feat: add cloud spanner connection support

PiperOrigin-RevId: 384325792

google/cloud/bigquery/connection/v1/connection.proto

@@ -1,4 +1,4 @@
-// Copyright 2020 Google LLC
+// Copyright 2021 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -233,6 +233,9 @@ message Connection {
 
     // Amazon Web Services (AWS) properties.
     AwsProperties aws = 8;
+
+    // Cloud Spanner properties.
+    CloudSpannerProperties cloud_spanner = 21;
   }
 
   // Output only. The creation timestamp of the connection.
@@ -281,13 +284,26 @@ message CloudSqlCredential {
   string password = 2;
 }
 
+// Connection properties specific to Cloud Spanner.
+message CloudSpannerProperties {
+  // Cloud Spanner database in the form `project/instance/database'
+  string database = 1;
+
+  // If parallelism should be used when reading from Cloud Spanner
+  bool use_parallelism = 2;
+}
+
 // Connection properties specific to Amazon Web Services (AWS).
 message AwsProperties {
   // Authentication method chosen at connection creation.
   oneof authentication_method {
     // Authentication using Google owned AWS IAM user's access key to assume
     // into customer's AWS IAM Role.
     AwsCrossAccountRole cross_account_role = 2;
+
+    // Authentication using Google owned service account to assume into
+    // customer's AWS IAM Role.
+    AwsAccessRole access_role = 3;
   }
 }
 
@@ -306,3 +322,15 @@ message AwsCrossAccountRole {
   // https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-user_externalid.html
   string external_id = 3 [(google.api.field_behavior) = OUTPUT_ONLY];
 }
+
+// Authentication method for Amazon Web Services (AWS) that uses Google owned
+// Google service account to assume into customer's AWS IAM Role.
+message AwsAccessRole {
+  // The user’s AWS IAM Role that trusts the Google-owned AWS IAM user
+  // Connection.
+  string iam_role_id = 1;
+
+  // A unique Google-owned and Google-generated identity for the Connection.
+  // This identity will be used to access the user's AWS IAM Role.
+  string identity = 2;
+}