cloud-formation-rds-properties

A Lambda backed custom resource for CloudFormation that provides information about an RDS instance or cluster

Purpose:

This custom resource provides information about an AWS RDS instance or cluster.

It might be useful in situations where your RDS resource is outside of a CloudFormation stack where it would be helpful to have that information without the need to enter several parameters. It might also be helpful in situations where you need additional information about an RDS resource that the return values for AWS::RDS::DBInstance and AWS::RDS::DBCluster do not include.

Installation

This custom resource can be installed on your AWS account by deploying the CloudFormation template at cloud-formation/cloud-formation.yml, and then updating the Lambda function it creates with the code from python/index.py

The Lambda function's ARN, which is needed for use as a service token when using this custom resource in your CloudFormation templates, will be exported as an output with the name ${AWS::StackName}-FunctionArn. This service token will also be stored in Systems Manager Parameter Store at /cloud-formation/service-tokens/rds-properties

Once installed, you can test the custom resource by using the CloudFormation template at cloud-formation/example-cloud-formation.yml, which will create a stack with outputs from the custom resource.

Syntax:

The syntax for declaring this resource:

RdsProperties:
  Type: "AWS::CloudFormation::CustomResource"
  Version: "1.0"
  Properties:
    ServiceToken: LAMDA_FUNCTION_ARN
    DBInstanceIdentifier: DB_INSTANCE_IDENTIFIER
    DBClusterIdentifier: DB_CLUSTER_IDENTIFIER,

Properties

Service Token

The ARN of the Lambda function backing the custom resource

Type: String

Required: Yes

DBInstanceIdentifier

The DBInstanceIdentifier of an RDS instance to query

Type: String

Required: Conditional. Exactly one of either DBInstanceIdentifier or DBClusterIdentifier are required

DBClusterIdentifier

The DBClusterIdentifier of an RDS cluster to query

Type: String

Required: Conditional. Exactly one of either DBInstanceIdentifier or DBClusterIdentifier are required

Return Values

Ref

When the logical ID of this resource is provided to the Ref intrinsic function, Ref returns the DBInstanceIdentifier property

Fn::GetAtt

Fn::GetAtt returns a value for a specified attribute of this type. The following are the available attributes.

Arn

The ARN of the RDS resource.

ResourceId

The AWS Region-unique, immutable identifier for the RDS resource. For instances, this will be the DbiResourceId. For clusters, this will be the DbClusterResourceId.

DBName

The name of the database that was created with the RDS resource

Endpoint.Address

The endpoint address of the RDS resource

Endpoint.Port

The endpoint port of the RDS resource

ReadEndpoint.Address

The reader endpoint for the RDS resource. For instances, this will always be the same as Endpoint.Address

Engine

The engine of the RDS resource

EngineVersion

The engine version of the RDS resource

IAMDatabaseAuthenticationEnabled

True if mapping of AWS Identity and Access Management (IAM) accounts to database accounts is enabled, and otherwise false.

MasterUsername

The master username for the RDS instance