aws-lambda is a serverless plugin built into Apache APISIX for seamless integration with AWS Lambda, a widely used serverless solution, as a dynamic upstream to proxy all requests for a particular URI to the AWS cloud - one of the highly used public cloud platforms for production environment. If enabled, this plugin terminates the ongoing request to that particular URI and initiates a new request to the AWS lambda gateway uri (the new upstream) on behalf of the client with the suitable authorization details set by the users, request headers, request body, params (all these three components are passed from the original request) and returns the response body, status code and the headers back to the original client that has invoked the request to the APISIX agent. At present, the plugin supports authorization via AWS api key and AWS IAM Secrets.

The following is an example of how to enable the aws-lambda faas plugin for a specific route URI. Calling the APISIX route uri will make an invocation to the lambda function uri (the new upstream). We are assuming your cloud function is already up and running.

# enable aws lambda for a route via api key authorization
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
        "aws-lambda": {
            "function_uri": "https://x9w6z07gb9.execute-api.us-east-1.amazonaws.com/default/test-apisix",
            "authorization": {
                "apikey": "<Generated API Key from aws console>",
            },
            "ssl_verify":false
        }
    },
    "uri": "/aws"
}'

Now any requests (HTTP/1.1, HTTPS, HTTP2) to URI /aws will trigger an HTTP invocation to the aforesaid function URI and response body along with the response headers and response code will be proxied back to the client. For example (here AWS lambda function just take the name query param and returns Hello $name) :

$ curl -i -XGET localhost:9080/aws\?name=APISIX
HTTP/1.1 200 OK
Content-Type: application/json
Connection: keep-alive
Date: Sat, 27 Nov 2021 13:08:27 GMT
x-amz-apigw-id: JdwXuEVxIAMFtKw=
x-amzn-RequestId: 471289ab-d3b7-4819-9e1a-cb59cac611e0
Content-Length: 16
X-Amzn-Trace-Id: Root=1-61a22dca-600c552d1c05fec747fd6db0;Sampled=0
Server: APISIX/2.10.2

"Hello, APISIX!"

For requests where the mode of communication between the client and the Apache APISIX gateway is HTTP/2, the example looks like ( make sure you are running APISIX agent with enable_http2: true for a port in config-default.yaml. You can do it by uncommenting the port 9081 from apisix.node_listen field ) :

$ curl -i -XGET --http2 --http2-prior-knowledge localhost:9081/aws\?name=APISIX
HTTP/2 200
content-type: application/json
content-length: 16
x-amz-apigw-id: JdwulHHrIAMFoFg=
date: Sat, 27 Nov 2021 13:10:53 GMT
x-amzn-trace-id: Root=1-61a22e5d-342eb64077dc9877644860dd;Sampled=0
x-amzn-requestid: a2c2b799-ecc6-44ec-b586-38c0e3b11fe4
server: APISIX/2.10.2

"Hello, APISIX!"

Similarly, the lambda can be triggered via AWS API Gateway by using AWS IAM permissions to authorize access to your API via APISIX aws-lambda plugin. Plugin includes authentication signatures in their HTTP calls via AWS v4 request signing. Here is an example:

# enable aws lambda for a route via iam authorization
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
        "aws-lambda": {
            "function_uri": "https://ajycz5e0v9.execute-api.us-east-1.amazonaws.com/default/test-apisix",
            "authorization": {
                "iam": {
                    "accesskey": "<access key>",
                    "secretkey": "<access key secret>"
                }
            },
            "ssl_verify": false
        }
    },
    "uri": "/aws"
}'

Note: This approach assumes you already have an iam user with the programmatic access enabled and required permissions (AmazonAPIGatewayInvokeFullAccess) to access the endpoint.

AWS Lambda plugin supports url path forwarding while proxying request to the modified upstream (AWS Gateway URI endpoint). With that being said, any extension to the path of the base request APISIX gateway URI gets "appended" (path join) to the function_uri specified in the plugin configuration.

Note: APISIX route uri must be ended with an asterisk (*) for this feature to work properly. APISIX routes are strictly matched and the extra asterisk at the suffix means any subpath appended to the original parent path will use the same route object configurations.

Here is an example:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
        "aws-lambda": {
            "function_uri": "https://x9w6z07gb9.execute-api.us-east-1.amazonaws.com",
            "authorization": {
                "apikey": "<Generate API key>"
            },
            "ssl_verify":false
        }
    },
    "uri": "/aws/*"
}'

Now any request with path aws/default/test-apisix will invoke the aws api gateway endpoint. Here the extra path (where the magic character * has been used) up to the query params have been forwarded.

curl -i -XGET http://127.0.0.1:9080/aws/default/test-apisix\?name\=APISIX
HTTP/1.1 200 OK
Content-Type: application/json
Connection: keep-alive
Date: Wed, 01 Dec 2021 14:23:27 GMT
X-Amzn-Trace-Id: Root=1-61a7855f-0addc03e0cf54ddc683de505;Sampled=0
x-amzn-RequestId: f5f4e197-9cdd-49f9-9b41-48f0d269885b
Content-Length: 16
x-amz-apigw-id: JrHG8GC4IAMFaGA=
Server: APISIX/2.11.0

"Hello, APISIX!"

Remove the corresponding JSON configuration in the plugin configuration to disable the aws-lambda plugin and add the suitable upstream configuration. APISIX plugins are hot-reloaded, therefore no need to restart APISIX.

$ curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/aws",
    "plugins": {},
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'