Fix #349: Added VM Retry Counter & the functionalities to set it to d…

…efault (PR #398)

- Introduces the VmCreation class and moves some attributes and methods from broker there
- Renames some methods and change signature to simplify calls

Signed-off-by: Manoel Campos <manoelcampos@gmail.com>
Co-authored-by: Manoel Campos <manoelcampos@gmail.com>

src/main/java/org/cloudbus/cloudsim/brokers/DatacenterBroker.java

@@ -449,51 +449,10 @@ public interface DatacenterBroker extends SimEntity {
      *
      * @param <T> the class of VMs inside the list
      * @return the list of failed VMs
-     * @see #setFailedVmsRetryDelay(double)
+     * @see VmCreation#setRetryDelay(double)
      */
     <T extends Vm> List<T> getVmFailedList();
 
-    /**
-     * Checks if the broker has to retry allocating VMs
-     * that couldn't be placed due to lack of suitable Hosts.
-     * @return
-     */
-    boolean isRetryFailedVms();
-
-    /**
-     * Gets a delay (in seconds) for the broker to retry allocating VMs
-     * that couldn't be placed due to lack of suitable active Hosts.
-     *
-     * @return
-     * <ul>
-     *  <li>a value larger than zero to indicate the broker will retry
-     *  to place failed VM as soon as new VMs or Cloudlets
-     *  are submitted or after the given delay.</li>
-     *  <li>otherwise, to indicate failed VMs will be just added to the
-     *  {@link #getVmFailedList()} and the user simulation have to deal with it.
-     *  If the VM has an {@link Vm#addOnCreationFailureListener(EventListener) OnCreationFailureListener},
-     *  it will be notified about the failure.</li>
-     * </ul>
-     */
-    double getFailedVmsRetryDelay();
-
-    /**
-     * Sets a delay (in seconds) for the broker to retry allocating VMs
-     * that couldn't be placed due to lack of suitable active Hosts.
-     *
-     * Setting the attribute as:
-     * <ul>
-     *  <li>larger than zero, the broker will retry to place failed VM as soon as new VMs or Cloudlets
-     *  are submitted or after the given delay.</li>
-     *  <li>otherwise, failed VMs will be just added to the {@link #getVmFailedList()}
-     *  and the user simulation have to deal with it.
-     *  If the VM has an {@link Vm#addOnCreationFailureListener(EventListener) OnCreationFailureListener},
-     *  it will be notified about the failure.</li>
-     * </ul>
-     * @param failedVmsRetryDelay
-     */
-    void setFailedVmsRetryDelay(double failedVmsRetryDelay);
-
     /**
      * Checks if the broker must be shut down after becoming idle.
      * @return
@@ -505,4 +464,11 @@ public interface DatacenterBroker extends SimEntity {
      * @return
      */
     DatacenterBroker setShutdownWhenIdle(boolean shutdownWhenIdle);
+
+    /**
+     * Gets the object that keeps track of number of VM creation retries sent by the broker
+     * and enables configuring creation retries.
+     * @return
+     */
+    VmCreation getVmCreation();
 }

src/main/java/org/cloudbus/cloudsim/brokers/DatacenterBrokerAbstract.java

@@ -74,8 +74,7 @@ public abstract class DatacenterBrokerAbstract extends CloudSimEntity implements
      */
     private Datacenter lastSelectedDc;
 
-    /** @see #setFailedVmsRetryDelay(double)  */
-    private double failedVmsRetryDelay;
+    private VmCreation vmCreation;
 
     /** @see #getVmFailedList() */
     private final List<Vm> vmFailedList;
@@ -118,9 +117,6 @@ public abstract class DatacenterBrokerAbstract extends CloudSimEntity implements
     /** @see #setCloudletComparator(Comparator) */
     private Comparator<Cloudlet> cloudletComparator;
 
-    /** @see #getVmCreationRequests() */
-    private int vmCreationRequests;
-
     /** @see #getDatacenterList() */
     private List<Datacenter> datacenterList;
 
@@ -158,8 +154,7 @@ public DatacenterBrokerAbstract(final CloudSim simulation, final String name) {
         this.lastSelectedDc = Datacenter.NULL;
         this.shutdownWhenIdle = true;
 
-        this.vmCreationRequests = 0;
-        this.failedVmsRetryDelay = 5;
+        this.vmCreation = new VmCreation();
         this.vmFailedList = new ArrayList<>();
         this.vmWaitingList = new ArrayList<>();
         this.vmExecList = new ArrayList<>();
@@ -622,7 +617,7 @@ private boolean processVmCreateResponseFromDatacenter(final SimEvent evt) {
             vm.notifyOnHostAllocationListeners();
         } else {
             vm.setFailed(true);
-            if(!isRetryFailedVms()){
+            if(!vmCreation.isRetryFailedVms()){
                 vmWaitingList.remove(vm);
                 vmFailedList.add(vm);
                 LOGGER.warn(
@@ -634,9 +629,9 @@ private boolean processVmCreateResponseFromDatacenter(final SimEvent evt) {
         }
 
         //Decreases to indicate an ack for the request was received (either if the VM was created or not)
-        vmCreationRequests--;
+        vmCreation.incCreationRequests(-1);
 
-        if(vmCreationRequests == 0 && !vmWaitingList.isEmpty()) {
+        if(vmCreation.getCreationRequests() == 0 && !vmWaitingList.isEmpty()) {
             requestCreationOfWaitingVmsToFallbackDatacenter();
         }
 
@@ -669,6 +664,10 @@ private void notifyOnVmsCreatedListeners() {
             final var listener = onVmsCreatedListeners.get(i);
             listener.update(DatacenterBrokerEventInfo.of(listener, this));
         }
+
+        if (vmWaitingList.isEmpty()) {
+            vmCreation.resetCurrentRetries();
+        }
     }
 
     /**
@@ -686,7 +685,7 @@ private void requestCreationOfWaitingVmsToFallbackDatacenter() {
 
         final var msg =
             "{}: {}: {} of the requested {} VMs couldn't be created because suitable Hosts weren't found in any available Datacenter."
-            + (vmExecList.isEmpty() && !isRetryFailedVms() ? " Shutting broker down..." : "");
+            + (vmExecList.isEmpty() && !vmCreation.isRetryFailedVms() ? " Shutting broker down..." : "");
         LOGGER.error(msg, getSimulation().clockStr(), getName(), vmWaitingList.size(), getVmsNumber());
 
         /* If it gets here, it means that all datacenters were already queried and not all VMs could be created. */
@@ -699,10 +698,11 @@ private void requestCreationOfWaitingVmsToFallbackDatacenter() {
     }
 
     private void processVmCreationFailure() {
-        if (isRetryFailedVms()) {
+        if (vmCreation.isRetryFailedVms()) {
             lastSelectedDc = datacenterList.get(0);
             this.vmCreationRetrySent = true;
-            schedule(failedVmsRetryDelay, CloudSimTag.VM_CREATE_RETRY);
+            schedule(vmCreation.getRetryDelay(), CloudSimTag.VM_CREATE_RETRY);
+            vmCreation.incCurrentRetries();
         } else shutdown();
     }
 
@@ -729,7 +729,7 @@ private boolean requestDatacenterToCreateWaitingVms(final boolean isFallbackData
             if(creationRetry) {
                 vm.setLastTriedDatacenter(Datacenter.NULL);
             }
-            this.vmCreationRequests += requestVmCreation(lastSelectedDc, isFallbackDatacenter, vm);
+            vmCreation.incCreationRequests(requestVmCreation(lastSelectedDc, isFallbackDatacenter, vm));
         }
 
         return lastSelectedDc != Datacenter.NULL;
@@ -1122,15 +1122,6 @@ protected Vm getVmFromCreatedList(final int vmIndex) {
         return vmIndex >= 0 && vmIndex < vmExecList.size() ? vmExecList.get(vmIndex) : Vm.NULL;
     }
 
-    /**
-     * Gets the number of VM creation requests.
-     *
-     * @return the number of VM creation requests
-     */
-    protected int getVmCreationRequests() {
-        return vmCreationRequests;
-    }
-
     /**
      * Gets the list of available datacenters.
      *
@@ -1300,21 +1291,6 @@ public <T extends Vm> List<T> getVmFailedList() {
         return  (List<T>) vmFailedList;
     }
 
-    @Override
-    public boolean isRetryFailedVms() {
-        return failedVmsRetryDelay > 0;
-    }
-
-    @Override
-    public double getFailedVmsRetryDelay() {
-        return failedVmsRetryDelay;
-    }
-
-    @Override
-    public void setFailedVmsRetryDelay(final double failedVmsRetryDelay) {
-        this.failedVmsRetryDelay = failedVmsRetryDelay;
-    }
-
     @Override
     public boolean isShutdownWhenIdle() {
         return shutdownWhenIdle;
@@ -1325,4 +1301,9 @@ public DatacenterBroker setShutdownWhenIdle(final boolean shutdownWhenIdle) {
         this.shutdownWhenIdle = shutdownWhenIdle;
         return this;
     }
+
+    @Override
+    public VmCreation getVmCreation() {
+        return vmCreation;
+    }
 }

src/main/java/org/cloudbus/cloudsim/brokers/DatacenterBrokerNull.java

@@ -82,9 +82,7 @@ final class DatacenterBrokerNull implements DatacenterBroker, SimEntityNullBase
     @Override public DatacenterBroker setVmDestructionDelay(double delay) { return this; }
     @Override public List<Cloudlet> getCloudletSubmittedList() { return Collections.emptyList(); }
     @Override public <T extends Vm> List<T> getVmFailedList() { return Collections.emptyList(); }
-    @Override public boolean isRetryFailedVms() { return false; }
-    @Override public double getFailedVmsRetryDelay() { return 0; }
-    @Override public void setFailedVmsRetryDelay(double failedVmsRetryDelay) {/**/}
+    @Override public VmCreation getVmCreation() { return VmCreation.ofZero(); }
     @Override public boolean isShutdownWhenIdle() { return false; }
     @Override public DatacenterBroker setShutdownWhenIdle(boolean shutdownWhenIdle) { return this; }
     @Override public DatacenterBroker setVmComparator(Comparator<Vm> comparator) { return this; }