サービス アカウント キー ファイルを使用してクライアントを作成する

var credentials = GoogleCredential.FromFile(jsonPath);
var client = BigQueryClient.Create(projectId, credentials);

public static void explicit() throws IOException {
  // TODO(developer): Replace these variables before running the sample.
  String projectId = "MY_PROJECT_ID";
  File credentialsPath = new File("path/to/your/service_account.json");

  // Load credentials from JSON key file. If you can't set the GOOGLE_APPLICATION_CREDENTIALS
  // environment variable, you can explicitly load the credentials file to construct the
  // credentials.
  GoogleCredentials credentials;
  try (FileInputStream serviceAccountStream = new FileInputStream(credentialsPath)) {
    credentials = ServiceAccountCredentials.fromStream(serviceAccountStream);
  }

  // Instantiate a client.
  BigQuery bigquery =
      BigQueryOptions.newBuilder()
          .setCredentials(credentials)
          .setProjectId(projectId)
          .build()
          .getService();

  // Use the client.
  System.out.println("Datasets:");
  for (Dataset dataset : bigquery.listDatasets().iterateAll()) {
    System.out.printf("%s%n", dataset.getDatasetId().getDataset());
  }
}

// Create a BigQuery client explicitly using service account credentials.
// by specifying the private key file.
const {BigQuery} = require('@google-cloud/bigquery');

const options = {
  keyFilename: 'path/to/service_account.json',
  projectId: 'my_project',
};

const bigquery = new BigQuery(options);

from google.cloud import bigquery
from google.oauth2 import service_account

# TODO(developer): Set key_path to the path to the service account key
#                  file.
# key_path = "path/to/service_account.json"

credentials = service_account.Credentials.from_service_account_file(
    key_path,
    scopes=["https://www.googleapis.com/auth/cloud-platform"],
)

# Alternatively, use service_account.Credentials.from_service_account_info()
# to set credentials directly via a json object rather than set a filepath
# TODO(developer): Set key_json to the content of the service account key file.
# credentials = service_account.Credentials.from_service_account_info(key_json)

client = bigquery.Client(
    credentials=credentials,
    project=credentials.project_id,
)