Add Brotli Support for NGINX in ESP (#784)

* added workspace

* rearrange

* order matters

* remove an extra brotli

* rearrange text

* fix a duplicate function name

* some extra changes

* clear out work

* add brotli flag

* added nginx build

* added brotli content-encoding test

WORKSPACE

@@ -52,6 +52,7 @@ load("@nginx//:build.bzl", "nginx_repositories")
 nginx_repositories(
     bind = True,
     nginx = "@nginx//",
+    ngx_brotli = True,
 )
 
 # Needs to come after nginx

src/nginx/BUILD

@@ -121,5 +121,7 @@ cc_library(
         "//src/grpc:zero_copy_stream",
         "@nginx//:core",
         "@nginx//:http",
+        "@ngx_brotli//:http_brotli_filter",
+        "@ngx_brotli//:http_brotli_static",
     ],
 )

src/nginx/t/BUILD

@@ -196,6 +196,7 @@ nginx_suite(
         "backend_routing_append_path.t",
         "backend_routing_constant_address.t",
         "by_consumer_metrics.t",
+        "brotli.t",
         "check.t",
         "check_api_key.t",
         "check_api_target_blocked.t",

src/nginx/t/brotli.t

@@ -0,0 +1,114 @@
+# Copyright (C) Extensible Service Proxy Authors
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+################################################################################
+#
+use strict;
+use warnings;
+
+################################################################################
+
+use src::nginx::t::ApiManager;   # Must be first (sets up import path to the Nginx test module)
+use src::nginx::t::HttpServer;
+use Test::Nginx;  # Imports Nginx's test module
+use Test::More;   # And the test framework
+
+################################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http proxy brotli/)->plan(6);
+
+$t->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+        location / {
+            brotli on;
+        }
+        location /proxy/ {
+            brotli on;
+            proxy_pass http://127.0.0.1:8080/local/;
+        }
+        location /local/ {
+            brotli off;
+            alias %%TESTDIR%%/;
+        }
+    }
+}
+
+EOF
+
+$t->write_file('index.html', 'X' x 64);
+
+$t->run();
+
+###############################################################################
+
+my $r;
+
+$r = http_brotli_request('/');
+like($r, qr/^Content-Encoding: br/m, 'br');
+
+$r = http_brotli_request('/proxy/');
+like($r, qr/^Content-Encoding: br/m, 'br proxied');
+
+# Accept-Ranges headers should be cleared
+
+unlike(http_brotli_request('/'), qr/Accept-Ranges/im, 'cleared accept-ranges');
+unlike(http_brotli_request('/proxy/'), qr/Accept-Ranges/im,
+	'cleared headers from proxy');
+
+# HEAD requests should return correct headers
+
+like(http_brotli_request('/'), qr/Content-Encoding: br/, 'br head');
+unlike(http_head('/'), qr/Content-Encoding: br/, 'no br head');
+
+###############################################################################
+
+sub http_brotli_request {
+	my ($url) = @_;
+	my $r = http(<<EOF);
+GET $url HTTP/1.1
+Host: localhost
+Connection: close
+Accept-Encoding: br
+
+EOF
+}
+
+
+###############################################################################