Process for exception cases

Case: No other node active when self node is init
- Start the exchange system.
Case: When node becomes master when prev node goes down
- Add self share to collectShare
- collect shares from other node to re-construct sink private key
- Fixed some minor bugs

src/backup/head.js

@@ -140,11 +140,13 @@ function send_dataImmutable(timestamp, ws) {
 //Shares
 function generateNewSink() {
     let sink = floCrypto.generateNewID();
-    let nextNodes = KB.nextNode(global.myFloID, null);
-    let shares = floCrypto.createShamirsSecretShares(sink.privKey, nextNodes.length, Math.ceil(nextNodes.length * shareThreshold));
     sink.shares = {};
-    for (let i in nextNodes)
-        sink.shares[nextNodes[i]] = shares[i];
+    let nextNodes = nodeKBucket.nextNode(global.myFloID, null);
+    if (nextNodes.length) {
+        let shares = floCrypto.createShamirsSecretShares(sink.privKey, nextNodes.length, Math.ceil(nextNodes.length * shareThreshold));
+        for (let i in nextNodes)
+            sink.shares[nextNodes[i]] = shares[i];
+    }
     return sink;
 }
 
@@ -212,20 +214,20 @@ function collectShares(floID, sinkID, share) {
 function connectWS(floID) {
     let url = nodeURL[floID];
     return new Promise((resolve, reject) => {
-        const ws = new WebSocket(url);
+        const ws = new WebSocket('ws://' + url);
         ws.on('open', _ => resolve(ws));
-        ws.on('error', _ => reject(error));
+        ws.on('error', error => reject(error));
     })
 }
 
-function connectToMaster(i = 0) {
+function connectToMaster(i = 0, init = false) {
     if (i >= nodeList.length) {
         console.error("No master is found, and myFloID is not in list. This should not happen!");
         process.exit(1);
     }
     let floID = nodeList[i];
     if (floID === myFloID)
-        serveAsMaster();
+        serveAsMaster(init);
     else
         connectWS(floID).then(ws => {
             ws.floID = floID;
@@ -233,26 +235,27 @@ function connectToMaster(i = 0) {
             serveAsSlave(ws);
         }).catch(error => {
             console.log(`Node(${floID}) is offline`);
-            connectToMaster(i + 1)
+            connectToMaster(i + 1, init)
         });
 }
 
 //Node becomes master
-function serveAsMaster() {
-    app.resume();
+function serveAsMaster(init) {
+    console.debug('Starting master process');
     slave.stop();
     mod = MASTER_MODE;
-    informLiveNodes();
-    collectShares.active = true;
+    informLiveNodes(init);
+    app.resume();
 }
 
 function serveAsSlave(ws) {
+    console.debug('Starting slave process');
     app.pause();
     slave.start(ws);
     mod = SLAVE_MODE;
 }
 
-function informLiveNodes() {
+function informLiveNodes(init) {
     let message = {
         floID: global.myFloID,
         type: "UPDATE_MASTER",
@@ -261,12 +264,34 @@ function informLiveNodes() {
     };
     message.sign = floCrypto.signData(message.type + "|" + message.req_time, global.myPrivKey);
     message = JSON.stringify(message);
-    for (let n in nodeURL)
-        if (n !== global.myFloID)
-            connectWS(n).then(ws => {
+    let nodes = nodeList.filter(n => n !== global.myFloID);
+    Promise.allSettled(nodes.map(n => connectWS(n))).then(result => {
+        let flag = false;
+        for (let i in result)
+            if (result[i].status === "fulfilled") {
+                let ws = result[i].value;
                 ws.send(message);
                 ws.close();
-            }).catch(error => console.warn(`Node ${n} is offline`));
+                flag = true;
+            } else
+                console.warn(`Node(${nodes[i]}) is offline`);
+        if (init) {
+            if (flag === true)
+                collectShares.active = true;
+            else {
+                //No other node is active (possible 1st node to start exchange)
+                console.debug("Starting the exchange...")
+                let newSink = generateNewSink();
+                storeSink(newSink.floID, newSink.privKey);
+                sendSharesToNodes(newSink.floID, newSink.shares);
+            }
+        } else {
+            collectShares.active = true;
+            DB.query("SELECT floID, share FROM sinkShares ORDER BY time_ DESC LIMIT 1")
+                .then(result => collectShares(global.myFloID, result[0].floID, result[0].share))
+                .catch(error => console.error(error))
+        }
+    });
 }
 
 function updateMaster(floID) {
@@ -343,7 +368,7 @@ function startBackupTransmitter(server) {
 function initProcess(a) {
     app = a;
     startBackupTransmitter(app.server);
-    connectToMaster();
+    connectToMaster(0, true);
 }
 
 module.exports = {
@@ -352,6 +377,7 @@ module.exports = {
         nodeURL = list;
         nodeKBucket = new K_Bucket(floGlobals.adminID, Object.keys(nodeURL));
         nodeList = nodeKBucket.order;
+        console.debug(nodeList);
     },
     set DB(db) {
         DB = db;