ahmedabu98 commented on code in PR #25927: URL: https://github.com/apache/beam/pull/25927#discussion_r1179591064
########## sdks/java/io/file-schema-transform/src/main/java/org/apache/beam/sdk/io/fileschematransform/FileReadSchemaTransformProvider.java: ########## @@ -0,0 +1,231 @@ +/* + * 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.io.fileschematransform; + +import static java.nio.charset.StandardCharsets.UTF_8; +import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument; + +import com.google.auto.service.AutoService; +import java.io.IOException; +import java.io.Reader; +import java.nio.channels.Channels; +import java.nio.channels.ReadableByteChannel; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.stream.Collectors; +import org.apache.beam.sdk.Pipeline; +import org.apache.beam.sdk.io.FileIO; +import org.apache.beam.sdk.io.FileSystems; +import org.apache.beam.sdk.io.fs.MatchResult; +import org.apache.beam.sdk.io.fs.ResourceId; +import org.apache.beam.sdk.schemas.io.Providers; +import org.apache.beam.sdk.schemas.transforms.SchemaTransform; +import org.apache.beam.sdk.schemas.transforms.SchemaTransformProvider; +import org.apache.beam.sdk.schemas.transforms.TypedSchemaTransformProvider; +import org.apache.beam.sdk.transforms.MapElements; +import org.apache.beam.sdk.transforms.PTransform; +import org.apache.beam.sdk.transforms.Watch.Growth; +import org.apache.beam.sdk.transforms.Watch.Growth.TerminationCondition; +import org.apache.beam.sdk.values.PCollection; +import org.apache.beam.sdk.values.PCollectionRowTuple; +import org.apache.beam.sdk.values.Row; +import org.apache.beam.sdk.values.TypeDescriptors; +import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Strings; +import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.io.CharStreams; +import org.joda.time.Duration; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +@SuppressWarnings({ + "nullness" // TODO(https://github.com/apache/beam/issues/20497) +}) +@AutoService(SchemaTransformProvider.class) +public class FileReadSchemaTransformProvider + extends TypedSchemaTransformProvider<FileReadSchemaTransformConfiguration> { + private static final Logger LOG = LoggerFactory.getLogger(FileReadSchemaTransformProvider.class); + private static final String IDENTIFIER = "beam:schematransform:org.apache.beam:file_read:v1"; + static final String INPUT_TAG = "input"; + static final String OUTPUT_TAG = "output"; + + @Override + protected Class<FileReadSchemaTransformConfiguration> configurationClass() { + return FileReadSchemaTransformConfiguration.class; + } + + @Override + protected SchemaTransform from(FileReadSchemaTransformConfiguration configuration) { + return new FileReadSchemaTransform(configuration); + } + + @Override + public String identifier() { + return IDENTIFIER; + } + + @Override + public List<String> inputCollectionNames() { + return Collections.singletonList(INPUT_TAG); + } + + @Override + public List<String> outputCollectionNames() { + return Collections.singletonList(OUTPUT_TAG); + } + + private static class FileReadSchemaTransform + extends PTransform<PCollectionRowTuple, PCollectionRowTuple> implements SchemaTransform { + private FileReadSchemaTransformConfiguration configuration; + + FileReadSchemaTransform(FileReadSchemaTransformConfiguration configuration) { + configuration.validate(); + this.configuration = configuration; + } + + @Override + public PCollectionRowTuple expand(PCollectionRowTuple input) { + checkArgument( + input.getAll().isEmpty() ^ Strings.isNullOrEmpty(configuration.getFilepattern()), + "Either an input PCollection of file patterns or the filepattern parameter must be set," + + "but not both."); + + // Input schema can be a schema String or a path to a file containing the schema + // Resolve to get a schema String + String schema = configuration.getSchema(); + if (!Strings.isNullOrEmpty(schema)) { + schema = resolveSchemaStringOrFilePath(schema); + configuration = configuration.toBuilder().setSchema(schema).build(); + } + + PCollection<MatchResult.Metadata> files; + if (!Strings.isNullOrEmpty(configuration.getFilepattern())) { + Pipeline p = input.getPipeline(); + FileIO.Match matchFiles = FileIO.match().filepattern(configuration.getFilepattern()); + // Handle streaming case + matchFiles = (FileIO.Match) maybeApplyStreaming(matchFiles); + + files = p.apply(matchFiles); + } else { + FileIO.MatchAll matchAllFiles = FileIO.matchAll(); + // Handle streaming case + matchAllFiles = (FileIO.MatchAll) maybeApplyStreaming(matchAllFiles); + + files = + input + .get(INPUT_TAG) + .apply( + "Get filepatterns", + MapElements.into(TypeDescriptors.strings()) + .via((row) -> row.getString("filepattern"))) + .apply("Match files", matchAllFiles); + } + + // Pass readable files to the appropriate source and output rows. + PCollection<Row> output = + files + .apply(FileIO.readMatches()) + .apply("Read files", getProvider().buildTransform(configuration)); + + return PCollectionRowTuple.of(OUTPUT_TAG, output); + } + + public PTransform<?, PCollection<MatchResult.Metadata>> maybeApplyStreaming( + PTransform<?, PCollection<MatchResult.Metadata>> matchTransform) { + // Two parameters are provided to configure watching for new files. + Long terminateAfterSeconds = configuration.getTerminateAfterSecondsSinceNewOutput(); + Long pollIntervalMillis = configuration.getPollIntervalMillis(); + + // Streaming is enabled when a poll interval is provided + if (pollIntervalMillis != null && pollIntervalMillis > 0L) { + Duration pollDuration = Duration.millis(pollIntervalMillis); + + // By default, the file match transform never terminates + TerminationCondition<String, ?> terminationCondition = Growth.never(); + + // If provided, will terminate after this many seconds since seeing a new file + if (terminateAfterSeconds != null && terminateAfterSeconds > 0L) { + terminationCondition = + Growth.afterTimeSinceNewOutput(Duration.standardSeconds(terminateAfterSeconds)); + } + + // Apply watch for new files + if (matchTransform instanceof FileIO.Match) { + matchTransform = + ((FileIO.Match) matchTransform).continuously(pollDuration, terminationCondition); + } else if (matchTransform instanceof FileIO.MatchAll) { + matchTransform = + ((FileIO.MatchAll) matchTransform).continuously(pollDuration, terminationCondition); + } + } + return matchTransform; + } + + public String resolveSchemaStringOrFilePath(String schema) { Review Comment: I prefer keeping one field that does both, I think that would be simpler from the user's perspective. One field that can handle both use cases. Maybe the documentation for Schema isn't clear enough? I'll try rewording it -- 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]
