cfn-api-gateway-resource-tree

Purpose

AWS CloudFormation does not support AWS API Gateway. This is a Lambda-backed custom resource to add AWS API Gateway's Resource to CloudFormation. This module allows construction of an arbitrarily large tree of resources. The standalone module for a single resource is cfn-gateway-resource (NPM / GitHub).

This package on NPM
This package on GitHub

Implementation

This Lambda makes use of the Lambda-Backed CloudFormation Custom Resource flow module, cfn-lambda (GitHub / NPM).

Usage

See ./example.template.json for a sample CloudFormation template. The example uses Condition statements, Parameters, and dynamic ServiceToken generation fully.

"ResourceLogicalIdInResourcesObject": {
  "Type": "Type": "Custom::ApiGatewayResourceTree",
  "Properties": {
    "ServiceToken": "arn:aws:lambda:<cfn-region-id>:<your-account-id>:function:<this-deployed-lambda-name>",
    "ParentId": {   // REQUIRED - can be any APIG Resource ID
      "Fn::GetAtt": [       // This example uses the root of an API RestApi object.
        "MyRestApi",
        "RootResourceId"
      ]
    },
    "RestApiId": {
      "Ref": "MyRestApiId"  //  REQUIRED 10 char alphanum ID for RestApi
    },
    "ChildResources": <A ChildResources Object>, // REQUIRED see struct below.
  }
}

CAUTION: ResourceTree will destroy any other properties on the ParentId Resource. CAUTION: Any modification to any property triggers a full replacement.

ChildResources Object

Recursively nestable tree structure definition for your API Gateway structure.

[ 
  {
    "PathPart": "pathwithoutchildren"
    // Do not need to include ChildResources.
  },
  {
    "PathPart": "pathwithchildren",
    "ChildResources": <A ChildResourcesObject>
  },
  {
    "PathPart": "{pathparam}",
    "ChildResources": `<a ChildResourcesObject>`
  }
]

Ref and Fn::GetAtt

Fn::GetAtt provides a key-value pair set for the ResourceId's of each path. These operate relative to the trees.

// This will return the `ResourceId` for the resource at relative path `/foo/{id}/bar`.
// The root is defined as the `ParentResourceId`'s Path on the `RestApi` object.
{"Fn::GetAtt": "/foo/{id}/bar"}

Ref returns a value only used for tracking internal state:

[
  <RestApiId>,
  <ParentResourceId>,
  SHA256(JSON.stringify(<ChildResources>))
].join('---')

Prerequisites for the Sample Template

While the resource works on its own, the ./example.template.json requires use of some more custom resources...:

1. Custom::ApiGatewayRestApi (GitHub / NPM)
2. Custom::ApiGatewayMethod (GitHub / NPM)
3. Custom::ApiGatewayMethodResponse (GitHub / NPM)
4. Custom::ApiGatewayIntegration (GitHub / NPM)
5. Custom::ApiGatewayIntegrationResponse (GitHub / NPM)
6. Custom::ApiGatewayDeployment (GitHub / NPM)

Installation of the Resource Service Lambda

Using the Provided Instant Install Script

The way that takes 10 seconds...

# Have aws CLI installed + permissions for IAM and Lamdba
$ npm run cfn-lambda-deploy

You will have this resource installed in every supported Region globally!

Using the AWS Console

... And the way more difficult way.

IMPORTANT: With this method, you must install this custom service Lambda in each AWS Region in which you want CloudFormation to be able to access the ApiGatewayResourceTree custom resource!

1. Go to the AWS Lambda Console Create Function view:

• us-east-1 / N. Virginia
• us-west-2 / Oregon
• eu-west-1 / Ireland
• ap-northeast-1 / Tokyo

2. Zip this repository into /tmp/ApiGatewayResourceTree.zip

   $ cd $REPO_ROOT && zip -r /tmp/ApiGatewayResourceTree.zip;

3. Enter a name in the Name blank. I suggest: CfnLambdaResouce-ApiGatewayResourceTree

4. Enter a Description (optional).

5. Toggle Code Entry Type to "Upload a .ZIP file"

6. Click "Upload", navigate to and select /tmp/ApiGatewayResourceTree.zip

7. Set the Timeout under Advanced Settings to 10 sec

8. Click the Role dropdown then click "Basic Execution Role". This will pop out a new window.

9. Select IAM Role, then select option "Create a new IAM Role"

10. Name the role lambda_cfn_api_gateway_resource (or something descriptive)

11. Click "View Policy Document", click "Edit" on the right, then hit "OK"

12. Copy and paste the ./execution-policy.json document.

13. Hit "Allow". The window will close. Go back to the first window if you are not already there.

14. Click "Create Function". Finally, done! Now go to Usage or see the example template. Next time, stick to the instant deploy script.

Miscellaneous

Collaboration & Requests

Submit pull requests or Tweet @ayetempleton if you want to get involved with roadmap as well, or if you want to do this for a living :)

License

MIT

Want More CloudFormation or API Gateway?

Work is (extremely) active, published here:
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