WIP2 More tests on file lock

org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/FilesystemPackageCacheManagerLocks.java

@@ -195,7 +195,7 @@ public class FilesystemPackageCacheManagerLocks {
       try (FileChannel channel = new RandomAccessFile(lockFile, "rw").getChannel()) {
         FileLock fileLock = null;
         while (fileLock == null) {
-          fileLock = channel.tryLock(0, Long.MAX_VALUE, true);
+          fileLock = channel.tryLock(0, Long.MAX_VALUE, false);
           if (fileLock == null) {
             Thread.sleep(100); // Wait and retry
           }

org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/npm/FilesystemPackageManagerTests.java

@@ -137,6 +137,24 @@ public class FilesystemPackageManagerTests {
     assertThat(exception.getMessage()).contains("Lock file exists, but is not locked by a process");
   }
 
+  private static Thread lockWaitAndDelete(String path, String lockFileName, int seconds)  {
+    Thread t = new Thread(() -> {
+    ProcessBuilder processBuilder = new ProcessBuilder("java", "-cp", "target/test-classes:.", "org.hl7.fhir.utilities.npm.LockfileUtility", path, lockFileName, Integer.toString(seconds));
+      try {
+        Process process = processBuilder.start();
+        process.getErrorStream().transferTo(System.err);
+        process.getInputStream().transferTo(System.out);
+        process.waitFor();
+      } catch (IOException | InterruptedException e) {
+        throw new RuntimeException(e);
+      }
+      });
+    t.start();
+    return t;
+  }
+
+
+
   @Test
   //@EnabledOnOs(OS.LINUX)
   public void testCacheCleanupForUnlockedLockFiles() throws IOException, InterruptedException {
@@ -150,34 +168,19 @@ public class FilesystemPackageManagerTests {
     String lockFileName = packageAndVersion + ".lock";
     //Now sneak in a new lock file and directory:
     File lockFile = ManagedFileAccess.file(pcmPath, lockFileName);
-    lockFile.createNewFile();
+    //lockFile.createNewFile();
     File directory = ManagedFileAccess.file(pcmPath, packageAndVersion);
     directory.mkdir();
 
-    // We can't create a lock file from within the same JVM, so we have to use the flock utility, which is OS dependent.
-    // The following works for Linux only.
-    ProcessBuilder processBuilder = new ProcessBuilder("flock", lockFileName, "--command", "sleep 10");
-    processBuilder.directory(new File(pcmPath));
-    processBuilder.start();
-
-    ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
-
-    executorService.schedule(()->{
-      try {
-        Utilities.clearDirectory(directory.getAbsolutePath());
-        directory.delete();
-      } catch (IOException e) {
-        throw new RuntimeException(e);
-      }
-      lockFile.delete();
-    }, 15, TimeUnit.SECONDS);
+    Thread lockingThread = lockWaitAndDelete(pcmPath, lockFileName, 10);
 
+    Thread.sleep(200);
     IOException ioException = assertThrows(IOException.class, () -> { pcm.loadPackageFromCacheOnly("example.fhir.uv.myig", "1.2.3"); });
 
 
     ioException.printStackTrace();
 
-
+    lockingThread.join();
   }
 
   /**

org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/npm/LockfileUtility.java

@@ -0,0 +1,44 @@
+package org.hl7.fhir.utilities.npm;
+
+import org.hl7.fhir.utilities.filesystem.ManagedFileAccess;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.file.Paths;
+
+public class LockfileUtility {
+  public static void main(String[] args) {
+    String lockFileName = args[1];
+    String path = args[0];
+    int seconds = Integer.parseInt(args[2]);
+
+    try {
+      lockWaitAndDelete(path, lockFileName, seconds);
+    } catch (InterruptedException | IOException e) {
+      throw new RuntimeException(e);
+    }
+
+  }
+
+  private static void lockWaitAndDelete(String path, String lockFileName, int seconds) throws InterruptedException, IOException {
+    File file = Paths.get(path,lockFileName).toFile();
+    try (FileChannel channel = new RandomAccessFile(file.getAbsolutePath(), "rw").getChannel()) {
+      FileLock fileLock = channel.tryLock(0, Long.MAX_VALUE, false);
+      if (fileLock != null) {
+        System.out.println("File "+lockFileName+" is locked. Waiting for " + seconds + " seconds to release");
+        Thread.sleep(seconds * 1000L);
+        fileLock.release();
+        System.out.println("File "+lockFileName+" is released.");
+
+        channel.close();
+    }}finally {
+      if (file.exists()) {
+        file.delete();
+      }
+    }
+  }
+}