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docs(samples): added extract to json and accompanying test (#416)
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ejdarrow committed Jun 4, 2020
1 parent de0d97f commit 16a956db0aa545df84f7885ffb4425460cf55a16
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/*
* Copyright 2020 Google LLC
*
* 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.example.bigquery;

// [START bigquery_extract_table_json]
import com.google.cloud.RetryOption;
import com.google.cloud.bigquery.BigQuery;
import com.google.cloud.bigquery.BigQueryException;
import com.google.cloud.bigquery.BigQueryOptions;
import com.google.cloud.bigquery.FormatOptions;
import com.google.cloud.bigquery.Job;
import com.google.cloud.bigquery.Table;
import com.google.cloud.bigquery.TableId;
import org.threeten.bp.Duration;

public class ExtractTableToJson {

public static void runExtractTableToJson() {
// TODO(developer): Replace these variables before running the sample.
String projectId = "bigquery-public-data";
String datasetName = "samples";
String tableName = "shakespeare";
String bucketName = "my-bucket";
String destinationUri = "gs://" + bucketName + "/path/to/file";
// For more information on export formats available see:
// https://cloud.google.com/bigquery/docs/exporting-data#export_formats_and_compression_types
// For more information on Job see:
// https://googleapis.dev/java/google-cloud-clients/latest/index.html?com/google/cloud/bigquery/package-summary.html

// Note that FormatOptions.json().toString() is not "JSON" but "NEWLINE_DELIMITED_JSON"
// Using FormatOptions Enum for this will prevent problems with unexpected format names.
String dataFormat = FormatOptions.json().toString();

extractTableToJson(projectId, datasetName, tableName, destinationUri, dataFormat);
}

// Exports datasetName:tableName to destinationUri as a JSON file
public static void extractTableToJson(
String projectId, String datasetName, String tableName, String destinationUri,
String dataFormat) {
try {
// Initialize client that will be used to send requests. This client only needs to be created
// once, and can be reused for multiple requests.
BigQuery bigquery = BigQueryOptions.getDefaultInstance().getService();

TableId tableId = TableId.of(projectId, datasetName, tableName);
Table table = bigquery.getTable(tableId);

Job job = table.extract(dataFormat, destinationUri);

// Blocks until this job completes its execution, either failing or succeeding.
Job completedJob =
job.waitFor(
RetryOption.initialRetryDelay(Duration.ofSeconds(1)),
RetryOption.totalTimeout(Duration.ofMinutes(3)));
if (completedJob == null) {
System.out.println("Job not executed since it no longer exists.");
return;
} else if (completedJob.getStatus().getError() != null) {
System.out.println(
"BigQuery was unable to extract due to an error: \n" + job.getStatus().getError());
return;
}
System.out.println("Table export successful. Check in GCS bucket for the " +
dataFormat + " file.");
} catch (BigQueryException | InterruptedException e) {
System.out.println("Table extraction job was interrupted. \n" + e.toString());
}
}
}
// [END bigquery_extract_table_json]
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/*
* Copyright 2020 Google LLC
*
* 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.example.bigquery;

import static com.google.common.truth.Truth.assertThat;
import static junit.framework.TestCase.assertNotNull;

import com.google.cloud.bigquery.FormatOptions;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import org.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class ExtractTableToJsonIT {
private ByteArrayOutputStream bout;
private PrintStream out;

private static final String GCS_BUCKET = System.getenv("GCS_BUCKET");

private static void requireEnvVar(String varName) {
assertNotNull(
"Environment variable " + varName + " is required to perform these tests.",
System.getenv(varName));
}

@BeforeClass
public static void checkRequirements() {
requireEnvVar("GCS_BUCKET");
}

@Before
public void setUp() throws Exception {
bout = new ByteArrayOutputStream();
out = new PrintStream(bout);
System.setOut(out);
}

@After
public void tearDown() {
System.setOut(null);
}

@Test
public void testExtractTableToJson() {
String projectId = "bigquery-public-data";
String datasetName = "samples";
String tableName = "shakespeare";
String destinationUri = "gs://" + GCS_BUCKET + "/extractTest.json";
// FormatOptions.json() is not "JSON" but "NEWLINE_DELIMITED_JSON"
String dataFormat = FormatOptions.json().toString();

// Extract table content to GCS in JSON format
ExtractTableToJson.extractTableToJson(projectId, datasetName, tableName, destinationUri,
dataFormat);
assertThat(bout.toString())
.contains("Table export successful. Check in GCS bucket for the " + dataFormat + " file.");
}
}

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