MetaCall Express FaaS REPL Example

An example of building a FaaS server with NodeJS and Express, which implements a REPL protocol, suitable for projects like IPython / Jupyter where the exec constraints make embedding MetaCall difficult. This offers a multi-language REPL protocol and an inline module loader in order to allow loading and calling functions between languages in the REPL.

Run it

1. Install MetaCall:

   curl -sL https://raw.githubusercontent.com/metacall/install/master/install.sh | sh

2. Install dependencies:

   metacall npm install

3. In a terminal, run:

   metacall server.js

4. For testing with CURL:

   a) Inline Module Loading:

   curl -X POST -H 'Content-Type: application/json' localhost:7777/eval/node -d '{"data": "module.exports = { f: () => 4 }"}'

   b) REPL:

   curl -X POST -H 'Content-Type: application/json' localhost:7777/repl/node -d '{"data": "5555555554\n"}'

   c) Calling the function f in the REPL, previously loaded by step a:

   curl -X POST -H 'Content-Type: application/json' localhost:7777/repl/node -d '{"data": "require(\"metacall\").metacall(\"f\")\n"}'

5. In order to close it:

   curl localhost:7777/shutdown