Authenticating With a Service Account Key File

Manually create and obtain service account credentials to use BigQuery when an application is deployed on-premises or to other public clouds. You can set the environment variable to load the credentials using Application Default Credentials, or you can specify the path to load the credentials manually in your application code.

This guide will show you how to load the credentials from a file.

Before you begin

• Follow the getting started with authentication for Google Cloud Platform guide to set up and download service account credentials.

Loading credentials from a file

Create credentials in your application from the service account file. Then use the credentials to create a service object with the BigQuery Client Libraries.

C#

Load the credentials from the JSON file using GoogleCredential.FromStream(Stream).

After you create a GoogleCredential, pass it to BigQueryClient.Create(String, GoogleCredential) to create the BigQuery service object.

For examples, see Setting Up Authentication for Server to Server Production Applications.

Java

Create a ServiceAccountCredentials object from a file using ServiceAccountCredentials.fromStream(InputStream). Pass the credentials to a BigQueryOptions.Builder and create the BigQuery service from those options.

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public static void explicit() throws IOException {
  // 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;
  File credentialsPath = new File("service_account.json");  // TODO: update to your key path.
  try (FileInputStream serviceAccountStream = new FileInputStream(credentialsPath)) {
    credentials = ServiceAccountCredentials.fromStream(serviceAccountStream);
  }

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

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

Python

Use bigquery.Client.from_service_account_json(path) to create a BigQuery Client using the service account key file.

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from google.cloud import bigquery

# Explicitly use service account credentials by specifying the private
# key file. All clients in google-cloud-python have this helper.
client = bigquery.Client.from_service_account_json(
    "path/to/service_account.json"
)

What's next

• Learn about other ways to authenticate your application to access the BigQuery API.
• Learn more about authenticating server to server production applications.