AWS Region-Specific Information Directory

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cdk-constructs: Stable


Usage

Some information used in CDK Applications differs from one AWS region to another, such as service principals used in IAM policies, S3 static website endpoints, …

The RegionInfo class

The library offers a simple interface to obtain region specific information in the form of the RegionInfo class. This is the preferred way to interact with the regional information database:

# Example automatically generated. See https://github.com/aws/jsii/issues/826
from aws_cdk.region_info import RegionInfo

# Get the information for "eu-west-1":
region = RegionInfo.get("eu-west-1")

# Access attributes:
region.s3_static_website_endpoint# s3-website-eu-west-1.amazonaws.com
region.service_principal("logs.amazonaws.com")

The RegionInfo layer is built on top of the Low-Level API, which is described below and can be used to register additional data, including user-defined facts that are not available through the RegionInfo interface.

Low-Level API

This library offers a primitive database of such information so that CDK constructs can easily access regional information. The FactName class provides a list of known fact names, which can then be used with the RegionInfo to retrieve a particular value:

# Example automatically generated. See https://github.com/aws/jsii/issues/826
import aws_cdk.region_info as region_info

code_deploy_principal = region_info.Fact.find("us-east-1", region_info.FactName.service_principal("codedeploy.amazonaws.com"))
# => codedeploy.us-east-1.amazonaws.com

static_website = region_info.Fact.find("ap-northeast-1", region_info.FactName.S3_STATIC_WEBSITE_ENDPOINT)

Supplying new or missing information

As new regions are released, it might happen that a particular fact you need is missing from the library. In such cases, the Fact.register method can be used to inject FactName into the database:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
region_info.Fact.register(
    region="bermuda-triangle-1",
    name=region_info.FactName.service_principal("s3.amazonaws.com"),
    value="s3-website.bermuda-triangle-1.nowhere.com"
)

Overriding incorrect information

In the event information provided by the library is incorrect, it can be overridden using the same Fact.register method demonstrated above, simply adding an extra boolean argument:

# Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
region_info.Fact.register({
    "region": "us-east-1",
    "name": region_info.FactName.service_principal("service.amazonaws.com"),
    "value": "the-correct-principal.amazonaws.com"
}, True)

If you happen to have stumbled upon incorrect data built into this library, it is always a good idea to report your findings in a GitHub issue, so we can fix it for everyone else!


This module is part of the AWS Cloud Development Kit project.