Integrated Pipeline: TreeParser now rejects non-existent file tree roots gracefully

integrated-pipeline/src/main/scala/eu/nomad_lab/integrated_pipeline/TreeParser.scala

@@ -20,10 +20,17 @@ trait TreeParser extends MessageProcessor[FileTreeScanTask, FileParsingTaskSigna
   final override def processSignal(in: FileTreeScanTask): Unit = {
     if (readyForInbound) {
       eventListener.processEvent(myId, TreeParserEventStart(in))
-      generator = Some(createProcessor(in))
-      request = Some(in)
-      taskCount = 0
-      readyForInbound = false
+      if (in.treeBasePath.toFile.exists()) {
+        generator = Some(createProcessor(in))
+        request = Some(in)
+        taskCount = 0
+        readyForInbound = false
+      } else {
+        eventListener.processEvent(myId, TreeParserEventTreeFailure(
+          in,
+          new IllegalArgumentException(s"file tree root '${in.treeBasePath}' does not exist, ignoring task")
+        ))
+      }
     } else {
       throw new IllegalStateException("cannot process message, still digesting previous message")
     }

integrated-pipeline/src/test/scala/eu/nomad_lab/integrated_pipeline_end_to_end_tests/UnderDevelopment.scala

@@ -21,7 +21,7 @@ class UnderDevelopment extends LoggingTestAsyncWrapper with CustomMatchers {
         val finished = Main.mainWithFuture(f.generateConsoleArgumentList(Some(info)))
         finished.map { _ =>
           atLeast(1, log.messages()) should (startWith("ERROR") and
-            includeAll("purely-imaginary", "not exist", "skipping file tree"))
+            includeAll("purely-imaginary", "not exist", "encountered failure", "ignoring task"))
         }
       }
     }

integrated-pipeline/src/test/scala/eu/nomad_lab/integrated_pipeline_tests/TreeParserSpec.scala

@@ -18,7 +18,8 @@ class TreeParserSpec extends WordSpec with TestDataBuilders with MockitoSugar
 
   private def argsCaptor(): ArgumentCaptor[TreeParserEvent] = ArgumentCaptor.forClass(classOf[TreeParserEvent])
 
-  private val sampleTreeTask = aFileTreeScanTask().withBasePath("/foo").build()
+  private val sampleTreeTask = aFileTreeScanTask().withBasePath(".").build()
+  private val invalidTreeTask = aFileTreeScanTask().withBasePath("/imaginary/foo/magic").build()
 
   class Fixture(sampleData: Iterator[Either[TreeParserEventScanError, FileParsingTask]]) {
     val events = mock[EventListener]
@@ -102,7 +103,26 @@ class TreeParserSpec extends WordSpec with TestDataBuilders with MockitoSugar
         f.treeParser.processSignal(sampleTreeTask)
         val captor = argsCaptor()
         verify(f.events).processEvent(any(), captor.capture())
-        captor.getValue should (be(a[TreeParserEventStart]) and have(basePath("/foo")))
+        captor.getValue should (be(a[TreeParserEventStart]) and have(basePath(".")))
+      }
+
+      "ignore file tree scan tasks if the tree root does not exist on file-system" in {
+        val f = createFixture()
+        f.treeParser.processSignal(invalidTreeTask)
+        f.treeParser.hasSignalToEmit() should be(false)
+      }
+
+      "send an error event to the eventListener if the tree root does not exist on file-system" in {
+        import MatcherTreeParserEventTreeFailure._
+        val f = createFixture()
+        f.treeParser.processSignal(invalidTreeTask)
+        val captor = argsCaptor()
+        verify(f.events, atLeastOnce).processEvent(any(), captor.capture())
+        val events = captor.getAllValues.asScala.collect { case x: TreeParserEventTreeFailure => x }
+        exactly(1, events) should have(
+          basePath("/imaginary/foo/magic"),
+          errorMessage("tree root", "not exist")
+        )
       }
     }
 
@@ -174,7 +194,7 @@ class TreeParserSpec extends WordSpec with TestDataBuilders with MockitoSugar
         verify(f.events, Mockito.atLeast(1)).processEvent(any(), captor.capture())
         val event = captor.getValue
         event should be(a[TreeParserEventEnd])
-        event.asInstanceOf[TreeParserEventEnd] should have(basePath("/foo"), numCandidates(3))
+        event.asInstanceOf[TreeParserEventEnd] should have(basePath("."), numCandidates(3))
       }
     }