Various RDS, RDS/Cloudformation, RDS/KMS improvements. (#789)

We need to mock out deploying RDS instances with full disk encryption
and detailed tagging. We also need to be able do deploy these instances
with Cloudformation, and then access them with both boto and boto3.

* Join RDS and RDS2 backends - this makes RDS resources created via
  either of the two boto RDS APIs visible to both, more closely
  mirroring how AWS works
* Fix RDS responses that were returning JSON but should be returning XML
* Add mocking of RDS Cloudformation calls
* Add mocking of RDS full disk encryption with KMS
* Add mocking of RDS DBParameterGroups
* Fix mocking of RDS DBSecurityGroupIngress rules
* Make mocking of RDS OptionGroupOptions more accurate
* Fix mocking of RDS cross-region DB replication
* Add RDS tag support to:
  * DBs
  * DBSubnetGroups
  * DBSecurityGroups

Signed-off-by: Andrew Garrett <andrew.garrett@getbraintree.com>

tests/test_cloudformation/test_cloudformation_stack_integration.py

@@ -27,6 +27,7 @@ from moto import (
     mock_kms,
     mock_lambda,
     mock_rds,
+    mock_rds2,
     mock_redshift,
     mock_route53,
     mock_sns,
@@ -36,6 +37,7 @@ from moto import (
 from .fixtures import (
     ec2_classic_eip,
     fn_join,
+    rds_mysql_with_db_parameter_group,
     rds_mysql_with_read_replica,
     redshift,
     route53_ec2_instance_with_public_ip,
@@ -693,6 +695,44 @@ def test_vpc_single_instance_in_subnet():
     eip_resource = [resource for resource in resources if resource.resource_type == 'AWS::EC2::EIP'][0]
     eip_resource.physical_resource_id.should.equal(eip.allocation_id)
 
+@mock_cloudformation()
+@mock_ec2()
+@mock_rds2()
+def test_rds_db_parameter_groups():
+    ec2_conn = boto.ec2.connect_to_region("us-west-1")
+    ec2_conn.create_security_group('application', 'Our Application Group')
+
+    template_json = json.dumps(rds_mysql_with_db_parameter_group.template)
+    conn = boto.cloudformation.connect_to_region("us-west-1")
+    conn.create_stack(
+        "test_stack",
+        template_body=template_json,
+        parameters=[
+            ("DBInstanceIdentifier", "master_db"),
+            ("DBName", "my_db"),
+            ("DBUser", "my_user"),
+            ("DBPassword", "my_password"),
+            ("DBAllocatedStorage", "20"),
+            ("DBInstanceClass", "db.m1.medium"),
+            ("EC2SecurityGroup", "application"),
+            ("MultiAZ", "true"),
+        ],
+    )
+
+    rds_conn = boto3.client('rds', region_name="us-west-1")
+
+    db_parameter_groups = rds_conn.describe_db_parameter_groups()
+    len(db_parameter_groups['DBParameterGroups']).should.equal(1)
+    db_parameter_group_name = db_parameter_groups['DBParameterGroups'][0]['DBParameterGroupName']
+
+    found_cloudformation_set_parameter = False
+    for db_parameter in rds_conn.describe_db_parameters(DBParameterGroupName=db_parameter_group_name)['Parameters']:
+        if db_parameter['ParameterName'] == 'BACKLOG_QUEUE_LIMIT' and db_parameter['ParameterValue'] == '2048':
+            found_cloudformation_set_parameter = True
+
+    found_cloudformation_set_parameter.should.equal(True)
+
+
 
 @mock_cloudformation()
 @mock_ec2()