nghttpx: Add APIDownstreamConnection to handle API request

For those connections via frontend with api parameter, they use solely
APIDownstreamConnection.

In this commit, APIDownstreamConnection just consumes all request
body, and do nothing.  The next few commits implements our first API
endpoint: /v1/api/dynamicconfig.

src/CMakeLists.txt

@@ -109,6 +109,7 @@ if(ENABLE_APP)
     shrpx_worker_process.cc
     shrpx_signal.cc
     shrpx_router.cc
+    shrpx_api_downstream_connection.cc
   )
   if(HAVE_SPDYLAY)
     list(APPEND NGHTTPX_SRCS

src/Makefile.am

@@ -132,6 +132,7 @@ NGHTTPX_SRCS = \
 	shrpx_process.h \
 	shrpx_signal.cc shrpx_signal.h \
 	shrpx_router.cc shrpx_router.h \
+	shrpx_api_downstream_connection.cc shrpx_api_downstream_connection.h \
 	buffer.h memchunk.h template.h allocator.h
 
 if HAVE_SPDYLAY

src/shrpx.cc

@@ -1157,6 +1157,11 @@ void fill_default_config() {
     nghttp2_option_new(&upstreamconf.option);
     nghttp2_option_set_no_auto_window_update(upstreamconf.option, 1);
     nghttp2_option_set_no_recv_client_magic(upstreamconf.option, 1);
+
+    // For API endpoint, we enable automatic window update.  This is
+    // because we are a sink.
+    nghttp2_option_new(&upstreamconf.api_option);
+    nghttp2_option_set_no_recv_client_magic(upstreamconf.api_option, 1);
   }
 
   {

src/shrpx_api_downstream_connection.cc

@@ -0,0 +1,107 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2016 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "shrpx_api_downstream_connection.h"
+
+#include "shrpx_client_handler.h"
+#include "shrpx_upstream.h"
+#include "shrpx_downstream.h"
+#include "shrpx_worker.h"
+
+namespace shrpx {
+
+APIDownstreamConnection::APIDownstreamConnection(Worker *worker)
+    : worker_(worker) {}
+
+APIDownstreamConnection::~APIDownstreamConnection() {}
+
+int APIDownstreamConnection::attach_downstream(Downstream *downstream) {
+  if (LOG_ENABLED(INFO)) {
+    DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
+  }
+
+  auto &req = downstream->request();
+
+  if (req.path != StringRef::from_lit("/api/v1/dynamicconfig")) {
+    // TODO this will return 503 error, which is not nice.  We'd like
+    // to use 404 in this case.
+    return -1;
+  }
+
+  downstream_ = downstream;
+
+  return 0;
+}
+
+void APIDownstreamConnection::detach_downstream(Downstream *downstream) {
+  if (LOG_ENABLED(INFO)) {
+    DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
+  }
+  downstream_ = nullptr;
+}
+
+int APIDownstreamConnection::push_request_headers() { return 0; }
+
+int APIDownstreamConnection::push_upload_data_chunk(const uint8_t *data,
+                                                    size_t datalen) {
+  auto output = downstream_->get_request_buf();
+
+  // TODO limit the maximum payload size
+  output->append(data, datalen);
+
+  // We don't have to call Upstream::resume_read() here, because
+  // request buffer is effectively unlimited.  Actually, we cannot
+  // call it here since it could recursively call this function again.
+
+  return 0;
+}
+
+int APIDownstreamConnection::end_upload_data() {
+  // TODO process request payload here
+  (void)worker_;
+  return 0;
+}
+
+void APIDownstreamConnection::pause_read(IOCtrlReason reason) {}
+
+int APIDownstreamConnection::resume_read(IOCtrlReason reason, size_t consumed) {
+  return 0;
+}
+
+void APIDownstreamConnection::force_resume_read() {}
+
+int APIDownstreamConnection::on_read() { return 0; }
+
+int APIDownstreamConnection::on_write() { return 0; }
+
+void APIDownstreamConnection::on_upstream_change(Upstream *uptream) {}
+
+bool APIDownstreamConnection::poolable() const { return false; }
+
+DownstreamAddrGroup *
+APIDownstreamConnection::get_downstream_addr_group() const {
+  return nullptr;
+}
+
+} // namespace shrpx

src/shrpx_api_downstream_connection.h

@@ -0,0 +1,65 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2016 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef SHRPX_API_DOWNSTREAM_CONNECTION_H
+#define SHRPX_API_DOWNSTREAM_CONNECTION_H
+
+#include "shrpx_downstream_connection.h"
+
+namespace shrpx {
+
+class Worker;
+
+class APIDownstreamConnection : public DownstreamConnection {
+public:
+  APIDownstreamConnection(Worker *worker);
+  virtual ~APIDownstreamConnection();
+  virtual int attach_downstream(Downstream *downstream);
+  virtual void detach_downstream(Downstream *downstream);
+
+  virtual int push_request_headers();
+  virtual int push_upload_data_chunk(const uint8_t *data, size_t datalen);
+  virtual int end_upload_data();
+
+  virtual void pause_read(IOCtrlReason reason);
+  virtual int resume_read(IOCtrlReason reason, size_t consumed);
+  virtual void force_resume_read();
+
+  virtual int on_read();
+  virtual int on_write();
+
+  virtual void on_upstream_change(Upstream *uptream);
+
+  // true if this object is poolable.
+  virtual bool poolable() const;
+
+  virtual DownstreamAddrGroup *get_downstream_addr_group() const;
+
+private:
+  Worker *worker_;
+};
+
+} // namespace shrpx
+
+#endif // SHRPX_API_DOWNSTREAM_CONNECTION_H

src/shrpx_client_handler.cc

@@ -48,6 +48,7 @@
 #include "shrpx_downstream.h"
 #include "shrpx_http2_session.h"
 #include "shrpx_connect_blocker.h"
+#include "shrpx_api_downstream_connection.h"
 #ifdef HAVE_SPDYLAY
 #include "shrpx_spdy_upstream.h"
 #endif // HAVE_SPDYLAY
@@ -820,6 +821,10 @@ ClientHandler::get_downstream_connection(Downstream *downstream) {
 
   const auto &req = downstream->request();
 
+  if (faddr_->api) {
+    return make_unique<APIDownstreamConnection>(worker_);
+  }
+
   // Fast path.  If we have one group, it must be catch-all group.
   // proxy mode falls in this case.
   if (groups.size() == 1) {

src/shrpx_config.h

@@ -540,6 +540,7 @@ struct Http2Config {
       ev_tstamp settings;
     } timeout;
     nghttp2_option *option;
+    nghttp2_option *api_option;
     nghttp2_session_callbacks *callbacks;
     size_t window_bits;
     size_t connection_window_bits;

src/shrpx_downstream.cc

@@ -500,6 +500,14 @@ bool Downstream::get_chunked_request() const { return chunked_request_; }
 void Downstream::set_chunked_request(bool f) { chunked_request_ = f; }
 
 bool Downstream::request_buf_full() {
+  auto handler = upstream_->get_client_handler();
+  auto faddr = handler->get_upstream_addr();
+
+  // We don't check buffer size here for API endpoint.
+  if (faddr->api) {
+    return false;
+  }
+
   if (dconn_) {
     return request_buf_.rleft() >=
            get_config()->conn.downstream.request_buffer_size;

src/shrpx_http2_upstream.cc

@@ -861,8 +861,11 @@ Http2Upstream::Http2Upstream(ClientHandler *handler)
 
   auto &http2conf = get_config()->http2;
 
-  rv = nghttp2_session_server_new2(&session_, http2conf.upstream.callbacks,
-                                   this, http2conf.upstream.option);
+  auto faddr = handler_->get_upstream_addr();
+
+  rv = nghttp2_session_server_new2(
+      &session_, http2conf.upstream.callbacks, this,
+      faddr->api ? http2conf.upstream.api_option : http2conf.upstream.option);
 
   assert(rv == 0);
 
@@ -874,7 +877,11 @@ Http2Upstream::Http2Upstream(ClientHandler *handler)
   entry[0].value = http2conf.upstream.max_concurrent_streams;
 
   entry[1].settings_id = NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE;
+  if (faddr->api) {
+    entry[1].value = (1u << 31) - 1;
+  } else {
     entry[1].value = (1 << http2conf.upstream.window_bits) - 1;
+  }
 
   rv = nghttp2_submit_settings(session_, NGHTTP2_FLAG_NONE, entry.data(),
                                entry.size());
@@ -883,8 +890,11 @@ Http2Upstream::Http2Upstream(ClientHandler *handler)
                       << nghttp2_strerror(rv);
   }
 
-  if (http2conf.upstream.connection_window_bits != 16) {
-    int32_t window_size = (1 << http2conf.upstream.connection_window_bits) - 1;
+  int32_t window_bits =
+      faddr->api ? 31 : http2conf.upstream.connection_window_bits;
+
+  if (window_bits != 16) {
+    int32_t window_size = (1u << window_bits) - 1;
     rv = nghttp2_session_set_local_window_size(session_, NGHTTP2_FLAG_NONE, 0,
                                                window_size);
 
@@ -1675,6 +1685,12 @@ int Http2Upstream::on_downstream_abort_request(Downstream *downstream,
 int Http2Upstream::consume(int32_t stream_id, size_t len) {
   int rv;
 
+  auto faddr = handler_->get_upstream_addr();
+
+  if (faddr->api) {
+    return 0;
+  }
+
   rv = nghttp2_session_consume(session_, stream_id, len);
 
   if (rv != 0) {

src/template.h

@@ -502,6 +502,10 @@ inline bool operator==(const char *lhs, const StringRef &rhs) {
   return rhs == lhs;
 }
 
+inline bool operator!=(const StringRef &lhs, const StringRef &rhs) {
+  return !(lhs == rhs);
+}
+
 inline bool operator!=(const StringRef &lhs, const std::string &rhs) {
   return !(lhs == rhs);
 }