NIFI-2996

- validate processors only when they are in STOPPED state
- report validation errors via REST API on processors/services/tasks/ports only when they are in the STOPPED state
- This closes #1192

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/FlowController.java

@@ -2722,16 +2722,16 @@ public class FlowController implements EventAccess, ControllerServiceProvider, R
             status.setFlowFilesRemoved(entry.getFlowFilesRemoved());
         }
 
-        // determine the run status and get any validation errors... must check
+        // Determine the run status and get any validation error... only validating while STOPPED
-        // is valid when not disabled since a processors validity could change due
+        // is a trade-off we are willing to make, even though processor validity could change due to
-        // to environmental conditions (property configured with a file path and
+        // environmental conditions (property configured with a file path and the file being externally
-        // the file being externally removed)
+        // removed). This saves on validation costs that would be unnecessary most of the time.
         if (ScheduledState.DISABLED.equals(procNode.getScheduledState())) {
             status.setRunStatus(RunStatus.Disabled);
-        } else if (!procNode.isValid()) {
-            status.setRunStatus(RunStatus.Invalid);
         } else if (ScheduledState.RUNNING.equals(procNode.getScheduledState())) {
             status.setRunStatus(RunStatus.Running);
+        } else if (!procNode.isValid()) {
+            status.setRunStatus(RunStatus.Invalid);
         } else {
             status.setRunStatus(RunStatus.Stopped);
         }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/StandardProcessorNode.java

@@ -987,6 +987,9 @@ public class StandardProcessorNode extends ProcessorNode implements Connectable
     public Collection<ValidationResult> getValidationErrors() {
         final List<ValidationResult> results = new ArrayList<>();
         try {
+            // Processors may go invalid while RUNNING, but only validating while STOPPED is a trade-off
+            // we are willing to make in order to save on validation costs that would be unnecessary most of the time.
+            if (getScheduledState() == ScheduledState.STOPPED) {
                 final ValidationContext validationContext = this.getValidationContextFactory()
                         .newValidationContext(getProperties(), getAnnotationData(), getProcessGroup().getIdentifier(), getIdentifier());
 
@@ -1032,6 +1035,7 @@ public class StandardProcessorNode extends ProcessorNode implements Connectable
                         break;
                     }
                 }
+            }
         } catch (final Throwable t) {
             results.add(new ValidationResult.Builder().explanation("Failed to run validation due to " + t.toString())
                     .valid(false).build());

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/reporting/AbstractReportingTaskNode.java

@@ -34,6 +34,7 @@ import org.apache.nifi.scheduling.SchedulingStrategy;
 import org.apache.nifi.util.FormatUtils;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
@@ -241,4 +242,13 @@ public abstract class AbstractReportingTaskNode extends AbstractConfiguredCompon
     public String getProcessGroupIdentifier() {
         return null;
     }
+
+    @Override
+    public Collection<ValidationResult> getValidationErrors(Set<String> serviceIdentifiersNotToValidate) {
+        Collection<ValidationResult> results = null;
+        if (getScheduledState() == ScheduledState.STOPPED) {
+            results = super.getValidationErrors(serviceIdentifiersNotToValidate);
+        }
+        return results != null ? results : Collections.emptySet();
+    }
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/main/java/org/apache/nifi/controller/service/StandardControllerServiceNode.java

@@ -438,4 +438,13 @@ public class StandardControllerServiceNode extends AbstractConfiguredComponent i
         final ProcessGroup procGroup = getProcessGroup();
         return procGroup == null ? null : procGroup.getIdentifier();
     }
+
+    @Override
+    public Collection<ValidationResult> getValidationErrors(Set<String> serviceIdentifiersNotToValidate) {
+        Collection<ValidationResult> results = null;
+        if (stateRef.get() == ControllerServiceState.DISABLED) {
+            results = super.getValidationErrors(serviceIdentifiersNotToValidate);
+        }
+        return results != null ? results : Collections.emptySet();
+    }
 }

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-core/src/test/java/org/apache/nifi/controller/TestStandardProcessorNode.java

@@ -117,6 +117,22 @@ public class TestStandardProcessorNode {
         assertEquals(1, processor.onStoppedCount);
     }
 
+    @Test
+    public void testDisabledValidationErrors() {
+        final ModifiesClasspathNoAnnotationProcessor processor = new ModifiesClasspathNoAnnotationProcessor();
+        final StandardProcessorNode procNode = createProcessorNode(processor);
+
+        // Set a property to an invalid value
+        final Map<String, String> properties = new HashMap<>();
+        properties.put(ModifiesClasspathNoAnnotationProcessor.CLASSPATH_RESOURCE.getName(), "");
+        procNode.setProperties(properties);
+        Assert.assertTrue(procNode.getValidationErrors().size() > 0);
+
+        // Disabled processors skip property validation
+        procNode.disable();
+        Assert.assertFalse(procNode.getValidationErrors().size() > 0);
+    }
+
     @Test
     public void testSinglePropertyDynamicallyModifiesClasspath() throws MalformedURLException {
         final PropertyDescriptor classpathProp = new PropertyDescriptor.Builder().name("Classpath Resources")

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-site-to-site/src/main/java/org/apache/nifi/remote/StandardRemoteGroupPort.java

@@ -34,6 +34,7 @@ import org.apache.nifi.components.ValidationResult;
 import org.apache.nifi.connectable.ConnectableType;
 import org.apache.nifi.connectable.Connection;
 import org.apache.nifi.controller.ProcessScheduler;
+import org.apache.nifi.controller.ScheduledState;
 import org.apache.nifi.flowfile.FlowFile;
 import org.apache.nifi.flowfile.attributes.CoreAttributes;
 import org.apache.nifi.groups.ProcessGroup;
@@ -367,7 +368,7 @@ public class StandardRemoteGroupPort extends RemoteGroupPort {
             final String uploadDataRate = stopWatch.calculateDataRate(bytesReceived);
             final long uploadMillis = stopWatch.getDuration(TimeUnit.MILLISECONDS);
             final String dataSize = FormatUtils.formatDataSize(bytesReceived);
-            logger.info("{} Successfully receveied {} ({}) from {} in {} milliseconds at a rate of {}", new Object[]{
+            logger.info("{} Successfully received {} ({}) from {} in {} milliseconds at a rate of {}", new Object[]{
                 this, flowFileDescription, dataSize, transaction.getCommunicant().getUrl(), uploadMillis, uploadDataRate});
         }
 
@@ -381,12 +382,14 @@ public class StandardRemoteGroupPort extends RemoteGroupPort {
 
     @Override
     public boolean isValid() {
-        return getValidationErrors().isEmpty();
+        return targetExists.get()
+                && (getConnectableType() == ConnectableType.REMOTE_OUTPUT_PORT ? !getConnections(Relationship.ANONYMOUS).isEmpty() : true);
     }
 
     @Override
     public Collection<ValidationResult> getValidationErrors() {
         final Collection<ValidationResult> validationErrors = new ArrayList<>();
+        if (getScheduledState() == ScheduledState.STOPPED) {
             ValidationResult error = null;
             if (!targetExists.get()) {
                 error = new ValidationResult.Builder()
@@ -405,7 +408,7 @@ public class StandardRemoteGroupPort extends RemoteGroupPort {
             if (error != null) {
                 validationErrors.add(error);
             }
-
+        }
         return validationErrors;
     }
 

nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-site-to-site/src/main/java/org/apache/nifi/remote/StandardRootGroupPort.java

@@ -30,6 +30,7 @@ import org.apache.nifi.components.ValidationResult;
 import org.apache.nifi.connectable.ConnectableType;
 import org.apache.nifi.controller.AbstractPort;
 import org.apache.nifi.controller.ProcessScheduler;
+import org.apache.nifi.controller.ScheduledState;
 import org.apache.nifi.events.BulletinFactory;
 import org.apache.nifi.events.EventReporter;
 import org.apache.nifi.groups.ProcessGroup;
@@ -273,6 +274,7 @@ public class StandardRootGroupPort extends AbstractPort implements RootGroupPort
     @Override
     public Collection<ValidationResult> getValidationErrors() {
         final Collection<ValidationResult> validationErrors = new ArrayList<>();
+        if (getScheduledState() == ScheduledState.STOPPED) {
             if (!isValid()) {
                 final ValidationResult error = new ValidationResult.Builder()
                         .explanation(String.format("Output connection for port '%s' is not defined.", getName()))
@@ -281,6 +283,7 @@ public class StandardRootGroupPort extends AbstractPort implements RootGroupPort
                         .build();
                 validationErrors.add(error);
             }
+        }
         return validationErrors;
     }