SuperNodeStorage/src/intra.js
sairajzero a91df8a2b2 Bug fix
- Promisified the refresher invoke fn.
- Connect to next node upon 1st refresher resolve
2021-07-24 01:04:20 +05:30

697 lines
22 KiB
JavaScript

'use strict';
const WebSocket = require('ws');
//CONSTANTS
const SUPERNODE_INDICATOR = '$',
//Message type
ORDER_BACKUP = "orderBackup",
STORE_BACKUP_DATA = "backupData",
STORE_MIGRATED_DATA = "migratedData",
DELETE_MIGRATED_DATA = "migratedDelete",
//DELETE_BACKUP_DATA = "backupDelete",
TAG_BACKUP_DATA = "backupTag",
//EDIT_BACKUP_DATA = "backupEdit",
INITIATE_REFRESH = "initiateRefresh",
DATA_REQUEST = "dataRequest",
DATA_SYNC = "dataSync",
BACKUP_HANDSHAKE_INIT = "handshakeInitate",
BACKUP_HANDSHAKE_END = "handshakeEnd",
RETRY_TIMEOUT = 5 * 60 * 1000, //5 mins
MIGRATE_WAIT_DELAY = 5 * 60 * 1000; //5 mins
var DB, refresher; //container for database and refresher
//List of node backups stored
const _list = {};
Object.defineProperty(_list, 'delete', {
value: function(id) {
delete this[id];
}
});
Object.defineProperty(_list, 'get', {
value: function(keys = null) {
if (keys === null) keys = Object.keys(this);
if (Array.isArray(keys))
return Object.fromEntries(keys.map(k => [k, this[k]]));
else
return this[keys];
}
});
Object.defineProperty(_list, 'stored', {
get: function() {
return Object.keys(this);
}
});
Object.defineProperty(_list, 'serving', {
get: function() {
let serveList = [];
for (let id in this)
if (this[id] === 0)
serveList.push(id);
return serveList;
}
});
//Node container
function NodeContainer() {
var _ws, _id, _onmessage, _onclose;
Object.defineProperty(this, 'set', {
value: function(id, ws) {
if (_ws !== undefined)
this.close();
_id = id;
_ws = ws;
if (_onmessage)
_ws.onmessage = _onmessage;
if (_onclose)
_ws.onclose = _onclose;
}
});
Object.defineProperty(this, 'id', {
get: function() {
return _id;
}
});
Object.defineProperty(this, 'readyState', {
get: function() {
if (_ws instanceof WebSocket)
return _ws.readyState;
else
return null;
}
});
Object.defineProperty(this, 'send', {
value: function(packet) {
_ws.send(packet);
}
});
Object.defineProperty(this, 'onmessage', {
set: function(fn) {
if (fn instanceof Function)
_onmessage = fn;
}
});
Object.defineProperty(this, 'onclose', {
set: function(fn) {
if (fn instanceof Function)
_onclose = fn;
}
});
Object.defineProperty(this, 'is', {
value: function(ws) {
return ws === _ws;
}
});
Object.defineProperty(this, 'close', {
value: function() {
if (_ws.readyState === 1) {
_ws.onclose = () => console.warn('Closing: ' + _id);
_ws.close();
};
_ws = _id = undefined;
}
});
};
//Container for next-node
const _nextNode = new NodeContainer();
_nextNode.onmessage = evt => processTaskFromNextNode(evt.data);
_nextNode.onclose = evt => reconnectNextNode();
//Container for prev-node
const _prevNode = new NodeContainer();
_prevNode.onmessage = evt => processTaskFromPrevNode(evt.data);
_prevNode.onclose = evt => _prevNode.close();
//Packet processing
const packet_ = {};
packet_.constuct = function(message) {
const packet = {
from: myFloID,
message: message,
time: Date.now()
};
packet.sign = floCrypto.signData(this.s(packet), myPrivKey);
return SUPERNODE_INDICATOR + JSON.stringify(packet);
};
packet_.s = d => [JSON.stringify(d.message), d.time].join("|");
packet_.parse = function(str) {
let packet = JSON.parse(str.substring(SUPERNODE_INDICATOR.length));
let curTime = Date.now();
if (packet.time > curTime - floGlobals.sn_config.delayDelta &&
packet.from in floGlobals.supernodes &&
floCrypto.verifySign(this.s(packet), packet.sign, floGlobals.supernodes[packet.from].pubKey)) {
if (!Array.isArray(packet.message))
packet.message = [packet.message];
return packet;
};
};
//-----NODE CONNECTORS (WEBSOCKET)-----
//Connect to Node websocket
function connectToNode(snID) {
return new Promise((resolve, reject) => {
if (!(snID in floGlobals.supernodes))
return reject(`${snID} is not a supernode`);
const ws = new WebSocket("wss://" + floGlobals.supernodes[nextNodeID].uri + "/");
ws.on("error", () => reject(`${snID} is offline`));
ws.on('open', () => resolve(ws));
});
};
//Connect to Node websocket thats online
function connectToActiveNode(snID, reverse = false) {
return new Promise((resolve, reject) => {
if (!(snID in floGlobals.supernodes))
return reject(`${snID} is not a supernode`);
if (snID === myFloID)
return reject(`Reached end of circle. Next node avaiable is self`);
connectToNode(snID)
.then(ws => resolve(ws))
.catch(error => {
var next = (reverse ? kBucket.prevNode(snID) : kBucket.nextNode(snID));
connectToActiveNode(next, reverse)
.then(ws => resolve(ws))
.catch(error => reject(error));
});
});
};
//Connect to next available node
function connectToNextNode() {
return new Promise((resolve, reject) => {
let nextNodeID = kBucket.nextNode(nodeID);
connectToActiveNode(nextNodeID).then(ws => {
_nextNode.set(nextNodeID, ws);
_nextNode.send(packet_.constuct({
type: BACKUP_HANDSHAKE_INIT
}));
resolve("BACKUP_HANDSHAKE_INIT: " + nextNodeID);
}).catch(error => reject(error));
});
};
function connectToAliveNodes(nodes = null) {
if (!Array.isArray(nodes)) nodes = Object.keys(floGlobals.supernodes);
return new Promise((resolve, reject) => {
Promise.allSettled(nodes.map(n => connectToNode(n))).then(results => {
let ws_connections = {};
nodes.forEach((n, i) =>
ws_connections[n] = (results.status === "fulfilled") ? results[i].value : null);
resolve(ws_connections);
});
});
};
//Connect to all given nodes [Array] (Default: All super-nodes)
function connectToAllActiveNodes(nodes = null) {
if (!Array.isArray(nodes)) nodes = Object.keys(floGlobals.supernodes);
return new Promise((resolve, reject) => {
Promise.allSettled(nodes.map(n => connectToActiveNode(n))).then(results => {
let ws_connections = {};
nodes.forEach((n, i) =>
ws_connections[n] = (results.status === "fulfilled") ? results[i].value : null);
resolve(ws_connections);
});
});
};
//-----PROCESS TASKS-----
//Tasks from next-node
function processTaskFromNextNode(packet) {
var {
from,
message
} = packet_.parse(packet);
if (message) {
message.forEach(task => {
switch (task.type) {
case RECONNECT_NEXT_NODE: //Triggered when a node inbetween is available
reconnectNextNode();
break;
case BACKUP_HANDSHAKE_END:
handshakeEnd();
break;
case DATA_REQUEST:
sendStoredData(task.nodes, _nextNode);
break;
case DATA_SYNC:
dataSyncIndication(task.id, task.status, from);
break;
case STORE_BACKUP_DATA:
storeBackupData(task.data);
break;
default:
console.log("Invalid task type:" + task.type + "from next-node");
};
});
};
};
//Tasks from prev-node
function processTaskFromPrevNode(packet) {
var {
from,
message
} = packet_.parse(packet);
if (message) {
message.forEach(task => {
switch (task.type) {
case ORDER_BACKUP:
orderBackup(task.order);
break;
case STORE_BACKUP_DATA:
storeBackupData(task.data, from, packet);
break;
case TAG_BACKUP_DATA:
tagBackupData(task.data, from, packet);
break;
case DATA_REQUEST:
sendStoredData(task.nodes, _prevNode);
break;
case DATA_SYNC:
dataSyncIndication(task.id, task.status, from);
break;
case DELETE_MIGRATED_DATA:
deleteMigratedData(task.data, from, packet);
break;
default:
console.log("Invalid task type:" + task.type + "from prev-node");
};
});
};
};
//Tasks from any supernode
function processTaskFromSupernode(packet, ws) {
var {
from,
message
} = packet_.parse(packet);
if (message) {
message.forEach(task => {
switch (task.type) {
case BACKUP_HANDSHAKE_INIT:
handshakeMid(from, ws);
break;
case STORE_MIGRATED_DATA:
storeMigratedData(task.data);
break;
case INITIATE_REFRESH:
initiateRefresh();
break;
default:
console.log("Invalid task type:" + task.type + "from super-node");
};
});
};
};
//-----HANDSHAKE PROCESS-----
//Acknowledge handshake
function handshakeMid(id, ws) {
if (_prevNode.id && _prevNode.id in floGlobals.supernodes) {
if (kBucket.innerNodes(_prevNode.id, myFloID).includes(id)) {
//close existing prev-node connection
_prevNode.send(packet_.constuct({
type: RECONNECT_NEXT_NODE
}));
_prevNode.close();
//set the new prev-node connection
_prevNode.set(id, ws);
_prevNode.send(packet_.constuct({
type: BACKUP_HANDSHAKE_END
}));
} else {
//Incorrect order, existing prev-node is already after the incoming node
ws.send(packet_.constuct({
type: RECONNECT_NEXT_NODE
}));
return;
};
} else {
//set the new prev-node connection
_prevNode.set(id, ws);
_prevNode.send(packet_.constuct({
type: BACKUP_HANDSHAKE_END
}));
};
//Reorder storelist
let nodes = kBucket.innerNodes(_prevNode.id, myFloID).concat(myFloID),
req_sync = [],
new_order = [];
nodes.forEach(n => {
switch (_list[n]) {
case 0: //Do nothing
break;
case undefined:
req_sync.push(n);
default:
_list[n] = 0;
new_order.push(n);
};
});
if (!req_sync.length && !new_order.length)
return; //No order change and no need for any data sync
else
handshakeMid.requestData(req_sync, new_order);
};
handshakeMid.requestData = function(req_sync, new_order) {
if (handshakeMid.timeout) {
clearTimeout(handshakeMid.timeout);
delete handshakeMid.timeout;
};
Promise.allSettled(req_sync.map(n => DB.createGetLastLog(n))).then(result => {
let tasks = [],
lastlogs = {},
failed = [],
order = [],
failed_order = [];
req_sync.forEach((s, i) => {
if (result[i].status === "fulfilled")
lastlogs[s] = result[i].value;
else
failed.push(s);
});
if (Object.keys(lastlogs).length)
tasks.push({
type: DATA_REQUEST,
nodes: lastlogs
});
new_order.forEach(n => {
if (failed.includes(n))
failed_order.push(n);
else
order.push(n);
});
if (order.length)
tasks.push({
type: ORDER_BACKUP,
order: _list.get(order)
});
_nextNode.send(packet_.constuct(tasks));
if (failed.length)
handshakeMid.timeout = setTimeout(_ => handshakeMid.requestData(failed, failed_order), RETRY_TIMEOUT);
});
};
//Complete handshake
function handshakeEnd() {
console.log("Backup connected: " + _nextNode.id);
_nextNode.send(packet_.constuct({
type: ORDER_BACKUP,
order: _list.get()
}));
};
//Reconnect to next available node
function reconnectNextNode() {
_nextNode.close();
connectToNextNode()
.then(result => console.log(result))
.catch(error => {
//Case: No other node is online
console.error(error);
//Serve all nodes
for (let sn in floGlobals.supernodes)
DB.createTable(sn)
.then(result => _list[sn] = 0)
.catch(error => console.error(error));
});
};
//-----BACKUP TASKS-----
//Order the stored backup
function orderBackup(order) {
let new_order = [];
let cur_serve = kBucket.innerNodes(_prevNode.id, myFloID);
for (let n in order) {
if (order[n] + 1 !== _list[n]) {
if (order[n] >= floGlobals.sn_config.backupDepth)
DB.dropTable(n).then(_ => null)
.catch(error => console.error(error))
.finally(_ => _list.delete(n));
else if (_list[n] !== 0 || !cur_serve.includes(n)) {
_list[n] = order[n] + 1;
new_order.push(n);
};
};
};
if (new_order.length) {
_nextNode.send(packet_.constuct({
type: ORDER_BACKUP,
order: _list.get(new_order)
}));
};
};
//Send stored data
function sendStoredData(lastlogs, node) {
for (n in lastlogs) {
if (_list.stored.includes(n)) {
DB.getData(n, lastlogs[n]).then(result => {
node.send(packet_.constuct({
type: DATA_SYNC,
id: n,
status: true
}));
console.log(`START: ${snID} data sync(send) to ${node.id}`);
//TODO: efficiently handle large number of data instead of loading all into memory
result.forEach(d => node.send(packet_.constuct({
type: STORE_BACKUP_DATA,
data: d
})));
console.log(`END: ${snID} data sync(send) to ${node.id}`);
node.send(packet_.constuct({
type: DATA_SYNC,
id: n,
status: false
}));
}).catch(error => console.error(error));
};
};
};
//Indicate sync of data
function dataSyncIndication(snID, status, from) {
console.log(`${status ? 'START':'END'}: ${snID} data sync(receive) form ${from}`);
};
//Store (backup) data
function storeBackupData(data, from, packet) {
let closestNode = kBucket.closestNode(data.receiverID);
if (_list.stored.includes(closestNode)) {
DB.storeData(closestNode, data);
if (_list[closestNode] < floGlobals.sn_config.backupDepth && _nextNode.id !== from)
_nextNode.send(packet);
};
};
//Tag (backup) data
function tagBackupData(data, from, packet) {
let closestNode = kBucket.closestNode(data.receiverID);
if (_list.stored.includes(closestNode)) {
DB.storeTag(closestNode, data);
if (_list[closestNode] < floGlobals.sn_config.backupDepth && _nextNode.id !== from)
_nextNode.send(packet);
};
};
//Store (migrated) data
function storeMigratedData(data) {
let closestNode = kBucket.closestNode(data.receiverID);
if (_list.serving.includes(closestNode)) {
DB.storeData(closestNode, data);
_nextNode.send(packet_.constuct({
type: STORE_BACKUP_DATA,
data: data
}));
};
};
//Delete (migrated) data
function deleteMigratedData(old_sn, vectorClock, receiverID, from, packet) {
let closestNode = kBucket.closestNode(receiverID);
if (old_sn !== closestNode && _list.stored.includes(old_sn)) {
DB.deleteData(old_sn, vectorClock);
if (_list[old_sn] < floGlobals.sn_config.backupDepth && _nextNode.id !== from)
_nextNode.send(packet);
};
};
function initiateRefresh() {
refresher.invoke(false).then(_ => null).catch(_ => null);
};
//Forward incoming to next node
function forwardToNextNode(mode, data) {
var modeMap = {
'TAG': TAG_BACKUP_DATA,
'DATA': STORE_BACKUP_DATA
};
if (mode in modeMap && _nextNode.id)
_nextNode.send(packet_.constuct({
type: modeMap[mode],
data: data
}));
};
//Data migration processor
function dataMigration(node_change, flag) {
if (!Object.keys(node_change).length)
return;
console.log("Node list changed! Data migration required");
if (flag) dataMigration.intimateAllNodes(); //Initmate All nodes to call refresher
let new_nodes = [],
del_nodes = [];
for (let n in node_change)
(node_change[n] ? new_nodes : del_nodes).push(n);
if (del_nodes.includes(_prevNode.id)) {
_list[_prevNode.id] = 0; //Temporary serve for the deleted node
_prevNode.close();
};
setTimeout(() => {
//reconnect next node if current next node is deleted
if (del_nodes.includes(_nextNode.id))
reconnectNextNode();
else { //reconnect next node if there are newly added nodes in between self and current next node
let innerNodes = kBucket.innerNodes(myFloID, _nextNode.id);
if (new_nodes.filter(n => innerNodes.includes(n)).length)
reconnectNextNode();
};
setTimeout(() => {
dataMigration.process_new(new_nodes);
dataMigration.process_del(del_nodes);
}, MIGRATE_WAIT_DELAY);
}, MIGRATE_WAIT_DELAY);
};
//data migration sub-process: Deleted nodes
dataMigration.process_del = async function(del_nodes) {
if (!del_nodes.length)
return;
let process_nodes = del_nodes.filter(n => _list.serving.includes(n));
if (process_nodes.length) {
connectToAllActiveNodes().then(ws_connections => {
let remaining = process_nodes.length;
process_nodes.forEach(n => {
DB.getData(n, 0).then(result => {
console.log(`START: Data migration for ${n}`);
//TODO: efficiently handle large number of data instead of loading all into memory
result.forEach(d => {
let closest = kBucket.closestNode(d.receiverID);
if (_list.serving.includes(closest)) {
DB.storeData(closest, d);
_nextNode.send(packet_.constuct({
type: STORE_BACKUP_DATA,
data: d
}));
} else
ws_connections[closest].send(packet_.constuct({
type: STORE_MIGRATED_DATA,
data: d
}));
});
console.log(`END: Data migration for ${n}`);
_list.delete(n);
DB.dropTable(n);
remaining--;
}).catch(error => reject(error));
});
const interval = setInterval(() => {
if (remaining <= 0) {
for (let c in ws_connections)
if (ws_connections[c])
ws_connections[c].close();
clearInterval(interval);
};
}, RETRY_TIMEOUT);
});
};
del_nodes.forEach(n => {
if (!process_nodes.includes(n) && _list.stored.includes(n)) {
_list.delete(n);
DB.dropTable(n);
};
});
};
//data migration sub-process: Added nodes
dataMigration.process_new = async function(new_nodes) {
if (!new_nodes.length)
return;
connectToAllActiveNodes(new_nodes).then(ws_connections => {
let process_nodes = _list.serving,
remaining = process_nodes.length;
process_nodes.forEach(n => {
DB.getData(n, 0).then(result => {
//TODO: efficiently handle large number of data instead of loading all into memory
result.forEach(d => {
let closest = kBucket.closestNode(d.receiverID);
if (new_nodes.includes(closest)) {
if (_list.serving.includes(closest)) {
DB.storeData(closest, d);
_nextNode.send(packet_.constuct({
type: STORE_BACKUP_DATA,
data: d
}));
} else
ws_connections[closest].send(packet_.constuct({
type: STORE_MIGRATED_DATA,
data: d
}));
_nextNode.send(packet_.constuct({
type: DELETE_MIGRATED_DATA,
vectorClock: d.vectorClock,
receiverID: d.receiverID,
snID: n
}));
};
});
remaining--;
}).catch(error => reject(error));
});
const interval = setInterval(() => {
if (remaining <= 0) {
for (let c in ws_connections)
if (ws_connections[c])
ws_connections[c].close();
clearInterval(interval);
};
}, RETRY_TIMEOUT);
});
};
dataMigration.intimateAllNodes = function() {
connectToAliveNodes().then(ws_connections => {
let packet = packet_.constuct({
type: INITIATE_REFRESH
});
for (let n in ws_connections)
if (ws_connections[n]) {
ws_connections[n].send(packet);
ws_connections[n].close();
};
});
};
//-----EXPORTS-----
module.exports = {
reconnectNextNode,
processTaskFromSupernode,
forwardToNextNode,
dataMigration,
SUPERNODE_INDICATOR,
_list,
set DB(db) {
DB = db;
},
set refresher(r) {
refresher = r;
}
};