CloudWatch 使用 Java 2.x SDK 的記錄範例

下列程式碼範例說明如何使用 and CloudWatch Logs 來執行動作和實作常見案例。 AWS SDK for Java 2.x

Actions 是大型程式的程式碼摘錄，必須在內容中執行。雖然動作會告訴您如何呼叫個別服務函數，但您可以在其相關情境和跨服務範例中查看內容中的動作。

Scenarios (案例) 是向您展示如何呼叫相同服務中的多個函數來完成特定任務的程式碼範例。

每個範例都包含一個連結 GitHub，您可以在其中找到如何在內容中設定和執行程式碼的指示。

動作

DeleteSubscriptionFilter

下列程式碼範例會示範如何使用DeleteSubscriptionFilter。

SDK對於爪哇 2.x

注意

還有更多關於 GitHub。尋找完整範例，並了解如何在AWS 設定和執行程式碼範例儲存庫。

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);
        }
    }
}

• 如需詳API細資訊，請參閱AWS SDK for Java 2.x API參考DeleteSubscriptionFilter中的。

DescribeSubscriptionFilters

下列程式碼範例會示範如何使用DescribeSubscriptionFilters。

SDK對於爪哇 2.x

注意

還有更多關於 GitHub。尋找完整範例，並了解如何在AWS 設定和執行程式碼範例儲存庫。

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");
    }
}

• 如需詳API細資訊，請參閱AWS SDK for Java 2.x API參考DescribeSubscriptionFilters中的。

PutSubscriptionFilter

下列程式碼範例會示範如何使用PutSubscriptionFilter。

SDK對於爪哇 2.x

注意

還有更多關於 GitHub。尋找完整範例，並了解如何在AWS 設定和執行程式碼範例儲存庫。

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);
        }
    }
}

• 如需詳API細資訊，請參閱AWS SDK for Java 2.x API參考PutSubscriptionFilter中的。

StartLiveTail

下列程式碼範例會示範如何使用StartLiveTail。

SDK對於爪哇 2.x

包括必需的檔案。

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;

處理來自即時尾巴工作階段的事件。

    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();
    }

啟動「即時尾巴」工作階段。

        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));

經過一段時間後，停止「即時尾端」工作階段。

        /* 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");
        }

• 如需詳API細資訊，請參閱AWS SDK for Java 2.x API參考StartLiveTail中的。