Use a service account

You can use service accounts in your Community Connectors for centralized management of resource access. A common use case would be to delegate access to data that users would not able to access using their own credentials.

Review Understanding service accounts to familiarize yourself with the topic.

Benefits

You can consolidate billing for data access.
You can implement your own access control layer in your connector.
You can delegate access to data or resources that the user's credentials does not have access to.

Implementation steps

Create a service account for the platform from which you are fetching data.
Provide the necessary permissions to the service account so it can access required resources.
Store the service account's credentials in your connector's script properties.
During connector execution, use the stored credentials to fetch required data.
Optional: Implement access control logic to filter the data.

Example: Accessing BigQuery with Looker Studio Advanced Services and a service account

You are building a solution where your users will build dashboards from a BigQuery table. If your users use Looker Studio's BigQuery connector, they will need read access to the BigQuery table. They will also require a billing account for Google Cloud Platform (GCP). The following steps illustrate how to use a service account to consolidate billing and delegate access to the BigQuery data.

Create a service account in your desired GCP project.
Ensure the service account can create BigQuery jobs and view the data for the required table. See BigQuery Access Control for details.
Create a key for the service account and store the credentials in your connector's script properties.
Include the OAuth2 Apps Script library in your Apps Script project.
For your getData function, authenticate the service account and generate an access token. Set the OAuth2 scope to https://www.googleapis.com/auth/bigquery.readonly.
Return access token with other configuration items in getData response.

The following is a complete example of the connector code:

main.js

var cc = DataStudioApp.createCommunityConnector();
var scriptProperties = PropertiesService.getScriptProperties();

function isAdminUser() {
  return true;
}

function getAuthType() {
  var AuthTypes = cc.AuthType;
  return cc
    .newAuthTypeResponse()
    .setAuthType(AuthTypes.NONE)
    .build();
}

function getConfig(request) {
  var config = cc.getConfig();

  config
    .newInfo()
    .setId('generalInfo')
    .setText('This is an example connector to showcase row level security.');

  return config.build();
}

function getFields() {
  var fields = cc.getFields();
  var types = cc.FieldType;
  var aggregations = cc.AggregationType;

  fields
    .newDimension()
    .setId('region')
    .setName('Region')
    .setType(types.TEXT);

  fields
    .newMetric()
    .setId('sales')
    .setName('Sales')
    .setType(types.NUMBER)
    .setAggregation(aggregations.SUM);

  fields
    .newDimension()
    .setId('date')
    .setName('Date')
    .setType(types.YEAR_MONTH_DAY);

  return fields;
}

function getSchema(request) {
  return {schema: getFields().build()};
}

var SERVICE_ACCOUNT_CREDS = 'SERVICE_ACCOUNT_CREDS';
var SERVICE_ACCOUNT_KEY = 'private_key';
var SERVICE_ACCOUNT_EMAIL = 'client_email';
var BILLING_PROJECT_ID = 'project_id';

/**
 * Copy the entire credentials JSON file from creating a service account in GCP.
 */
function getServiceAccountCreds() {
  return JSON.parse(scriptProperties.getProperty(SERVICE_ACCOUNT_CREDS));
}

function getOauthService() {
  var serviceAccountCreds = getServiceAccountCreds();
  var serviceAccountKey = serviceAccountCreds[SERVICE_ACCOUNT_KEY];
  var serviceAccountEmail = serviceAccountCreds[SERVICE_ACCOUNT_EMAIL];

  return OAuth2.createService('RowLevelSecurity')
    .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
    .setTokenUrl('https://accounts.google.com/o/oauth2/token')
    .setPrivateKey(serviceAccountKey)
    .setIssuer(serviceAccountEmail)
    .setPropertyStore(scriptProperties)
    .setCache(CacheService.getScriptCache())
    .setScope(['https://www.googleapis.com/auth/bigquery.readonly']);
}

var BASE_SQL =
  'SELECT d.region, d.sales, d.date ' +
  'FROM `datastudio-solutions.row_level_security.data` d ' +
  'INNER JOIN `datastudio-solutions.row_level_security.access` a ' +
  'ON d.region = a.region ' +
  'where a.email=@email';

function getData(request) {
  var accessToken = getOauthService().getAccessToken();
  var serviceAccountCreds = getServiceAccountCreds();
  var billingProjectId = serviceAccountCreds[BILLING_PROJECT_ID];
  var email = Session.getEffectiveUser().getEmail();

  var bqTypes = DataStudioApp.createCommunityConnector().BigQueryParameterType;

  return cc
    .newBigQueryConfig()
    .setAccessToken(accessToken)
    .setBillingProjectId(billingProjectId)
    .setUseStandardSql(true)
    .setQuery(BASE_SQL)
    .addQueryParameter('email', bqTypes.STRING, email)
    .build();
}