Viterbi algorithm

The probability model generated so far is generative in nature, in the sense that it tries to model the true probability distribution of the incoming requests. After a large number of requests have been received we can expect to have a reasonable MLE model of the probability distribution. We will then use the viterbi algorithm to detect the most likely path to be taken by a request. This can be used to preallocate the resources in the functions chain span to reduce cascading cold starts.
Path detection has been implemented.
TODO: resource pre-allocation

dispatch_system/dispatch_daemon/config.json

-{"id":"10.196.6.51","master_node":"10.129.6.5"}
\ No newline at end of file
+{"id":"192.168.31.51","master_node":"10.129.6.5"}
\ No newline at end of file

dispatch_system/dispatch_daemon/execute.js

@@ -57,7 +57,7 @@ function runProcess(local_repository, metadata) {
         });
 
         process.on('close', (code) => {
-            resolve(code);
+            resolve(process.pid);
             logger.info(`Process Environment with resource_id ${resource_id} blown`);
         });
     })
@@ -100,7 +100,7 @@ function runContainer(metadata) {
                             let timeDifference = Math.ceil((Date.now() - timeStart))
                             logger.info("container run time taken: ", timeDifference);
                             result += data;
-                            resolve(result);
+                            resolve(resource_id);
                         });
 
                         process.stderr.on('data', (data) => {
@@ -126,7 +126,7 @@ function runContainer(metadata) {
                         logger.info(`stdout: ${data}`);
                         let timeDifference = Math.ceil((Date.now() - timeStart))
                         logger.info("container run time taken: ", timeDifference);
-                        resolve(result);
+                        resolve(resource_id);
                     });
 
                     process.stderr.on('data', (data) => {

dispatch_system/dispatch_daemon/lib.js

@@ -55,7 +55,7 @@ var download = function (url, dest, cb) {
         console.log(url);
         if (!fs.existsSync(dest)) {
             var file = fs.createWriteStream(dest);
-            var request = http.get(url, function (response) {
+            var request = https.get(url, function (response) {
                 response.pipe(file);
                 file.on('finish', function () {
                     file.close(cb);  // close() is async, call cb after close completes.

dispatch_system/dispatch_manager/index.js

@@ -264,6 +264,7 @@ function dispatch() {
                 messages: JSON.stringify({
                     resource_id,
                     "memory": 332,
+                    timestamp: Date.now()
                 }),
                 partition: 0
             }]
@@ -327,12 +328,14 @@ function postDeploy(message) {
             topic: log_channel,
             messages: JSON.stringify({
                 resource_id: message.resource_id,
+                // type: "deployment_launch",
                 node_id: resource.node_id,
                 runtime: resource.runtime,
                 function_id: resource.functionHash,
+                entity_id: message.entity_id,
                 "reason": "deployment",
                 "status": true,
-                "timestamp": date.toISOString()
+                "timestamp": Date.now()
             }),
             partition: 0
         }]
@@ -362,6 +365,7 @@ consumer.on('message', function (message) {
     
     let topic = message.topic
         message = message.value
+    // console.log(topic, message)
     if (topic === "response") {
         logger.info("response " + message);
         
@@ -443,11 +447,17 @@ consumer.on('message', function (message) {
         
         logger.info("Response from RM: " + message);
         message = JSON.parse(message)
-        let resourceChoice = message.grunts[0]
+        let resourceChoice = message.nodes[0]
         if (resourceMap.has(message.resource_id)) {
             let resource = resourceMap.get(message.resource_id)
-            resource.port = (resourceChoice.port) ? resourceChoice.port : libSupport.getPort(usedPort)
-            resource.node_id = resourceChoice.node_id
+            if (typeof resourceChoice === 'string') {
+                resource.port = libSupport.getPort(usedPort)
+                resource.node_id = resourceChoice
+            } else {
+                resource.port = (resourceChoice.port) ? resourceChoice.port : libSupport.getPort(usedPort)
+                resource.node_id = resourceChoice.node_id
+            }
+            
             let payload = [{
                 topic: resource.node_id,
                 messages: JSON.stringify({

dispatch_system/dispatch_manager/lib.js

@@ -191,9 +191,76 @@ function branchChainPredictor(req, resourceMap) {
       }
    }
    
-   console.log(functionBranchTree);   
+   console.log("branch tree", functionBranchTree);   
 }
 
+function viterbi() {
+   let path = []
+   functionBranchTree.forEach((metadata, node) => {
+      if (metadata.parent) {
+         let parents = [[node, {
+            prob: 1,
+            metadata
+         }]]
+         path.push({node, probability: 1})
+         let siblings = new Map()
+         while(parents.length > 0) {
+            // console.log("parent_group", parents);
+            
+            for (const parent of parents) {
+               // console.log("=========begin==========\n",parent, "\n=============end============");
+               // console.log(parent[1].metadata);
+               
+               if (parent[1].metadata === undefined)
+                  continue
+               let forwardBranches = parent[1].metadata.branches
+               // console.log(forwardBranches);
+               
+               let parentProbability = parent[1].prob
+               
+               forwardBranches.forEach((branchProb, subNode) => {
+                  let probability = 0
+                  if (siblings.has(subNode))
+                     probability = siblings.get(subNode)
+                  probability += branchProb * parentProbability
+                  // console.log("prob", probability);
+                  
+                  siblings.set(subNode, probability)
+               })
+               // console.log("siblings", siblings);
+               
+            }
+            parents = []
+            let maxSibling, maxProb = 0
+            siblings.forEach((prob, sibling) => {
+               if (prob > maxProb) {
+                  maxSibling = sibling
+                  maxProb = prob
+               }
+            })
+            parentIDs = Array.from( siblings.keys() );
+            for (const id of parentIDs) {
+               let metadata = functionBranchTree.get(id)
+               parents.push([
+                  id, {
+                     prob: siblings.get(id),
+                     metadata
+                  }
+               ])
+            }
+            if (maxSibling !== undefined)
+               path.push({node: maxSibling, probability: maxProb})
+            siblings = new Map()
+         }
+      }
+   });
+   if (path.length > 0)
+      console.log("path", path);
+   
+}
+
+setInterval(viterbi, 5000)
+
  module.exports = {
     makeid, generateExecutor, reverseProxy, getPort, logger, compare
  }
\ No newline at end of file

dispatch_system/dispatch_manager/repository/worker_env/env.js

@@ -2,7 +2,7 @@
 const express = require('express')
 const bodyParser = require('body-parser')
 let request = require('request')
-
+const process = require('process')
 
 const app = express()
 let port = 5000, resource_id, functionHash, runtime
@@ -51,7 +51,7 @@ app.listen(port, () => {
     producer.send(
     [{
         topic: "deployed",
-        messages: JSON.stringify({ functionHash, portExternal: port, runtime, resource_id }),
+        messages: JSON.stringify({ functionHash, portExternal: port, runtime, resource_id, entity_id: process.pid}),
         "status": true
     }], () => { })
 })
@@ -63,7 +63,7 @@ function shouldDie() {
         producer.send(
             [{
                 topic: "removeWorker",
-                messages: JSON.stringify({ functionHash, portExternal: port, runtime, resource_id })
+                messages: JSON.stringify({ functionHash, portExternal: port, runtime, resource_id, entity_id: process.pid})
             }], () => {
                 console.log("Ending worker for function", functionHash, "resource_id", resource_id);
                 process.exit(0)

dispatch_system/dispatch_manager/repository/worker_env/node_modules/.bin/mime

-#!/usr/bin/env node
-
-var mime = require('./mime.js');
-var file = process.argv[2];
-var type = mime.lookup(file);
-
-process.stdout.write(type + '\n');
-

dispatch_system/dispatch_manager/repository/worker_env/node_modules/.bin/mime

+../mime/cli.js
\ No newline at end of file