CloudWatch Logs examples using SDK for Java 2.x

The following code examples show you how to perform actions and implement common scenarios by using the AWS SDK for Java 2.x with CloudWatch Logs.

Actions are code excerpts from larger programs and must be run in context. While actions show you how to call individual service functions, you can see actions in context in their related scenarios and cross-service examples.

Scenarios are code examples that show you how to accomplish a specific task by calling multiple functions within the same service.

Each example includes a link to GitHub, where you can find instructions on how to set up and run the code in context.

Topics

Actions

Actions

The following code example shows how to use DeleteSubscriptionFilter.

SDK for Java 2.x

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.


import software.amazon.awssdk.services.cloudwatch.model.CloudWatchException;
import software.amazon.awssdk.services.cloudwatchlogs.CloudWatchLogsClient;
import software.amazon.awssdk.services.cloudwatchlogs.model.DeleteSubscriptionFilterRequest;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class DeleteSubscriptionFilter {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                  <filter> <logGroup>

                Where:
                  filter - The name of the subscription filter (for example, MyFilter).
                  logGroup - The name of the log group. (for example, testgroup).
                """;

        if (args.length != 2) {
            System.out.println(usage);
            System.exit(1);
        }

        String filter = args[0];
        String logGroup = args[1];
        CloudWatchLogsClient logs = CloudWatchLogsClient.builder()
                .build();

        deleteSubFilter(logs, filter, logGroup);
        logs.close();
    }

    public static void deleteSubFilter(CloudWatchLogsClient logs, String filter, String logGroup) {
        try {
            DeleteSubscriptionFilterRequest request = DeleteSubscriptionFilterRequest.builder()
                    .filterName(filter)
                    .logGroupName(logGroup)
                    .build();

            logs.deleteSubscriptionFilter(request);
            System.out.printf("Successfully deleted CloudWatch logs subscription filter %s", filter);

        } catch (CloudWatchException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

For API details, see DeleteSubscriptionFilter in AWS SDK for Java 2.x API Reference.

The following code example shows how to use DescribeSubscriptionFilters.

SDK for Java 2.x

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.


import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.services.cloudwatch.model.CloudWatchException;
import software.amazon.awssdk.services.cloudwatchlogs.CloudWatchLogsClient;
import software.amazon.awssdk.services.cloudwatchlogs.model.DescribeSubscriptionFiltersRequest;
import software.amazon.awssdk.services.cloudwatchlogs.model.DescribeSubscriptionFiltersResponse;
import software.amazon.awssdk.services.cloudwatchlogs.model.SubscriptionFilter;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class DescribeSubscriptionFilters {
    public static void main(String[] args) {

        final String usage = """

                Usage:
                  <logGroup>

                Where:
                  logGroup - A log group name (for example, myloggroup).
                """;

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

        String logGroup = args[0];
        CloudWatchLogsClient logs = CloudWatchLogsClient.builder()
                .credentialsProvider(ProfileCredentialsProvider.create())
                .build();

        describeFilters(logs, logGroup);
        logs.close();
    }

    public static void describeFilters(CloudWatchLogsClient logs, String logGroup) {
        try {
            boolean done = false;
            String newToken = null;

            while (!done) {
                DescribeSubscriptionFiltersResponse response;
                if (newToken == null) {
                    DescribeSubscriptionFiltersRequest request = DescribeSubscriptionFiltersRequest.builder()
                            .logGroupName(logGroup)
                            .limit(1).build();

                    response = logs.describeSubscriptionFilters(request);
                } else {
                    DescribeSubscriptionFiltersRequest request = DescribeSubscriptionFiltersRequest.builder()
                            .nextToken(newToken)
                            .logGroupName(logGroup)
                            .limit(1).build();
                    response = logs.describeSubscriptionFilters(request);
                }

                for (SubscriptionFilter filter : response.subscriptionFilters()) {
                    System.out.printf("Retrieved filter with name %s, " + "pattern %s " + "and destination arn %s",
                            filter.filterName(),
                            filter.filterPattern(),
                            filter.destinationArn());
                }

                if (response.nextToken() == null) {
                    done = true;
                } else {
                    newToken = response.nextToken();
                }
            }

        } catch (CloudWatchException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        System.out.printf("Done");
    }
}

For API details, see DescribeSubscriptionFilters in AWS SDK for Java 2.x API Reference.

The following code example shows how to use PutSubscriptionFilter.

SDK for Java 2.x

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.


import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.cloudwatchlogs.CloudWatchLogsClient;
import software.amazon.awssdk.services.cloudwatchlogs.model.CloudWatchLogsException;
import software.amazon.awssdk.services.cloudwatchlogs.model.PutSubscriptionFilterRequest;

/**
 * Before running this code example, you need to grant permission to CloudWatch
 * Logs the right to execute your Lambda function.
 * To perform this task, you can use this CLI command:
 *
 * aws lambda add-permission --function-name "lamda1" --statement-id "lamda1"
 * --principal "logs.us-west-2.amazonaws.com" --action "lambda:InvokeFunction"
 * --source-arn "arn:aws:logs:us-west-2:111111111111:log-group:testgroup:*"
 * --source-account "111111111111"
 *
 * Make sure you replace the function name with your function name and replace
 * '111111111111' with your account details.
 * For more information, see "Subscription Filters with AWS Lambda" in the
 * Amazon CloudWatch Logs Guide.
 *
 *
 * Also, before running this Java V2 code example,set up your development
 * environment,including your credentials.
 *
 * For more information,see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 *
 */

public class PutSubscriptionFilter {
    public static void main(String[] args) {
        final String usage = """

                Usage:
                  <filter> <pattern> <logGroup> <functionArn>\s

                Where:
                  filter - A filter name (for example, myfilter).
                  pattern - A filter pattern (for example, ERROR).
                  logGroup - A log group name (testgroup).
                  functionArn - An AWS Lambda function ARN (for example, arn:aws:lambda:us-west-2:111111111111:function:lambda1) .
                """;

        if (args.length != 4) {
            System.out.println(usage);
            System.exit(1);
        }

        String filter = args[0];
        String pattern = args[1];
        String logGroup = args[2];
        String functionArn = args[3];
        Region region = Region.US_WEST_2;
        CloudWatchLogsClient cwl = CloudWatchLogsClient.builder()
                .region(region)
                .build();

        putSubFilters(cwl, filter, pattern, logGroup, functionArn);
        cwl.close();
    }

    public static void putSubFilters(CloudWatchLogsClient cwl,
            String filter,
            String pattern,
            String logGroup,
            String functionArn) {

        try {
            PutSubscriptionFilterRequest request = PutSubscriptionFilterRequest.builder()
                    .filterName(filter)
                    .filterPattern(pattern)
                    .logGroupName(logGroup)
                    .destinationArn(functionArn)
                    .build();

            cwl.putSubscriptionFilter(request);
            System.out.printf(
                    "Successfully created CloudWatch logs subscription filter %s",
                    filter);

        } catch (CloudWatchLogsException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

For API details, see PutSubscriptionFilter in AWS SDK for Java 2.x API Reference.

The following code example shows how to use StartLiveTail.

SDK for Java 2.x

Include the required files.


import io.reactivex.FlowableSubscriber;
import io.reactivex.annotations.NonNull;
import org.reactivestreams.Subscription;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.services.cloudwatchlogs.CloudWatchLogsAsyncClient;
import software.amazon.awssdk.services.cloudwatchlogs.model.LiveTailSessionLogEvent;
import software.amazon.awssdk.services.cloudwatchlogs.model.LiveTailSessionStart;
import software.amazon.awssdk.services.cloudwatchlogs.model.LiveTailSessionUpdate;
import software.amazon.awssdk.services.cloudwatchlogs.model.StartLiveTailRequest;
import software.amazon.awssdk.services.cloudwatchlogs.model.StartLiveTailResponseHandler;
import software.amazon.awssdk.services.cloudwatchlogs.model.CloudWatchLogsException;
import software.amazon.awssdk.services.cloudwatchlogs.model.StartLiveTailResponseStream;

import java.util.Date;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

Handle the events from the Live Tail session.


    private static StartLiveTailResponseHandler getStartLiveTailResponseStreamHandler(
            AtomicReference<Subscription> subscriptionAtomicReference) {
        return StartLiveTailResponseHandler.builder()
            .onResponse(r -> System.out.println("Received initial response"))
            .onError(throwable -> {
                CloudWatchLogsException e = (CloudWatchLogsException) throwable.getCause();
                System.err.println(e.awsErrorDetails().errorMessage());
                System.exit(1);
            })
            .subscriber(() -> new FlowableSubscriber<>() {
                @Override
                public void onSubscribe(@NonNull Subscription s) {
                    subscriptionAtomicReference.set(s);
                    s.request(Long.MAX_VALUE);
                }

                @Override
                public void onNext(StartLiveTailResponseStream event) {
                    if (event instanceof LiveTailSessionStart) {
                        LiveTailSessionStart sessionStart = (LiveTailSessionStart) event;
                        System.out.println(sessionStart);
                    } else if (event instanceof LiveTailSessionUpdate) {
                        LiveTailSessionUpdate sessionUpdate = (LiveTailSessionUpdate) event;
                        List<LiveTailSessionLogEvent> logEvents = sessionUpdate.sessionResults();
                        logEvents.forEach(e -> {
                            long timestamp = e.timestamp();
                            Date date = new Date(timestamp);
                            System.out.println("[" + date + "] " + e.message());
                        });
                    } else {
                        throw CloudWatchLogsException.builder().message("Unknown event type").build();
                    }
                }

                @Override
                public void onError(Throwable throwable) {
                    System.out.println(throwable.getMessage());
                    System.exit(1);
                }

                @Override
                public void onComplete() {
                    System.out.println("Completed Streaming Session");
                }
            })
            .build();
    }

Start the Live Tail session.


        CloudWatchLogsAsyncClient cloudWatchLogsAsyncClient =
                CloudWatchLogsAsyncClient.builder()
                    .credentialsProvider(ProfileCredentialsProvider.create())
                    .build();

        StartLiveTailRequest request =
                StartLiveTailRequest.builder()
                    .logGroupIdentifiers(logGroupIdentifiers)
                    .logStreamNames(logStreamNames)
                    .logEventFilterPattern(logEventFilterPattern)
                    .build();

        /* Create a reference to store the subscription */ 
        final AtomicReference<Subscription> subscriptionAtomicReference = new AtomicReference<>(null);

        cloudWatchLogsAsyncClient.startLiveTail(request, getStartLiveTailResponseStreamHandler(subscriptionAtomicReference));

Stop the Live Tail session after a period of time has elapsed.


        /* Set a timeout for the session and cancel the subscription. This will:
         * 1). Close the stream
         * 2). Stop the Live Tail session
         */
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        if (subscriptionAtomicReference.get() != null) {
            subscriptionAtomicReference.get().cancel();
            System.out.println("Subscription to stream closed");
        }

For API details, see StartLiveTail in AWS SDK for Java 2.x API Reference.

Warning Javascript is disabled or is unavailable in your browser.

To use the Amazon Web Services Documentation, Javascript must be enabled. Please refer to your browser's Help pages for instructions.

Document Conventions

CloudWatch Events

Amazon Cognito Identity