Support for API Gateway with a custom domain

[drissamri]

When using the API Gateway support added in micronaut-projects/micronaut-core#540 it works until you add a custom domain name to the API Gateway, then the Lambda is invoked but return a 404.

Steps to Reproduce

Not sure how I can add a easy to reproduce test case since some setup for the domain is needed.

1. Create Micronaut app with AWS API Gateway support
2. Create/use custom domain and add it to AWS API Gateway
3. Call the custom domain name API URL

Expected Behaviour

Same output as the generated API Gateway URL should be given

Actual Behaviour

Tell us what happens instead

The Lambda is invoked but a HTTP 404 is generated.

• There is some reference to this issue in the aws-serverless-java-container library: API Gateway Path Mapping Problem aws/serverless-java-container#112
• @musketyr has already pointed out the same issue in his library: ttps://github.com/agorapulse/micronaut-libraries/blob/master/micronaut-function-aws-agp/src/main/groovy/com/agorapulse/micronaut/agp/ApiGatewayProxyHttpRequest.java#L203-L212

Environment Information

• Operating System: AWS Lambda
• Micronaut Version: 1.1.0.M2
• JDK Version: 1.8

[graemerocher]

Can you provide an example of your API gateway request JSON when using a custom domain?

[musketyr]

@graemerocher the main difference is the path in the request

{ "path" : "/v1/tokens", "requestContext": { "path" : "/v1/tokens" }

where /v1 is the stage prefix

[graemerocher]

@musketyr So it is my understanding that is what the stripBasePath method is for which has to be configured by the user https://github.com/micronaut-projects/micronaut-aws/blob/master/function-aws-api-proxy/src/main/java/io/micronaut/function/aws/proxy/AbstractLambdaContainerHandler.java#L171

Or am I mistaken?

[musketyr]

that could be one of the solutions but it would be better if the integration is able to determine it itself. the API can be in theory accessed in both ways - using the custom domain and using the original AWS native URL. here's a sample JSON:

{
    "resource": "/tokens",
    "path": "/develop/tokens",
    "httpMethod": "OPTIONS",
    "headers": {
        "Accept-Encoding": "gzip,deflate",
        "CloudFront-Forwarded-Proto": "https",
        "CloudFront-Is-Desktop-Viewer": "true",
        "CloudFront-Is-Mobile-Viewer": "false",
        "CloudFront-Is-SmartTV-Viewer": "false",
        "CloudFront-Is-Tablet-Viewer": "false",
        "CloudFront-Viewer-Country": "CZ",
        "Host": "identity.beta.agorapulse.com",
        "User-Agent": "Apache-HttpClient/4.5.6 (Java/1.8.0_152-release)",
        "Via": "1.1 1a25e657bbdfbe4dde177fef28655f03.cloudfront.net (CloudFront)",
        "X-Amz-Cf-Id": "X-zJ3VmbMC6-6OZ8gcluAt-UdTv9A2LOPbGHv2MbExwS1erLeMz42g==",
        "X-Amzn-Trace-Id": "Root=1-5c8a0953-6c76ce00130c0fc6daee7f1c",
        "X-Forwarded-For": "37.48.19.34, 70.132.52.87",
        "X-Forwarded-Port": "443",
        "X-Forwarded-Proto": "https"
    },
    "multiValueHeaders": {
        "Accept-Encoding": [
            "gzip,deflate"
        ],
        "CloudFront-Forwarded-Proto": [
            "https"
        ],
        "CloudFront-Is-Desktop-Viewer": [
            "true"
        ],
        "CloudFront-Is-Mobile-Viewer": [
            "false"
        ],
        "CloudFront-Is-SmartTV-Viewer": [
            "false"
        ],
        "CloudFront-Is-Tablet-Viewer": [
            "false"
        ],
        "CloudFront-Viewer-Country": [
            "CZ"
        ],
        "Host": [
            "identity.beta.agorapulse.com"
        ],
        "User-Agent": [
            "Apache-HttpClient/4.5.6 (Java/1.8.0_152-release)"
        ],
        "Via": [
            "1.1 1a25e657bbdfbe4dde177fef28655f03.cloudfront.net (CloudFront)"
        ],
        "X-Amz-Cf-Id": [
            "X-zJ3VmbMC6-6OZ8gcluAt-UdTv9A2LOPbGHv2MbExwS1erLeMz42g=="
        ],
        "X-Amzn-Trace-Id": [
            "Root=1-5c8a0953-6c76ce00130c0fc6daee7f1c"
        ],
        "X-Forwarded-For": [
            "37.48.19.34, 70.132.52.87"
        ],
        "X-Forwarded-Port": [
            "443"
        ],
        "X-Forwarded-Proto": [
            "https"
        ]
    },
    "queryStringParameters": null,
    "multiValueQueryStringParameters": null,
    "pathParameters": null,
    "stageVariables": {
        "lambdaAlias": "DEV"
    },
    "requestContext": {
        "resourceId": "984ifg",
        "resourcePath": "/tokens",
        "httpMethod": "OPTIONS",
        "extendedRequestId": "WhZlBFIsjoEFZhQ=",
        "requestTime": "14/Mar/2019:07:57:07 +0000",
        "path": "/develop/tokens",
        "accountId": "794392443626",
        "protocol": "HTTP/1.1",
        "stage": "develop",
        "domainPrefix": "identity",
        "requestTimeEpoch": 1552550227369,
        "requestId": "c37cda63-462e-11e9-8866-09654a81e41b",
        "identity": {
            "cognitoIdentityPoolId": null,
            "accountId": null,
            "cognitoIdentityId": null,
            "caller": null,
            "sourceIp": "37.48.19.34",
            "accessKey": null,
            "cognitoAuthenticationType": null,
            "cognitoAuthenticationProvider": null,
            "userArn": null,
            "userAgent": "Apache-HttpClient/4.5.6 (Java/1.8.0_152-release)",
            "user": null
        },
        "domainName": "identity.beta.agorapulse.com",
        "apiId": "j1gqf453fi"
    },
    "body": null,
    "isBase64Encoded": false
}

resource is actually the path you are looking for but it may contain variables, therefore I reconstruct the path from the resource and path variables

static String reconstructPath(String resource, Map<String, String> pathVariables) {
        if (pathVariables == null) {
            return resource;
        }
        String path = resource;
        for (Map.Entry<String, String> variable : pathVariables.entrySet()) {
            path = path.replaceAll("\\{" + Pattern.quote(variable.getKey()) +"\\+?}", variable.getValue());
        }
        return path;
}

[musketyr]

FYI here's a sample request handler to inspect the request

public class RequestDump implements RequestHandler<Map, APIGatewayProxyResponseEvent> {

    @Override
    public APIGatewayProxyResponseEvent handleRequest(Map input, Context context) {
        try {
            return new APIGatewayProxyResponseEvent().withStatusCode(200).withBody(new ObjectMapper().writeValueAsString(input));
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            return new APIGatewayProxyResponseEvent().withStatusCode(500).withBody(e.toString());
        }
    }
}

my library uses com.amazonaws.services.lambda.runtime.events model instead of SAM libraries model.