转到Gmail API服务帐户

Question

我想使用服务帐户API通过Gmail发送电子邮件。我能够使用客户端ID和客户端密钥执行此操作，但服务帐户没有客户端密钥。这就是我所拥有的：

{
  "type": "service_account",
  "project_id": "my-project-id",
  "private_key_id": "107...",
  "private_key": "-----BEGIN PRIVATE KEY-----\nMII...=\n-----END PRIVATE KEY-----\n",
  "client_email": "something@something.iam.gserviceaccount.com",
  "client_id": "103...",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://accounts.google.com/o/oauth2/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/something%40something.iam.gserviceaccount.com"
}

如何使用此信息连接和发送电子邮件？所有文档似乎都引用了非服务帐户。