Prevent APIcast fallback to global proxy settings for direct connection

With the newer version of lua-resty-http (0.7.1), if a proxy options
is not provided when calling the connect() method, it will fall back to
using the global proxy settings set by the "set_proxy_option" function
(has no effect in previous versions of the library). This then causes
unexpected behavior where the direct connection will now go through
the proxy server.

This PR explicitly sets the proxy options to an empty table to bypass
global proxy settings when connecting directly.

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Fixed 3scale Batcher policy unable to handle `app_id`/`access_token` contains special characters [PR #1457](https://github.com/3scale/APIcast/pull/1457) [THREESCALE-10934](https://issues.redhat.com/browse/THREESCALE-10934)
 
+- Fixed APIcast send request through proxy server even when `NO_PROXY` is used [PR #1478](https://github.com/3scale/APIcast/pull/1478) [THREESCALE-11128](https://issues.redhat.com/browse/THREESCALE-11128)
+
 ### Added
 
 - Bump openresty to 1.21.4.3 [PR #1461](https://github.com/3scale/APIcast/pull/1461) [THREESCALE-10601](https://issues.redhat.com/browse/THREESCALE-10601)

gateway/src/resty/http/proxy.lua

@@ -57,10 +57,13 @@ local function connect(request)
     -- openresty treat nil as false, so we need to explicitly set ssl_verify to false if nil
     local ssl_verify = request.options and request.options.ssl and request.options.ssl.verify or false
 
+    -- We need to set proxy_opts to an empty table here otherwise, lua-resty-http will fallback
+    -- to the global proxy options
     local options = {
       scheme = scheme,
       host = host,
-      port = port
+      port = port,
+      proxy_opts = {}
     }
     if scheme == 'https' then
         options.ssl_server_name = host

t/http-proxy.t

@@ -2083,3 +2083,46 @@ qr/a client request body is buffered to a temporary file/
 --- grep_error_log_out
 a client request body is buffered to a temporary file
 --- user_files fixture=tls.pl eval
+
+
+
+=== TEST 36: APIcast should not ingore NO_PROXY, when HTTP_PROXY and HTTPS_PROXY are also set
+It connects directly to backened and forwards request to the upstream via proxy.
+--- env random_port eval
+(
+  'http_proxy' => $ENV{TEST_NGINX_HTTP_PROXY},
+  'no_proxy' => '127.0.0.1,localhost,test_backend',
+)
+--- configuration
+{
+  "services": [
+    {
+      "id": 42,
+      "backend_version":  1,
+      "proxy": {
+        "api_backend": "http://test-upstream.lvh.me:$TEST_NGINX_SERVER_PORT/",
+        "proxy_rules": [
+          { "pattern": "/", "http_method": "GET", "metric_system_name": "hits", "delta": 2 }
+        ]
+      }
+    }
+  ]
+}
+--- backend
+  server_name test_backend.lvh.me;
+  location /transactions/authrep.xml {
+    content_by_lua_block {
+      ngx.exit(ngx.OK)
+    }
+  }
+--- upstream
+  server_name test-upstream.lvh.me;
+  location / {
+     echo 'yay, api backend: $http_host';
+  }
+--- request
+GET /?user_key=value
+--- response_body env
+yay, api backend: test-upstream.lvh.me:$TEST_NGINX_SERVER_PORT
+--- error_code: 200
+--- no_error_log