Add null checks in TowerClient onFlowComplete method (#6384)

Add defensive null checking for sender thread and workflowId to prevent NullPointerException when onFlowComplete is called after initialization failures in onFlowCreate or onFlowBegin methods.

Signed-off-by: Rob Syme <rob.syme@gmail.com>
Co-authored-by: Ben Sherman <bentshermann@gmail.com>

Author: robsyme

plugins/nf-tower/src/main/io/seqera/tower/plugin/TowerClient.groovy

@@ -402,14 +402,17 @@ class TowerClient implements TraceObserverV2 {
         // publish runtime reports
         reports.publishRuntimeReports()
         // wait the submission of pending events
-        sender.join()
+        if( sender )
+            sender.join()
         // wait and flush reports content
         reports.flowComplete()
         // notify the workflow completion
         terminated = true
-        final req = makeCompleteReq(session)
-        final resp = sendHttpMessage(urlTraceComplete, req, 'PUT')
-        logHttpResponse(urlTraceComplete, resp)
+        if( workflowId ) {
+            final req = makeCompleteReq(session)
+            final resp = sendHttpMessage(urlTraceComplete, req, 'PUT')
+            logHttpResponse(urlTraceComplete, resp)
+        }
     }
 
     @Override