feat: refactor layers registration

internal/proxy/director/layer/queue/queue.go

@@ -0,0 +1,201 @@
+package queue
+
+import (
+	"context"
+	"fmt"
+	"html/template"
+	"net/http"
+	"path/filepath"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"forge.cadoles.com/Cadoles/go-proxy"
+	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director"
+	"forge.cadoles.com/cadoles/bouncer/internal/store"
+	"github.com/Masterminds/sprig/v3"
+	"github.com/google/uuid"
+	"github.com/pkg/errors"
+	"gitlab.com/wpetit/goweb/logger"
+)
+
+const LayerType store.LayerType = "queue"
+
+type Queue struct {
+	adapter Adapter
+
+	defaultKeepAlive time.Duration
+
+	templateDir string
+	loadOnce    sync.Once
+	tmpl        *template.Template
+
+	refreshJobRunning uint32
+}
+
+// LayerType implements director.MiddlewareLayer
+func (q *Queue) LayerType() store.LayerType {
+	return LayerType
+}
+
+// Middleware implements director.MiddlewareLayer
+func (q *Queue) Middleware(layer *store.Layer) proxy.Middleware {
+	return func(h http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
+
+			options, err := fromStoreOptions(layer.Options, q.defaultKeepAlive)
+			if err != nil {
+				logger.Error(ctx, "could not parse layer options", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			cookieName := q.getCookieName(layer.Name)
+
+			cookie, err := r.Cookie(cookieName)
+			if err != nil && !errors.Is(err, http.ErrNoCookie) {
+				logger.Error(ctx, "could not retrieve cookie", logger.E(errors.WithStack(err)))
+			}
+
+			if cookie == nil {
+				cookie = &http.Cookie{
+					Name:  cookieName,
+					Value: uuid.NewString(),
+					Path:  "/",
+				}
+
+				w.Header().Add("Set-Cookie", cookie.String())
+			}
+
+			sessionID := cookie.Value
+			queueName := string(layer.Name)
+
+			q.refreshQueue(queueName, options.KeepAlive)
+
+			rank, err := q.adapter.Touch(ctx, queueName, sessionID)
+			if err != nil {
+				logger.Error(ctx, "could not retrieve session rank", logger.E(errors.WithStack(err)))
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+				return
+			}
+
+			if rank >= options.Capacity {
+				q.renderQueuePage(w, r, queueName, options, rank)
+
+				return
+			}
+
+			ctx = logger.With(ctx,
+				logger.F("queueSessionId", sessionID),
+				logger.F("queueName", queueName),
+				logger.F("queueSessionRank", rank),
+			)
+			r = r.WithContext(ctx)
+
+			h.ServeHTTP(w, r)
+		}
+
+		return http.HandlerFunc(fn)
+	}
+}
+
+func (q *Queue) renderQueuePage(w http.ResponseWriter, r *http.Request, queueName string, options *LayerOptions, rank int64) {
+	ctx := r.Context()
+
+	status, err := q.adapter.Status(ctx, queueName)
+	if err != nil {
+		logger.Error(ctx, "could not retrieve queue status", logger.E(errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+
+	q.loadOnce.Do(func() {
+		pattern := filepath.Join(q.templateDir, "*.gohtml")
+
+		logger.Info(ctx, "loading queue page templates", logger.F("pattern", pattern))
+
+		tmpl, err := template.New("").Funcs(sprig.FuncMap()).ParseGlob(pattern)
+		if err != nil {
+			logger.Error(ctx, "could not load queue templates", logger.E(errors.WithStack(err)))
+
+			return
+		}
+
+		q.tmpl = tmpl
+	})
+
+	if q.tmpl == nil {
+		logger.Error(ctx, "queue page templates not loaded", logger.E(errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+
+	templateData := struct {
+		QueueName       string
+		LayerOptions    *LayerOptions
+		Rank            int64
+		CurrentSessions int64
+		MaxSessions     int64
+		RefreshRate     int64
+	}{
+		QueueName:       queueName,
+		LayerOptions:    options,
+		Rank:            rank + 1,
+		CurrentSessions: status.Sessions,
+		MaxSessions:     options.Capacity,
+		RefreshRate:     5,
+	}
+
+	w.WriteHeader(http.StatusServiceUnavailable)
+
+	if err := q.tmpl.ExecuteTemplate(w, "queue", templateData); err != nil {
+		logger.Error(ctx, "could not render queue page", logger.E(errors.WithStack(err)))
+		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+
+		return
+	}
+}
+
+func (q *Queue) refreshQueue(queueName string, keepAlive time.Duration) {
+	if !atomic.CompareAndSwapUint32(&q.refreshJobRunning, 0, 1) {
+		return
+	}
+
+	go func() {
+		defer atomic.StoreUint32(&q.refreshJobRunning, 0)
+
+		ctx, cancel := context.WithTimeout(context.Background(), keepAlive*2)
+		defer cancel()
+
+		if err := q.adapter.Refresh(ctx, queueName, keepAlive); err != nil {
+			logger.Error(ctx, "could not refresh queue",
+				logger.E(errors.WithStack(err)),
+				logger.F("queue", queueName),
+			)
+		}
+	}()
+}
+
+func (q *Queue) getCookieName(layerName store.LayerName) string {
+	return fmt.Sprintf("_%s_%s", LayerType, layerName)
+}
+
+func New(adapter Adapter, funcs ...OptionFunc) *Queue {
+	opts := defaultOptions()
+	for _, fn := range funcs {
+		fn(opts)
+	}
+
+	return &Queue{
+		adapter:          adapter,
+		templateDir:      opts.TemplateDir,
+		defaultKeepAlive: opts.DefaultKeepAlive,
+	}
+}
+
+var _ director.MiddlewareLayer = &Queue{}