lrpc

LRPC

AWS Lambda net/rpc server, client via AWS API.

The packages provided are intended to allow deploying net/rpc services to AWS Lambda and calling them with net/rpc Client conventions or via a JSON-RPC 1.0 payload.

Server

Servers use Register or RegisterName from lrpc/server, or RPCServer to set the net/rpc server to serve. The server.Serve() function is then called from a main package. Deploying such main packages is facilitated with lago.

Client

Clients access net/rpc servers running as Lambda handlers via the lrpc/client package. Call (and Invoke) issues the request via the AWS Lambda API.

Demo

See the demo package.

How it works

The server inspects the payload and handles the request as gob-encoded or a JSON-RPC 1.0

With client package

The client gob-encodes an rpc.Request and request body to the Invoke payload. The server invokes the rpc.Request with the supplied body. If a method error occurs, it is encoded as a rpc.Response. Otherwise, the response body is also encoded.

With JSON-RPC

The JSON-RPC request is sent as a Lambda payload directly, either via REST call or any AWS SDK. The "id" field of the request may be of any type. If the "id" is null or omitted, the output of any method call is discarded. Otherwise, the "id" field as supplied will be returned with the response. Method call output is marshalled to the "result" field. If an error occurs or a panic is recovered at any point in the Lambda invocation, the "error" field will be populated with a message and the "result" field will be null. All marshalling and unmarshalling is by the json package's conventions.

Notes

The Lambda environment must be considered stateless (unless you're aware of how it isn't and design your net/rpc service accordingly). If a server cannot decode a request (which should be impossible), an out-of-band error occurs. In-band errors use a unique convention: errors returned by a method invocation append a newline followed by the request ID, errors and panics that occur before or after a method invocation append a tab character followed by the request ID. The intent is not nessisarily for clients to inspect returned delimiters but provide additional information in a unique way when read by a human. Errors returned by the client (in general due to invalid invocation) are unadorned.

Related

The lh package makes it easy to serve (many or most) http.Handlers with the AWS Lambda Go runtime. The lago tool makes it easy to deploy Go handlers to the Lambda Go runtime.