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docs(samples): add query on external table from gcs (#588)
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Praful Makani committed Jul 23, 2020
1 parent 55cd52c commit 64bed2591daefed7bb8c8f93aa0a3d748a41a20d
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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_query_external_gcs_perm]
import com.google.cloud.bigquery.BigQuery;
import com.google.cloud.bigquery.BigQueryException;
import com.google.cloud.bigquery.BigQueryOptions;
import com.google.cloud.bigquery.CsvOptions;
import com.google.cloud.bigquery.ExternalTableDefinition;
import com.google.cloud.bigquery.Field;
import com.google.cloud.bigquery.QueryJobConfiguration;
import com.google.cloud.bigquery.Schema;
import com.google.cloud.bigquery.StandardSQLTypeName;
import com.google.cloud.bigquery.TableId;
import com.google.cloud.bigquery.TableInfo;
import com.google.cloud.bigquery.TableResult;

// Sample to queries an external data source using a permanent table
public class QueryExternalGCSPerm {

public static void runQueryExternalGCSPerm() {
// TODO(developer): Replace these variables before running the sample.
String datasetName = "MY_DATASET_NAME";
String tableName = "MY_TABLE_NAME";
String sourceUri = "gs://cloud-samples-data/bigquery/us-states/us-states.csv";
Schema schema =
Schema.of(
Field.of("name", StandardSQLTypeName.STRING),
Field.of("post_abbr", StandardSQLTypeName.STRING));
String query =
String.format("SELECT * FROM %s.%s WHERE name LIKE 'W%%'", datasetName, tableName);
queryExternalGCSPerm(datasetName, tableName, sourceUri, schema, query);
}

public static void queryExternalGCSPerm(
String datasetName, String tableName, String sourceUri, Schema schema, String query) {
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();

// Skip header row in the file.
CsvOptions csvOptions = CsvOptions.newBuilder().setSkipLeadingRows(1).build();

TableId tableId = TableId.of(datasetName, tableName);
// Create a permanent table linked to the GCS file
ExternalTableDefinition externalTable =
ExternalTableDefinition.newBuilder(sourceUri, csvOptions).setSchema(schema).build();
bigquery.create(TableInfo.of(tableId, externalTable));

// Example query to find states starting with 'W'
TableResult results = bigquery.query(QueryJobConfiguration.of(query));

results
.iterateAll()
.forEach(row -> row.forEach(val -> System.out.printf("%s,", val.toString())));

System.out.println("Query on external permanent table performed successfully.");
} catch (BigQueryException | InterruptedException e) {
System.out.println("Query not performed \n" + e.toString());
}
}
}
// [END bigquery_query_external_gcs_perm]
@@ -0,0 +1,89 @@
/*
* 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.Field;
import com.google.cloud.bigquery.Schema;
import com.google.cloud.bigquery.StandardSQLTypeName;
import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.util.UUID;
import org.junit.After;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class QueryExternalGCSPermIT {

private String tableName;
private ByteArrayOutputStream bout;
private PrintStream out;

private static final String BIGQUERY_DATASET_NAME = requireEnvVar("BIGQUERY_DATASET_NAME");

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

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

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

// Create a test table
tableName = "EXTERNAL_CSV_TABLE_FROM_GCS_TEST_" + UUID.randomUUID().toString().substring(0, 8);
bout = new ByteArrayOutputStream();
out = new PrintStream(bout);
System.setOut(out);
}

@After
public void tearDown() {
// Clean up
DeleteTable.deleteTable(BIGQUERY_DATASET_NAME, tableName);
System.setOut(null);
}

@Test
public void testQueryExternalGCSPerm() {
String sourceUri = "gs://cloud-samples-data/bigquery/us-states/us-states.csv";
Schema schema =
Schema.of(
Field.of("name", StandardSQLTypeName.STRING),
Field.of("post_abbr", StandardSQLTypeName.STRING));
String query =
String.format(
"SELECT * FROM %s.%s WHERE name LIKE 'W%%'", BIGQUERY_DATASET_NAME, tableName);
QueryExternalGCSPerm.queryExternalGCSPerm(
BIGQUERY_DATASET_NAME, tableName, sourceUri, schema, query);
assertThat(bout.toString())
.contains("Query on external permanent table performed successfully.");
}
}

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