feat: Add maximum jobs per template configuration

pom.xml

@@ -35,7 +35,7 @@
     <properties>
         <revision>0.10.1</revision>
         <changelist>-SNAPSHOT</changelist>
-        <jenkins.version>2.375</jenkins.version>
+        <jenkins.version>2.407</jenkins.version>
         <json-path-assert.version>2.8.0</json-path-assert.version>
     </properties>
 

src/main/java/org/jenkinsci/plugins/nomad/NomadCloud.java

@@ -134,8 +134,14 @@ public Collection<NodeProvisioner.PlannedNode> provision(Label label, int excess
             if (prune)
                 pruneOrphanedWorkers(template);
 
+            int existingNodes = 0;
+            // Let's avoid an useless request to nomad api if no MaxConcurrentJobs is configured
+            if(template.getMaxConcurrentJobs() >= 0) {
+                existingNodes = this.nomad.getRunningWorkers(template.getPrefix()).length;
+            }
+
             try {
-                while (excessWorkload > 0) {
+                while (excessWorkload > 0 && checkExcessJobs(template,existingNodes,nodes.size())) {
                     LOGGER.log(Level.INFO, "Excess workload of " + excessWorkload + ", provisioning new Jenkins worker on Nomad cluster");
 
                     final String workerName = template.createWorkerName();
@@ -156,6 +162,25 @@ public Collection<NodeProvisioner.PlannedNode> provision(Label label, int excess
         return Collections.emptyList();
     }
 
+    /**
+     * Determine if we reached the maximum number of job we can create for a specific template.
+     * If the maximum configured is negative, we consider this configuration as unlimited.
+     * @param template
+     * @param existingNodes
+     * @param created
+     * @return false if the template maximum configured jobs isn't reached, otherwise, return true
+     */
+    private boolean checkExcessJobs(NomadWorkerTemplate template,int existingNodes, int created) {
+        int maxAllowed = template.getMaxConcurrentJobs();
+        int maxAllowedLeft = maxAllowed - existingNodes - created;
+
+        if (maxAllowed >= 0 && created >= maxAllowedLeft) {
+            LOGGER.log((Level.INFO), "Maximum jobs for template prefix: "+template.getPrefix()+" excedeed | Maximum: "+maxAllowed);
+            return false;
+        }
+        return true;
+    }
+
 
     /**
      * Determines if some nomad worker needs to be stopped.

src/main/java/org/jenkinsci/plugins/nomad/NomadWorkerTemplate.java

@@ -29,6 +29,7 @@ public class NomadWorkerTemplate implements Describable<NomadWorkerTemplate> {
 
     // persistent fields
     private final String prefix;
+    private final int maxConcurrentJobs;
     private final int idleTerminationInMinutes;
     private final boolean reusable;
     private final int numExecutors;
@@ -98,13 +99,15 @@ public class NomadWorkerTemplate implements Describable<NomadWorkerTemplate> {
     public NomadWorkerTemplate(
             String prefix,
             String labels,
+            int maxConcurrentJobs,
             int idleTerminationInMinutes,
             boolean reusable,
             int numExecutors,
             String remoteFs,
             String jobTemplate
     ) {
         this.prefix = prefix.isEmpty() ? SLAVE_PREFIX : prefix;
+        this.maxConcurrentJobs = maxConcurrentJobs;
         this.idleTerminationInMinutes = idleTerminationInMinutes;
         this.reusable = reusable;
         this.numExecutors = numExecutors;
@@ -127,6 +130,10 @@ public String getPrefix() {
         return prefix;
     }
 
+    public int getMaxConcurrentJobs() {
+        return maxConcurrentJobs;
+    }
+
     public int getIdleTerminationInMinutes() {
         return idleTerminationInMinutes;
     }
@@ -201,6 +208,7 @@ public FormValidation doValidation(
             NomadWorkerTemplate template = new NomadWorkerTemplate(
                     "validate-template",
                     null,
+                    -1,
                     0,
                     false,
                     1,

src/main/resources/org/jenkinsci/plugins/nomad/NomadWorkerTemplate/config.jelly

@@ -12,6 +12,10 @@
             <f:textbox />
         </f:entry>
 
+        <f:entry title="Maximum Number of concurrent Job (-1 for unmimited)" field="maxConcurrentJobs">
+            <f:number default="-1" />
+        </f:entry>
+
         <f:entry title="Idle termination time" field="idleTerminationInMinutes">
             <f:number default="10" />
         </f:entry>

src/test/java/org/jenkinsci/plugins/nomad/NomadCloudTest.java

@@ -122,6 +122,7 @@ private NomadWorkerTemplate createTemplate(String labels) {
         return new NomadWorkerTemplate(
                 "jenkins",
                 labels,
+                -1,
                 1,
                 true,
                 1,