[GitHub] [kafka] rhauch commented on a change in pull request #11797: KAFKA-12879: Revert changes from KAFKA-12339 and instead add retry capability to KafkaBasedLog

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

rhauch commented on a change in pull request #11797:
URL: https://github.com/apache/kafka/pull/11797#discussion_r814336427



##########
File path: connect/runtime/src/main/java/org/apache/kafka/connect/util/TopicAdmin.java
##########
@@ -703,6 +706,20 @@ public Config describeTopicConfig(String topic) {
         return result;
     }
 
+    protected Map<TopicPartition, Long> retryEndOffsets(Set<TopicPartition> partitions) {
+        int maxRetries = Integer.parseInt(adminConfig.getOrDefault(AdminClientConfig.RETRIES_CONFIG, DEFAULT_ADMIN_CLIENT_RETRIES).toString());
+        long retryBackoffMs = Long.parseLong(adminConfig.getOrDefault(AdminClientConfig.RETRY_BACKOFF_MS_CONFIG, DEFAULT_ADMIN_CLIENT_BACKOFF_MS).toString());
+
+        try {
+            return RetryUtil.retry(
+                    () -> endOffsets(partitions),
+                    maxRetries,

Review comment:
       The values of `maxRetries` and `retryBackoffMs` can each be `0`, and these are passed directly into the `RetryUtil.retry(...)` method. See my comment there. 

##########
File path: connect/runtime/src/test/java/org/apache/kafka/connect/util/RetryUtilTest.java
##########
@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.apache.kafka.common.errors.TimeoutException;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.util.concurrent.Callable;
+
+@RunWith(PowerMockRunner.class)
+public class RetryUtilTest {
+
+    @Mock
+    private Callable<String> mockCallable;
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setUp() throws Exception {
+        mockCallable = Mockito.mock(Callable.class);
+    }
+
+    @Test
+    public void TestSuccess() throws Exception {
+        Mockito.when(mockCallable.call()).thenReturn("success");
+        //EasyMock.expect(mockCallable.call()).andReturn("success").times(1);
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }
+        Mockito.verify(mockCallable, Mockito.times(1)).call();
+    }
+
+    @Test
+    public void TestFailingRetries() throws Exception {
+        Mockito.when(mockCallable.call()).thenThrow(new TimeoutException());
+        try {
+            RetryUtil.retry(mockCallable, 10, 100);
+            fail("Expect exception being thrown here");
+        } catch (ConnectException e) {
+            // expecting a connect exception
+        } catch (Exception e) {
+            fail("Only expecting ConnectException");
+        }

Review comment:
       It's much better to use `Assertion.assertThrows(...)`:
   ```suggestion
           ConnectException e = assertThrows(ConnectException.class, RetryUtil.retry(mockCallable, 10, 100));
           assertTrue(e.getMesssage().startsWith("Fail to retry the operation after 10 attempts."));
   ```

##########
File path: connect/runtime/src/test/java/org/apache/kafka/connect/util/RetryUtilTest.java
##########
@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.apache.kafka.common.errors.TimeoutException;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.util.concurrent.Callable;
+
+@RunWith(PowerMockRunner.class)
+public class RetryUtilTest {
+
+    @Mock
+    private Callable<String> mockCallable;
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setUp() throws Exception {
+        mockCallable = Mockito.mock(Callable.class);
+    }
+
+    @Test
+    public void TestSuccess() throws Exception {
+        Mockito.when(mockCallable.call()).thenReturn("success");
+        //EasyMock.expect(mockCallable.call()).andReturn("success").times(1);

Review comment:
       Let's remove this line

##########
File path: connect/runtime/src/test/java/org/apache/kafka/connect/util/RetryUtilTest.java
##########
@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.apache.kafka.common.errors.TimeoutException;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.util.concurrent.Callable;
+
+@RunWith(PowerMockRunner.class)
+public class RetryUtilTest {
+
+    @Mock
+    private Callable<String> mockCallable;
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setUp() throws Exception {
+        mockCallable = Mockito.mock(Callable.class);
+    }
+
+    @Test
+    public void TestSuccess() throws Exception {
+        Mockito.when(mockCallable.call()).thenReturn("success");
+        //EasyMock.expect(mockCallable.call()).andReturn("success").times(1);
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }
+        Mockito.verify(mockCallable, Mockito.times(1)).call();
+    }
+
+    @Test
+    public void TestFailingRetries() throws Exception {
+        Mockito.when(mockCallable.call()).thenThrow(new TimeoutException());
+        try {
+            RetryUtil.retry(mockCallable, 10, 100);
+            fail("Expect exception being thrown here");
+        } catch (ConnectException e) {
+            // expecting a connect exception
+        } catch (Exception e) {
+            fail("Only expecting ConnectException");
+        }
+        Mockito.verify(mockCallable, Mockito.times(10)).call();
+    }
+
+    @Test
+    public void RetriesEventuallySucceed() throws Exception {
+        Mockito.when(mockCallable.call())
+                .thenThrow(new TimeoutException())
+                .thenThrow(new TimeoutException())
+                .thenThrow(new TimeoutException())
+                .thenReturn("success");
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }
+        Mockito.verify(mockCallable, Mockito.times(4)).call();
+    }
+
+    @Test
+    public void FailWithNonRetriableException() throws Exception {
+        Mockito.when(mockCallable.call())
+                .thenThrow(new TimeoutException("timeout"))
+                .thenThrow(new TimeoutException("timeout"))
+                .thenThrow(new TimeoutException("timeout"))
+                .thenThrow(new TimeoutException("timeout"))
+                .thenThrow(new TimeoutException("timeout"))
+                .thenThrow(new NullPointerException("Non retriable"));
+        try {
+            for (int i = 0; i < 10; i++) {
+                RetryUtil.retry(mockCallable, 10, 100);
+            }
+            fail("Not expecting an exception: ");
+        } catch (ConnectException e) {
+            fail("Should fail with NPE");
+        } catch (NullPointerException e) {
+            // good
+        }

Review comment:
       What is the purpose of the for loop? Why not just:
   ```suggestion
           NullPointerException e = assertThrows(NullPointerException.class, RetryUtil.retry(mockCallable, 10, 100));
           assertTrue(e.getMesssage().startsWith("Non retriable"));
   ```

##########
File path: connect/runtime/src/main/java/org/apache/kafka/connect/util/RetryUtil.java
##########
@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import org.apache.kafka.common.errors.RetriableException;
+import org.apache.kafka.common.errors.WakeupException;
+import org.apache.kafka.common.utils.Utils;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.Callable;
+
+public class RetryUtil {
+    private static final Logger log = LoggerFactory.getLogger(RetryUtil.class);
+
+    public static <T> T retry(Callable<T> callable, long maxRetries, long retryBackoffMs) throws Exception {
+        Throwable lastError = null;
+        int retries = 0;
+        while (retries++ < maxRetries) {
+            try {
+                return callable.call();

Review comment:
       Even though this method will not be part of our public API, we should still add JavaDoc so that we can document what the allowed values for `maxRetries` and `retryBackoffMs` can be, and what exceptions might be thrown by this method.
   
   Second, is `maxRetries` the total number of _attempts_, or the total number of _retries_ that are allowed. With the way this method is called by `KafkaBasedLog`, it is possible that both or either of these values are `0` -- which makes sense for "retries". But if `retries` is `0`, then this method will retry for a long period of times. Let's fix this logic to handle either or both `maxRetries` and/or `retryBackoffMs` being `0`, and add unit tests to covert this situation.

##########
File path: connect/runtime/src/test/java/org/apache/kafka/connect/util/RetryUtilTest.java
##########
@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.apache.kafka.common.errors.TimeoutException;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.util.concurrent.Callable;
+
+@RunWith(PowerMockRunner.class)
+public class RetryUtilTest {
+
+    @Mock
+    private Callable<String> mockCallable;
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setUp() throws Exception {
+        mockCallable = Mockito.mock(Callable.class);
+    }
+
+    @Test
+    public void TestSuccess() throws Exception {
+        Mockito.when(mockCallable.call()).thenReturn("success");
+        //EasyMock.expect(mockCallable.call()).andReturn("success").times(1);
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }

Review comment:
       Is this any better than just:
   ```suggestion
           assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
   ```

##########
File path: connect/runtime/src/test/java/org/apache/kafka/connect/util/RetryUtilTest.java
##########
@@ -0,0 +1,107 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.connect.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.apache.kafka.common.errors.TimeoutException;
+import org.apache.kafka.connect.errors.ConnectException;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.util.concurrent.Callable;
+
+@RunWith(PowerMockRunner.class)
+public class RetryUtilTest {
+
+    @Mock
+    private Callable<String> mockCallable;
+
+    @SuppressWarnings("unchecked")
+    @Before
+    public void setUp() throws Exception {
+        mockCallable = Mockito.mock(Callable.class);
+    }
+
+    @Test
+    public void TestSuccess() throws Exception {
+        Mockito.when(mockCallable.call()).thenReturn("success");
+        //EasyMock.expect(mockCallable.call()).andReturn("success").times(1);
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }
+        Mockito.verify(mockCallable, Mockito.times(1)).call();
+    }
+
+    @Test
+    public void TestFailingRetries() throws Exception {
+        Mockito.when(mockCallable.call()).thenThrow(new TimeoutException());
+        try {
+            RetryUtil.retry(mockCallable, 10, 100);
+            fail("Expect exception being thrown here");
+        } catch (ConnectException e) {
+            // expecting a connect exception
+        } catch (Exception e) {
+            fail("Only expecting ConnectException");
+        }
+        Mockito.verify(mockCallable, Mockito.times(10)).call();
+    }
+
+    @Test
+    public void RetriesEventuallySucceed() throws Exception {
+        Mockito.when(mockCallable.call())
+                .thenThrow(new TimeoutException())
+                .thenThrow(new TimeoutException())
+                .thenThrow(new TimeoutException())
+                .thenReturn("success");
+        try {
+            assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
+        } catch (Exception e) {
+            fail("Not expecting an exception: ", e.getCause());
+        }

Review comment:
       The try-catch is not really needed, since any exception thrown will fail the test:
   ```suggestion
           assertEquals("success", RetryUtil.retry(mockCallable, 10, 100));
   ```




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