phrocker commented on a change in pull request #551: MINIFICPP-773 Implemented. URL: https://github.com/apache/nifi-minifi-cpp/pull/551#discussion_r282305936
########## File path: extensions/windows-event-log/ConsumeWindowsEventLog.cpp ########## @@ -0,0 +1,322 @@ +/** + * @file ConsumeWindowsEventLog.cpp + * ConsumeWindowsEventLog class declaration + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 "ConsumeWindowsEventLog.h" +#include <vector> +#include <queue> +#include <map> +#include <set> +#include <sstream> +#include <stdio.h> +#include <string> +#include <iostream> +#include <memory> +#include <codecvt> + +#include "io/DataStream.h" +#include "core/ProcessContext.h" +#include "core/ProcessSession.h" + +#pragma comment(lib, "wevtapi.lib") + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace processors { + +static const size_t MAX_RECORD_BUFFER_SIZE = 0x10000; // 64k +const std::string ConsumeWindowsEventLog::ProcessorName("ConsumeWindowsEventLog"); + +static const int DEFAULT_MAX_BUFFER = 1024 * 1024; + +core::Property ConsumeWindowsEventLog::Channel( + core::PropertyBuilder::createProperty("Channel")-> + isRequired(true)-> + withDefaultValue("System")-> + withDescription("The Windows Event Log Channel to listen to.")-> + supportsExpressionLanguage(true)-> + build()); + +core::Property ConsumeWindowsEventLog::Query( + core::PropertyBuilder::createProperty("Query")-> + isRequired(true)-> + withDefaultValue("*")-> + withDescription("XPath Query to filter events. (See https://msdn.microsoft.com/en-us/library/windows/desktop/dd996910(v=vs.85).aspx for examples.)")-> + supportsExpressionLanguage(true)-> + build()); + +core::Property ConsumeWindowsEventLog::MaxBufferSize( + core::PropertyBuilder::createProperty("Max Buffer Size")-> + isRequired(true)-> + withDefaultValue(std::to_string(1024 * 1024))-> + withDescription( + "The individual Event Log XMLs are rendered to a buffer." + " This specifies the maximum size in bytes that the buffer will be allowed to grow to. (Limiting the maximum size of an individual Event XML.)")-> + build()); + +core::Property ConsumeWindowsEventLog::InactiveDurationToReconnect( + core::PropertyBuilder::createProperty("Inactive Duration To Reconnect")-> + isRequired(true)-> + withDefaultValue("10 mins")-> + withDescription( + "If no new event logs are processed for the specified time period, " + " this processor will try reconnecting to recover from a state where any further messages cannot be consumed." + " Such situation can happen if Windows Event Log service is restarted, or ERROR_EVT_QUERY_RESULT_STALE (15011) is returned." + " Setting no duration, e.g. '0 ms' disables auto-reconnection.")-> + build()); + +core::Relationship ConsumeWindowsEventLog::Success("success", "Relationship for successfully consumed events."); + +ConsumeWindowsEventLog::ConsumeWindowsEventLog(const std::string& name, utils::Identifier uuid) + : core::Processor(name, uuid), logger_(logging::LoggerFactory<ConsumeWindowsEventLog>::getLogger()) { + char buff[MAX_COMPUTERNAME_LENGTH + 1]; + DWORD size = sizeof(buff); + if (GetComputerName(buff, &size)) + { + computerName_ = buff; + } + else + { + LogWindowsError(); + } +} + +void ConsumeWindowsEventLog::initialize() { + //! Set the supported properties + setSupportedProperties({Channel, Query, MaxBufferSize, InactiveDurationToReconnect}); + + //! Set the supported relationships + setSupportedRelationships({Success}); +} + +void ConsumeWindowsEventLog::onSchedule(const std::shared_ptr<core::ProcessContext> &context, const std::shared_ptr<core::ProcessSessionFactory> &sessionFactory) { + if (subscriptionHandle_) { + logger_->log_error("Processor already subscribed to Event Log, expected cleanup to unsubscribe."); + } else { + subscribe(context); + } +} + +void ConsumeWindowsEventLog::onTrigger(const std::shared_ptr<core::ProcessContext> &context, const std::shared_ptr<core::ProcessSession> &session) { + session_ = session; + + if (!subscriptionHandle_) { + if (!subscribe(context)) { + context->yield(); + return; + } + } + + const auto flowFileCount = processQueue(session); + + const auto now = GetTickCount(); + + if (flowFileCount > 0) { + lastActivityTimestamp_ = now; + } + else if (inactiveDurationToReconnect_ > 0) { + if ((now - lastActivityTimestamp_) > inactiveDurationToReconnect_) { + logger_->log_info("Exceeds configured 'inactive duration to reconnect' %lld ms. Unsubscribe to reconnect..", inactiveDurationToReconnect_); + unsubscribe(); + } + } +} + + +bool ConsumeWindowsEventLog::subscribe(const std::shared_ptr<core::ProcessContext> &context) +{ + std::string channel; + context->getProperty(Channel.getName(), channel); + + std::string query; + context->getProperty(Query.getName(), query); + + // Get 'maxBufferSize_'. + std::string value; + if (context->getProperty(MaxBufferSize.getName(), value) && !value.empty() && core::Property::StringToInt(value, maxBufferSize_)) { + logger_->log_debug("ConsumeWindowsEventLog: maxBufferSize_ %d", maxBufferSize_); + } + + provenanceUri_ = "winlog://" + computerName_ + "/" + channel + "?" + query; + + std::string strInactiveDurationToReconnect; + context->getProperty(InactiveDurationToReconnect.getName(), strInactiveDurationToReconnect); + + // Get 'inactiveDurationToReconnect_'. + core::TimeUnit unit; + if (core::Property::StringToTime(strInactiveDurationToReconnect, inactiveDurationToReconnect_, unit) && + core::Property::ConvertTimeUnitToMS(inactiveDurationToReconnect_, unit, inactiveDurationToReconnect_)) { + logger_->log_info("inactiveDurationToReconnect: [%lld] ms", inactiveDurationToReconnect_); + } + + subscriptionHandle_ = EvtSubscribe( + NULL, + NULL, + std::wstring(channel.begin(), channel.end()).c_str(), + std::wstring(query.begin(), query.end()).c_str(), + NULL, + this, + [](EVT_SUBSCRIBE_NOTIFY_ACTION action, PVOID pContext, EVT_HANDLE hEvent) + { + auto pConsumeWindowsEventLog = static_cast<ConsumeWindowsEventLog*>(pContext); + + auto& logger = pConsumeWindowsEventLog->logger_; + + if (action == EvtSubscribeActionError) + { + if (ERROR_EVT_QUERY_RESULT_STALE == (DWORD)hEvent) { + logger->log_error("Received missing event notification. Consider triggering processor more frequently or increasing queue size."); + } + else { + logger->log_error("Received the following Win32 error: %x", hEvent); + } + } + else if (action == EvtSubscribeActionDeliver) { + DWORD size = 0; + DWORD used = 0; + DWORD propertyCount = 0; + + if (!EvtRender(NULL, hEvent, EvtRenderEventXml, size, 0, &used, &propertyCount)) { + if (ERROR_INSUFFICIENT_BUFFER == GetLastError()) { + if (used > pConsumeWindowsEventLog->maxBufferSize_) + { + logger->log_error("Dropping event %x because it couldn't be rendered within %ll bytes.", hEvent, pConsumeWindowsEventLog->maxBufferSize_); + return 0UL; + } + + size = used; + std::vector<char> buf(size); + if (EvtRender(NULL, hEvent, EvtRenderEventXml, size, &buf[0], &used, &propertyCount)) { + std::string xml = std::wstring_convert<std::codecvt_utf8<wchar_t>>().to_bytes(reinterpret_cast<wchar_t*>(&buf[0])); + + pConsumeWindowsEventLog->renderedXMLs_.enqueue(std::move(xml)); + } + else { + logger->log_error("EvtRender returned the following error code: %d.", GetLastError()); + } + } + } + } + + return 0UL; + }, + EvtSubscribeToFutureEvents | EvtSubscribeStrict); + + if (!subscriptionHandle_) { + logger_->log_error("Unable to subscribe with provided parameters, received the following error code: %d", GetLastError()); + return false; + } + + lastActivityTimestamp_ = GetTickCount(); + + return true; +} + +void ConsumeWindowsEventLog::unsubscribe() +{ + if (subscriptionHandle_) + { + EvtClose(subscriptionHandle_); + subscriptionHandle_ = 0; + } +} + + +int ConsumeWindowsEventLog::processQueue(const std::shared_ptr<core::ProcessSession> &session) +{ + struct WriteCallback: public OutputStreamCallback { + WriteCallback(const std::string& str) + : str_(str) { + status_ = 0; + } + std::string str_; + int64_t process(std::shared_ptr<io::BaseStream> stream) { + auto len = stream->writeData((uint8_t*)&str_[0], str_.size()); + if (len < 0) + status_ = -1; + return len; + } + int status_; + }; + + int flowFileCount = 0; + + std::string xml; + while (renderedXMLs_.try_dequeue(xml)) { + auto flowFile = session->create(); + + session->write(flowFile, &WriteCallback(xml)); + session->putAttribute(flowFile, FlowAttributeKey(MIME_TYPE), "application/xml"); + session->getProvenanceReporter()->receive(flowFile, provenanceUri_, getUUIDStr(), "Consume windows event logs", 0); + session->transfer(flowFile, Success); + session->commit(); + + flowFileCount++; + } + + return flowFileCount; +} + +void ConsumeWindowsEventLog::notifyStop() +{ + unsubscribe(); + + if (renderedXMLs_.size_approx() != 0) { + if (session_) { + logger_->log_info("Finishing processing leftover events"); + + processQueue(session_); + } else { + logger_->log_error( + "Stopping the processor but there is no ProcessSessionFactory stored and there are messages in the internal queue. " + "Removing the processor now will clear the queue but will result in DATA LOSS. This is normally due to starting the processor, " + "receiving events and stopping before the onTrigger happens. The messages in the internal queue cannot finish processing until " + "the processor is triggered to run."); + } + } + + session_ = nullptr; +} + +void ConsumeWindowsEventLog::LogWindowsError() +{ + auto error_id = GetLastError(); + LPVOID lpMsg; + + FormatMessage( + FORMAT_MESSAGE_ALLOCATE_BUFFER | + FORMAT_MESSAGE_FROM_SYSTEM, + NULL, + error_id, + MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), + (LPTSTR)&lpMsg, + 0, NULL); + + logger_->log_debug("Error %d: %s\n", (int)error_id, (char *)lpMsg); Review comment: log_error may be more appropriate. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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