feat: uses brotli on the fly for static files and gzip for streaming (#3825)

internal/support/web/sse.go

@@ -2,26 +2,27 @@ package support_web
 
 import (
 	"bytes"
+	"compress/gzip"
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
+	"strings"
 
 	"net/http"
 )
 
 type SSEWriter struct {
+	w io.Writer
 	f http.Flusher
-	w http.ResponseWriter
 }
 
 type HasId interface {
 	MessageId() int64
 }
 
-func NewSSEWriter(ctx context.Context, w http.ResponseWriter) (*SSEWriter, error) {
-	f, ok := w.(http.Flusher)
-
-	if !ok {
+func NewSSEWriter(ctx context.Context, w http.ResponseWriter, r *http.Request) (*SSEWriter, error) {
+	if _, ok := w.(http.Flusher); !ok {
 		return nil, http.ErrNotSupported
 	}
 
@@ -31,9 +32,15 @@ func NewSSEWriter(ctx context.Context, w http.ResponseWriter) (*SSEWriter, error
 	w.Header().Set("Connection", "keep-alive")
 	w.Header().Set("X-Accel-Buffering", "no")
 
+	var writer io.Writer = w
+	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+		w.Header().Set("Content-Encoding", "gzip")
+		writer = gzip.NewWriter(w)
+	}
+
 	sse := &SSEWriter{
-		f: f,
-		w: w,
+		w: writer,
+		f: w.(http.Flusher),
 	}
 
 	return sse, nil
@@ -50,6 +57,13 @@ func (s *SSEWriter) Write(data []byte) (int, error) {
 		return written, err
 	}
 
+	if f, ok := s.w.(*gzip.Writer); ok {
+		err := f.Flush()
+		if err != nil {
+			return written, err
+		}
+	}
+
 	s.f.Flush()
 
 	return written, nil
@@ -60,6 +74,12 @@ func (s *SSEWriter) Ping() error {
 	return err
 }
 
+func (s *SSEWriter) Close() {
+	if closer, ok := s.w.(io.Closer); ok && s.w != nil {
+		closer.Close()
+	}
+}
+
 func (s *SSEWriter) Message(data any) error {
 	encoded, err := json.Marshal(data)
 

internal/web/brotli.go

@@ -0,0 +1,37 @@
+package web
+
+import (
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/andybalholm/brotli"
+)
+
+type brotliWriter struct {
+	io.Writer
+	http.ResponseWriter
+}
+
+func (w brotliWriter) Write(b []byte) (int, error) {
+	return w.Writer.Write(b)
+}
+
+func Brotli(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Check if client supports Brotli
+		if !strings.Contains(r.Header.Get("Accept-Encoding"), "br") {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		w.Header().Set("Content-Encoding", "br")
+		w.Header().Add("Vary", "Accept-Encoding")
+
+		brWriter := brotli.NewWriter(w)
+		defer brWriter.Close()
+
+		bw := brotliWriter{Writer: brWriter, ResponseWriter: w}
+		next.ServeHTTP(bw, r)
+	})
+}

internal/web/events.go

@@ -13,7 +13,9 @@ import (
 )
 
 func (h *handler) streamEvents(w http.ResponseWriter, r *http.Request) {
-	sseWriter, err := support_web.NewSSEWriter(r.Context(), w)
+	sseWriter, err := support_web.NewSSEWriter(r.Context(), w, r)
+	defer sseWriter.Close()
+
 	if err != nil {
 		log.Error().Err(err).Msg("error creating sse writer")
 		http.Error(w, err.Error(), http.StatusInternalServerError)

internal/web/index.go

@@ -3,10 +3,7 @@ package web
 import (
 	"html/template"
 	"io"
-	"mime"
-	"path/filepath"
 	"sort"
-	"strings"
 
 	"encoding/json"
 
@@ -24,14 +21,7 @@ func (h *handler) index(w http.ResponseWriter, req *http.Request) {
 	_, err := h.content.Open(path)
 	if err == nil && req.URL.Path != "" && req.URL.Path != "/" {
 		w.Header().Set("Cache-Control", "max-age=31536000, immutable")
-		// if brotli is enabled, then just send over the compressed file
-		if file, err := h.content.Open(path + ".br"); strings.Contains(req.Header.Get("Accept-Encoding"), "br") && err == nil {
-			w.Header().Set("Content-Encoding", "br")
-			w.Header().Set("Content-Type", mime.TypeByExtension(filepath.Ext(path)))
-			io.Copy(w, file)
-		} else {
-			fileServer.ServeHTTP(w, req)
-		}
+		fileServer.ServeHTTP(w, req)
 	} else {
 		h.executeTemplate(w, req)
 	}

internal/web/logs.go

@@ -112,14 +112,12 @@ func (h *handler) fetchLogsBetweenDates(w http.ResponseWriter, r *http.Request)
 		lastSeenId = uint32(num)
 	}
 
-	var encoder *json.Encoder
+	encoder := json.NewEncoder(w)
 	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 		w.Header().Set("Content-Encoding", "gzip")
 		writer := gzip.NewWriter(w)
 		defer writer.Close()
 		encoder = json.NewEncoder(writer)
-	} else {
-		encoder = json.NewEncoder(w)
 	}
 
 	for {
@@ -247,7 +245,8 @@ func (h *handler) streamLogsForContainers(w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	sseWriter, err := support_web.NewSSEWriter(r.Context(), w)
+	sseWriter, err := support_web.NewSSEWriter(r.Context(), w, r)
+	defer sseWriter.Close()
 	if err != nil {
 		log.Error().Err(err).Msg("error creating sse writer")
 		http.Error(w, err.Error(), http.StatusInternalServerError)

internal/web/routes.go

@@ -140,7 +140,7 @@ func createRouter(h *handler) *chi.Mux {
 		r.Get("/healthcheck", h.healthcheck)
 
 		defaultHandler := http.StripPrefix(strings.Replace(base+"/", "//", "/", 1), http.HandlerFunc(h.index))
-		r.Get("/*", func(w http.ResponseWriter, req *http.Request) {
+		r.With(Brotli).Get("/*", func(w http.ResponseWriter, req *http.Request) {
 			defaultHandler.ServeHTTP(w, req)
 		})
 	})