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Heartbeats

This commit is contained in:
Tony Garnock-Jones 2019-06-20 13:35:04 +01:00
parent 1b71d1811d
commit 8199917335
5 changed files with 94 additions and 16 deletions
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1
packages/server/package.json
View File

@ -27,6 +27,7 @@
"@syndicate-lang/driver-http-node": "^0.2.7",
"@syndicate-lang/driver-mdns": "^0.2.7",
"@syndicate-lang/driver-streams-node": "^0.2.7",
"@syndicate-lang/driver-timer": "^0.2.7",
"@syndicate-lang/driver-websocket": "^0.2.7",
"debug": "^4.1.1"
},

50
packages/server/src/client.js
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@ -17,9 +17,11 @@ const {
Add, Del, Msg, Err, End,
Ping, Pong,
makeDecoder,
shouldDebugPrint,
} = activate require("./protocol");
const P = activate require("./internal_protocol");
const { recorder } = activate require("./turn");
const { heartbeat } = activate require("./heartbeat");
assertion type WSServer(url, scope) = Symbol.for('server-websocket-connection');
assertion type Loopback(scope) = Symbol.for('server-loopback-connection');
@ -39,7 +41,7 @@ Object.assign(module.exports, {
ForceServerDisconnect,
});
export function _genericClientSessionFacet(addr, scope, w0, debug) {
export function _genericClientSessionFacet(addr, scope, w0, teardown, debug) {
if (debug === void 0) {
debug = debugFactory('syndicate/server:client:' + genUuid('?'));
}
@ -48,10 +50,10 @@ export function _genericClientSessionFacet(addr, scope, w0, debug) {
on start debug('+', addr.toString(), scope);
on stop debug('-', addr.toString(), scope);
on message _ServerPacket(addr, $m) debug('<', m.toString());
on message _ServerPacket(addr, $m) if (shouldDebugPrint(m)) debug('<', m.toString());
const w = (x) => {
debug('>', x.toString());
if (shouldDebugPrint(x)) debug('>', x.toString());
w0(x);
};
@ -96,6 +98,9 @@ export function _genericClientSessionFacet(addr, scope, w0, debug) {
this.subs = this.subs.remove(spec);
}
const resetHeartbeat = heartbeat(this, ['client', addr, scope], w, teardown);
on message _ServerPacket(addr, _) resetHeartbeat();
const _instantiate = (m, vs) => Skeleton.instantiateAssertion(FromServer(addr, m.spec), vs);
const _lookup = (CTOR, item) => {
@ -140,20 +145,36 @@ spawn named "ServerClientFactory" {
during Observe(ServerConnected($addr)) assert ServerConnection(addr);
during ServerConnection($addr(WSServer($url, $scope))) spawn named ['ServerClient', addr] {
const wsId = genUuid('ws');
const debug = debugFactory('syndicate/server:client:' + wsId);
const reestablish = () => {
react {
const establishingFacet = currentFacet();
const wsId = genUuid('ws');
during WS.WebSocket(wsId, url, {}) {
on message WS.DataIn(wsId, $data) {
if (data instanceof Bytes) send _ServerPacket(addr, makeDecoder(data).next());
during WS.WebSocket(wsId, url, {}) {
on message WS.DataIn(wsId, $data) {
if (data instanceof Bytes) send _ServerPacket(addr, makeDecoder(data).next());
}
_genericClientSessionFacet.call(
this,
addr, scope,
(x) => { send WS.DataOut(wsId, new Encoder().push(x).contents()); },
() => {
establishingFacet.stop(() => {
// TODO: abstract this into a flush() function somewhere
const ACK = Symbol('ACK');
react {
stop on message ACK reestablish();
on start send ACK;
}
});
},
debugFactory('syndicate/server:client:' + wsId));
}
}
};
_genericClientSessionFacet.call(
this,
addr, scope,
(x) => { send WS.DataOut(wsId, new Encoder().push(x).contents()); },
debug);
}
on start reestablish();
}
during ServerConnection($addr(Loopback($scope))) spawn named ['ServerClient', addr] {
@ -166,6 +187,7 @@ spawn named "ServerClientFactory" {
this,
addr, scope,
(x) => { send P.FromPOA(addr, x); },
() => { throw new Error("Cannot teardown and reset Loopback connection"); },
debug);
}
}

43
packages/server/src/heartbeat.js Normal file
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@ -0,0 +1,43 @@
"use strict";
const { TimeLaterThan } = activate require("@syndicate-lang/driver-timer");
const debug = require('debug')('syndicate/server:heartbeat');
const W = require('./protocol');
const PERIOD = 60 * 1000; // milliseconds
const GRACE = 3 * PERIOD;
function heartbeat(fields, who, sendMessage, teardown) {
debug('Configuring heartbeat', who, PERIOD, GRACE);
const NEXT_PING_TIME = Symbol('NEXT_PING_TIME');
const LAST_RECEIVED_TRAFFIC = Symbol('LAST_RECEIVED_TRAFFIC');
function now() { return (+(new Date())); } // returns milliseconds
field fields[NEXT_PING_TIME] = 0;
field fields[LAST_RECEIVED_TRAFFIC] = now();
const scheduleNextPing = () => { fields[NEXT_PING_TIME] = now() + PERIOD; };
on asserted TimeLaterThan(fields[NEXT_PING_TIME]) {
scheduleNextPing();
sendMessage(W.Ping());
}
on asserted TimeLaterThan(fields[LAST_RECEIVED_TRAFFIC] + GRACE) {
debug('Heartbeat timeout', who, GRACE);
teardown();
}
return () => {
scheduleNextPing();
fields[LAST_RECEIVED_TRAFFIC] = now();
};
}
Object.assign(module.exports, {
PERIOD,
GRACE,
heartbeat,
});

6
packages/server/src/protocol.js
View File

@ -29,6 +29,11 @@ function makeDecoder(initialBuffer) {
});
}
function shouldDebugPrint(m) {
// return !(Ping.isClassOf(m) || Pong.isClassOf(m));
return true;
}
Object.assign(module.exports, {
Connect,
Turn,
@ -36,4 +41,5 @@ Object.assign(module.exports, {
Add, Del, Msg, Err, End,
Ping, Pong,
makeDecoder,
shouldDebugPrint,
});

10
packages/server/src/server.js
View File

@ -14,6 +14,7 @@ const P = activate require("./internal_protocol");
const W = activate require("./protocol");
const B = activate require("./buffer");
const { recorder } = activate require("./turn");
const { heartbeat } = activate require("./heartbeat");
export function websocketServerFacet(reqId) {
assert P.POA(reqId);
@ -58,8 +59,8 @@ spawn named '@syndicate-lang/server/server/POAHandler' {
const debug = debugFactory('syndicate/server:server:' + connId.toString());
on start debug('+');
on stop debug('-');
on message P.FromPOA(connId, $m) debug('<', m.toString());
on message P.ToPOA(connId, $m) debug('>', m.toString());
on message P.FromPOA(connId, $m) if (W.shouldDebugPrint(m)) debug('<', m.toString());
on message P.ToPOA(connId, $m) if (W.shouldDebugPrint(m)) debug('>', m.toString());
field this.scope = null;
assert P.POAReady(connId);
@ -76,6 +77,11 @@ spawn named '@syndicate-lang/server/server/POAHandler' {
const sendToPOA = (m) => { send P.ToPOA(connId, m); };
const outboundTurn = recorder(this, 'commitNeeded', (items) => sendToPOA(W.Turn(items)));
const poaFacet = currentFacet();
const resetHeartbeat = heartbeat(this, ['server', connId], sendToPOA, () => {poaFacet.stop();});
on message P.FromPOA(connId, _) resetHeartbeat();
on message P.FromPOA(connId, W.Ping()) sendToPOA(W.Pong());
on message P.FromPOA(connId, W.Turn($items)) {
items.forEach((item) => {
if (W.Assert.isClassOf(item)) {