Merge on pull

.gitignore

@@ -6,3 +6,4 @@ firecracker*
 secrets.json
 resource_system/bin/**
 resource_system/version.linux
+local_experiments/

dispatch_system/constants.json

 {
-    "registry_url" :"10.129.6.5:5000/",
+    "registry_url" :"localhost:5000/",
     "master_port": 8080,
     "master_address": "localhost",
-    "kafka_host": "10.129.6.5:9092",
     "grunt_host": "https://www.namandixit.net/lovecraftian_nightmares/grunt",
-    "log_channel": "LOG_COMMON",
-    "couchdb_host": "10.129.6.5:5984",
-    "couchdb_db_name": "serverless",
+    "couchdb_host": "localhost:5984",
+    "function_db_name": "serverless",
+    "metrics_db_name": "metrics",
+    "implicit_chain_db_name": "implicit_chain",
+    "network": {
+        "network_bridge": "hybrid_kafka-serverless",
+        "internal": {
+            "kafka_host": "kafka:9092"
+        },
+        "external": {
+            "kafka_host": "localhost:29092"
+        }
+    },
     "topics": {
         "request_dm_2_rm": "request",
         "heartbeat": "heartbeat",
         "deployed": "deployed",
         "remove_worker": "removeWorker",
         "response_rm_2_dm": "RESPONSE_RM_2_DM_DUMMY",
-        "hscale": "hscale"
+        "hscale": "hscale",
+        "log_channel": "LOG_COMMON"
     },
     "autoscalar_metrics": {
         "open_request_threshold": 100
     },
-    "speculative_deployment": true
-}
\ No newline at end of file
+    "speculative_deployment": false,
+    "JIT_deployment": false,
+    "id_size": 20
+}

dispatch_system/dispatch_daemon/config.json

-{"id":"192.168.31.51","master_node":"10.129.6.5"}
\ No newline at end of file
+{"id":"192.168.0.105","master_node":"192.168.0.105"}
\ No newline at end of file

dispatch_system/dispatch_daemon/execute.js

@@ -17,7 +17,7 @@ function runIsolate(local_repository, metadata) {
     return new Promise((resolve, reject) => {
 
         const worker = new Worker(filename, {
-            argv: [resource_id, functionHash, port, "isolate"],
+            argv: [resource_id, functionHash, port, "isolate", constants.network.external.kafka_host],
             resourceLimits: {
                 maxOldGenerationSizeMb: memory
             }
@@ -43,7 +43,8 @@ function runProcess(local_repository, metadata) {
     return new Promise((resolve, reject) => {
         let timeStart = Date.now()
         
-        const process = spawn('node', [filename, resource_id, functionHash, port, "process", `--max-old-space-size=${memory}` ]);
+        const process = spawn('node', [filename, resource_id, functionHash, port, "process", 
+                constants.network.external.kafka_host, `--max-old-space-size=${memory}` ]);
         process.stdout.on('data', (data) => {
             console.log(`stdout: ${data}`);
             let timeDifference = Math.ceil((Date.now() - timeStart))
@@ -91,8 +92,9 @@ function runContainer(metadata) {
                     if (code != 0)
                         reject("error")
                     else {
-                        const process = spawn('docker', ["run", "--rm", "-p", `${port}:${port}`, "--name", resource_id, registry_url + imageName,
-                            resource_id, imageName, port, "container"]);
+                        const process = spawn('docker', ["run", "--rm", `--network=${constants.network.network_bridge}`, "-p", `${port}:${port}`, 
+                            "--name", resource_id, registry_url + imageName,
+                            resource_id, imageName, port, "container", constants.network.internal.kafka_host]);
                         let result = "";
                         // timeStart = Date.now()
                         process.stdout.on('data', (data) => {
@@ -118,8 +120,9 @@ function runContainer(metadata) {
             } else {
                     logger.info("container starting at port", port);
                     
-                    const process = spawn('docker', ["run", "--rm", "-p", `${port}:${port}`, "--name", resource_id, 
-                            registry_url + imageName, resource_id, imageName, port, "container"]);
+                    const process = spawn('docker', ["run", "--rm", `--network=${constants.network.network_bridge}`, 
+                            "-p", `${port}:${port}`, "--name", resource_id, 
+                        registry_url + imageName, resource_id, imageName, port, "container", constants.network.internal.kafka_host]);
                     let result = "";
                     // timeStart = Date.now()
                     process.stdout.on('data', (data) => {

dispatch_system/dispatch_daemon/index.js

@@ -11,7 +11,7 @@ const fs = require('fs')
 const fetch = require('node-fetch');
 
 let metadataDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
-metadataDB = metadataDB + "/" + constants.couchdb_db_name + "/"
+metadataDB = metadataDB + "/" + constants.function_db_name + "/"
 
 const kafka = require('kafka-node')
 const logger = libSupport.logger
@@ -21,7 +21,7 @@ const host_url = "http://" + constants.master_address + ":" + constants.master_p
 
 let Producer = kafka.Producer,
     client = new kafka.KafkaClient({ 
-        kafkaHost: constants.kafka_host,
+        kafkaHost: constants.network.external.kafka_host,
         autoConnect: true
     }),
     producer = new Producer(client),
@@ -77,9 +77,9 @@ libSupport.makeTopic(node_id).then(() => {
 /**
  * download and start grunt
  */
-libSupport.download(constants.grunt_host, "grunt").then(() => {
+libSupport.download(constants.grunt_host, "grunt", false).then(() => {
     logger.info("Downloaded grunt binary from repository")
-    fs.chmod('grunt', 0o555, (err) => {
+    fs.chmod('grunt', 0o755, (err) => {
         logger.info("grunt made executable. Starting grunt")
         let grunt = spawn('./grunt', [node_id])
         grunt.stdout.on('data', data => {

dispatch_system/dispatch_daemon/lib.js

-const http = require('http');
+const fetch = require('node-fetch');
 const fs = require('fs');
 const process = require('process')
 const { spawnSync } = require('child_process');
@@ -30,7 +30,7 @@ function makeTopic(id) {
     console.log("Using Primary IP", id, "as topic");
     
     let client = new kafka.KafkaClient({
-        kafkaHost: constants.kafka_host,
+        kafkaHost: constants.network.external.kafka_host,
         autoConnect: true
     }),
     Producer = kafka.Producer,
@@ -50,28 +50,48 @@ function makeTopic(id) {
     })
 }
 
-var download = function (url, dest, cb) {
-    return new Promise((resolve, reject) => {
+// var download = function (url, dest, check = true, cb) {
+//     return new Promise((resolve, reject) => {
+//         console.log(url);
+//         if (!check || !fs.existsSync(dest)) {
+//             var file = fs.createWriteStream(dest);
+//             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.
+//                     resolve();
+//                 });
+//             }).on('error', function (err) { // Handle errors
+//                 fs.unlink(dest); // Delete the file async. (But we don't check the result)
+//                 logger.error("download failed" + err.message);
+                
+//                 if (cb) cb(err.message);
+//                 reject(err);
+//             });
+//         } else {
+//             resolve();
+//         }
+//     })
+    
+// };
+
+const download = (async (url, path, check = true) => {
+    
+    if (!check || !fs.existsSync(path)) {
         console.log(url);
-        if (!fs.existsSync(dest)) {
-            var file = fs.createWriteStream(dest);
-            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.
-                    resolve();
-                });
-            }).on('error', function (err) { // Handle errors
-                fs.unlink(dest); // Delete the file async. (But we don't check the result)
-                if (cb) cb(err.message);
+        const res = await fetch(url);
+        const fileStream = fs.createWriteStream(path);
+        await new Promise((resolve, reject) => {
+            res.body.pipe(fileStream);
+            res.body.on("error", (err) => {
                 reject(err);
             });
-        } else {
-            resolve();
-        }
-    })
-    
-};
+            fileStream.on("finish", function () {
+                resolve();
+            });
+        });
+    }
+});
 
 function makeid(length) {
     var result = '';

dispatch_system/dispatch_daemon/package.json

@@ -16,6 +16,7 @@
     "kafka-node": "^5.0.0",
     "morgan": "^1.9.1",
     "mqtt": "^3.0.0",
+    "node-fetch": "^2.6.0",
     "redis": "^2.8.0",
     "request": "^2.88.2",
     "winston": "^3.2.1"

dispatch_system/dispatch_manager/explicit_chain_handler.js

+'use strict';
+const express = require('express')
+const libSupport = require('./lib')
+const router = express.Router()
+const fs = require('fs')
+const { spawn } = require('child_process')
+const fetch = require('node-fetch')
+const constants = require('../constants.json')
+const secrets = require('./secrets.json')
+const operator = require('./operator')
+let metadataDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
+metadataDB = metadataDB + "/" + constants.function_db_name + "/"
+
+let metricsDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
+metricsDB = metricsDB + "/" + constants.metrics_db_name + "/"
+
+const logger = libSupport.logger
+
+const registry_url = constants.registry_url
+
+router.post('/deploy', (req, res) => {
+    
+    // let runtime = req.body.runtime
+    let files = req.files
+
+    const chain_id = libSupport.makeid(constants.id_size)
+    const file_path = __dirname + "/repository/"
+    let aliases = {}
+    let deployHandles = []
+    createDirectory(file_path).then(() => {
+        
+        for (const [file_alias, file] of Object.entries(files)) {
+            let functionHash = file.md5
+            if (file_alias === 'map') {
+                    file.mv(file_path + 'map' + chain_id + ".json")
+                    continue     
+            }
+            // aliases[file_alias] = functionHash
+            deployHandles.push(deploy(file_path, functionHash, file, aliases, file_alias))
+        }
+
+        console.log("aliases", aliases);
+        Promise.all(deployHandles).then(() => {
+            console.log("done");
+            fs.writeFile(file_path + `aliases${chain_id}.json`, JSON.stringify(aliases, null, 2), function(err) {
+                res.json({
+                    status: "success",
+                    function_id: chain_id
+                })
+            })
+            
+        }).catch(err => {
+            res.json({
+                status: "error",
+                reason: err
+            }).status(400)
+        })
+    })
+   
+})
+
+async function deploy(file_path, functionHash, file, aliases, file_alias) {
+    let runtime = "container", memory = 330
+    try {
+        await moveFile(file, file_path, functionHash)
+        functionHash = libSupport.generateExecutor(file_path, functionHash)
+        aliases[file_alias] = functionHash
+        /**
+         * Adding meta caching via couchdb
+         * This will create / update function related metadata like resource limits etc
+         * on a database named "serverless".
+         */
+        let res = await fetch(metadataDB + functionHash)
+        let json = await res.json()
+        console.log(json);
+        
+        if (json.error === "not_found") {
+            logger.warn("New function, creating metadata")
+            await fetch(metadataDB + functionHash, {
+                method: 'put',
+                body: JSON.stringify({
+                    memory: memory
+                }),
+                headers: { 'Content-Type': 'application/json' },
+            })
+            // let json = await res.json()
+            // console.log(json)
+        } else {
+            logger.warn('Repeat deployment, updating metadata')
+            try {
+                await fetch(metadataDB + functionHash, {
+                    method: 'put',
+                    body: JSON.stringify({
+                        memory: memory,
+                        _rev: json._rev
+                    }),
+                    headers: { 'Content-Type': 'application/json' },
+                })
+                // let json = await res.json()
+                // console.log(json)
+            } catch (err) {
+                console.log(err);
+                
+            }
+        }
+
+        if (runtime === "container") {
+            try {
+                await deployContainer(file_path, functionHash)
+                console.log("called");
+                return Promise.resolve(functionHash)
+            } catch(err) {
+                return Promise.reject(err)
+            }
+        } else {
+            return Promise.resolve(functionHash)
+        }
+    } catch (err) {
+        logger.error(err)
+        return Promise.reject(err)
+    }
+}
+
+function moveFile(file, file_path, functionHash) {
+    return new Promise((resolve, reject) =>{ 
+        file.mv(file_path + functionHash, function (err) {
+            if (err)
+                reject(err)
+            resolve()
+        })
+    })
+}
+
+async function deployContainer(path, imageName) {
+    return new Promise((resolve, reject) => {
+        let buildStart = Date.now()
+
+        fs.writeFile('./repository/Dockerfile' + imageName,
+            `FROM node:latest
+            WORKDIR /app
+            COPY ./worker_env/package.json /app
+            ADD ./worker_env/node_modules /app/node_modules
+            COPY ${imageName}.js /app
+            ENTRYPOINT ["node", "${imageName}.js"]`
+            , function (err) {
+                if (err) {
+                    logger.error("failed", err);
+
+
+                    reject(err);
+                }
+                else {
+                    logger.info('Dockerfile created');
+                    const process = spawn('docker', ["build", "-t", registry_url + imageName, path, "-f", path + `Dockerfile${imageName}`]);
+
+                    process.stdout.on('data', (data) => {
+                        logger.info(`stdout: ${data}`);
+
+                    });
+
+                    process.stderr.on('data', (data) => {
+                        logger.error(`stderr: ${data}`);
+                    });
+
+                    process.on('close', (code) => {
+                        logger.warn(`child process exited with code ${code}`);
+                        let timeDifference = Math.ceil((Date.now() - buildStart))
+                        logger.info("image build time taken: ", timeDifference);
+                        const process_push = spawn('docker', ["push", registry_url + imageName]);
+
+                        process_push.stdout.on('data', (data) => {
+                            console.log(`stdout: ${data}`);
+
+                        });
+
+                        process_push.stderr.on('data', (data) => {
+                            logger.error(`stderr: ${data}`);
+                        });
+
+                        process_push.on('close', (code) => {
+                            logger.info("image pushed to repository");
+                            resolve();
+                        })
+
+                    });
+                }
+            });
+    })
+}
+
+router.post('/execute/:id', (req, res) => {
+    let map, aliases
+    // if (req.body.map)
+    //     map = req.body.map
+    // else {
+    if (req.files && req.files.map) {
+        map = JSON.parse(req.files.map.data.toString());
+        let mapPlanner = JSON.parse(req.files.map.data.toString());
+        readMap(`./repository/aliases${req.params.id}.json`, true)
+            .then(data => {
+                aliases = data
+                let payload = JSON.parse(req.body.data)
+                console.log(payload);
+                speculative_deployment(aliases, mapPlanner);
+                orchestrator(res, payload, map, aliases, {})
+            })
+    } else {
+        readMap(`./repository/map${req.params.id}.json`)
+            .then(data => {
+                map = data
+                let mapPlanner = JSON.parse(JSON.stringify(map))
+                
+                readMap(`./repository/aliases${req.params.id}.json`, true)
+                    .then(data => {
+                        aliases = data
+                        let payload = JSON.parse(req.body.data)
+                        speculative_deployment(aliases, mapPlanner);
+                        orchestrator(res, payload, map, aliases, {})
+                    })
+            })
+    }
+    
+})
+
+async function orchestrator(res, payload, map, aliases, result) {
+
+    if (Object.keys(map).length == 0) {
+        console.log("time to resolve", result);
+        res.json(result)
+        // return resolve(result)
+    }
+        
+    else {
+        for (const [functionName, metadata] of Object.entries(map)) {
+            // console.log(functionName, metadata, aliases[functionName]);
+            // console.log(metadata);
+            
+            if (metadata.type === "function" && metadata.wait_for.length == 0) {
+                let url = `http://${constants.master_address}:${constants.master_port}/serverless/execute/${aliases[functionName].alias}`
+                console.log(url);
+                let data = {
+                    method: 'post',
+                    body: JSON.stringify({
+                        runtime: metadata.runtime,
+                        payload
+                    }),
+                    headers: { 'Content-Type': 'application/json' }
+                }
+                delete map[functionName]
+                aliases[functionName].status = "running"
+                
+                fetch(url, data).then(res => res.json())
+                    .then(json => {
+                        // console.log(json);
+                        result[functionName] = json
+                        
+                        aliases[functionName].status = "done"
+                        let branchMap = null
+                        for (const [_key, metadata] of Object.entries(map)) {
+
+                            if (metadata.type === "function" || metadata.type === "conditional") {
+                                let index = metadata.wait_for.indexOf(functionName)
+                                if (index >= 0)
+                                    metadata.wait_for.splice(index, 1);
+                            }
+                            
+                            if (metadata.type === "conditional" && metadata.wait_for.length == 0) {
+                                
+                                let conditionResult = checkCondition(metadata.condition.op1, metadata.condition.op2, metadata.condition.op, result)
+                                console.log(conditionResult, "aliases", aliases);
+                                let branchToTake = metadata[conditionResult]
+                                branchMap = map[branchToTake]
+                                delete map[_key]
+                                makeBranchRunnable(branchMap, aliases)
+                                
+                            }
+                        }
+                        orchestrator(res, payload, (branchMap == null)? map: branchMap, aliases, result)
+                    })
+            }
+        }
+    }
+}
+
+function makeBranchRunnable(branchMap, aliases) {
+    delete branchMap['type']
+    for (const [_key, metadata] of Object.entries(branchMap)) {
+        if (metadata.type === "function" || metadata.type === "conditional") {
+            let wait_for = []
+            for (const dependent of metadata.wait_for) {
+                if (aliases[dependent].status !== "done")
+                    wait_for.push(dependent)
+                metadata.wait_for = wait_for
+            }
+        }
+    }
+}
+
+function checkCondition(op1, op2, op, result) {
+    op1 = op1.split(".")
+    let data = result[op1[0]][op1[1]]
+    return (operator[op](data, op2))? "success": "fail"
+}
+
+async function speculative_deployment(aliases, map) {
+    if (constants.speculative_deployment) {
+        console.log(aliases);
+        let getData = []
+        for (const [mod, metadata] of Object.entries(map)) {
+            if (constants.JIT_deployment) {
+                console.log(mod, metadata, aliases[mod].alias);
+
+                let url = metricsDB + aliases[mod].alias
+                console.log(url);
+
+                let data = libSupport.fetchData(url)
+                console.log(data);
+
+                getData.push(data)
+            } else {
+                let payload = [{
+                    topic: constants.topics.hscale,
+                    messages: JSON.stringify({ "runtime": metadata.runtime, "functionHash": aliases[mod].alias })
+                }]
+                notify(payload)
+            }
+        }
+        if (constants.JIT_deployment) {
+            Promise.all(getData).then((values) => {
+                let dataMap = new Map()
+                for (const data of values) {
+                    dataMap[data._id] = data
+                }
+
+                let done = new Map()
+                let toBeDone = new Set()
+                // var plannerMap = new Map(map)
+                do {
+                    for (const [mod, metadata] of Object.entries(map)) {
+                        if (metadata.wait_for.length == 0 && done[mod] === undefined) {
+                            done[mod] = dataMap[aliases[mod].alias][metadata.runtime].coldstart // expecting the first ones to run
+                            // to be hit by coldstarts
+                            // delete plannerMap[mod];
+                        } else if (done[mod] === undefined) {
+                            let flag = true
+                            let maxWait = 0
+                            for (const dependency of metadata.wait_for) {
+                                console.log(dependency);
+
+                                if (done[dependency] === undefined) {
+                                    flag = false
+                                    break
+                                } else if (maxWait < done[dependency])
+                                    maxWait = done[dependency]
+                            }
+                            if (flag) {
+                                console.log("notifying", mod);
+                                let notifyTime = ((maxWait - dataMap[aliases[mod].alias][metadata.runtime].starttime) > 0) ?
+                                    maxWait - dataMap[aliases[mod].alias][metadata.runtime].starttime : 0
+                                console.log(mod, "max wait", maxWait, "notify time:", notifyTime);
+                                let payload = [{
+                                    topic: constants.topics.hscale,
+                                    messages: JSON.stringify({ "runtime": metadata.runtime, "functionHash": aliases[mod].alias })
+                                }]
+                                setTimeout(notify, notifyTime, payload)
+                                done[mod] = maxWait + dataMap[aliases[mod].alias][metadata.runtime].warmstart
+                                if (toBeDone.has(mod))
+                                    delete toBeDone[mod]
+                                // delete plannerMap[mod]
+                            } else {
+                                toBeDone.add(mod)
+                            }
+                        }
+                        console.log(done, toBeDone);
+                    }
+                } while (toBeDone.size != 0)
+            })
+        }
+    }
+}
+
+function readMap(filename, alias = false) {
+    return new Promise((resolve, reject) => {
+        fs.readFile(filename, (err, blob) => {
+            if (err)
+                reject(err)
+            else {
+                const data = JSON.parse(blob)
+                if (alias) {
+                    for (const [key, functionHash] of Object.entries(data)) {
+                        data[key] = {
+                            alias: functionHash,
+                            status: "waiting"
+                        }
+
+                        // libSupport.fetchData(metricsDB + functionHash, null)
+                        // .then(metrics => {
+                        //     data[key]
+                        // })
+                    }
+                }
+                resolve(data)
+            }
+        })
+    })
+}
+
+function notify(payload) {
+    libSupport.producer.send(payload, function () { })
+}
+
+function createDirectory(path) {
+    return new Promise((resolve, reject) => {
+        if (!fs.existsSync(path)) {
+            fs.mkdir(path, err => {
+                if (err)
+                    reject();
+                resolve();
+            })
+        } else {
+            resolve();
+        }
+    })
+}
+
+module.exports = router;

dispatch_system/dispatch_manager/index.js

 "use strict";
 
-const express = require('express')
-const bodyParser = require('body-parser')
+const express = require('express');
 const fileUpload = require('express-fileupload');
-const constants = require('.././constants.json')
-const secrets = require('./secrets.json')
-const fs = require('fs')
+const constants = require('.././constants.json');
+const chainHandler = require('./explicit_chain_handler');
+const secrets = require('./secrets.json');
+const fs = require('fs');
 const { spawn } = require('child_process');
-const morgan = require('morgan')
-const heap = require('heap')
+const morgan = require('morgan');
+const heap = require('heap');
 const fetch = require('node-fetch');
 const swStats = require('swagger-stats');
 const apiSpec = require('./swagger.json');
+const util = require('util')
 
+/**
+ * URL to the couchdb database server used to store function metadata
+ */
 let metadataDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
-metadataDB = metadataDB + "/" + constants.couchdb_db_name + "/"
+metadataDB = metadataDB + "/" + constants.function_db_name + "/"
+
+let metricsDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
+metricsDB = metricsDB + "/" + constants.metrics_db_name + "/"
 
 const app = express()
 const libSupport = require('./lib')
 const logger = libSupport.logger
 let date = new Date();
-let log_channel = constants.log_channel
+let log_channel = constants.topics.log_channel
 
 let usedPort = new Map(), // TODO: remove after integration with RM
     db = new Map(), // queue holding request to be dispatched
@@ -29,11 +36,12 @@ let usedPort = new Map(), // TODO: remove after integration with RM
                                    // resources associated with the function
     workerNodes = new Map(), // list of worker nodes currently known to the DM
     functionBranchTree = new Map() // a tree to store function branch predictions
+    
 
 let kafka = require('kafka-node'),
     Producer = kafka.Producer,
     client = new kafka.KafkaClient({ 
-        kafkaHost: constants.kafka_host,
+        kafkaHost: constants.network.external.kafka_host,
         autoConnect: true
     }),
     producer = new Producer(client),
@@ -53,20 +61,25 @@ let kafka = require('kafka-node'),
 app.use(morgan('combined', {
     skip: function (req, res) { return res.statusCode < 400 }
 }))
-app.use(bodyParser.urlencoded({ extended: true }))
-app.use(bodyParser.json())
+app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
 const file_path = __dirname + "/repository/"
 
-app.use('/repository', express.static(file_path));
+app.use('/repository', express.static(file_path)); // file server hosting deployed functions
 app.use(fileUpload())
-app.use(swStats.getMiddleware({ swaggerSpec: apiSpec }));
-
+app.use(swStats.getMiddleware({ swaggerSpec: apiSpec })); // statistics middleware
+app.use('/serverless/chain', chainHandler); // chain router (explicit_chain_handler.js) for handling explicit chains
 let requestQueue = []
 
 const WINDOW_SIZE = 10
 const port = constants.master_port
 const registry_url = constants.registry_url
 
+app.get('/metrics', (req, res) => {
+    res.set('Content-Type', libSupport.metrics.register.contentType);
+    res.end(libSupport.metrics.register.metrics());
+});
+
 /**
  * REST API to receive deployment requests
  */
@@ -77,7 +90,7 @@ app.post('/serverless/deploy', (req, res) => {
 
     let functionHash = file.md5
 
-    file.mv(file_path + functionHash, function (err) {
+    file.mv(file_path + functionHash, function (err) { // move function file to repository
         functionHash = libSupport.generateExecutor(file_path, functionHash)
         /**
          * Adding meta caching via couchdb
@@ -146,7 +159,9 @@ app.post('/serverless/deploy', (req, res) => {
 function deployContainer(path, imageName) {
     return new Promise((resolve, reject) => {
         let buildStart = Date.now()
-        
+        /**
+         * Generating dockerfile for the received function
+         */
         fs.writeFile('./repository/Dockerfile',
             `FROM node:latest
             WORKDIR /app
@@ -163,7 +178,7 @@ function deployContainer(path, imageName) {
                 }
                 else {
                     logger.info('Dockerfile created');
-                    const process = spawn('docker', ["build", "-t", registry_url + imageName, path]);
+                    const process = spawn('docker', ["build", "-t", registry_url + imageName, path]); // docker build
 
                     process.stdout.on('data', (data) => {
                         logger.info(`stdout: ${data}`);
@@ -178,7 +193,7 @@ function deployContainer(path, imageName) {
                         logger.warn(`child process exited with code ${code}`);
                         let timeDifference = Math.ceil((Date.now() - buildStart))
                         logger.info("image build time taken: ", timeDifference);
-                        const process_push = spawn('docker', ["push", registry_url + imageName]);
+                        const process_push = spawn('docker', ["push", registry_url + imageName]); // docker push image to local registry
 
                         process_push.stdout.on('data', (data) => {
                             console.log(`stdout: ${data}`);
@@ -207,10 +222,12 @@ app.post('/serverless/execute/:id', (req, res) => {
 
     let runtime = req.body.runtime
     let id = req.params.id + runtime
-
+    res.timestamp = Date.now() 
     if (functionToResource.has(id)) {
+        res.start = 'warmstart'
         libSupport.reverseProxy(req, res, functionToResource, resourceMap, functionBranchTree)
     } else {
+        res.start = 'coldstart'
         /**
          * Requests are queued up before being dispatched. To prevent requests coming in for the 
          * same function from starting too many workers, they are grouped together
@@ -234,6 +251,10 @@ app.post('/serverless/execute/:id', (req, res) => {
  * Send dispatch signal to Worker nodes and deploy resources after consultation with the RM
  */
 function dispatch() {
+    /**
+     * The lookahead window will be used for optimisation purposes
+     * Ex. It might be used to co-group similar runtimes on same machines
+     */
     let lookbackWindow = Math.min(WINDOW_SIZE, requestQueue.length)
     for (let i = 0; i < lookbackWindow; i++) {
         let {req, res} = requestQueue.shift()
@@ -244,67 +265,14 @@ function dispatch() {
         if (!db.has(functionHash + runtime)) {
             db.set(functionHash + runtime, [])
             db.get(functionHash + runtime).push({ req, res })
-            let resource_id = libSupport.makeid(20) // each function resource request is associated with an unique ID
-            logger.info(`Generated new resource ID: ${resource_id} for runtime: ${runtime}`);
-
-            logger.info("Requesting RM " + JSON.stringify({
-                resource_id,
-                "memory": 332,
-            }))
-
-            /** uncomment when RM is unavailable */
             
-            resourceMap.set(resource_id, {
-                runtime, functionHash, port: null, node_id: null,
-                deployed: false
-            })
-
-
-            let payloadToRM = [{
-                topic: constants.topics.request_dm_2_rm, // changing from REQUEST_DM_2_RM
-                messages: JSON.stringify({
-                    resource_id,
-                    "memory": 332,
-                    timestamp: Date.now()
-                }),
-                partition: 0
+            let payload = [{
+                topic: constants.topics.hscale,
+                messages: JSON.stringify({ runtime, functionHash })
             }]
-            producer.send(payloadToRM, () => {
-                // db.set(functionHash + runtime, { req, res })
-                console.log("sent rm");
-            })
-
-            /**
-             * Speculative deployment:
-             * If function MLE path is present then deploy those parts of the path which are 
-             * not already running
-             */
-            if (constants.speculative_deployment && req.headers['x-resource-id'] === undefined) {
-                console.log(functionBranchTree, req.params.id);
-
-                if (functionBranchTree.has(req.params.id)) {
-                    let branchInfo = functionBranchTree.get(req.params.id)
-                    console.log("mle_path", branchInfo.mle_path);
-
-                    if (branchInfo.mle_path && branchInfo.mle_path.length > 1) {
-                        for (let node of branchInfo.mle_path) {
-                            // console.log(functionToResource);
-
-                            if (!functionToResource.has(node.node + runtime) && !db.has(node.node + runtime)) {
-                                console.log("Deploying according to MLE path: ", node.node);
-
-                                let payload = [{
-                                    topic: constants.topics.hscale,
-                                    messages: JSON.stringify({ "runtime": "container", "functionHash": node.node })
-                                }]
-                                producer.send(payload, function () { })
-                                db.set(node.node + runtime, [])
-                            }
-                        }
-                    }
-                }
-            }
+            producer.send(payload, function () { })
 
+            speculative_deployment(req, runtime)
         } else {
             logger.info("deployment process already started waiting")
             db.get(functionHash + runtime).push({ req, res })
@@ -314,29 +282,32 @@ function dispatch() {
     }
 }
 
-
+/**
+ * Handles post deployment metadata updates and starts reverse-proxying
+ * @param {string} message Message received from DD after deployment
+ */
 function postDeploy(message) {
     logger.info("Deployed Resource: " + JSON.stringify(message));
-
+    let id = message.functionHash + message.runtime
     if (message.status == false) {
-        let sendQueue = db.get(message.functionHash + message.runtime)
+        let sendQueue = db.get(id)
         // TODO: handle failure
         while (sendQueue && sendQueue.length != 0) {
             let { req, res } = sendQueue.shift()
             res.status(400).json({ reason: message.reason })
         }
-        db.delete(message.functionHash + message.runtime)
+        db.delete(id)
         
         return;
     }
-    if (functionToResource.has(message.functionHash + message.runtime)) {
-        let resourceHeap = functionToResource.get(message.functionHash + message.runtime)
+    if (functionToResource.has(id)) {
+        let resourceHeap = functionToResource.get(id)
         heap.push(resourceHeap, {
             resource_id: message.resource_id,
             open_request_count: 0
         }, libSupport.compare)
         logger.warn("Horizontally scaling up: " +
-            JSON.stringify(functionToResource.get(message.functionHash + message.runtime)));
+            JSON.stringify(functionToResource.get(id)));
 
     } else {
         /**
@@ -349,36 +320,24 @@ function postDeploy(message) {
             resource_id: message.resource_id,
             open_request_count: 0
         }, libSupport.compare)
-        functionToResource.set(message.functionHash + message.runtime, resourceHeap)
+        functionToResource.set(id, resourceHeap)
         logger.warn("Creating new resource pool"
-            + JSON.stringify(functionToResource.get(message.functionHash + message.runtime)));
+            + JSON.stringify(functionToResource.get(id)));
 
     }
     
     try {
         let resource = resourceMap.get(message.resource_id)
         resource.deployed = true
-        let confirmRM = [{
-            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.now()
-            }),
-            partition: 0
-        }]
-        producer.send(confirmRM, () => {
-            logger.info(`Confirmed RM for successful deployment resource_id: ${message.resource_id} deployment`)
-        })
-    
-        if (db.has(message.functionHash + message.runtime)) {
-            let sendQueue = db.get(message.functionHash + message.runtime)
+        libSupport.logBroadcast({
+            entity_id: message.entity_id,
+            "reason": "deployment",
+            "status": true,
+            starttime: (Date.now() - resource.deploy_request_time)
+        }, message.resource_id, resourceMap)
+        
+        if (db.has(id)) {
+            let sendQueue = db.get(id)
             logger.info("forwarding request via reverse proxy to: " + JSON.stringify(resource));
             while (sendQueue && sendQueue.length != 0) {
                 let { req, res } = sendQueue.shift()
@@ -387,8 +346,13 @@ function postDeploy(message) {
 
                     })
             }
-            db.delete(message.functionHash + message.runtime)
+            db.delete(id)
         }
+        
+        libSupport.metrics.collectMetrics({type: "scale", value: 
+            functionToResource.get(id).length, 
+            functionHash: message.functionHash, runtime: message.runtime, 
+            starttime: (Date.now() - resource.deploy_request_time)})
     } catch (e) {
         logger.error(e.message)
     }
@@ -428,8 +392,9 @@ consumer.on('message', function (message) {
             // process.exit(0)
         }
         usedPort.delete(message.port)
-        if (functionToResource.has(message.functionHash + message.runtime)) {
-            let resourceArray = functionToResource.get(message.functionHash + message.runtime)
+        let id = message.functionHash + message.runtime
+        if (functionToResource.has(id)) {
+            let resourceArray = functionToResource.get(id)
             for (let i = 0; i < resourceArray.length; i++)
                 if (resourceArray[i].resource_id === message.resource_id) {
                     resourceArray.splice(i, 1);
@@ -437,31 +402,44 @@ consumer.on('message', function (message) {
                 }
 
             heap.heapify(resourceArray, libSupport.compare)
-            
-            resourceMap.delete(message.resource_id)
-            if (resourceArray.length == 0)
-                functionToResource.delete(message.functionHash + message.runtime)
+            libSupport.metrics.collectMetrics({type: "scale", value: 
+                resourceArray.length, 
+                functionHash: message.functionHash, runtime: message.runtime})
+            libSupport.logBroadcast({
+                entity_id: message.entity_id,
+                "reason": "terminate",
+                "total_request": message.total_request,
+                "status": true
+            }, message.resource_id, resourceMap)
+            .then(() => {
+                resourceMap.delete(message.resource_id)
+                if (resourceArray.length == 0)
+                    functionToResource.delete(id)
+            })
             
         }
+
         
 
     } else if (topic == constants.topics.hscale) {
         message = JSON.parse(message)
-        let resource_id = libSupport.makeid(20), // each function resource request is associated with an unique ID
+        let resource_id = libSupport.makeid(constants.id_size), // each function resource request is associated with an unique ID
             runtime = message.runtime,
             functionHash = message.functionHash
+        logger.info(`Generated new resource ID: ${resource_id} for runtime: ${runtime}`);
         console.log("Resource Status: ", functionToResource);
         
+        /**
+         * Request RM for resource
+         */
         logger.info("Requesting RM " + JSON.stringify({
             resource_id,
             "memory": 332,
         }))
 
-        /** uncomment when RM is unavailable */
-
         resourceMap.set(resource_id, {
             runtime, functionHash, port: null, node_id: null,
-            deployed: false
+            deployed: false, deploy_request_time: Date.now()
         })
 
 
@@ -499,11 +477,13 @@ consumer.on('message', function (message) {
                     "type": "execute", // Request sent to Dispatch Daemon via Kafka for actual deployment at the Worker
                     resource_id: message.resource_id,
                     runtime: resource.runtime, functionHash: resource.functionHash,
-                    port: resource.port
+                    port: resource.port, resources: {
+                        memory: resource.memory
+                    }
                 }),
                 partition: 0
             }]
-            logger.info(resourceMap);
+            // logger.info(resourceMap);
             producer.send(payload, () => {
                 logger.info(`Resource Deployment request sent to Dispatch Agent`)
             })
@@ -531,6 +511,53 @@ function autoscalar() {
 
 }
 
+/**
+ * Speculative deployment:
+ * If function MLE path is present then deploy those parts of the path which are
+ * not already running
+ * 
+ * FIXME: Currently supports homogenous runtime chain i.e takes runtime as a param. 
+ * Change it to also profile runtime
+ */
+async function speculative_deployment(req, runtime) {
+    if (constants.speculative_deployment && req.headers['x-resource-id'] === undefined) {
+        console.log(functionBranchTree, req.params.id);
+
+        if (functionBranchTree.has(req.params.id)) {
+            let branchInfo = functionBranchTree.get(req.params.id)
+            console.log("mle_path", branchInfo.mle_path);
+
+            if (branchInfo.mle_path && branchInfo.mle_path.length > 1) {
+                for (let node of branchInfo.mle_path)
+                    node.id = node.node
+                let metrics = await libSupport.fetchData(metricsDB + "_bulk_get", {
+                    method: 'post',
+                    body: JSON.stringify({
+                        docs: branchInfo.mle_path
+                    }),
+                    headers: { 'Content-Type': 'application/json' },
+                })
+                console.log(util.inspect(metrics, false, null, true /* enable colors */))
+                
+                for (let node of branchInfo.mle_path) {
+                    // console.log(functionToResource);
+
+                    if (!functionToResource.has(node.node + runtime) && !db.has(node.node + runtime)) {
+                        console.log("Deploying according to MLE path: ", node.node);
+
+                        let payload = [{
+                            topic: constants.topics.hscale,
+                            messages: JSON.stringify({ "runtime": "container", "functionHash": node.node })
+                        }]
+                        producer.send(payload, function () { })
+                        db.set(node.node + runtime, [])
+                    }
+                }
+            }
+        }
+    }
+}
+setInterval(libSupport.metrics.broadcastMetrics, 5000)
 setInterval(libSupport.viterbi, 1000, functionBranchTree)
 setInterval(autoscalar, 1000);
 setInterval(dispatch, 1000);

dispatch_system/dispatch_manager/lib.js

@@ -4,10 +4,23 @@ const rp = require('request-promise');
 const fetch = require('node-fetch');
 const winston = require('winston')
 const constants = require('.././constants.json')
-
+const secrets = require('./secrets.json')
+const metrics = require('./metrics')
 const { createLogger, format, transports } = winston;
 const heap = require('heap')
 
+
+let kafka = require('kafka-node'),
+   Producer = kafka.Producer,
+   client = new kafka.KafkaClient({
+      kafkaHost: constants.network.external.kafka_host,
+      autoConnect: true
+   }),
+   producer = new Producer(client)
+
+let implicitChainDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
+implicitChainDB = implicitChainDB + "/" + constants.implicit_chain_db_names + "/"
+
 /**
  * Generates unique IDs of arbitrary length
  * @param {Length of the ID} length 
@@ -45,6 +58,14 @@ function generateExecutor(functionPath, functionHash) {
     return hash
  }
 
+ /**
+  * Reverse proxy to take user requests and forward them to appropriate workers using a loadbalacer
+  * @param {JSON} req the user request to be forwarded to the worker
+  * @param {JSON} res Object to use to return the response to the user
+  * @param {Map} functionToResource Function to resource Map
+  * @param {Map} resourceMap Map from resource ID to resource metadata
+  * @param {Map} functionBranchTree Holds the function path's and related probability distribution
+  */
 function reverseProxy(req, res, functionToResource, resourceMap, functionBranchTree) {
    branchChainPredictor(req, resourceMap, functionToResource, functionBranchTree)
    return new Promise((resolve, reject) => {
@@ -54,6 +75,7 @@ function reverseProxy(req, res, functionToResource, resourceMap, functionBranchT
        * Bypass deployment pipeline if resource available
        */
       let functionHeap = functionToResource.get(id)
+      // loadbalancing by choosing worker with lowest load
       let forwardTo = functionHeap[0]
       let resource = resourceMap.get(forwardTo.resource_id)
       // logger.info(`Choosing resource ${JSON.stringify(forwardTo.resource_id)}` +
@@ -62,7 +84,7 @@ function reverseProxy(req, res, functionToResource, resourceMap, functionBranchT
    
       // logger.info("Request received at reverseproxy. Forwarding to: " + url);
       forwardTo.open_request_count += 1
-      heap.heapify(functionHeap, compare)
+      heap.heapify(functionHeap, compare) // maintain loadbalancer by heapifying the Map
       // logger.info(functionHeap);
       
       var options = {
@@ -71,22 +93,23 @@ function reverseProxy(req, res, functionToResource, resourceMap, functionBranchT
          body: req.body,
          json: true // Automatically stringifies the body to JSON
       };
-
-      // console.log(options);
       
       
       rp(options)
          .then(function (parsedBody) {
+            let serviceTime = Date.now() - res.timestamp
             
             res.json(parsedBody)
             forwardTo.open_request_count -= 1
             heap.heapify(functionHeap, compare)
+            
+            metrics.collectMetrics({type: res.start, value: serviceTime, functionHash: req.params.id, runtime})
             resolve()
          })
          .catch(function (err) {
             forwardTo.open_request_count -= 1
             heap.heapify(functionHeap, compare)
-            logger.error("error" + err.error.errno);
+            logger.error("error" + err);
             res.json(err.message).status(err.statusCode)
             resolve()
          });
@@ -109,7 +132,6 @@ function getPort(usedPort) {
    return port
 }
 
-
 const logger = winston.createLogger({
    level: 'info',
    format: winston.format.combine(
@@ -252,17 +274,61 @@ function viterbi(functionBranchTree) {
                path.push({node: maxSibling, probability: maxProb})
             siblings = new Map()
          }
-         if (path.length > 0)
-            console.log("path", path);
+         // if (path.length > 0)
+         //    console.log("path", path);
          metadata.mle_path = path
+         if (path.length > 1) {
+            let payload = {
+               method: 'put',
+               body: JSON.stringify(path),
+               headers: { 'Content-Type': 'application/json' }
+            }
+            fetch(implicitChainDB + functionHash, payload)
+         }
       }
    });
-  
+}
+
+function logBroadcast(message, resource_id, resourceMap) {
+   return new Promise((resolve, reject) => {
+      try {
+
+         message.timestamp = Date.now()
+         if (resource_id && resourceMap.has(resource_id)) {
+            let resource = resourceMap.get(resource_id)
+            message.resource_id = resource_id
+            message.node_id = resource.node_id
+            message.runtime = resource.runtime
+            message.function_id = resource.functionHash
+         }
+         let log = [{
+            topic: constants.topics.log_channel,
+            messages: JSON.stringify(message),
+            partition: 0
+         }]
+         producer.send(log, () => {
+            resolve()
+         })
+      } catch (err) {
+         console.log(err);
+         reject()
+      }
+   })
    
 }
 
+async function fetchData(url, data = null) {
+   let res
+   if (data === undefined || data === null)
+      res = await fetch(url)
+   else
+      res = await fetch(url, data)
+   return await res.json()
+}
+
  module.exports = {
     makeid, generateExecutor, reverseProxy, 
     getPort, logger, compare,
-    viterbi
+    viterbi, logBroadcast, fetchData, metrics,
+    producer
  }
\ No newline at end of file

dispatch_system/dispatch_manager/metrics.js

+'use strict';
+
+const constants = require('.././constants.json');
+const secrets = require('./secrets.json')
+const fetch = require('node-fetch');
+const util = require('util')
+const prom = require('prom-client');
+
+const Registry = prom.Registry;
+const register = new Registry();
+
+const alpha = 0.99
+let log_channel = constants.topics.log_channel,
+    metrics = {  }
+
+
+const intervalCollector = prom.collectDefaultMetrics({ prefix: 'xanadu', timeout: 5000, register });
+const workerCountMetric = new prom.Gauge({ name: "worker_count", help: "worker count" });
+const warmstartMetric = new prom.Histogram({ name: "warmstart", help: "warm start latency" });
+const coldstartMetric = new prom.Histogram({ name: "coldstart", help: "cold start latency"});
+const starttimeMetric = new prom.Histogram({ name: "starttime", help: "worker start times" });
+const requestMetric = new prom.Summary({ name: "requests", help: "request RTT times",
+    percentiles: [0.01, 0.05, 0.5, 0.9, 0.95, 0.99, 0.999]
+});
+
+register.registerMetric(workerCountMetric);
+register.registerMetric(warmstartMetric);
+register.registerMetric(coldstartMetric);
+register.registerMetric(starttimeMetric);
+register.registerMetric(requestMetric);
+
+let metricsDB = `http://${secrets.couchdb_username}:${secrets.couchdb_password}@${constants.couchdb_host}`
+metricsDB = metricsDB + "/" + constants.metrics_db_name + "/"
+let kafka = require('kafka-node'),
+    Producer = kafka.Producer,
+    client = new kafka.KafkaClient({
+        kafkaHost: constants.network.external.kafka_host,
+        autoConnect: true
+    }),
+    producer = new Producer(client)
+
+/**
+ * Function called to report metric data related to functions
+ * @param {JSON} metric 
+ */
+function collectMetrics(metric) {
+    /**
+     * If metrics for a new function comes in, 
+     * provision required structure for the function
+     */
+    if (!(metric.functionHash in metrics)) {
+        metrics[metric.functionHash] = {}
+    } 
+    if (!(metric.runtime in metrics[metric.functionHash])) {
+        metrics[metric.functionHash][metric.runtime] = {
+            shortterm: {
+                coldstart: 0,
+                coldstart_total_request: 0,
+                warm_total_request: 0,
+                scale_count: 0,
+                warmstart: 0,
+                worker_count: 0,
+                starttime: 0
+            }
+        }
+    }
+    if (metric.type === 'coldstart') {
+        metrics[metric.functionHash][metric.runtime].shortterm.coldstart += metric.value
+        metrics[metric.functionHash][metric.runtime].shortterm.coldstart_total_request += 1
+        coldstartMetric.observe(metric.value)
+        requestMetric.observe(metric.value)
+    } else if (metric.type === 'warmstart') {
+        metrics[metric.functionHash][metric.runtime].shortterm.warmstart += metric.value
+        metrics[metric.functionHash][metric.runtime].shortterm.warm_total_request += 1
+        warmstartMetric.observe(metric.value)
+        requestMetric.observe(metric.value)
+    } else if (metric.type === 'scale') {
+        metrics[metric.functionHash][metric.runtime].shortterm.worker_count = metric.value
+        workerCountMetric.set(metric.value)
+        if (metric.starttime !== undefined) {
+            metrics[metric.functionHash][metric.runtime].shortterm.starttime += metric.starttime
+            metrics[metric.functionHash][metric.runtime].shortterm.scale_count += 1
+            starttimeMetric.observe(metric.starttime)
+        }
+    }
+    
+}
+
+
+/**
+ * Run periodically to calculate average runtime metrics like coldstart and
+ * warmstart latencies.
+ * The module provides two granularities for metrics - shortterm and longterm
+ * shortterm - realtime data at a granularity of 5s (set in dispatch_manager/lib.js)
+ *             shortterm data is calculated using Simple Moving Average (SMA)
+ * longterm - longterm data is held and averaged out over a period of time.
+ *            longterm data is calculated using Expontential Moving Average (EMA)
+ */
+async function broadcastMetrics() {
+    if (Object.keys(metrics).length !== 0) {
+        for (let [functionHash, data] of Object.entries(metrics)) {
+            for (let [runtime, metricData] of Object.entries(data)) {
+                if (metricData.shortterm.coldstart != 0 || metricData.shortterm.longterm != 0) {
+                    let { metric, dbData } = await fetchData(functionHash, metricData, runtime)
+                    /**
+                    * Shortterm moving average
+                    */
+                    metric.shortterm.coldstart /= (metric.shortterm.coldstart_total_request != 0) ?
+                        metric.shortterm.coldstart_total_request : 1
+                    metric.shortterm.starttime /= (metric.shortterm.scale_count != 0) ?
+                        metric.shortterm.scale_count : 1
+                    metric.shortterm.warmstart /= (metric.shortterm.warm_total_request != 0) ?
+                        metric.shortterm.warm_total_request : 1
+                    
+                    /**
+                     * Longterm exponential moving average
+                     */
+                    if (metric.shortterm.coldstart != 0)
+                        metric.longterm.coldstart = (metric.longterm.coldstart != 0) ? metric.longterm.coldstart * alpha
+                            + metric.shortterm.coldstart * (1 - alpha) : metric.shortterm.coldstart
+                    if (metric.shortterm.starttime && metric.shortterm.starttime != 0)
+                        metric.longterm.starttime = (metric.longterm.starttime != 0) ? metric.longterm.starttime * alpha
+                            + metric.shortterm.starttime * (1 - alpha) : metric.shortterm.starttime
+                    if (metric.shortterm.warmstart != 0)
+                        metric.longterm.warmstart = (metric.longterm.warmstart != 0) ? metric.longterm.warmstart * alpha
+                            + metric.shortterm.warmstart * (1 - alpha) : metric.shortterm.warmstart
+                    dbData[runtime] = {
+                        coldstart: metric.longterm.coldstart,
+                        warmstart: metric.longterm.warmstart,
+                        starttime: metric.longterm.starttime
+                    }
+                    let payload = {
+                        method: 'put',
+                        body: JSON.stringify(dbData),
+                        headers: { 'Content-Type': 'application/json' }
+                    }
+                    await fetch(metricsDB + functionHash, payload)
+                    
+                    metric.timestamp = Date.now()
+                }
+            }
+        }
+        
+        let log = [{
+            topic: log_channel,
+            messages: JSON.stringify({
+                metrics
+            }),
+            partition: 0
+        }]
+        producer.send(log, () => { })
+        
+        for (let [functionHash, data] of Object.entries(metrics)) {
+            for (let [runtime, metric] of Object.entries(data)) {
+                metric.shortterm = {
+                    coldstart: 0,
+                    coldstart_total_request: 0,
+                    warm_total_request: 0,
+                    warmstart: 0,
+                    worker_count: 0,
+                    starttime: 0,
+                    scale_count: 0
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Function to fetch the latest data from metric DB
+ * @param {String} functionHash 
+ * @param {JSON} metric 
+ */
+async function fetchData(functionHash, metric, runtime) {
+    let res = await fetch(metricsDB + functionHash)
+    let json = await res.json()
+    
+    if (json.error === "not_found" || json[runtime] === undefined) {
+        metric.longterm = {
+            coldstart: 0,
+            warmstart: 0,
+            starttime: 0
+        }
+    } else {
+        metric.longterm = {
+            coldstart: json[runtime].coldstart,
+            warmstart: json[runtime].warmstart,
+            starttime: (json[runtime].starttime) ? json[runtime].starttime: 0
+        }
+    }
+    return {
+        metric,
+        dbData: (json.error === "not_found")? {}: json
+    }
+}
+
+module.exports = {
+    collectMetrics, broadcastMetrics, register
+}
\ No newline at end of file

dispatch_system/dispatch_manager/operator.js

+const op = {
+    'lt': function (x, y) { return x < y },
+    'gt': function (x, y) { return x > y },
+    'lte': function (x, y) { return x <= y },
+    'gte': function (x, y) { return x >= y },
+    'eq': function (x, y) { return x === y },
+    'neq': function (x, y) { return x !== y },
+};
+
+module.exports = op
\ No newline at end of file

dispatch_system/dispatch_manager/package.json

@@ -20,6 +20,7 @@
     "morgan": "^1.9.1",
     "mqtt": "^3.0.0",
     "node-fetch": "^2.6.0",
+    "prom-client": "^12.0.0",
     "redis": "^2.8.0",
     "request": "^2.88.0",
     "request-promise": "^4.2.5",

dispatch_system/dispatch_manager/repository/worker_env/env.js

@@ -5,7 +5,8 @@ let request = require('request')
 const process = require('process')
 
 const app = express()
-let port = 5000, resource_id, functionHash, runtime, idleTime = 30
+let port = 5000, resource_id, functionHash, runtime, idleTime = 60, flagFirstRequest = true
+let waitTime
 
 resource_id = process.argv[2]
 functionHash = process.argv[3]
@@ -18,7 +19,7 @@ request = request.defaults({
 let kafka = require('kafka-node'),
     Producer = kafka.Producer,
     client = new kafka.KafkaClient({
-        kafkaHost: '10.129.6.5:9092',
+        kafkaHost: process.argv[6],
         autoConnect: true
     }),
     producer = new Producer(client)
@@ -28,6 +29,10 @@ app.use(bodyParser.json())
 
 let lastRequest = Date.now(), totalRequest = 0
 app.post('/serverless/function/execute/', (req, res) => {
+    if (flagFirstRequest) {
+        waitTime = Date.now() - waitTime
+        flagFirstRequest = false
+    }
     let payload = req.body
     lastRequest = Date.now()
     totalRequest++
@@ -36,13 +41,15 @@ app.post('/serverless/function/execute/', (req, res) => {
     })
 })
 
-app.post('/serverless/worker/timeout', (req, res) => {
+app.post('/serverless/function/timeout', (req, res) => {
     idleTime = req.body.timeout
     console.log("Idle time set to: ", idleTime);
-    
+    res.json({
+        status: "success"
+    })
 })
 
-function executor(payload) {
+async function executor(payload) {
     return new Promise((resolve, reject) => {
         
     })
@@ -57,6 +64,7 @@ app.listen(port, () => {
             runtime, resource_id, entity_id: process.pid}),
         "status": true
     }], () => { })
+    waitTime = Date.now()
 })
 
 function shouldDie() {
@@ -65,14 +73,17 @@ function shouldDie() {
         let message = JSON.stringify({
             functionHash, portExternal: port,
             runtime, resource_id, entity_id: process.pid,
-            total_request: totalRequest
+            total_request: totalRequest, wait_time: waitTime
         })
 
         console.log("Idle for too long. Exiting");
         producer.send(
             [
                 {topic: "removeWorker", messages: message }
-            ], () => {
+            ], (err, data) => {
+                if (err)
+                    console.log(err);
+                    
                 console.log("Ending worker for function", functionHash, "resource_id", resource_id);
                 process.exit(0)
             })

dispatch_system/log_listener.js

+const constants = require('./constants.json')
+const util = require('util')
+let kafka = require('kafka-node'),
+    Producer = kafka.Producer,
+    client = new kafka.KafkaClient({
+        kafkaHost: constants.network.external.kafka_host,
+        autoConnect: true
+    }),
+    producer = new Producer(client),
+    Consumer = kafka.Consumer,
+    consumer = new Consumer(client,
+        [
+            { topic: constants.topics.log_channel }
+        ])
+
+consumer.on('message', function (message) {
+    message = JSON.parse(message.value)
+    console.log(util.inspect(message, false, null, true /* enable colors */))
+    
+})
\ No newline at end of file

dispatch_system/prometheus.yml

+# my global config
+global:
+  scrape_interval:     15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
+  evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
+  # scrape_timeout is set to the global default (10s).
+
+  # Attach these labels to any time series or alerts when communicating with
+  # external systems (federation, remote storage, Alertmanager).
+  external_labels:
+      monitor: 'codelab-monitor'
+
+# Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
+rule_files:
+  # - "first.rules"
+  # - "second.rules"
+
+# A scrape configuration containing exactly one endpoint to scrape:
+# Here it's Prometheus itself.
+scrape_configs:
+  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
+  - job_name: 'prometheus'
+
+    # metrics_path defaults to '/metrics'
+    # scheme defaults to 'http'.
+
+    static_configs:
+      - targets: ['localhost:9090']
+
+  - job_name: 'docker'
+         # metrics_path defaults to '/metrics'
+         # scheme defaults to 'http'.
+
+    static_configs:
+      - targets: ['localhost:9323']
+  
+  - job_name: 'xanadu'
+    static_configs:
+      - targets: ['localhost:8080']

dispatch_system/setup_topics.js

+const constants = require('./constants.json')
+
+var kafka = require('kafka-node');
+let client = new kafka.KafkaClient({
+    kafkaHost: constants.network.external.kafka_host,
+    autoConnect: true
+})
+var topicsToCreate = [];
+for (const [key, value] of Object.entries(constants.topics)) {
+    topicsToCreate.push({ topic: value, partitions: 1, replicationFactor: 1 })
+}
+client.createTopics(topicsToCreate, (error, result) => {
+    console.log("topic created", result);
+    
+});
\ No newline at end of file

docker-compose.yml

+version: '2'
+networks:
+  kafka-serverless:
+    driver: bridge
+services:
+  zookeeper:
+    image: 'bitnami/zookeeper:3'
+    restart: unless-stopped
+    networks:
+      - kafka-serverless
+    ports:
+      - '2182:2181'
+    volumes:
+      - 'zookeeper_data:/bitnami'
+    environment:
+      - ALLOW_ANONYMOUS_LOGIN=yes
+  kafka:
+    image: 'bitnami/kafka:2'
+    restart: unless-stopped
+    networks:
+      - kafka-serverless
+    ports:
+      - '9093:9092'
+      - '29092:29092'
+    volumes:
+      - 'kafka_data:/bitnami'
+    environment:
+      - KAFKA_CFG_ZOOKEEPER_CONNECT=zookeeper:2181
+      - ALLOW_PLAINTEXT_LISTENER=yes
+      - KAFKA_CFG_LISTENER_SECURITY_PROTOCOL_MAP=PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
+      - KAFKA_CFG_LISTENERS=PLAINTEXT://0.0.0.0:9092,PLAINTEXT_HOST://0.0.0.0:29092
+      - KAFKA_CFG_ADVERTISED_LISTENERS=PLAINTEXT://kafka:9092,PLAINTEXT_HOST://localhost:29092
+      - KAFKA_CFG_AUTO_CREATE_TOPICS_ENABLE=true
+    depends_on:
+      - zookeeper
+
+volumes:
+  zookeeper_data:
+    driver: local
+  kafka_data:
+    driver: local

local_experiments/function_chain.drawio

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\ No newline at end of file

readme.md

@@ -145,6 +145,7 @@ to run and execute the function on the specified worker node.
 - Docker
 - Java
 - Apache Kafka (Configure to allow auto-delete and auto-registration of topics)
+- couchdb (needs a database named serverless)
 
 ### Starting the server