Add PauseAction when throttling pipelines

The PauseAction is used by pipeline visualisers (such as
pipeline-stage-view) to indicate when a stage has been paused, and
for how long is was staged for. This can improve the display of
stages timings, as the paused time is removed from the overall stage
time.

The PauseAction only applies to stages, so only applies when the
throttle step is used in conjunction with a pipeline stage.

pom.xml

@@ -151,6 +151,12 @@ THE SOFTWARE.
       <artifactId>matrix-auth</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.jenkins-ci.plugins.pipeline-stage-view</groupId>
+      <artifactId>pipeline-stage-view</artifactId>
+      <version>2.13</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.jenkins-ci.plugins.workflow</groupId>
       <artifactId>workflow-basic-steps</artifactId>

src/main/java/hudson/plugins/throttleconcurrents/ThrottleQueueTaskDispatcher.java

@@ -41,6 +41,7 @@
 import org.jenkinsci.plugins.workflow.graph.StepNode;
 import org.jenkinsci.plugins.workflow.graphanalysis.LinearBlockHoppingScanner;
 import org.jenkinsci.plugins.workflow.steps.StepDescriptor;
+import org.jenkinsci.plugins.workflow.support.actions.PauseAction;
 import org.jenkinsci.plugins.workflow.support.concurrent.Timeout;
 import org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution.PlaceholderTask;
 
@@ -54,14 +55,17 @@ public class ThrottleQueueTaskDispatcher extends QueueTaskDispatcher {
     @Deprecated
     @Override
     public @CheckForNull CauseOfBlockage canTake(Node node, Task task) {
+        CauseOfBlockage cause = null;
         if (Jenkins.getAuthentication().equals(ACL.SYSTEM)) {
-            return canTakeImpl(node, task);
-        }
-
-        // Throttle-concurrent-builds requires READ permissions for all projects.
-        try (ACLContext ctx = ACL.as(ACL.SYSTEM)) {
-            return canTakeImpl(node, task);
+            cause = canTakeImpl(node, task);
+        } else {
+            // Throttle-concurrent-builds requires READ permissions for all projects.
+            try (ACLContext ctx = ACL.as(ACL.SYSTEM)) {
+                cause = canTakeImpl(node, task);
+            }
         }
+        updatePauseAction(task, cause);
+        return cause;
     }
 
     private CauseOfBlockage canTakeImpl(Node node, Task task) {
@@ -218,14 +222,17 @@ private boolean shouldBeThrottled(@NonNull Task task, @CheckForNull ThrottleJobP
     }
 
     private CauseOfBlockage canRun(Task task, ThrottleJobProperty tjp, List<String> pipelineCategories) {
+        CauseOfBlockage cause = null;
         if (Jenkins.getAuthentication().equals(ACL.SYSTEM)) {
-            return canRunImpl(task, tjp, pipelineCategories);
-        }
-
-        // Throttle-concurrent-builds requires READ permissions for all projects.
-        try (ACLContext ctx = ACL.as(ACL.SYSTEM)) {
-            return canRunImpl(task, tjp, pipelineCategories);
+            cause = canRunImpl(task, tjp, pipelineCategories);
+        } else {
+            // Throttle-concurrent-builds requires READ permissions for all projects.
+            try (ACLContext ctx = ACL.as(ACL.SYSTEM)) {
+                cause = canRunImpl(task, tjp, pipelineCategories);
+            }
         }
+        updatePauseAction(task, cause);
+        return cause;
     }
 
     private CauseOfBlockage canRunImpl(Task task, ThrottleJobProperty tjp, List<String> pipelineCategories) {
@@ -695,5 +702,31 @@ private int getMaxConcurrentPerNodeBasedOnMatchingLabels(
         return maxConcurrentPerNodeLabeledIfMatch;
     }
 
+    private void updatePauseAction(Task task, CauseOfBlockage cause) {
+        if (task instanceof PlaceholderTask) {
+            PlaceholderTask placeholderTask = (PlaceholderTask) task;
+            try {
+                FlowNode flowNode = placeholderTask.getNode();
+                if (flowNode == null) {
+                    return;
+                }
+
+                if (cause != null) {
+                    if (PauseAction.getCurrentPause(flowNode) == null) {
+                        flowNode.addAction(new PauseAction(cause.getShortDescription()));
+                    }
+                } else {
+                    if (PauseAction.getCurrentPause(flowNode) != null) {
+                        PauseAction.endCurrentPause(flowNode);
+                    }
+                }
+            } catch (IOException | InterruptedException e) {
+                LOGGER.log(Level.WARNING, "Error setting pause action on pipeline {0}: {1}", new Object[] {
+                    task.getDisplayName(), e
+                });
+            }
+        }
+    }
+
     private static final Logger LOGGER = Logger.getLogger(ThrottleQueueTaskDispatcher.class.getName());
 }

src/test/java/hudson/plugins/throttleconcurrents/TestUtil.java

@@ -8,6 +8,7 @@
 import hudson.model.Computer;
 import hudson.model.Executor;
 import hudson.model.Node;
+import hudson.model.Queue;
 import hudson.model.queue.CauseOfBlockage;
 import hudson.slaves.DumbSlave;
 import hudson.slaves.RetentionStrategy;
@@ -17,6 +18,7 @@
 import java.util.Set;
 import jenkins.model.queue.CompositeCauseOfBlockage;
 import org.jenkinsci.plugins.workflow.job.WorkflowRun;
+import org.jenkinsci.plugins.workflow.support.actions.PauseAction;
 import org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution;
 import org.junit.rules.TemporaryFolder;
 import org.jvnet.hudson.test.JenkinsRule;
@@ -96,6 +98,12 @@ static Set<String> getBlockageReasons(CauseOfBlockage cob) {
         }
     }
 
+    static void hasPauseActionForItem(Queue.Item item) throws Exception {
+        assertTrue(item.task instanceof ExecutorStepExecution.PlaceholderTask);
+        ExecutorStepExecution.PlaceholderTask task = (ExecutorStepExecution.PlaceholderTask) item.task;
+        assertNotNull(task.getNode().getAction(PauseAction.class));
+    }
+
     static void hasPlaceholderTaskForRun(Node n, WorkflowRun r) throws Exception {
         for (Executor exec : n.toComputer().getExecutors()) {
             if (exec.getCurrentExecutable() != null) {

src/test/java/hudson/plugins/throttleconcurrents/ThrottleStepTest.java

@@ -95,6 +95,7 @@ public void onePerNode() throws Exception {
                 blockageReasons,
                 hasItem(Messages._ThrottleQueueTaskDispatcher_MaxCapacityOnNode(1)
                         .toString()));
+        TestUtil.hasPauseActionForItem(queuedItem);
         assertEquals(1, agent.toComputer().countBusy());
         TestUtil.hasPlaceholderTaskForRun(agent, firstJobFirstRun);
 
@@ -176,6 +177,8 @@ public void multipleCategories() throws Exception {
         WorkflowRun thirdJobFirstRun = thirdJob.scheduleBuild2(0).waitForStart();
         j.waitForMessage("Still waiting to schedule task", thirdJobFirstRun);
         assertFalse(j.jenkins.getQueue().isEmpty());
+        Queue.Item queuedItem = j.jenkins.getQueue().getItems()[0];
+        TestUtil.hasPauseActionForItem(queuedItem);
         assertEquals(1, firstAgent.toComputer().countBusy());
         TestUtil.hasPlaceholderTaskForRun(firstAgent, firstJobFirstRun);
 
@@ -245,6 +248,9 @@ public void onePerNodeParallel() throws Exception {
         j.waitForMessage("Still waiting to schedule task", run1);
         j.waitForMessage("Still waiting to schedule task", run2);
 
+        Queue.Item queuedItem = j.jenkins.getQueue().getItems()[0];
+        TestUtil.hasPauseActionForItem(queuedItem);
+
         SemaphoreStep.success("wait-first-branch-a-job/1", null);
         SemaphoreStep.waitForStart("wait-first-branch-c-job/1", run1);
         assertEquals(1, firstAgent.toComputer().countBusy());
@@ -293,6 +299,8 @@ public void twoTotal() throws Exception {
         j.waitForMessage("Still waiting to schedule task", thirdJobFirstRun);
         j.jenkins.getQueue().maintain();
         assertFalse(j.jenkins.getQueue().isEmpty());
+        Queue.Item queuedItem = j.jenkins.getQueue().getItems()[0];
+        TestUtil.hasPauseActionForItem(queuedItem);
         assertEquals(1, firstAgent.toComputer().countBusy());
         TestUtil.hasPlaceholderTaskForRun(firstAgent, firstJobFirstRun);
 
@@ -377,6 +385,8 @@ public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListen
         WorkflowRun secondJobFirstRun = secondJob.scheduleBuild2(0).waitForStart();
         j.waitForMessage("Still waiting to schedule task", secondJobFirstRun);
         assertFalse(j.jenkins.getQueue().isEmpty());
+        Queue.Item queuedItem = j.jenkins.getQueue().getItems()[0];
+        TestUtil.hasPauseActionForItem(queuedItem);
 
         assertEquals(1, agent.toComputer().countBusy());
         for (Executor e : agent.toComputer().getExecutors()) {
@@ -460,6 +470,7 @@ private String getThrottleScript(String jobName, List<String> categories, String
         return "throttle(["
                 + StringUtils.join(quoted, ", ")
                 + "]) {\n"
+                + "stage('wait') {\n"
                 + "  echo 'hi there'\n"
                 + "  node('"
                 + label
@@ -468,6 +479,7 @@ private String getThrottleScript(String jobName, List<String> categories, String
                 + jobName
                 + "-job'\n"
                 + "  }\n"
+                + "}\n"
                 + "}\n";
     }