docs/backends/forward.go

114 lines
2.6 KiB
Go

package backends
import (
"fmt"
"github.com/docker/libswarm/beam"
"github.com/dotcloud/docker/engine"
"io/ioutil"
"net/http"
"net/url"
"strings"
"time"
)
func Forward() beam.Sender {
backend := beam.NewServer()
backend.OnSpawn(beam.Handler(func(ctx *beam.Message) error {
if len(ctx.Args) != 1 {
return fmt.Errorf("forward: spawn takes exactly 1 argument, got %d", len(ctx.Args))
}
client, err := newClient(ctx.Args[0], "v0.10")
if err != nil {
return fmt.Errorf("%v", err)
}
f := &forwarder{client: client}
instance := beam.NewServer()
instance.OnAttach(beam.Handler(f.attach))
instance.OnStart(beam.Handler(f.start))
instance.OnLs(beam.Handler(f.ls))
_, err = ctx.Ret.Send(&beam.Message{Verb: beam.Ack, Ret: instance})
return err
}))
return backend
}
type forwarder struct {
client *client
}
func (f *forwarder) attach(ctx *beam.Message) error {
ctx.Ret.Send(&beam.Message{Verb: beam.Ack})
for {
time.Sleep(1 * time.Second)
(&beam.Object{ctx.Ret}).Log("forward: heartbeat")
}
return nil
}
func (f *forwarder) start(ctx *beam.Message) error {
ctx.Ret.Send(&beam.Message{Verb: beam.Ack})
return nil
}
func (f *forwarder) ls(ctx *beam.Message) error {
resp, err := f.client.call("GET", "/containers/json", "")
if err != nil {
return fmt.Errorf("%s: get: %v", f.client.URL.String(), err)
}
// FIXME: check for response error
c := engine.NewTable("Created", 0)
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return fmt.Errorf("%s: read body: %v", f.client.URL.String(), err)
}
if _, err := c.ReadListFrom(body); err != nil {
return fmt.Errorf("%s: readlist: %v", f.client.URL.String(), err)
}
names := []string{}
for _, env := range c.Data {
names = append(names, env.GetList("Names")[0][1:])
}
if _, err := ctx.Ret.Send(&beam.Message{Verb: beam.Set, Args: names}); err != nil {
return fmt.Errorf("%s: send response: %v", f.client.URL.String(), err)
}
return nil
}
type client struct {
URL *url.URL
proto string
addr string
version string
}
func newClient(peer, version string) (*client, error) {
u, err := url.Parse(peer)
if err != nil {
return nil, err
}
c := &client{
URL: u,
version: version,
}
c.URL.Scheme = "http"
return c, nil
}
func (c *client) call(method, path, body string) (*http.Response, error) {
u, err := url.Parse(path)
if err != nil {
return nil, err
}
u.Host = c.URL.Host
u.Scheme = c.URL.Scheme
req, err := http.NewRequest(method, u.String(), strings.NewReader(body))
if err != nil {
return nil, err
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
return resp, nil
}