syndicate-js/packages/driver-unixsocket-node/src/index.js

138 lines
4.7 KiB
JavaScript

//---------------------------------------------------------------------------
// @syndicate-lang/driver-unixsocket-node, Unix socket support for Syndicate/js
// Copyright (C) 2016-2018 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//---------------------------------------------------------------------------
import { currentFacet, Observe, Dataspace, genUuid, Bytes } from "@syndicate-lang/core";
const net = require('net');
const fs = require('fs');
assertion type UnixSocketConnection(id, spec);
assertion type UnixSocketAccepted(id);
assertion type UnixSocketRejected(id, reason);
// message type LineIn(id, line); // TODO: abstract out this common protocol
message type DataIn(id, chunk);
message type DataOut(id, chunk);
assertion type UnixSocketClient(path);
assertion type UnixSocketServer(path);
export {
UnixSocketConnection, UnixSocketAccepted, UnixSocketRejected,
DataOut, DataIn,
UnixSocketClient, UnixSocketServer,
};
spawn named 'driver/UnixSocketDriver' {
during Observe(UnixSocketConnection(_, UnixSocketServer($path)))
spawn named ['driver/UnixSocketServer', path] {
let finish = Dataspace.backgroundTask();
on stop finish();
let server = net.createServer(Dataspace.wrapExternal((socket) => {
let id = genUuid('unix:' + path);
spawn named ['driver/UnixSocketInbound', id] {
assert UnixSocketConnection(id, UnixSocketServer(path));
on asserted UnixSocketAccepted(id) _connectionCommon.call(this, currentFacet(), id, socket, true);
stop on retracted UnixSocketAccepted(id);
stop on asserted UnixSocketRejected(id, _);
}
}));
let retried = false;
server.on('error', Dataspace.wrapExternal((err) => {
if (err.code === 'EADDRINUSE') {
// Potentially-stale socket file sitting around. Try
// connecting to it to see if it is alive, and remove it if
// not.
if (retried) {
// We're on our second go already, give up.
throw err;
} else {
retried = true;
const probe = new net.Socket();
probe.on('error', Dataspace.wrapExternal((e) => {
if (e.code === 'ECONNREFUSED') {
fs.unlinkSync(path);
server.listen(path);
} else {
// Something else went wrong! Give up the original listen.
console.error('Problem while probing potentially-stale socket', e);
throw err;
}
}));
probe.connect(path, Dataspace.wrapExternal((sock) => {
try { sock.destroy() } catch (e) { console.error(e); }
throw err;
}));
}
} else {
throw err;
}
}));
server.listen(path);
on stop try { server.close() } catch (e) { console.error(e); }
}
during UnixSocketConnection($id, UnixSocketClient($path))
spawn named ['driver/UnixSocketOutbound', id, path] {
let finish = Dataspace.backgroundTask();
on stop finish();
let socket = new net.Socket();
on start {
socket.connect(path);
_connectionCommon.call(this, currentFacet(), id, socket, false);
}
}
}
function _connectionCommon(rootFacet, id, socket, established) {
react {
field this.ready = established;
socket.on('ready', Dataspace.wrapExternal(() => {
if (!established) react assert UnixSocketAccepted(id);
this.ready = true;
}));
socket.on('error', Dataspace.wrapExternal((err) => {
if (!this.ready) {
// Pre-connection error: "rejected"
react assert UnixSocketRejected(id, err);
} else {
// Post-establishment error
if (err.errno !== 'ECONNRESET') {
console.error(err);
}
rootFacet.stop();
}
}));
socket.on('close', Dataspace.wrapExternal(() => { rootFacet.stop(); }));
on stop try { socket.destroy() } catch (e) { console.error(e); }
on start react stop on asserted Observe(DataIn(id, _)) {
socket.on('data', Dataspace.wrapExternal((data) => { send DataIn(id, Bytes.fromIO(data)); }));
}
on message DataOut(id, $data) {
socket.write(Bytes.toIO(data));
}
}
}