allow init cooldown to jobAutoScaler (#811)

Author: Andyz26

mantis-common/src/main/java/io/mantisrx/common/SystemParameters.java

@@ -29,6 +29,7 @@ public final class SystemParameters {
 
     public static final String JOB_AUTOSCALE_V2_ENABLED_PARAM = "mantis.job.autoscale.v2.enabled";
     public static final String JOB_AUTOSCALE_V2_LOADER_CONFIG_PARAM = "mantis.job.autoscale.v2.loader.config";
+    public static final String JOB_AUTOSCALE_APPLY_INITIAL_COOLDOWN_PARAM = "mantis.job.autoscale.apply.initial.cooldown";
 
 
     @Deprecated

mantis-runtime-autoscaler-api/src/main/java/io/mantisrx/server/worker/jobmaster/JobAutoScaler.java

@@ -536,13 +536,20 @@ private class StageScaleOperator<T, R> implements Observable.Operator<Object, Ev
       private final int stage;
       private final StageScalingPolicy scalingPolicy;
       private final StageScaler scaler;
-      private volatile long lastScaledAt = 0L;
+      private volatile long lastScaledAt;
 
       private StageScaleOperator(int stage, StageScalingPolicy stageScalingPolicy, String scalerId, Context context) {
         this.stage = stage;
         this.scalingPolicy = stageScalingPolicy;
         this.scaler = new StageScaler(stage, this.scalingPolicy, scalerId, context);
-        logger.info("cooldownSecs set to {}", stageScalingPolicy.getCoolDownSecs());
+        
+        boolean applyInitialCooldown = Boolean.parseBoolean(
+            Optional.ofNullable(MantisProperties.getProperty(SystemParameters.JOB_AUTOSCALE_APPLY_INITIAL_COOLDOWN_PARAM))
+                .orElse("true"));
+        this.lastScaledAt = applyInitialCooldown ? System.currentTimeMillis() : 0L;
+        
+        logger.info("cooldownSecs set to {}, applyInitialCooldown={}", 
+            stageScalingPolicy.getCoolDownSecs(), applyInitialCooldown);
       }
 
 

mantis-runtime-executor/src/test/java/io/mantisrx/server/worker/jobmaster/JobAutoScalerTest.java

@@ -25,6 +25,7 @@
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.*;
 
+import io.mantisrx.common.SystemParameters;
 import io.mantisrx.runtime.Context;
 import io.mantisrx.runtime.MachineDefinition;
 import io.mantisrx.runtime.descriptor.JobScalingRule;
@@ -45,6 +46,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
@@ -59,6 +61,11 @@ public class JobAutoScalerTest {
 
     private static final Logger logger = LoggerFactory.getLogger(JobAutoScalerTest.class);
 
+    @BeforeClass
+    public static void setup() {
+        System.setProperty(SystemParameters.JOB_AUTOSCALE_APPLY_INITIAL_COOLDOWN_PARAM, "false");
+    }
+
     @Test
     public void testScaleUp() throws InterruptedException {
         final String jobId = "test-job-1";