feat(functions): Add support for REST based remote functions

Co-authored-by: Wills Feng <[email protected]>

CMakeLists.txt

@@ -523,6 +523,9 @@ if(VELOX_ENABLE_REMOTE_FUNCTIONS)
   find_package(fizz CONFIG REQUIRED)
   find_package(wangle CONFIG REQUIRED)
   find_package(FBThrift CONFIG REQUIRED)
+  set(cpr_SOURCE BUNDLED)
+  velox_resolve_dependency(cpr)
+  FetchContent_MakeAvailable(cpr)
 endif()
 
 if(VELOX_ENABLE_GCS)

velox/functions/remote/client/CMakeLists.txt

@@ -16,11 +16,19 @@ velox_add_library(velox_functions_remote_thrift_client ThriftClient.cpp)
 velox_link_libraries(velox_functions_remote_thrift_client
                      PUBLIC remote_function_thrift FBThrift::thriftcpp2)
 
+velox_add_library(velox_functions_remote_rest_client RestClient.cpp)
+velox_link_libraries(velox_functions_remote_rest_client Folly::folly cpr::cpr)
+
 velox_add_library(velox_functions_remote Remote.cpp)
 velox_link_libraries(
   velox_functions_remote
   PUBLIC velox_expression
+         velox_memory
+         velox_exec
+         velox_vector
+         velox_presto_serializer
          velox_functions_remote_thrift_client
+         velox_functions_remote_rest_client
          velox_functions_remote_get_serde
          velox_type_fbhive
          Folly::folly)

velox/functions/remote/client/Remote.cpp

@@ -16,34 +16,71 @@
 
 #include "velox/functions/remote/client/Remote.h"
 
+#include <fmt/format.h>
 #include <folly/io/async/EventBase.h>
+#include <sstream>
+#include <string>
+
+#include "velox/common/memory/ByteStream.h"
 #include "velox/expression/Expr.h"
 #include "velox/expression/VectorFunction.h"
+#include "velox/functions/remote/client/RestClient.h"
 #include "velox/functions/remote/client/ThriftClient.h"
 #include "velox/functions/remote/if/GetSerde.h"
 #include "velox/functions/remote/if/gen-cpp2/RemoteFunctionServiceAsyncClient.h"
+#include "velox/serializers/PrestoSerializer.h"
 #include "velox/type/fbhive/HiveTypeSerializer.h"
 #include "velox/vector/VectorStream.h"
 
+using namespace folly;
 namespace facebook::velox::functions {
 namespace {
 
 std::string serializeType(const TypePtr& type) {
-  // Use hive type serializer.
   return type::fbhive::HiveTypeSerializer::serialize(type);
 }
 
+std::string extractFunctionName(const std::string& input) {
+  size_t lastDot = input.find_last_of('.');
+  if (lastDot != std::string::npos) {
+    return input.substr(lastDot + 1);
+  }
+  return input;
+}
+
+std::string urlEncode(const std::string& value) {
+  std::ostringstream escaped;
+  escaped.fill('0');
+  escaped << std::hex;
+  for (char c : value) {
+    if (isalnum(static_cast<unsigned char>(c)) || c == '-' || c == '_' ||
+        c == '.' || c == '~') {
+      escaped << c;
+    } else {
+      escaped << '%' << std::setw(2) << int(static_cast<unsigned char>(c));
+    }
+  }
+  return escaped.str();
+}
+
 class RemoteFunction : public exec::VectorFunction {
  public:
   RemoteFunction(
       const std::string& functionName,
       const std::vector<exec::VectorFunctionArg>& inputArgs,
       const RemoteVectorFunctionMetadata& metadata)
       : functionName_(functionName),
-        location_(metadata.location),
-        thriftClient_(getThriftClient(location_, &eventBase_)),
+        metadata_(metadata),
         serdeFormat_(metadata.serdeFormat),
-        serde_(getSerde(serdeFormat_)) {
+        serde_(getSerde(serdeFormat_)),
+        location_(metadata.location) {
+    if (metadata.location.type() == typeid(SocketAddress)) {
+      thriftClient_ =
+          getThriftClient(boost::get<SocketAddress>(location_), &eventBase_);
+    } else if (metadata.location.type() == typeid(std::string)) {
+      restClient_ = getRestClient();
+    }
+
     std::vector<TypePtr> types;
     types.reserve(inputArgs.size());
     serializedInputTypes_.reserve(inputArgs.size());
@@ -62,7 +99,11 @@ class RemoteFunction : public exec::VectorFunction {
       exec::EvalCtx& context,
       VectorPtr& result) const override {
     try {
-      applyRemote(rows, args, outputType, context, result);
+      if ((metadata_.location.type() == typeid(SocketAddress))) {
+        applyRemote(rows, args, outputType, context, result);
+      } else if (metadata_.location.type() == typeid(std::string)) {
+        applyRestRemote(rows, args, outputType, context, result);
+      }
     } catch (const VeloxRuntimeError&) {
       throw;
     } catch (const std::exception&) {
@@ -71,6 +112,50 @@ class RemoteFunction : public exec::VectorFunction {
   }
 
  private:
+  void applyRestRemote(
+      const SelectivityVector& rows,
+      const std::vector<VectorPtr>& args,
+      const TypePtr& outputType,
+      const exec::EvalCtx& context,
+      VectorPtr& result) const {
+    try {
+      serializer::presto::PrestoVectorSerde serde;
+      auto remoteRowVector = std::make_shared<RowVector>(
+          context.pool(),
+          remoteInputType_,
+          BufferPtr{},
+          rows.end(),
+          std::move(args));
+
+      std::unique_ptr<IOBuf> requestBody =
+          std::make_unique<IOBuf>(rowVectorToIOBuf(
+              remoteRowVector, rows.end(), *context.pool(), &serde));
+
+      // Because location_ is a variant, we must get the string:
+      const auto& url = boost::get<std::string>(location_);
+      const std::string fullUrl = fmt::format(
+          "{}/v1/functions/{}/{}/{}/{}",
+          url,
+          metadata_.schema.value_or("default"),
+          extractFunctionName(functionName_),
+          urlEncode(metadata_.functionId.value_or("default_function_id")),
+          metadata_.version.value_or("1"));
+
+      std::unique_ptr<IOBuf> responseBody =
+          restClient_->invokeFunction(fullUrl, std::move(requestBody));
+
+      auto outputRowVector = IOBufToRowVector(
+          *responseBody, ROW({outputType}), *context.pool(), &serde);
+
+      result = outputRowVector->childAt(0);
+    } catch (const std::exception& e) {
+      VELOX_FAIL(
+          "Error while executing remote function '{}': {}",
+          functionName_,
+          e.what());
+    }
+  }
+
   void applyRemote(
       const SelectivityVector& rows,
       std::vector<VectorPtr>& args,
@@ -109,7 +194,7 @@ class RemoteFunction : public exec::VectorFunction {
       VELOX_FAIL(
           "Error while executing remote function '{}' at '{}': {}",
           functionName_,
-          location_.describe(),
+          boost::get<SocketAddress>(location_).describe(),
           e.what());
     }
 
@@ -142,14 +227,18 @@ class RemoteFunction : public exec::VectorFunction {
   }
 
   const std::string functionName_;
-  folly::SocketAddress location_;
+  EventBase eventBase_;
+  const RemoteVectorFunctionMetadata metadata_;
 
-  folly::EventBase eventBase_;
-  std::unique_ptr<RemoteFunctionClient> thriftClient_;
   remote::PageFormat serdeFormat_;
   std::unique_ptr<VectorSerde> serde_;
 
-  // Structures we construct once to cache:
+  boost::variant<SocketAddress, std::string> location_;
+
+  // Depending on which active type we have, one of these clients will be used:
+  std::unique_ptr<RemoteFunctionClient> thriftClient_;
+  std::unique_ptr<HttpClient> restClient_;
+
   RowTypePtr remoteInputType_;
   std::vector<std::string> serializedInputTypes_;
 };
@@ -169,7 +258,7 @@ void registerRemoteFunction(
     std::vector<exec::FunctionSignaturePtr> signatures,
     const RemoteVectorFunctionMetadata& metadata,
     bool overwrite) {
-  exec::registerStatefulVectorFunction(
+  registerStatefulVectorFunction(
       name,
       signatures,
       std::bind(

velox/functions/remote/client/Remote.h

@@ -16,20 +16,37 @@
 
 #pragma once
 
+#include <boost/variant.hpp>
 #include <folly/SocketAddress.h>
 #include "velox/expression/VectorFunction.h"
 #include "velox/functions/remote/if/gen-cpp2/RemoteFunction_types.h"
 
 namespace facebook::velox::functions {
 
 struct RemoteVectorFunctionMetadata : public exec::VectorFunctionMetadata {
-  /// Network address of the servr to communicate with. Note that this can hold
-  /// a network location (ip/port pair) or a unix domain socket path (see
+  /// URL of the HTTP/REST server for remote function.
+  /// Or Network address of the server to communicate with. Note that this can
+  /// hold a network location (ip/port pair) or a unix domain socket path (see
   /// SocketAddress::makeFromPath()).
-  folly::SocketAddress location;
+  boost::variant<folly::SocketAddress, std::string> location;
 
-  /// The serialization format to be used
+  /// The serialization format to be used when sending data to the remote.
   remote::PageFormat serdeFormat{remote::PageFormat::PRESTO_PAGE};
+
+  /// Optional schema defining the structure of the data or input/output types
+  /// involved in the remote function. This may include details such as column
+  /// names and data types.
+  std::optional<std::string> schema;
+
+  /// Optional identifier for the specific remote function to be invoked.
+  /// This can be useful when the same server hosts multiple functions,
+  /// and the client needs to specify which function to call.
+  std::optional<std::string> functionId;
+
+  /// Optional version information to be used when calling the remote function.
+  /// This can help in ensuring compatibility with a particular version of the
+  /// function if multiple versions are available on the server.
+  std::optional<std::string> version;
 };
 
 /// Registers a new remote function. It will use the meatadata defined in

velox/functions/remote/client/RestClient.cpp

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * 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.
+ */
+
+#include "velox/functions/remote/client/RestClient.h"
+
+#include <cpr/cpr.h>
+#include <folly/io/IOBufQueue.h>
+
+#include "velox/common/base/Exceptions.h"
+
+using namespace folly;
+namespace facebook::velox::functions {
+
+std::unique_ptr<IOBuf> RestClient::invokeFunction(
+    const std::string& fullUrl,
+    std::unique_ptr<IOBuf> requestPayload) {
+  IOBufQueue inputBufQueue(IOBufQueue::cacheChainLength());
+  inputBufQueue.append(std::move(requestPayload));
+
+  std::string requestBody;
+  for (auto range : *inputBufQueue.front()) {
+    requestBody.append(
+        reinterpret_cast<const char*>(range.data()), range.size());
+  }
+
+  cpr::Response response = cpr::Post(
+      cpr::Url{fullUrl},
+      cpr::Header{
+          {"Content-Type", "application/X-presto-pages"},
+          {"Accept", "application/X-presto-pages"}},
+      cpr::Body{requestBody});
+
+  if (response.error) {
+    VELOX_FAIL(fmt::format(
+        "Error communicating with server: {} URL: {}",
+        response.error.message,
+        fullUrl));
+  }
+
+  auto outputBuf = IOBuf::copyBuffer(response.text);
+  return outputBuf;
+}
+
+std::unique_ptr<HttpClient> getRestClient() {
+  return std::make_unique<RestClient>();
+}
+
+} // namespace facebook::velox::functions

velox/functions/remote/client/RestClient.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <folly/io/IOBuf.h>
+#include <memory>
+#include <string>
+
+namespace facebook::velox::functions {
+
+/// @brief Abstract interface for an HTTP client.
+/// Provides a method to invoke a function by sending an HTTP request
+/// and receiving a response, both in Presto's serialized wire format.
+class HttpClient {
+ public:
+  virtual ~HttpClient() = default;
+
+  /// @brief Invokes a function over HTTP.
+  /// @param url The endpoint URL to send the request to.
+  /// @param requestPayload The request payload in Presto's serialized wire
+  /// format.
+  /// @return A unique pointer to the response payload in Presto's serialized
+  /// wire format.
+  virtual std::unique_ptr<folly::IOBuf> invokeFunction(
+      const std::string& url,
+      std::unique_ptr<folly::IOBuf> requestPayload) = 0;
+};
+
+/// @brief Concrete implementation of HttpClient using REST.
+/// Handles HTTP communication by sending requests and receiving responses
+/// using RESTful APIs with payloads in Presto's serialized wire format.
+class RestClient : public HttpClient {
+ public:
+  /// @brief Invokes a function over HTTP using cpr.
+  /// Sends an HTTP POST request to the specified URL with the request payload
+  /// and receives the response payload. Both payloads are in Presto's
+  /// serialized wire format.
+  /// @param url The endpoint URL to send the request to.
+  /// @param requestPayload The request payload in Presto's serialized wire
+  /// format.
+  /// @return A unique pointer to the response payload in Presto's serialized
+  /// wire format.
+  /// @throws VeloxException if there is an error initializing cpr or during
+  /// the request.
+  std::unique_ptr<folly::IOBuf> invokeFunction(
+      const std::string& url,
+      std::unique_ptr<folly::IOBuf> requestPayload) override;
+};
+
+/// @brief Factory function to create an instance of RestClient.
+/// @return A unique pointer to an HttpClient implementation.
+std::unique_ptr<HttpClient> getRestClient();
+
+} // namespace facebook::velox::functions