[GitHub] [pulsar] srkukarni commented on a change in pull request #7180: FunctionAssignmentTailer should use its own thread

[GitBox <gi...@apache.org>]

srkukarni commented on a change in pull request #7180:
URL: https://github.com/apache/pulsar/pull/7180#discussion_r435739838



##########
File path: pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionAssignmentTailer.java
##########
@@ -18,56 +18,90 @@
  */
 package org.apache.pulsar.functions.worker;
 
-import java.io.IOException;
-import java.util.function.Function;
-
+import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
 import org.apache.pulsar.client.api.Message;
-import org.apache.pulsar.client.api.PulsarClientException.AlreadyClosedException;
+import org.apache.pulsar.client.api.MessageId;
+import org.apache.pulsar.client.api.PulsarClientException;
 import org.apache.pulsar.client.api.Reader;
-import org.apache.pulsar.common.util.FutureUtil;
+import org.apache.pulsar.client.api.ReaderBuilder;
 import org.apache.pulsar.functions.proto.Function.Assignment;
 
-import lombok.extern.slf4j.Slf4j;
+import java.io.IOException;
 
 @Slf4j
-public class FunctionAssignmentTailer
-    implements java.util.function.Consumer<Message<byte[]>>, Function<Throwable, Void>, AutoCloseable {
+public class FunctionAssignmentTailer implements AutoCloseable {
 
     private final FunctionRuntimeManager functionRuntimeManager;
+    @Getter
     private final Reader<byte[]> reader;
-    private boolean closed = false;
+    private volatile boolean isRunning = false;
 
-    public FunctionAssignmentTailer(FunctionRuntimeManager functionRuntimeManager, Reader<byte[]> reader) {
+    private final Thread tailerThread;
+    
+    public FunctionAssignmentTailer(FunctionRuntimeManager functionRuntimeManager, ReaderBuilder readerBuilder, WorkerConfig workerConfig) throws PulsarClientException {
         this.functionRuntimeManager = functionRuntimeManager;
-        this.reader = reader;
-    }
+        
+        this.reader = readerBuilder
+          .subscriptionRolePrefix(workerConfig.getWorkerId() + "-function-runtime-manager")
+          .readerName(workerConfig.getWorkerId() + "-function-runtime-manager")
+          .topic(workerConfig.getFunctionAssignmentTopic())
+          .readCompacted(true)
+          .startMessageId(MessageId.earliest)
+          .create();
 
-    public void start() {
-        receiveOne();
+        this.tailerThread = new Thread(() -> {
+            while(true) {
+                try {
+                    while(isRunning) {
+                        Message<byte[]> msg = reader.readNext();
+                        processAssignment(msg);
+                    }
+                } catch (Exception e) {
+                    if (isRunning) {
+                        log.error("Encountered error in assignment tailer", e);
+
+                        // trigger fatal error
+                        // TODO add mechanism to notify main thread
+                    } else {
+                        if (!(e instanceof InterruptedException)) {
+                            log.warn("Encountered error when assignment tailer is not running", e);
+                        }
+                    }
+
+                }
+            }
+        });
+        this.tailerThread.setName("assignment-tailer-thread");
     }
 
-    private void receiveOne() {
-        reader.readNextAsync()
-                .thenAccept(this)
-                .exceptionally(this);
+    public void start() {
+        isRunning = true;
+        tailerThread.start();
     }
 
     @Override
     public void close() {
-        if (closed) {
+        if (!isRunning) {

Review comment:
       reader is still not closed here




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