How to add an API endpoint for a Lambda function?

I’m trying to automate bringing up an API gateway, uploading a lambda function, and tying the two together.

I can successfully create a new REST API, add a Resource, and add a method to that Resource. I can successfully upload my lambda function.

However, I can’t figure out how to integrate it so that my API triggers a lambda function because I don’t know how to add an API endpoint to my lambda function using boto3.

Trying to call this function, not sure how to get a uri for my newly created lambda function -

response = apiClient.put_integration(
                restApiId=restApiId,
                resourceId=helloWorldId,
                httpMethod="POST",
                integrationHttpMethod="POST",
                type="AWS",
                uri=??????????????????,
  )

In short, I need help figuring out how to programmatically fill this portion of my lambda function using boto3 (and then retrieving that URI):

Any help would be appreciated. Thanks.

[AJRenold]

I ran into this issue implementing something similar today. Here’s a copy paste of code that should get your Lambda hooked up with an API Gateway endpoint. Way too many steps if you ask me!

lambda_func_name = 'callmemaybe'
AWS_LAMBDA_API_ID = 'abcd1234'
AWS_REGION = 'us-east-1'

api_client = boto3.client('apigateway', region_name=AWS_REGION)
aws_lambda = boto3.client('lambda', region_name=AWS_REGION)

## create resource
resource_resp = api_client.create_resource(
    restApiId=AWS_LAMBDA_API_ID,
    parentId='foo', # resource id for the Base API path
    pathPart=lambda_func_name
)

## create POST method
put_method_resp = api_client.put_method(
    restApiId=AWS_LAMBDA_API_ID,
    resourceId=resource_resp['id'],
    httpMethod="POST",
    authorizationType="NONE",
    apiKeyRequired=True,

)

lambda_version = aws_lambda.meta.service_model.api_version

uri_data = {
    "aws-region": AWS_REGION,
    "api-version": lambda_version,
    "aws-acct-id": "xyzABC",
    "lambda-function-name": lambda_func_name,
}

uri = "arn:aws:apigateway:{aws-region}:lambda:path/{api-version}/functions/arn:aws:lambda:{aws-region}:{aws-acct-id}:function:{lambda-function-name}/invocations".format(**uri_data)

## create integration
integration_resp = api_client.put_integration(
    restApiId=AWS_LAMBDA_API_ID,
    resourceId=resource_resp['id'],
    httpMethod="POST",
    type="AWS",
    integrationHttpMethod="POST",
    uri=uri,
)

api_client.put_integration_response(
    restApiId=AWS_LAMBDA_API_ID,
    resourceId=resource_resp['id'],
    httpMethod="POST",
    statusCode="200",
    selectionPattern=".*"
)

## create POST method response
api_client.put_method_response(
    restApiId=AWS_LAMBDA_API_ID,
    resourceId=resource_resp['id'],
    httpMethod="POST",
    statusCode="200",
)

uri_data['aws-api-id'] = AWS_LAMBDA_API_ID
source_arn = "arn:aws:execute-api:{aws-region}:{aws-acct-id}:{aws-api-id}/*/POST/{lambda-function-name}".format(**uri_data)

aws_lambda.add_permission(
    FunctionName=lambda_func_name,
    StatementId=uuid.uuid4().hex,
    Action="lambda:InvokeFunction",
    Principal="apigateway.amazonaws.com",
    SourceArn=source_arn
)

# state 'your stage name' was already created via API Gateway GUI
api_client.create_deployment(
    restApiId=AWS_LAMBDA_API_ID,
    stageName="your stage name",
)

[ajcrites]

@ndcampbell the issue for me was just that lambda can only be invoked with POST so if you are creating an integration request to lambda it must be POST no matter what the method request is.