Example for using FilterLogEventsAsync()

[spamulap12]

Hi, I am trying to filter logs based on a search string. I am unable to see all the results with FilterLogEventsAsync(). AWS cli returns expected results. Can you provide an example code to successfully retrieve log events for a log group based on a search string? Below is the example code I tried.

==============

FilterLogEventsRequest request;
 request.SetLogGroupName(logGroupName);
 // request.SetLogStreamNames({logStreamName});
 // auto startTime = Aws::Utils::DateTime(time(nullptr) - 60 * 60 * 24 * 15);
 // request.SetStartTime(startTime.Millis());
 // request.SetEndTime(Aws::Utils::DateTime::Now().Millis());
 request.SetFilterPattern(pattern);
   client->FilterLogEventsAsync(
     req,
     [this](
       const Aws::CloudWatchLogs::CloudWatchLogsClient* /* client */,
       const Model::FilterLogEventsRequest& /* request */,
       const Model::FilterLogEventsOutcome& outcome,
       const std::shared_ptr<
         const Aws::Client::AsyncCallerContext>& /* context */) noexcept {
       this->runFinished(outcome);
     });
 if (filterEventsHandler.isSuccess()) {
   auto& outcome = filterEventsHandler.getOutcome().GetResult();
   const auto& events = outcome.GetEvents();
   for (const auto& event : events) {
std::cout << event.GetMessage();
std::cout << event.GetTimestamp();
   }
 } 

[bhavya2109sharma]

Hello @spamulap12

You can try the below code.

class LogEventRetriever {
public:
    LogEventRetriever(const Aws::String& logGroupName, const Aws::String& filterPattern) : m_logGroupName(logGroupName), m_filterPattern(filterPattern) {}

    void retrieveLogEvents() {
        Aws::SDKOptions options;
        Aws::InitAPI(options);

        m_cwlClient = std::make_unique<Aws::CloudWatchLogs::CloudWatchLogsClient>();

        retrieveLogEvents();

        Aws::ShutdownAPI(options);
    }

private:
    void retrieveLogEvents() {
        Aws::CloudWatchLogs::Model::FilterLogEventsRequest request;
        request.SetLogGroupName(m_logGroupName);
        request.SetFilterPattern(m_filterPattern);

        m_cwlClient->FilterLogEventsAsync(
            request,
            [this](const Aws::CloudWatchLogs::CloudWatchLogsClient* /*client*/,
                  const Aws::CloudWatchLogs::Model::FilterLogEventsRequest& /*request*/,
                  const Aws::CloudWatchLogs::Model::FilterLogEventsOutcome& outcome,
                  const std::shared_ptr<const Aws::Client::AsyncCallerContext>& /*context*/) noexcept {
                handleLogEventsOutcome(outcome);
            });
    }

   void handleLogEventsOutcome(const Aws::CloudWatchLogs::Model::FilterLogEventsOutcome& outcome) {
        if (outcome.IsSuccess()) {
            const auto& logEvents = outcome.GetResult().GetEvents();
            for (const auto& event : logEvents) {
                std::cout << "Log event: " << event.GetMessage() << std::endl;
            }

            // Check if there are more log events to retrieve
            const auto& nextToken = outcome.GetResult().GetNextToken();
            if (!nextToken.empty()) {
                // Retrieve the next page of log events
                Aws::CloudWatchLogs::Model::FilterLogEventsRequest request;
                request.SetLogGroupName(m_logGroupName);
                request.SetFilterPattern(m_filterPattern);
                request.SetNextToken(nextToken);

                m_cwlClient->FilterLogEventsAsync(
                    request,
                    [this](const Aws::CloudWatchLogs::CloudWatchLogsClient* /*client*/,
                          const Aws::CloudWatchLogs::Model::FilterLogEventsRequest& /*request*/,
                          const Aws::CloudWatchLogs::Model::FilterLogEventsOutcome& outcome,
                          const std::shared_ptr<const Aws::Client::AsyncCallerContext>& /*context*/) noexcept {
                        handleLogEventsOutcome(outcome);
                    });
            }
        } else {
            std::cerr << "Failed to retrieve log events: " << outcome.GetError().GetMessage() << std::endl;
        }
    }

private:
    Aws::String m_logGroupName;
    Aws::String m_filterPattern;
    std::unique_ptr<Aws::CloudWatchLogs::CloudWatchLogsClient> m_cwlClient;
};

int main() {
    LogEventRetriever retriever("my-log-group", "ERROR"); //"ERROR" is pattern here which I am searching
    retriever.retrieveLogEvents();
    return 0;
}