Using the PutLogEvents API to send manually-created embedded metric format logs

You can send embedded metric format logs to CloudWatch Logs using the CloudWatch Logs PutLogEvents API. When calling PutLogEvents, you may optionally include the following HTTP header to instruct CloudWatch Logs that the metrics should be extracted, but it is no longer necessary.

x-amzn-logs-format: json/emf

The following is a full example using the AWS SDK for Java 2.x:

package org.example.basicapp;

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.cloudwatchlogs.CloudWatchLogsClient;
import software.amazon.awssdk.services.cloudwatchlogs.model.DescribeLogStreamsRequest;
import software.amazon.awssdk.services.cloudwatchlogs.model.DescribeLogStreamsResponse;
import software.amazon.awssdk.services.cloudwatchlogs.model.InputLogEvent;
import software.amazon.awssdk.services.cloudwatchlogs.model.PutLogEventsRequest;

import java.util.Collections;

public class EmbeddedMetricsExample {
        public static void main(String[] args) {

                final String usage = "To run this example, supply a Region code (eg. us-east-1), log group, and stream name as command line arguments"
                                + "Ex: PutLogEvents <region-id> <log-group-name> <stream-name>";

                if (args.length != 3) {
                        System.out.println(usage);
                        System.exit(1);
                }

                String regionId = args[0];
                String logGroupName = args[1];
                String logStreamName = args[2];

                CloudWatchLogsClient logsClient = CloudWatchLogsClient.builder().region(Region.of(regionId)).build();

                // Build a JSON log using the EmbeddedMetricFormat.
                long timestamp = System.currentTimeMillis();
                String message = "{" +
                                "  \"_aws\": {" +
                                "    \"Timestamp\": " + timestamp  + "," +
                                "    \"CloudWatchMetrics\": [" +
                                "      {" +
                                "        \"Namespace\": \"MyApp\"," +
                                "        \"Dimensions\": [[\"Operation\"], [\"Operation\", \"Cell\"]]," +
                                "        \"Metrics\": [{ \"Name\": \"ProcessingLatency\", \"Unit\": \"Milliseconds\", \"StorageResolution\": 60 }]" +
                                "      }" +
                                "    ]" +
                                "  }," +
                                "  \"Operation\": \"Aggregator\"," +
                                "  \"Cell\": \"001\"," +
                                "  \"ProcessingLatency\": 100" +
                                "}";
                InputLogEvent inputLogEvent = InputLogEvent.builder()
                        .message(message)
                        .timestamp(timestamp)
                        .build();

                // Specify the request parameters.
                PutLogEventsRequest putLogEventsRequest = PutLogEventsRequest.builder()
                        .logEvents(Collections.singletonList(inputLogEvent))
                        .logGroupName(logGroupName)
                        .logStreamName(logStreamName)
                        .build();

                logsClient.putLogEvents(putLogEventsRequest);

                System.out.println("Successfully put CloudWatch log event");
        }

}

Note

With the embedded metric format, you can track the processing of your EMF logs by metrics that are published in the AWS/Logs namespace of your account. These can be used to track failed metric generation from EMF, as well as whether failures happen due to parsing or validation. For more details see Monitoring with CloudWatch metrics.