <= 0 {
return
}
log.Printf("adding %v containers to %v pool, standby: %vs\n", num, pool.Image, pool.Standby)
for i := 0; i < num; i++ {
err := pool.Add()
if err != nil {
log.Println("error while adding to pool:", err)
}
}
}
func (pool *Pool) Monitor() {
for {
pool.Fill()
time.Sleep(time.Second * 3)
}
}
func (pool *Pool) Remove(id string) {
pool.Lock()
defer pool.Unlock()
if pool.Containers[id] != nil {
go destroyContainer(pool.Client, id)
delete(pool.Containers, id)
}
}
func (pool *Pool) Get() (*docker.Container, error) {
pool.Lock()
defer pool.Unlock()
var container *docker.Container
for _, v := range pool.Containers {
container = v
break
}
if container != nil {
delete(pool.Containers, container.ID)
return container, nil
}
return nil, fmt.Errorf("no contaienrs are available")
}
func RunPool(config *Config, client *docker.Client) {
chEvents := make(chan *docker.APIEvents)
pools = make(map[string]*Pool)
// Setup docker event listener
if err := client.AddEventListener(chEvents); err != nil {
log.Fatalln(err)
}
go func() {
for {
event := <-chEvents
if event == nil {
continue
}
if event.Status == "die" {
for _, pool := range pools {
if pool.Exists(event.ID) {
log.Println("pool's container got destroyed:", event.ID)
pool.Remove(event.ID)
}
}
}
}
}()
for _, cfg := range config.Pools {
if cfg.Capacity < 1 {
continue
}
log.Println("initializing pool for:", cfg.Image)
pool, err := NewPool(config, client, cfg.Image, cfg.Capacity, cfg.Standby)
if err != nil {
log.Fatalln(err)
}
err = pool.Load()
if err != nil {
log.Fatalln(err)
}
go pool.Monitor()
pools[cfg.Image] = pool
}
}