# 使用 AWS 开发工具包处理数据库活动流
<a name="DBActivityStreams.CodeExample"></a>

您可以使用 AWS 开发工具包以编程方式处理活动流。以下功能完善的 Java 和 Python 示例是关于使用数据库活动流记录实现基于实例的实施。

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#### [ Java ]

```
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.zip.GZIPInputStream;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.encryptionsdk.AwsCrypto;
import com.amazonaws.encryptionsdk.CryptoInputStream;
import com.amazonaws.encryptionsdk.jce.JceMasterKey;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.InvalidStateException;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.ShutdownException;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.ThrottlingException;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessor;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorCheckpointer;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorFactory;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.InitialPositionInStream;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.KinesisClientLibConfiguration;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.ShutdownReason;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker;
import com.amazonaws.services.kinesis.clientlibrary.lib.worker.Worker.Builder;
import com.amazonaws.services.kinesis.model.Record;
import com.amazonaws.services.kms.AWSKMS;
import com.amazonaws.services.kms.AWSKMSClientBuilder;
import com.amazonaws.services.kms.model.DecryptRequest;
import com.amazonaws.services.kms.model.DecryptResult;
import com.amazonaws.util.Base64;
import com.amazonaws.util.IOUtils;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.annotations.SerializedName;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class DemoConsumer {

    private static final String STREAM_NAME = "aws-rds-das-[instance-external-resource-id]"; // aws-rds-das-db-ABCD123456
    private static final String APPLICATION_NAME = "AnyApplication"; //unique application name for dynamo table generation that holds kinesis shard tracking
    private static final String AWS_ACCESS_KEY = "[AWS_ACCESS_KEY_TO_ACCESS_KINESIS]";
    private static final String AWS_SECRET_KEY = "[AWS_SECRET_KEY_TO_ACCESS_KINESIS]";
    private static final String RESOURCE_ID = "[external-resource-id]"; // db-ABCD123456
    private static final String REGION_NAME = "[region-name]"; //us-east-1, us-east-2...
    private static final BasicAWSCredentials CREDENTIALS = new BasicAWSCredentials(AWS_ACCESS_KEY, AWS_SECRET_KEY);
    private static final AWSStaticCredentialsProvider CREDENTIALS_PROVIDER = new AWSStaticCredentialsProvider(CREDENTIALS);

    private static final AwsCrypto CRYPTO = new AwsCrypto();
    private static final AWSKMS KMS = AWSKMSClientBuilder.standard()
            .withRegion(REGION_NAME)
            .withCredentials(CREDENTIALS_PROVIDER).build();

    class Activity {
        String type;
        String version;
        String databaseActivityEvents;
        String key;
    }

    class ActivityEvent {
        @SerializedName("class") String _class;
        String clientApplication;
        String command;
        String commandText;
        String databaseName;
        String dbProtocol;
        String dbUserName;
        String endTime;
        String errorMessage;
        String exitCode;
        String logTime;
        String netProtocol;
        String objectName;
        String objectType;
        List<String> paramList;
        String pid;
        String remoteHost;
        String remotePort;
        String rowCount;
        String serverHost;
        String serverType;
        String serverVersion;
        String serviceName;
        String sessionId;
        String startTime;
        String statementId;
        String substatementId;
        String transactionId;
        String type;
    }

    class ActivityRecords {
        String type;
        String clusterId; // note that clusterId will contain an empty string on RDS Oracle and RDS SQL Server
        String instanceId;
        List<ActivityEvent> databaseActivityEventList;
    }

    static class RecordProcessorFactory implements IRecordProcessorFactory {
        @Override
        public IRecordProcessor createProcessor() {
            return new RecordProcessor();
        }
    }

    static class RecordProcessor implements IRecordProcessor {

        private static final long BACKOFF_TIME_IN_MILLIS = 3000L;
        private static final int PROCESSING_RETRIES_MAX = 10;
        private static final long CHECKPOINT_INTERVAL_MILLIS = 60000L;
        private static final Gson GSON = new GsonBuilder().serializeNulls().create();

        private static final Cipher CIPHER;
        static {
            Security.insertProviderAt(new BouncyCastleProvider(), 1);
            try {
                CIPHER = Cipher.getInstance("AES/GCM/NoPadding", "BC");
            } catch (NoSuchAlgorithmException | NoSuchPaddingException | NoSuchProviderException e) {
                throw new ExceptionInInitializerError(e);
            }
        }

        private long nextCheckpointTimeInMillis;

        @Override
        public void initialize(String shardId) {
        }

        @Override
        public void processRecords(final List<Record> records, final IRecordProcessorCheckpointer checkpointer) {
            for (final Record record : records) {
                processSingleBlob(record.getData());
            }

            if (System.currentTimeMillis() > nextCheckpointTimeInMillis) {
                checkpoint(checkpointer);
                nextCheckpointTimeInMillis = System.currentTimeMillis() + CHECKPOINT_INTERVAL_MILLIS;
            }
        }

        @Override
        public void shutdown(IRecordProcessorCheckpointer checkpointer, ShutdownReason reason) {
            if (reason == ShutdownReason.TERMINATE) {
                checkpoint(checkpointer);
            }
        }

        private void processSingleBlob(final ByteBuffer bytes) {
            try {
                // JSON $Activity
                final Activity activity = GSON.fromJson(new String(bytes.array(), StandardCharsets.UTF_8), Activity.class);

                // Base64.Decode
                final byte[] decoded = Base64.decode(activity.databaseActivityEvents);
                final byte[] decodedDataKey = Base64.decode(activity.key);

                Map<String, String> context = new HashMap<>();
                context.put("aws:rds:db-id", RESOURCE_ID);

                // Decrypt
                final DecryptRequest decryptRequest = new DecryptRequest()
                        .withCiphertextBlob(ByteBuffer.wrap(decodedDataKey)).withEncryptionContext(context);
                final DecryptResult decryptResult = KMS.decrypt(decryptRequest);
                final byte[] decrypted = decrypt(decoded, getByteArray(decryptResult.getPlaintext()));

                // GZip Decompress
                final byte[] decompressed = decompress(decrypted);
                // JSON $ActivityRecords
                final ActivityRecords activityRecords = GSON.fromJson(new String(decompressed, StandardCharsets.UTF_8), ActivityRecords.class);

                // Iterate throught $ActivityEvents
                for (final ActivityEvent event : activityRecords.databaseActivityEventList) {
                    System.out.println(GSON.toJson(event));
                }
            } catch (Exception e) {
                // Handle error.
                e.printStackTrace();
            }
        }

        private static byte[] decompress(final byte[] src) throws IOException {
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(src);
            GZIPInputStream gzipInputStream = new GZIPInputStream(byteArrayInputStream);
            return IOUtils.toByteArray(gzipInputStream);
        }

        private void checkpoint(IRecordProcessorCheckpointer checkpointer) {
            for (int i = 0; i < PROCESSING_RETRIES_MAX; i++) {
                try {
                    checkpointer.checkpoint();
                    break;
                } catch (ShutdownException se) {
                    // Ignore checkpoint if the processor instance has been shutdown (fail over).
                    System.out.println("Caught shutdown exception, skipping checkpoint." + se);
                    break;
                } catch (ThrottlingException e) {
                    // Backoff and re-attempt checkpoint upon transient failures
                    if (i >= (PROCESSING_RETRIES_MAX - 1)) {
                        System.out.println("Checkpoint failed after " + (i + 1) + "attempts." + e);
                        break;
                    } else {
                        System.out.println("Transient issue when checkpointing - attempt " + (i + 1) + " of " + PROCESSING_RETRIES_MAX + e);
                    }
                } catch (InvalidStateException e) {
                    // This indicates an issue with the DynamoDB table (check for table, provisioned IOPS).
                    System.out.println("Cannot save checkpoint to the DynamoDB table used by the Amazon Kinesis Client Library." + e);
                    break;
                }
                try {
                    Thread.sleep(BACKOFF_TIME_IN_MILLIS);
                } catch (InterruptedException e) {
                    System.out.println("Interrupted sleep" + e);
                }
            }
        }
    }

    private static byte[] decrypt(final byte[] decoded, final byte[] decodedDataKey) throws IOException {
        // Create a JCE master key provider using the random key and an AES-GCM encryption algorithm
        final JceMasterKey masterKey = JceMasterKey.getInstance(new SecretKeySpec(decodedDataKey, "AES"),
                "BC", "DataKey", "AES/GCM/NoPadding");
        try (final CryptoInputStream<JceMasterKey> decryptingStream = CRYPTO.createDecryptingStream(masterKey, new ByteArrayInputStream(decoded));
             final ByteArrayOutputStream out = new ByteArrayOutputStream()) {
            IOUtils.copy(decryptingStream, out);
            return out.toByteArray();
        }
    }

    public static void main(String[] args) throws Exception {
        final String workerId = InetAddress.getLocalHost().getCanonicalHostName() + ":" + UUID.randomUUID();
        final KinesisClientLibConfiguration kinesisClientLibConfiguration =
                new KinesisClientLibConfiguration(APPLICATION_NAME, STREAM_NAME, CREDENTIALS_PROVIDER, workerId);
        kinesisClientLibConfiguration.withInitialPositionInStream(InitialPositionInStream.LATEST);
        kinesisClientLibConfiguration.withRegionName(REGION_NAME);
        final Worker worker = new Builder()
                .recordProcessorFactory(new RecordProcessorFactory())
                .config(kinesisClientLibConfiguration)
                .build();

        System.out.printf("Running %s to process stream %s as worker %s...\n", APPLICATION_NAME, STREAM_NAME, workerId);

        try {
            worker.run();
        } catch (Throwable t) {
            System.err.println("Caught throwable while processing data.");
            t.printStackTrace();
            System.exit(1);
        }
        System.exit(0);
    }

    private static byte[] getByteArray(final ByteBuffer b) {
        byte[] byteArray = new byte[b.remaining()];
        b.get(byteArray);
        return byteArray;
    }
}
```

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#### [ Python ]

```
import base64
import json
import zlib
import aws_encryption_sdk
from aws_encryption_sdk import CommitmentPolicy
from aws_encryption_sdk.internal.crypto import WrappingKey
from aws_encryption_sdk.key_providers.raw import RawMasterKeyProvider
from aws_encryption_sdk.identifiers import WrappingAlgorithm, EncryptionKeyType
import boto3

REGION_NAME = '<region>'                    # us-east-1
RESOURCE_ID = '<external-resource-id>'      # db-ABCD123456
STREAM_NAME = 'aws-rds-das-' + RESOURCE_ID  # aws-rds-das-db-ABCD123456

enc_client = aws_encryption_sdk.EncryptionSDKClient(commitment_policy=CommitmentPolicy.FORBID_ENCRYPT_ALLOW_DECRYPT)

class MyRawMasterKeyProvider(RawMasterKeyProvider):
    provider_id = "BC"

    def __new__(cls, *args, **kwargs):
        obj = super(RawMasterKeyProvider, cls).__new__(cls)
        return obj

    def __init__(self, plain_key):
        RawMasterKeyProvider.__init__(self)
        self.wrapping_key = WrappingKey(wrapping_algorithm=WrappingAlgorithm.AES_256_GCM_IV12_TAG16_NO_PADDING,
                                        wrapping_key=plain_key, wrapping_key_type=EncryptionKeyType.SYMMETRIC)

    def _get_raw_key(self, key_id):
        return self.wrapping_key


def decrypt_payload(payload, data_key):
    my_key_provider = MyRawMasterKeyProvider(data_key)
    my_key_provider.add_master_key("DataKey")
    decrypted_plaintext, header = enc_client.decrypt(
        source=payload,
        materials_manager=aws_encryption_sdk.materials_managers.default.DefaultCryptoMaterialsManager(master_key_provider=my_key_provider))
    return decrypted_plaintext


def decrypt_decompress(payload, key):
    decrypted = decrypt_payload(payload, key)
    return zlib.decompress(decrypted, zlib.MAX_WBITS + 16)


def main():
    session = boto3.session.Session()
    kms = session.client('kms', region_name=REGION_NAME)
    kinesis = session.client('kinesis', region_name=REGION_NAME)

    response = kinesis.describe_stream(StreamName=STREAM_NAME)
    shard_iters = []
    for shard in response['StreamDescription']['Shards']:
        shard_iter_response = kinesis.get_shard_iterator(StreamName=STREAM_NAME, ShardId=shard['ShardId'],
                                                         ShardIteratorType='LATEST')
        shard_iters.append(shard_iter_response['ShardIterator'])

    while len(shard_iters) > 0:
        next_shard_iters = []
        for shard_iter in shard_iters:
            response = kinesis.get_records(ShardIterator=shard_iter, Limit=10000)
            for record in response['Records']:
                record_data = record['Data']
                record_data = json.loads(record_data)
                payload_decoded = base64.b64decode(record_data['databaseActivityEvents'])
                data_key_decoded = base64.b64decode(record_data['key'])
                data_key_decrypt_result = kms.decrypt(CiphertextBlob=data_key_decoded,
                                                      EncryptionContext={'aws:rds:db-id': RESOURCE_ID})
                print (decrypt_decompress(payload_decoded, data_key_decrypt_result['Plaintext']))
            if 'NextShardIterator' in response:
                next_shard_iters.append(response['NextShardIterator'])
        shard_iters = next_shard_iters


if __name__ == '__main__':
    main()
```

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