aws-rds: cannot use connections in rds.DatabaseInstance.fromLookup #35192
Description
Describe the bug
When importing an RDS instance using rds.DatabaseInstance.fromLookup and attempting to use the connections property, the following error occurs:
CfnSynthesisError: Resolution error: Supplied properties not correct for "CfnSecurityGroupIngressProps"
fromPort: "3306" should be a number
toPort: "3306" should be a number.
at ValidationResult.assertSuccess (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/runtime.js:1:2876)
at convertCfnSecurityGroupIngressPropsToCloudFormation (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/aws-ec2/lib/ec2.generated.js:1:710632)
at CfnSecurityGroupIngress.renderProperties (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/aws-ec2/lib/ec2.generated.js:1:708378)
at PostResolveToken.Resources (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/cfn-resource.js:1:7982)
at PostResolveToken.postProcess (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/util.js:1:1648)
at Object.postProcess (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/private/resolve.js:1:1313)
at DefaultTokenResolver.resolveToken (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/resolvable.js:1:1554)
at resolve (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/private/resolve.js:1:2909)
at Object.resolve (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/private/resolve.js:1:1187)
at resolve (/Users/ykmatsud/Documents/git/cdk-conf-2025/node_modules/aws-cdk-lib/core/lib/private/resolve.js:1:3218) {
type: 'CfnSynthesisError'
}Regression Issue
- Select this option if this issue appears to be a regression.
Last Known Working CDK Library Version
No response
Expected Behavior
The connections property should be usable with an RDS instance imported via rds.DatabaseInstance.fromLookup.
Current Behavior
Unable to use the connections property with an RDS instance imported via rds.DatabaseInstance.fromLookup.
Reproduction Steps
const clientSecurityGroup = new ec2.SecurityGroup(
this,
'ClientSecurityGroup',
{
vpc,
},
);
const rdsInstanceFromLookup = rds.DatabaseInstance.fromLookup(
this,
'RdsInstanceFromLookup',
{
instanceIdentifier,
},
);
rdsInstanceFromLookup.connections.allowDefaultPortFrom(
clientSecurityGroup,
);
Possible Solution
The port property in the fromLookup method of rds.DatabaseInstance should be cast to Number. This is not currently done, resulting in the error.
https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk-lib/aws-rds/lib/instance.ts#L191
In contrast, the fromLookup method in rds.DatabaseCluster does cast the port to a number, which works correctly.
https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk-lib/aws-rds/lib/cluster.ts#L1391
Additional Information/Context
No response
AWS CDK Library version (aws-cdk-lib)
v2.210.0
AWS CDK CLI version
2.1024.0
Node.js Version
v22.14.0
OS
OSX
Language
TypeScript
Language Version
No response
Other information
No response