#1687 Fix native image build with CloudWatchLoggingAppender (#1688)

* Fix native image build with CloudWatchLoggingAppender
- Start the thread to send logs to cloudwatch only when append command is called, so it is not started during build time
- Create dispatchOnStart property to return to previous behavior

* Modify CloudWatchLoggingAppender tests

Author: andriy-dmytruk

aws-cloudwatch-logging/src/main/java/io/micronaut/aws/cloudwatch/logging/CloudWatchLoggingAppender.java

@@ -67,6 +67,8 @@ public final class CloudWatchLoggingAppender extends AppenderBase<ILoggingEvent>
     private int maxBatchSize = DEFAULT_MAX_BATCH_SIZE;
     private String groupName;
     private String streamName;
+    private boolean dispatchOnStart = false;
+    private volatile boolean dispatchThreadStarted = false;
 
     public int getQueueSize() {
         return queueSize;
@@ -120,6 +122,14 @@ public void setCreateGroupAndStream(boolean createGroupAndStream) {
         this.createGroupAndStream = createGroupAndStream;
     }
 
+    public boolean isDispatchOnStart() {
+        return dispatchOnStart;
+    }
+
+    public void setDispatchOnStart(boolean dispatchOnStart) {
+        this.dispatchOnStart = dispatchOnStart;
+    }
+
     @Override
     public void start() {
         if (isStarted()) {
@@ -158,14 +168,21 @@ public void start() {
 
         deque = queueFactory.newLinkedBlockingDeque(queueSize);
 
+        if (dispatchOnStart) {
+            startDispatch();
+        }
+        super.start();
+    }
+
+    private void startDispatch() {
         task = getContext().getScheduledExecutorService().scheduleAtFixedRate(() -> {
             try {
                 dispatchEvents();
             } catch (InterruptedException e) {
                 Thread.currentThread().interrupt();
             }
         }, 0, 100, TimeUnit.MILLISECONDS);
-        super.start();
+        dispatchThreadStarted = true;
     }
 
     @Override
@@ -182,6 +199,13 @@ protected void append(ILoggingEvent eventObject) {
         if (eventObject == null || !isStarted() || blackListLoggerName.contains(eventObject.getLoggerName())) {
             return;
         }
+        if (!dispatchThreadStarted && !dispatchOnStart) {
+            synchronized(this) {
+                if (!dispatchThreadStarted) {
+                    startDispatch();
+                }
+            }
+        }
 
         try {
             final boolean inserted = deque.offer(eventObject, eventDelayLimit.getMilliseconds(), TimeUnit.MILLISECONDS);
@@ -347,7 +371,7 @@ public boolean detachAppender(String name) {
             return false;
         }
     }
-    
+
     private PutLogEventsResponse putLogs(List<InputLogEvent> logEvents,
                                          String groupName,
                                          String streamName,

aws-cloudwatch-logging/src/test/groovy/io/micronaut/aws/cloudwatch/logging/CloudWatchLoggingAppenderSpec.groovy

@@ -3,6 +3,7 @@ package io.micronaut.aws.cloudwatch.logging
 import ch.qos.logback.classic.Level
 import ch.qos.logback.classic.LoggerContext
 import ch.qos.logback.classic.PatternLayout
+import ch.qos.logback.classic.spi.ILoggingEvent
 import ch.qos.logback.classic.spi.LoggingEvent
 import ch.qos.logback.core.encoder.LayoutWrappingEncoder
 import io.micronaut.runtime.ApplicationConfiguration
@@ -64,6 +65,7 @@ class CloudWatchLoggingAppenderSpec extends Specification {
     void 'test error queue size equal to 0'() {
         when:
         appender.queueSize = 0
+        appender.dispatchOnStart = true
         appender.start()
 
         then:
@@ -75,6 +77,7 @@ class CloudWatchLoggingAppenderSpec extends Specification {
         when:
         appender.queueSize = 100
         appender.publishPeriod = 0
+        appender.dispatchOnStart = true
         appender.start()
 
         then:
@@ -85,6 +88,7 @@ class CloudWatchLoggingAppenderSpec extends Specification {
     void 'test error max batch size less or equal to 0'() {
         when:
         appender.maxBatchSize = 0
+        appender.dispatchOnStart = true
         appender.start()
 
         then:
@@ -97,6 +101,7 @@ class CloudWatchLoggingAppenderSpec extends Specification {
         appender.queueSize = 100
         appender.publishPeriod = 100
         appender.encoder = null
+        appender.dispatchOnStart = true
         appender.start()
 
         then:
@@ -167,6 +172,49 @@ class CloudWatchLoggingAppenderSpec extends Specification {
         thrown(UnsupportedOperationException)
     }
 
+    void 'test start dispatch on start'() {
+        given:
+        PollingConditions conditions = new PollingConditions(timeout: 10, initialDelay: 1.5, factor: 1.25)
+        LoggingEvent event = createEvent("name", Level.INFO, "testMessage", System.currentTimeMillis())
+
+        when:
+        appender.dispatchOnStart = true
+        appender.start()
+        appender.doAppend(event)
+
+        then:
+        conditions.eventually {
+            cloudWatchLogsClient.putLogsRequestList.size() == 1
+        }
+        cloudWatchLogsClient.putLogsRequestList.get(0).logEvents()[0].message().contains("testMessage")
+    }
+
+    void 'test start dispatch on append'() {
+        given:
+        PollingConditions conditions = new PollingConditions(timeout: 10, initialDelay: 1.5, factor: 1.25)
+        LoggingEvent event = createEvent("name", Level.INFO, "testMessage", System.currentTimeMillis())
+
+        when:
+        appender.groupName = "testGroup"
+        appender.streamName = "testStream"
+        appender.start()
+
+        then:
+        conditions.within(1) {
+            cloudWatchLogsClient.putLogsRequestList.size() == 0
+        }
+
+        when:
+        appender.doAppend(event)
+
+        then:
+        conditions.eventually {
+            cloudWatchLogsClient.putLogsRequestList.size() == 1
+        }
+        cloudWatchLogsClient.putLogsRequestList.get(0).logEvents()[0].message().contains("testMessage")
+        cloudWatchLogsClient.putLogsRequestList.get(0).logStreamName() == "testStream"
+    }
+
     void 'custom groupName and StreamName'() {
         given:
         def testGroup = "testGroup"
@@ -178,6 +226,7 @@ class CloudWatchLoggingAppenderSpec extends Specification {
         when:
         appender.groupName = testGroup
         appender.streamName = testStream
+        appender.dispatchOnStart = true
         appender.start()
         appender.doAppend(event)