add brotli-min-length configuration option (kubernetes#7854)

* add `brotli-min-length` configuration option

* add e2e tests for brotli

* include check for expected content type

* fix header and format

docs/user-guide/nginx-configuration/configmap.md

@@ -98,6 +98,7 @@ The following table shows a configuration option's name, type, and the default v
 |[use-geoip2](#use-geoip2)|bool|"false"|
 |[enable-brotli](#enable-brotli)|bool|"false"|
 |[brotli-level](#brotli-level)|int|4|
+|[brotli-min-length](#brotli-min-length)|int|20|
 |[brotli-types](#brotli-types)|string|"application/xml+rss application/atom+xml application/javascript application/x-javascript application/json application/rss+xml application/vnd.ms-fontobject application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/svg+xml image/x-icon text/css text/javascript text/plain text/x-component"|
 |[use-http2](#use-http2)|bool|"true"|
 |[gzip-level](#gzip-level)|int|1|
@@ -665,6 +666,10 @@ The default mime type list to compress is: `application/xml+rss application/atom
 
 Sets the Brotli Compression Level that will be used. _**default:**_ 4
 
+## brotli-min-length
+
+Minimum length of responses, in bytes, that will be eligible for brotli compression. _**default:**_ 20
+
 ## brotli-types
 
 Sets the MIME Types that will be compressed on-the-fly by brotli.

internal/ingress/controller/config/config.go

@@ -413,6 +413,9 @@ type Configuration struct {
 	// Brotli Compression Level that will be used
 	BrotliLevel int `json:"brotli-level,omitempty"`
 
+	// Minimum length of responses, in bytes, that will be eligible for brotli compression
+	BrotliMinLength int `json:"brotli-min-length,omitempty"`
+
 	// MIME Types that will be compressed on-the-fly using Brotli module
 	BrotliTypes string `json:"brotli-types,omitempty"`
 
@@ -778,6 +781,7 @@ func NewDefault() Configuration {
 		BlockUserAgents:                  defBlockEntity,
 		BlockReferers:                    defBlockEntity,
 		BrotliLevel:                      4,
+		BrotliMinLength:                  20,
 		BrotliTypes:                      brotliTypes,
 		ClientHeaderBufferSize:           "1k",
 		ClientHeaderTimeout:              60,

rootfs/etc/nginx/template/nginx.tmpl

@@ -320,6 +320,7 @@ http {
     {{ if $cfg.EnableBrotli }}
     brotli on;
     brotli_comp_level {{ $cfg.BrotliLevel }};
+    brotli_min_length {{ $cfg.BrotliMinLength }};
     brotli_types {{ $cfg.BrotliTypes }};
     {{ end }}
 

test/e2e/settings/brotli.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package settings
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/onsi/ginkgo"
+
+	"k8s.io/ingress-nginx/test/e2e/framework"
+)
+
+var _ = framework.IngressNginxDescribe("brotli", func() {
+	f := framework.NewDefaultFramework("brotli")
+
+	host := "brotli"
+
+	ginkgo.BeforeEach(func() {
+		f.NewHttpbinDeployment()
+	})
+
+	ginkgo.It("should only compress responses that meet the `brotli-min-length` condition", func() {
+		brotliMinLength := 24
+		contentEncoding := "application/octet-stream"
+		f.UpdateNginxConfigMapData("enable-brotli", "true")
+		f.UpdateNginxConfigMapData("brotli-types", contentEncoding)
+		f.UpdateNginxConfigMapData("brotli-min-length", strconv.Itoa(brotliMinLength))
+
+		f.EnsureIngress(framework.NewSingleIngress(host, "/", host, f.Namespace, framework.HTTPBinService, 80, nil))
+
+		f.WaitForNginxConfiguration(
+			func(server string) bool {
+				return strings.Contains(server, fmt.Sprintf("server_name %v", host)) &&
+					strings.Contains(server, "brotli on") &&
+					strings.Contains(server, fmt.Sprintf("brotli_types %v", contentEncoding)) &&
+					strings.Contains(server, fmt.Sprintf("brotli_min_length %d", brotliMinLength))
+			})
+
+		f.HTTPTestClient().
+			GET(fmt.Sprintf("/bytes/%d", brotliMinLength)).
+			WithHeader("Host", host).
+			WithHeader("Accept-Encoding", "br").
+			Expect().
+			Status(http.StatusOK).
+			ContentType(contentEncoding).
+			ContentEncoding("br")
+
+		f.HTTPTestClient().
+			GET(fmt.Sprintf("/bytes/%d", brotliMinLength-1)).
+			WithHeader("Host", host).
+			WithHeader("Accept-Encoding", "br").
+			Expect().
+			Status(http.StatusOK).
+			ContentType(contentEncoding).
+			ContentEncoding()
+	})
+})