Java tutorial
/* * Copyright (C) 2015 Google Inc. * * Licensed 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 com.google.cloud.dataflow.examples; import com.google.api.services.bigquery.model.TableFieldSchema; import com.google.api.services.bigquery.model.TableReference; import com.google.api.services.bigquery.model.TableRow; import com.google.api.services.bigquery.model.TableSchema; import com.google.cloud.dataflow.examples.common.DataflowExampleOptions; import com.google.cloud.dataflow.examples.common.DataflowExampleUtils; import com.google.cloud.dataflow.examples.common.ExampleBigQueryTableOptions; import com.google.cloud.dataflow.examples.common.ExamplePubsubTopicOptions; import com.google.cloud.dataflow.sdk.Pipeline; import com.google.cloud.dataflow.sdk.PipelineResult; import com.google.cloud.dataflow.sdk.coders.AvroCoder; import com.google.cloud.dataflow.sdk.coders.DefaultCoder; import com.google.cloud.dataflow.sdk.io.BigQueryIO; import com.google.cloud.dataflow.sdk.io.PubsubIO; import com.google.cloud.dataflow.sdk.io.TextIO; import com.google.cloud.dataflow.sdk.options.Default; import com.google.cloud.dataflow.sdk.options.Description; import com.google.cloud.dataflow.sdk.options.PipelineOptionsFactory; import com.google.cloud.dataflow.sdk.runners.DataflowPipelineRunner; import com.google.cloud.dataflow.sdk.transforms.Combine; import com.google.cloud.dataflow.sdk.transforms.DoFn; import com.google.cloud.dataflow.sdk.transforms.PTransform; import com.google.cloud.dataflow.sdk.transforms.ParDo; import com.google.cloud.dataflow.sdk.transforms.SerializableFunction; import com.google.cloud.dataflow.sdk.transforms.windowing.SlidingWindows; import com.google.cloud.dataflow.sdk.transforms.windowing.Window; import com.google.cloud.dataflow.sdk.values.KV; import com.google.cloud.dataflow.sdk.values.PCollection; import org.apache.avro.reflect.Nullable; import org.joda.time.Duration; import org.joda.time.Instant; import org.joda.time.format.DateTimeFormat; import org.joda.time.format.DateTimeFormatter; import java.io.IOException; import java.util.ArrayList; import java.util.List; /** * A Dataflow Example that runs in both batch and streaming modes with traffic sensor data. * You can configure the running mode by setting {@literal --streaming} to true or false. * * <p>Concepts: The batch and streaming runners, sliding windows, Google Cloud Pub/Sub * topic injection, use of the AvroCoder to encode a custom class, and custom Combine transforms. * * <p> This example analyzes traffic sensor data using SlidingWindows. For each window, * it finds the lane that had the highest flow recorded, for each sensor station. It writes * those max values along with auxiliary info to a BigQuery table. * * <p> In batch mode, the pipeline reads traffic sensor data from {@literal --inputFile}. * * <p> In streaming mode, the pipeline reads the data from a Pub/Sub topic. * By default, the example will run a separate pipeline to inject the data from the default * {@literal --inputFile} to the Pub/Sub {@literal --pubsubTopic}. It will make it available for * the streaming pipeline to process. You may override the default {@literal --inputFile} with the * file of your choosing. You may also set {@literal --inputFile} to an empty string, which will * disable the automatic Pub/Sub injection, and allow you to use separate tool to control the input * to this example. An example code, which publishes traffic sensor data to a Pub/Sub topic, * is provided in * <a href="https://github.com/GoogleCloudPlatform/cloud-pubsub-samples-python/tree/master/gce-cmdline-publisher"></a>. * * <p> The example is configured to use the default Pub/Sub topic and the default BigQuery table * from the example common package (there is no defaults for a general Dataflow pipeline). * You can override them by using the {@literal --pubsubTopic}, {@literal --bigQueryDataset}, and * {@literal --bigQueryTable} options. If the Pub/Sub topic or the BigQuery table do not exist, * the example will try to create them. * * <p> The example will try to cancel the pipelines on the signal to terminate the process (CTRL-C) * and then exits. */ public class TrafficMaxLaneFlow { static final int WINDOW_DURATION = 60; // Default sliding window duration in minutes static final int WINDOW_SLIDE_EVERY = 5; // Default window 'slide every' setting in minutes /** * This class holds information about each lane in a station reading, along with some general * information from the reading. */ @DefaultCoder(AvroCoder.class) static class LaneInfo { @Nullable String stationId; @Nullable String lane; @Nullable String direction; @Nullable String freeway; @Nullable String recordedTimestamp; @Nullable Integer laneFlow; @Nullable Integer totalFlow; @Nullable Double laneAO; @Nullable Double laneAS; public LaneInfo() { } public LaneInfo(String stationId, String lane, String direction, String freeway, String timestamp, Integer laneFlow, Double laneAO, Double laneAS, Integer totalFlow) { this.stationId = stationId; this.lane = lane; this.direction = direction; this.freeway = freeway; this.recordedTimestamp = timestamp; this.laneFlow = laneFlow; this.laneAO = laneAO; this.laneAS = laneAS; this.totalFlow = totalFlow; } public String getStationId() { return this.stationId; } public String getLane() { return this.lane; } public String getDirection() { return this.direction; } public String getFreeway() { return this.freeway; } public String getRecordedTimestamp() { return this.recordedTimestamp; } public Integer getLaneFlow() { return this.laneFlow; } public Double getLaneAO() { return this.laneAO; } public Double getLaneAS() { return this.laneAS; } public Integer getTotalFlow() { return this.totalFlow; } } /** * Extract flow information for each of the 8 lanes in a reading, and output as separate tuples. * This will let us determine which lane has the max flow for that station over the span of the * window, and output not only the max flow from that calculcation, but other associated * information. The number of lanes for which data is present depends upon which freeway the data * point comes from. */ static class ExtractFlowInfoFn extends DoFn<String, KV<String, LaneInfo>> { private static final long serialVersionUID = 0; private static final DateTimeFormatter dateTimeFormat = DateTimeFormat.forPattern("MM/dd/yyyy HH:mm:ss"); private final boolean outputTimestamp; public ExtractFlowInfoFn(boolean outputTimestamp) { this.outputTimestamp = outputTimestamp; } @Override public void processElement(ProcessContext c) { String[] items = c.element().split(","); if (items.length < 48) { // Skip the invalid input. return; } // extract the sensor information for the lanes from the input string fields. String timestamp = items[0]; String stationId = items[1]; String freeway = items[2]; String direction = items[3]; Integer totalFlow = tryIntParse(items[7]); for (int i = 1; i <= 8; ++i) { Integer laneFlow = tryIntParse(items[6 + 5 * i]); Double laneAvgOccupancy = tryDoubleParse(items[7 + 5 * i]); Double laneAvgSpeed = tryDoubleParse(items[8 + 5 * i]); if (laneFlow == null || laneAvgOccupancy == null || laneAvgSpeed == null) { return; } LaneInfo laneInfo = new LaneInfo(stationId, "lane" + i, direction, freeway, timestamp, laneFlow, laneAvgOccupancy, laneAvgSpeed, totalFlow); if (outputTimestamp) { try { c.outputWithTimestamp(KV.of(stationId, laneInfo), new Instant(dateTimeFormat.parseMillis(timestamp))); } catch (IllegalArgumentException e) { // Skip the invalid input. } } else { c.output(KV.of(stationId, laneInfo)); } } } } /** * A custom 'combine function' used with the Combine.perKey transform. Used to find the max lane * flow over all the data points in the Window. Extracts the lane flow from the input string and * determines whether it's the max seen so far. We're using a custom combiner instead of the Max * transform because we want to retain the additional information we've associated with the flow * value. */ public static class MaxFlow implements SerializableFunction<Iterable<LaneInfo>, LaneInfo> { private static final long serialVersionUID = 0; @Override public LaneInfo apply(Iterable<LaneInfo> input) { Integer max = 0; LaneInfo maxInfo = new LaneInfo(); for (LaneInfo item : input) { Integer flow = item.getLaneFlow(); if (flow != null && (flow >= max)) { max = flow; maxInfo = item; } } return maxInfo; } } /** * Format the results of the Max Lane flow calculation to a TableRow, to save to BigQuery. * Add the timestamp from the window context. */ static class FormatMaxesFn extends DoFn<KV<String, LaneInfo>, TableRow> { private static final long serialVersionUID = 0; @Override public void processElement(ProcessContext c) { LaneInfo laneInfo = c.element().getValue(); TableRow row = new TableRow().set("station_id", c.element().getKey()) .set("direction", laneInfo.getDirection()).set("freeway", laneInfo.getFreeway()) .set("lane_max_flow", laneInfo.getLaneFlow()).set("lane", laneInfo.getLane()) .set("avg_occ", laneInfo.getLaneAO()).set("avg_speed", laneInfo.getLaneAS()) .set("total_flow", laneInfo.getTotalFlow()) .set("recorded_timestamp", laneInfo.getRecordedTimestamp()) .set("window_timestamp", c.timestamp().toString()); c.output(row); } /** Defines the BigQuery schema used for the output. */ static TableSchema getSchema() { List<TableFieldSchema> fields = new ArrayList<>(); fields.add(new TableFieldSchema().setName("station_id").setType("STRING")); fields.add(new TableFieldSchema().setName("direction").setType("STRING")); fields.add(new TableFieldSchema().setName("freeway").setType("STRING")); fields.add(new TableFieldSchema().setName("lane_max_flow").setType("INTEGER")); fields.add(new TableFieldSchema().setName("lane").setType("STRING")); fields.add(new TableFieldSchema().setName("avg_occ").setType("FLOAT")); fields.add(new TableFieldSchema().setName("avg_speed").setType("FLOAT")); fields.add(new TableFieldSchema().setName("total_flow").setType("INTEGER")); fields.add(new TableFieldSchema().setName("window_timestamp").setType("TIMESTAMP")); fields.add(new TableFieldSchema().setName("recorded_timestamp").setType("STRING")); TableSchema schema = new TableSchema().setFields(fields); return schema; } } /** * This PTransform extracts lane info, calculates the max lane flow found for a given station (for * the current Window) using a custom 'combiner', and formats the results for BigQuery. */ static class MaxLaneFlow extends PTransform<PCollection<KV<String, LaneInfo>>, PCollection<TableRow>> { private static final long serialVersionUID = 0; @Override public PCollection<TableRow> apply(PCollection<KV<String, LaneInfo>> flowInfo) { // stationId, LaneInfo => stationId + max lane flow info PCollection<KV<String, LaneInfo>> flowMaxes = flowInfo .apply(Combine.<String, LaneInfo>perKey(new MaxFlow())); // <stationId, max lane flow info>... => row... PCollection<TableRow> results = flowMaxes.apply(ParDo.of(new FormatMaxesFn())); return results; } } /** * Options supported by {@link TrafficMaxLaneFlow}. * <p> * Inherits standard configuration options. */ private interface TrafficMaxLaneFlowOptions extends DataflowExampleOptions, ExamplePubsubTopicOptions, ExampleBigQueryTableOptions { @Description("Input file to inject to Pub/Sub topic") @Default.String("gs://dataflow-samples/traffic_sensor/" + "Freeways-5Minaa2010-01-01_to_2010-02-15_test2.csv") String getInputFile(); void setInputFile(String value); @Description("Numeric value of sliding window duration, in minutes") @Default.Integer(WINDOW_DURATION) Integer getWindowDuration(); void setWindowDuration(Integer value); @Description("Numeric value of window 'slide every' setting, in minutes") @Default.Integer(WINDOW_SLIDE_EVERY) Integer getWindowSlideEvery(); void setWindowSlideEvery(Integer value); } /** * Sets up and starts streaming pipeline. * * @throws IOException if there is a problem setting up resources */ public static void main(String[] args) throws IOException { TrafficMaxLaneFlowOptions options = PipelineOptionsFactory.fromArgs(args).withValidation() .as(TrafficMaxLaneFlowOptions.class); if (options.isStreaming()) { // In order to cancel the pipelines automatically, // {@literal DataflowPipelineRunner} is forced to be used. options.setRunner(DataflowPipelineRunner.class); } options.setBigQuerySchema(FormatMaxesFn.getSchema()); // Using DataflowExampleUtils to set up required resources. DataflowExampleUtils dataflowUtils = new DataflowExampleUtils(options); dataflowUtils.setup(); Pipeline pipeline = Pipeline.create(options); TableReference tableRef = new TableReference(); tableRef.setProjectId(options.getProject()); tableRef.setDatasetId(options.getBigQueryDataset()); tableRef.setTableId(options.getBigQueryTable()); PCollection<KV<String, LaneInfo>> input; if (options.isStreaming()) { input = pipeline.apply(PubsubIO.Read.topic(options.getPubsubTopic())) // row... => <stationId, LaneInfo> ... .apply(ParDo.of(new ExtractFlowInfoFn(false /* outputTimestamp */))); } else { input = pipeline.apply(TextIO.Read.from(options.getInputFile())) // row... => <stationId, LaneInfo> ... .apply(ParDo.of(new ExtractFlowInfoFn(true /* outputTimestamp */))); } // map the incoming data stream into sliding windows. The default window duration values // work well if you're running the accompanying Pub/Sub generator script with the // --replay flag, which simulates pauses in the sensor data publication. You may want to // adjust them otherwise. input.apply(Window .<KV<String, LaneInfo>>into(SlidingWindows.of(Duration.standardMinutes(options.getWindowDuration())) .every(Duration.standardMinutes(options.getWindowSlideEvery())))) .apply(new MaxLaneFlow()) .apply(BigQueryIO.Write.to(tableRef).withSchema(FormatMaxesFn.getSchema())); PipelineResult result = pipeline.run(); if (options.isStreaming() && !options.getInputFile().isEmpty()) { // Inject the data into the Pub/Sub topic with a Dataflow batch pipeline. dataflowUtils.runInjectorPipeline(options.getInputFile(), options.getPubsubTopic()); } // dataflowUtils will try to cancel the pipeline and the injector before the program exists. dataflowUtils.waitToFinish(result); } private static Integer tryIntParse(String number) { try { return Integer.parseInt(number); } catch (NumberFormatException e) { return null; } } private static Double tryDoubleParse(String number) { try { return Double.parseDouble(number); } catch (NumberFormatException e) { return null; } } }