libtabellarius function example

fn-example.rs

// Copyright 2022 Nathan Sizemore <[email protected]>
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

extern crate libtabellarius;
#[macro_use]
extern crate log;
extern crate uuid;

use libtabellarius::{core::comm::message::Message, function};
use uuid::Uuid;

static NAME: &'static str = "function-name";
static VERSION: &'static str = "0.1.0";
static DOMAIN: &'static str = "domain-name";
static SERVICE: &'static str = "service-name";

fn main() {
    loop {
        let r = function::init(NAME, VERSION, SERVICE);
        if r.is_err() {
            let e = r.unwrap_err();
            error!("{e}");
            return;
        }

        let (tx, rx) = r.unwrap();
        while let Ok(parcel) = rx.recv() {
            if parcel.is_err() {
                // The function has encountered an error.
                // This is non-recoverable and the process must restart.
                break;
            }

            let msg = parcel.unwrap();

            // Do stuff with msg...

            let some_bytes = [0u8; 69]; // Serialized data (JSON, XML, etc...)
            let reply = build_reply(&msg, &some_bytes);
            let _ = tx.send(reply);
        }
    }
}

fn build_reply(orig: &Message, buf: &[u8]) -> Message {
    let mut reply = Message::new(buf.len());
    reply.ids.set_id(Uuid::new_v4().as_u128());
    reply.ids.set_trace_id(orig.ids.trace_id());
    reply.ids.set_reply_to_id(orig.ids.id());
    reply.to.set_domain(orig.from.domain());
    reply.to.set_service(orig.from.service());
    reply.to.set_function(orig.from.function());
    reply.from.set_domain(DOMAIN);
    reply.from.set_service(SERVICE);
    reply.from.set_function(NAME);
    reply.data.extend_from_slice(buf);

    reply
}