API Gateway offers a way to create REST APIs by importing OpenAPI specs, with some limitations.
However API Gateway does not support nullable properties, there are two ways of defining a nullable field:
In OpenAPI:
{
"mySchema": {
"type": "number",
"nullable": true
}
}In JSON Schema:
{
"mySchema": {
"type": ["number", "null"]
}
}However API Gateway does not support either of these when you import the OpenAPI specs with AWS CLI or CDK.
Below I have documented two ways to reproduce this issue, AWC CLI and AWS CDK
Using AWS CLI, one should be able to import OpenAPI specs to API Gateway, source doc
importing api.json file which has both JSON schema and OpenAPI notations of nullable fields, shows API gateway is not correctly handling this.
Running this:
aws apigateway import-rest-api \
--region eu-west-1 \
--body 'fileb://api.json'will create a new API in ApiGateway, however the corresponding model lack the nullable notation.
Source Schema:
"Orders": {
"type": "array",
"items": {
"type": "object",
"properties": {
"orderId": { "type": "string" },
"parentId": { "type": ["string", "null"] },
"partIdentifier": {
"anyOf": [{ "type": "string" }, { "type": "null" }]
},
"description": { "type": "string", "nullable": true },
"extras": { "type": ["string", "null"], "nullable": true }
},
"required": ["orderId", "partIdentifier", "description"]
}
}Resulting Model in API Gateway, note that parentId and extras have become dumb fields, not having any schema definition.
Currently the only way to hack around this, is to make a composite type by using anyOf, take a look at partIdentifier
The same issue is reproducible by using AWS CDK's SpecRestAPI, take a look inside cdk folder.
The Specs are located in assets/api-type-array-error.json.
To deploy the CDK stack to your AWS account:
cd cdk && cdk deploy