Rust Function Invoker

The Rust function invoker, or simply the Rust invoker, loads and invokes a Rust function packaged as a shared library. The Rust invoker is a binary executable which listens on port 8080 and, for each HTTP request received, calls the function and responds with a HTTP response.

Rust functions which are callable by the Rust invoker must conform to one of the function types in the function_types directory.

The samples directory contains sample functions written in Rust.

To build the Rust invoker and the sample functions, install Rust, clone this repository, change directory to the clone, and issue the following:

$ cargo build --release

To try the invoker, issue:

$ target/release/rust_invoker target/release/libhello.dylib

and then, from another terminal window:

$ curl localhost:8080 -d Rust
hello Rust

Building Docker Images

To build the Rust invoker docker image, issue:

$ docker build . -t projectriff/rust-function-invoker:latest

To build the hello sample docker image, issue:

$ docker build . -t projectriff/rust-function-hello:latest -f samples/hello/Dockerfile

Supported Function Types

So that function shared libraries do not have to be compiled with the same version of Rust that was used to compile the function invoker and since Rust does not have a defined ABI, functions must conform to the C ABI: the function must be declared as extern "C"; parameter types must be declared as #[repr(C)].

Basic

The Basic function type takes a string containing the request body and returns a string which is used as the response body.