johnjcasey commented on code in PR #29164: URL: https://github.com/apache/beam/pull/29164#discussion_r1386844802
########## sdks/java/core/src/main/java/org/apache/beam/sdk/errorhandling/ErrorHandler.java: ########## @@ -0,0 +1,187 @@ +/* + * 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.beam.sdk.errorhandling; + +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.List; +import javax.annotation.Nullable; +import org.apache.beam.sdk.annotations.Internal; +import org.apache.beam.sdk.metrics.Counter; +import org.apache.beam.sdk.metrics.Metrics; +import org.apache.beam.sdk.transforms.DoFn; +import org.apache.beam.sdk.transforms.Flatten; +import org.apache.beam.sdk.transforms.PTransform; +import org.apache.beam.sdk.transforms.ParDo; +import org.apache.beam.sdk.util.Preconditions; +import org.apache.beam.sdk.values.PCollection; +import org.apache.beam.sdk.values.PCollectionList; +import org.apache.beam.sdk.values.POutput; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * An Error Handler is a utility object used for plumbing error PCollections to a configured sink + * Error Handlers must be closed before a pipeline is run to properly pipe error collections to the + * sink, and the pipeline will be rejected if any handlers aren't closed. + * + * @param <ErrorT> The type of the error object. This will usually be a {@link BadRecord}, but can + * be any type + * @param <OutputT> The return type of the sink PTransform. + * <p>Usage of Error Handlers: + * <p>Simple usage with one DLQ + * <pre>{@code + * PCollection<?> records = ...; + * try (ErrorHandler<E,T> errorHandler = pipeline.registerErrorHandler(SomeSink.write())) { + * PCollection<?> results = records.apply(SomeIO.write().withDeadLetterQueue(errorHandler)); + * } + * results.apply(SomeOtherTransform); + * }</pre> + * Usage with multiple DLQ stages + * <pre>{@code + * PCollection<?> records = ...; + * try (ErrorHandler<E,T> errorHandler = pipeline.registerErrorHandler(SomeSink.write())) { + * PCollection<?> results = records.apply(SomeIO.write().withDeadLetterQueue(errorHandler)) + * .apply(OtherTransform.builder().withDeadLetterQueue(errorHandler)); + * } + * results.apply(SomeOtherTransform); + * }</pre> + */ +public interface ErrorHandler<ErrorT, OutputT extends POutput> extends AutoCloseable { + + void addErrorCollection(PCollection<ErrorT> errorCollection); + + boolean isClosed(); + + OutputT getOutput(); + + class PTransformErrorHandler<ErrorT, OutputT extends POutput> + implements ErrorHandler<ErrorT, OutputT> { + + private static final Logger LOG = LoggerFactory.getLogger(PTransformErrorHandler.class); + private final PTransform<PCollection<ErrorT>, OutputT> sinkTransform; + + private final List<PCollection<ErrorT>> errorCollections = new ArrayList<>(); + + @Nullable private OutputT sinkOutput = null; + + private boolean closed = false; Review Comment: I don't think we need to be worried. This is closed at pipeline construction time, which should be single threaded anyways -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
