add proxy (WIP).

internal/proxy/manager.go

@@ -0,0 +1,256 @@
+package proxy
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"path"
+	"strings"
+	"sync"
+
+	dockerTypes "github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	dockerClient "github.com/docker/docker/client"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+
+	"github.com/m1k1o/neko-rooms/internal/config"
+)
+
+type ProxyManagerCtx struct {
+	logger   zerolog.Logger
+	mu       sync.RWMutex
+	ctx      context.Context
+	cancel   func()
+	prefix   string
+	client   *dockerClient.Client
+	config   *config.Room
+	handlers map[string]http.Handler
+}
+
+func New(client *dockerClient.Client, config *config.Room) *ProxyManagerCtx {
+	logger := log.With().Str("module", "proxy").Logger()
+
+	prefix := config.PathPrefix
+	if !strings.HasSuffix(prefix, "/") {
+		prefix += "/"
+	}
+
+	return &ProxyManagerCtx{
+		logger:   logger,
+		prefix:   prefix,
+		client:   client,
+		config:   config,
+		handlers: map[string]http.Handler{},
+	}
+}
+
+func (p *ProxyManagerCtx) Start() {
+	p.ctx, p.cancel = context.WithCancel(context.Background())
+
+	go func() {
+		err := p.Refresh()
+		if err != nil {
+			p.logger.Err(err).Msg("unable to refresh containers")
+		}
+
+		msgs, errs := p.client.Events(p.ctx, dockerTypes.EventsOptions{
+			Filters: filters.NewArgs(
+				filters.Arg("type", "container"),
+				filters.Arg("label", fmt.Sprintf("m1k1o.neko_rooms.instance=%s", p.config.InstanceName)),
+				filters.Arg("event", "create"),
+				filters.Arg("event", "start"),
+				filters.Arg("event", "stop"),
+				filters.Arg("event", "destroy"),
+			),
+		})
+
+		for {
+			select {
+			case err := <-errs:
+				p.logger.Info().Interface("err", err).Msg("eee")
+			case msg := <-msgs:
+				host := msg.ID[:12]
+				name, port, ok := p.parseLabels(msg.Actor.Attributes)
+				if !ok {
+					break
+				}
+
+				switch msg.Action {
+				case "create":
+					p.logger.Info().
+						Str("id", msg.ID).
+						Str("name", name).
+						Str("host", host).
+						Msg("container created")
+
+				case "start":
+					p.Add(name, host+":"+port)
+
+					p.logger.Info().
+						Str("id", msg.ID).
+						Str("name", name).
+						Str("host", host).
+						Msg("container started")
+
+				case "stop":
+					p.Remove(name)
+
+					p.logger.Info().
+						Str("id", msg.ID).
+						Str("name", name).
+						Str("host", host).
+						Msg("container stopped")
+
+				case "destroy":
+					p.logger.Info().
+						Str("id", msg.ID).
+						Str("name", name).
+						Str("host", host).
+						Msg("container destroyed")
+				}
+			}
+		}
+	}()
+}
+
+func (p *ProxyManagerCtx) Shutdown() error {
+	p.Clear()
+
+	p.cancel()
+	return p.ctx.Err()
+}
+
+func (p *ProxyManagerCtx) refresh() error {
+	containers, err := p.client.ContainerList(p.ctx, dockerTypes.ContainerListOptions{
+		All: true,
+		Filters: filters.NewArgs(
+			filters.Arg("label", fmt.Sprintf("m1k1o.neko_rooms.instance=%s", p.config.InstanceName)),
+		),
+	})
+
+	if err != nil {
+		return err
+	}
+
+	p.clear()
+
+	for _, cont := range containers {
+		name, port, ok := p.parseLabels(cont.Labels)
+		if ok {
+			host := cont.ID[:12]
+			p.add(name, host+":"+port)
+		}
+	}
+
+	return nil
+}
+
+func (p *ProxyManagerCtx) parseLabels(labels map[string]string) (name string, port string, ok bool) {
+	name, ok = labels["m1k1o.neko_rooms.name"]
+	if !ok {
+		return
+	}
+
+	// TODO: Do not use trafik for this.
+	port, ok = labels["traefik.http.services.neko-rooms-"+name+"-frontend.loadbalancer.server.port"]
+	return
+}
+
+func (p *ProxyManagerCtx) add(name, host string) {
+	p.handlers[name] = httputil.NewSingleHostReverseProxy(&url.URL{
+		Scheme: "http",
+		Host:   host,
+	})
+
+	p.logger.Debug().Str("name", name).Str("host", host).Msg("add handler")
+}
+
+func (p *ProxyManagerCtx) remove(name string) {
+	delete(p.handlers, name)
+	p.logger.Debug().Str("name", name).Msg("remove handler")
+}
+
+func (p *ProxyManagerCtx) clear() {
+	p.handlers = map[string]http.Handler{}
+	p.logger.Debug().Msg("clear handlers")
+}
+
+func (p *ProxyManagerCtx) Refresh() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	return p.refresh()
+}
+
+func (p *ProxyManagerCtx) Add(name, host string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.add(name, host)
+}
+
+func (p *ProxyManagerCtx) Remove(name string) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.remove(name)
+}
+
+func (p *ProxyManagerCtx) Clear() {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.clear()
+}
+
+func (p *ProxyManagerCtx) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// only if has prefix
+	if !strings.HasPrefix(r.URL.Path, p.prefix) {
+		http.NotFound(w, r)
+		return
+	}
+
+	// remove prefix and leading /
+	roomPath := strings.TrimPrefix(r.URL.Path, p.prefix)
+	roomPath = strings.TrimLeft(roomPath, "/")
+	if roomPath == "" {
+		http.NotFound(w, r)
+		return
+	}
+
+	// get room name
+	roomName, doRedir := roomPath, false
+	if i := strings.Index(roomPath, "/"); i != -1 {
+		roomName = roomPath[:i]
+	} else {
+		doRedir = true
+	}
+
+	// get proxy by room name
+	p.mu.RLock()
+	proxy, ok := p.handlers[roomName]
+	p.mu.RUnlock()
+
+	// if room not found
+	if !ok {
+		http.NotFound(w, r)
+		return
+	}
+
+	// redirect to room ending with /
+	if doRedir {
+		r.URL.Path += "/"
+		http.Redirect(w, r, r.URL.String(), http.StatusTemporaryRedirect)
+		return
+	}
+
+	// strip prefix from proxy
+	pathPrefix := path.Join(p.prefix, roomName)
+	proxy = http.StripPrefix(pathPrefix, proxy)
+
+	// handle by proxy
+	proxy.ServeHTTP(w, r)
+}