com.kdgregory.logback.aws.CloudWatchAppender Maven / Gradle / Ivy

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Appenders for Logback that writes log events to various AWS services
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// Copyright (c) Keith D Gregory
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.kdgregory.logback.aws;

import java.util.Date;

import com.kdgregory.logback.aws.internal.AbstractAppender;
import com.kdgregory.logging.aws.cloudwatch.CloudWatchWriterConfig;
import com.kdgregory.logging.aws.cloudwatch.CloudWatchWriterFactory;
import com.kdgregory.logging.aws.cloudwatch.CloudWatchWriterStatistics;
import com.kdgregory.logging.aws.cloudwatch.CloudWatchWriterStatisticsMXBean;
import com.kdgregory.logging.aws.common.Substitutions;
import com.kdgregory.logging.common.factories.DefaultThreadFactory;


/**
 *  Appender that writes to a CloudWatch log stream.
 */
public class CloudWatchAppender
extends AbstractAppender
{
    private String  logGroup;
    private String  logStream;
    private Integer retentionPeriod;


    public CloudWatchAppender()
    {
        super(new DefaultThreadFactory("logback-cloudwatch"),
              new CloudWatchWriterFactory(),
              new CloudWatchWriterStatistics(),
              CloudWatchWriterStatisticsMXBean.class);

        logStream = "{startupTimestamp}";
    }

//----------------------------------------------------------------------------
//  Configuration
//----------------------------------------------------------------------------

    /**
     *  Sets the CloudWatch Log Group associated with this appender.
     *  
     *  You typically assign a single log group to an application, and then
     *  use multiple log streams for instances of that application.
     *  

     *  There is no default value. If you do not configure the log group, the
     *  appender will be disabled and will report its misconfiguration.
     */
    public void setLogGroup(String value)
    {
        logGroup = value;
    }


    /**
     *  Returns the log group name; see {@link #setLogGroup}. Primarily used
     *  for testing.
     */
    public String getLogGroup()
    {
        return logGroup;
    }


    /**
     *  Sets the CloudWatch Log Stream associated with this appender.
     *  

     *  You typically create a separate log stream for each instance of the
     *  application.
     *  
     *  Default value is {startTimestamp}, the JVM startup timestamp.
     */
    public void setLogStream(String value)
    {
        logStream = value;
    }


    /**
     *  Returns the log stream name; see {@link #setLogStream}. Primarily used
     *  for testing.
     */
    public String getLogStream()
    {
        return logStream;
    }


    /**
     *  Sets the retention period, in days, for auto-created log groups. Beware that AWS
     *  limits the allowable values; see API documentation for details.
     */
    public void setRetentionPeriod(int value)
    {
        // per https://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutRetentionPolicy.html
        // as-of 2019-05-04
        switch (value)
        {
            case 1 :
            case 3 :
            case 5 :
            case 7 :
            case 14 :
            case 30 :
            case 60 :
            case 90 :
            case 120 :
            case 150 :
            case 180 :
            case 365 :
            case 400 :
            case 545 :
            case 731 :
            case 1827 :
            case 3653 :
                retentionPeriod = Integer.valueOf(value);
                break;
            default :
                throw new IllegalArgumentException("invalid retention period; see AWS API for allowed values");
        }
    }


    /**
     *  Returns the current retention period; null indicates records will be
     *  kept forever.
     */
    public Integer getRetentionPeriod()
    {
        return retentionPeriod;
    }

//----------------------------------------------------------------------------
//  AbstractAppender overrides
//----------------------------------------------------------------------------

    @Override
    /** {@inheritDoc} */
    public void setRotationMode(String value)
    {
        super.setRotationMode(value);
    }


    @Override
    /** {@inheritDoc} */
    public void rotate()
    {
        super.rotate();
    }


    @Override
    protected CloudWatchWriterConfig generateWriterConfig()
    {
        Substitutions subs     = new Substitutions(new Date(), sequence.get());
        String actualLogGroup  = subs.perform(logGroup);
        String actualLogStream = subs.perform(logStream);

        return new CloudWatchWriterConfig(
            actualLogGroup, actualLogStream, retentionPeriod,
            batchDelay, discardThreshold, discardAction,
            clientFactory, clientRegion, clientEndpoint);
    }
}