Prepare for development of new http client API.

Copy the old client to the new “test_client” package and update affected unit-tests. There is no functional change to the existing API or interfaces.

tensorflow_serving/util/net_http/client/test_client/internal/BUILD

@@ -0,0 +1,27 @@
+# Description: a lightweight http client
+
+package(
+    default_visibility = [
+        "//tensorflow_serving/util/net_http:__subpackages__",
+    ],
+)
+
+licenses(["notice"])
+
+cc_library(
+    name = "evhttp_client",
+    srcs = [
+        "evhttp_connection.cc",
+    ],
+    hdrs = [
+        "evhttp_connection.h",
+    ],
+    deps = [
+        "//tensorflow_serving/util/net_http/client/test_client/public:http_client_api",
+        "//tensorflow_serving/util/net_http/internal:net_logging",
+        "//tensorflow_serving/util/net_http/server/public:http_server_api",
+        "@com_github_libevent_libevent//:libevent",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/synchronization",
+    ],
+)

tensorflow_serving/util/net_http/client/test_client/internal/README.md

@@ -0,0 +1,5 @@
+The client library is still under development, and has yet to be finalized.
+
+It should be primarily used for writing tests for users of the
+ServerRequestInterface and HTTPServerInterface APIs to verify basic
+functionality, and the current state should be considered experimental.

tensorflow_serving/util/net_http/client/test_client/internal/evhttp_connection.cc

@@ -0,0 +1,256 @@
+/* Copyright 2018 Google Inc. All Rights Reserved.
+
+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.
+==============================================================================*/
+
+// libevent based client implementation
+
+#include "tensorflow_serving/util/net_http/client/test_client/internal/evhttp_connection.h"
+
+#include "absl/strings/str_cat.h"
+#include "tensorflow_serving/util/net_http/internal/net_logging.h"
+#include "tensorflow_serving/util/net_http/server/public/response_code_enum.h"
+
+namespace tensorflow {
+namespace serving {
+namespace net_http {
+
+TestEvHTTPConnection::~TestEvHTTPConnection() {
+  if (evcon_ != nullptr) {
+    evhttp_connection_free(evcon_);
+  }
+  if (http_uri_ != nullptr) {
+    evhttp_uri_free(http_uri_);
+  }
+
+  event_base_free(ev_base_);
+}
+
+// This needs be called with any async SendRequest()
+void TestEvHTTPConnection::Terminate() {
+  event_base_loopexit(ev_base_, nullptr);
+  if (loop_exit_ != nullptr) {
+    loop_exit_->WaitForNotification();
+  }
+}
+
+std::unique_ptr<TestEvHTTPConnection> TestEvHTTPConnection::Connect(
+    absl::string_view url) {
+  std::string url_str(url.data(), url.size());
+  struct evhttp_uri* http_uri = evhttp_uri_parse(url_str.c_str());
+  if (http_uri == nullptr) {
+    NET_LOG(ERROR, "Failed to connect : event_base_new()");
+    return nullptr;
+  }
+
+  const char* host = evhttp_uri_get_host(http_uri);
+  if (host == nullptr) {
+    NET_LOG(ERROR, "url must have a host %.*s", static_cast<int>(url.size()),
+            url.data());
+    return nullptr;
+  }
+
+  int port = evhttp_uri_get_port(http_uri);
+  if (port == -1) {
+    port = 80;
+  }
+
+  auto result = Connect(host, port);
+  evhttp_uri_free(http_uri);
+
+  return result;
+}
+
+std::unique_ptr<TestEvHTTPConnection> TestEvHTTPConnection::Connect(
+    absl::string_view host, int port) {
+  std::unique_ptr<TestEvHTTPConnection> result(new TestEvHTTPConnection());
+
+  result->ev_base_ = event_base_new();
+  if (result->ev_base_ == nullptr) {
+    NET_LOG(ERROR, "Failed to connect : event_base_new()");
+    return nullptr;
+  }
+
+  // blocking call (DNS resolution)
+  std::string host_str(host.data(), host.size());
+  result->evcon_ = evhttp_connection_base_bufferevent_new(
+      result->ev_base_, nullptr, nullptr, host_str.c_str(),
+      static_cast<uint16_t>(port));
+  if (result->evcon_ == nullptr) {
+    NET_LOG(ERROR,
+            "Failed to connect : evhttp_connection_base_bufferevent_new()");
+    return nullptr;
+  }
+
+  evhttp_connection_set_retries(result->evcon_, 0);
+
+  // TODO(wenboz): make this an option (default to 5s)
+  evhttp_connection_set_timeout(result->evcon_, 5);
+
+  return result;
+}
+
+namespace {
+
+// Copy ev response data to ClientResponse.
+void PopulateResponse(evhttp_request* req, TestClientResponse* response) {
+  response->status =
+      static_cast<HTTPStatusCode>(evhttp_request_get_response_code(req));
+
+  struct evkeyvalq* headers = evhttp_request_get_input_headers(req);
+  struct evkeyval* header;
+  for (header = headers->tqh_first; header; header = header->next.tqe_next) {
+    response->headers.emplace_back(header->key, header->value);
+  }
+
+  char buffer[1024];
+  int nread;
+
+  while ((nread = evbuffer_remove(evhttp_request_get_input_buffer(req), buffer,
+                                  sizeof(buffer))) > 0) {
+    absl::StrAppend(&response->body,
+                    absl::string_view(buffer, static_cast<size_t>(nread)));
+  }
+}
+
+evhttp_cmd_type GetMethodEnum(absl::string_view method, bool with_body) {
+  if (method.compare("GET") == 0) {
+    return EVHTTP_REQ_GET;
+  } else if (method.compare("POST") == 0) {
+    return EVHTTP_REQ_POST;
+  } else if (method.compare("HEAD") == 0) {
+    return EVHTTP_REQ_HEAD;
+  } else if (method.compare("PUT") == 0) {
+    return EVHTTP_REQ_PUT;
+  } else if (method.compare("DELETE") == 0) {
+    return EVHTTP_REQ_DELETE;
+  } else if (method.compare("OPTIONS") == 0) {
+    return EVHTTP_REQ_OPTIONS;
+  } else if (method.compare("TRACE") == 0) {
+    return EVHTTP_REQ_TRACE;
+  } else if (method.compare("CONNECT") == 0) {
+    return EVHTTP_REQ_CONNECT;
+  } else if (method.compare("PATCH") == 0) {
+    return EVHTTP_REQ_PATCH;
+  } else {
+    if (with_body) {
+      return EVHTTP_REQ_POST;
+    } else {
+      return EVHTTP_REQ_GET;
+    }
+  }
+}
+
+void ResponseDone(evhttp_request* req, void* ctx) {
+  TestClientResponse* response = reinterpret_cast<TestClientResponse*>(ctx);
+
+  if (req == nullptr) {
+    // TODO(wenboz): make this a util and check safety
+    int errcode = EVUTIL_SOCKET_ERROR();
+    NET_LOG(ERROR, "socket error = %s (%d)",
+            evutil_socket_error_to_string(errcode), errcode);
+    return;
+  }
+
+  PopulateResponse(req, response);
+
+  if (response->done != nullptr) {
+    response->done();
+  }
+}
+
+// Returns false if there is any error.
+bool GenerateEvRequest(evhttp_connection* evcon, const TestClientRequest& request,
+                       TestClientResponse* response) {
+  evhttp_request* evreq = evhttp_request_new(ResponseDone, response);
+  if (evreq == nullptr) {
+    NET_LOG(ERROR, "Failed to send request : evhttp_request_new()");
+    return false;
+  }
+
+  evkeyvalq* output_headers = evhttp_request_get_output_headers(evreq);
+  for (auto header : request.headers) {
+    std::string key(header.first.data(), header.first.size());
+    std::string value(header.second.data(), header.second.size());
+    evhttp_add_header(output_headers, key.c_str(), value.c_str());
+  }
+
+  evhttp_add_header(output_headers, "Connection", "close");
+
+  if (!request.body.empty()) {
+    evbuffer* output_buffer = evhttp_request_get_output_buffer(evreq);
+
+    std::string body(request.body.data(), request.body.size());
+    evbuffer_add(output_buffer, body.c_str(), request.body.size());
+
+    char length_header[16];
+    evutil_snprintf(length_header, sizeof(length_header) - 1, "%lu",
+                    request.body.size());
+    evhttp_add_header(output_headers, "Content-Length", length_header);
+  }
+
+  std::string uri(request.uri_path.data(), request.uri_path.size());
+  int r = evhttp_make_request(
+      evcon, evreq, GetMethodEnum(request.method, !request.body.empty()),
+      uri.c_str());
+  if (r != 0) {
+    NET_LOG(ERROR, "evhttp_make_request() failed");
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace
+
+// Sends the request and has the connection closed
+bool TestEvHTTPConnection::BlockingSendRequest(const TestClientRequest& request,
+                                           TestClientResponse* response) {
+  if (!GenerateEvRequest(evcon_, request, response)) {
+    NET_LOG(ERROR, "Failed to generate the ev_request");
+    return false;
+  }
+
+  // inline loop blocking
+  event_base_dispatch(ev_base_);
+  return true;
+}
+
+bool TestEvHTTPConnection::SendRequest(const TestClientRequest& request,
+                                   TestClientResponse* response) {
+  if (this->executor_ == nullptr) {
+    NET_LOG(ERROR, "EventExecutor is not configured.");
+    return false;
+  }
+
+  if (!GenerateEvRequest(evcon_, request, response)) {
+    NET_LOG(ERROR, "Failed to generate the ev_request");
+    return false;
+  }
+
+  executor_->Schedule([this]() {
+    loop_exit_.reset(new absl::Notification());
+    event_base_dispatch(ev_base_);
+    loop_exit_->Notify();
+  });
+
+  return true;
+}
+
+void TestEvHTTPConnection::SetExecutor(std::unique_ptr<EventExecutor> executor) {
+  this->executor_ = std::move(executor);
+}
+
+}  // namespace net_http
+}  // namespace serving
+}  // namespace tensorflow

tensorflow_serving/util/net_http/client/test_client/internal/evhttp_connection.h

@@ -0,0 +1,103 @@
+/* Copyright 2018 Google Inc. All Rights Reserved.
+
+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.
+==============================================================================*/
+
+#ifndef TENSORFLOW_SERVING_UTIL_NET_HTTP_CLIENT_TEST_CLIENT_INTERNAL_EVHTTP_CONNECTION_H_
+#define TENSORFLOW_SERVING_UTIL_NET_HTTP_CLIENT_TEST_CLIENT_INTERNAL_EVHTTP_CONNECTION_H_
+
+#include <functional>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/synchronization/notification.h"
+
+#include "libevent/include/event2/buffer.h"
+#include "libevent/include/event2/bufferevent.h"
+#include "libevent/include/event2/event.h"
+#include "libevent/include/event2/http.h"
+#include "libevent/include/event2/keyvalq_struct.h"
+#include "libevent/include/event2/util.h"
+
+// TODO(wenboz): move EventExecutor to net_http/common
+#include "tensorflow_serving/util/net_http/client/test_client/public/httpclient_interface.h"
+#include "tensorflow_serving/util/net_http/server/public/httpserver_interface.h"
+
+namespace tensorflow {
+namespace serving {
+namespace net_http {
+
+// The following types may be moved to an API interface in future.
+
+class TestEvHTTPConnection final : public TestHTTPClientInterface {
+ public:
+  TestEvHTTPConnection() = default;
+
+  ~TestEvHTTPConnection() override;
+
+  TestEvHTTPConnection(const TestEvHTTPConnection& other) = delete;
+  TestEvHTTPConnection& operator=(const TestEvHTTPConnection& other) = delete;
+
+  // Terminates the connection.
+  void Terminate() override;
+
+  // Returns a new connection given an absolute URL.
+  // Always treat the URL scheme as "http" for now.
+  // Returns nullptr if any error
+  static std::unique_ptr<TestEvHTTPConnection> Connect(absl::string_view url);
+
+  // Returns a new connection to the specified host:port.
+  // Returns nullptr if any error
+  static std::unique_ptr<TestEvHTTPConnection> Connect(absl::string_view host,
+                                                   int port);
+
+  // Returns a new connection to the specified port of localhost.
+  // Returns nullptr if any error
+  static std::unique_ptr<TestEvHTTPConnection> ConnectLocal(int port) {
+    return Connect("localhost", port);
+  }
+
+  // Sends a request and blocks the caller till a response is received
+  // or any error has happened.
+  // Returns false if any error.
+  bool BlockingSendRequest(const TestClientRequest& request,
+                           TestClientResponse* response) override;
+
+  // Sends a request and returns immediately. The response will be handled
+  // asynchronously via the response->done callback.
+  // Returns false if any error in sending the request, or if the executor
+  // has not been configured.
+  bool SendRequest(const TestClientRequest& request,
+                   TestClientResponse* response) override;
+
+  // Sets the executor for processing requests asynchronously.
+  void SetExecutor(std::unique_ptr<EventExecutor> executor) override;
+
+ private:
+  struct event_base* ev_base_;
+  struct evhttp_uri* http_uri_;
+  struct evhttp_connection* evcon_;
+
+  std::unique_ptr<EventExecutor> executor_;
+
+  std::unique_ptr<absl::Notification> loop_exit_;
+};
+
+}  // namespace net_http
+}  // namespace serving
+}  // namespace tensorflow
+
+#endif  // TENSORFLOW_SERVING_UTIL_NET_HTTP_CLIENT_TEST_CLIENT_INTERNAL_EVHTTP_CONNECTION_H_