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Node.js in 2020 - part 3

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Timur Shemsedinov
Timur Shemsedinov

Мы закончим обзор новых возможносте�� Node.js и сложив все это вместе в Node.js Starter Kit (шаблона проекта) от сообщества Metarhia для построения надежных и масштабируемых облачных и кластерных приложений и быстрой разработки API для высоконагруженных и интерактивных систем. Будет опубликован манифест Metaserverless. Мы разберем код, обсудим использование новейших возможностей платформы Node.js и фундаментальных знаний CS для построения грамотной структуры и архитектуры проекта.

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const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Node.js in 2020 #3 Выйди и зайди нормально Timur Shemsedinov github.com/HowProgrammingWorks github.com/tshemsedinov Chief Technology Architect at Metarhia Lecturer at Kiev Polytechnic Institute
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Limit сoncurrency to avoid resource starvation in high-intensive servers
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to limit concurrency? ● Counter variable ● Array, Linked list ● Asynchronous Queue ● Counting Semaphore ● Event Stream ● External ballancer + monitoring ● It works somehow
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Asynchronous Queue Usage const q1 = metasync.queue(3).priority() .process((item, cb) => {}); const q2 = metasync.queue(1).wait(100).timeout(200) .process((item, cb) => {}); q1.pipe(q2); q1.add({ id: 1 }, 0); q1.add({ id: 3 }, 1);
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Counting Semaphore const semaphore = new CountingSemaphore(concurrency); const handler = async (req, res) => { await semaphore.enter(); ... semaphore.leave(); };
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Reference implementations Асинхронная очередь https://github.com/metarhia/ metasync/blob/master/lib/queue.js Семафор со счетчиком https://github.com/HowProgrammingWorks/ NodejsStarterKit/blob/master/lib/semaphore.js
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Graceful shutdown after fatal errors and for reload applications
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c When we need to exit? ● On fatal errors, unhandled exceptions ● Update infrastructure or platform ● Scheduled restart, release leaks, etc. ● Manual stop or restart, maintenance
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to shutdown graceful? ● Close server network ports ● Notify all clients with special events ● Wait for timeout ● Close all connections with socket.destroy() ● Save all data and release critical resources ● exit 0
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) fs.watch fs.watchFile, fs.FSWatcher and live code reload
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Counting Semaphore const fs = require('fs'); fs.watch(dirPath, (event, fileName) => { const filePath = path.join(dirPath, fileName); reloadFile(filePath); });
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Tricks ● Wait for 3-5 sec. timeout after fs.watch event ● Put all changes to collection to reload ● Ignore temporary and unneeded files
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Multi-cure support child_process, cluster and worker_threads
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to use workers_threads for net load ● Don’t run business-logic in main thread ● Spawn one thread per one network port ● Spawn os.cpus().length / 2 threads ● Stick client to certain thread/port ● Separate log file for each thread ● Use shared memory for cache (for example static files)
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) FaaS Serverless Clouds and Node.js
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Infrastructure Clouds vs App Clouds Hardware Infrastructure Application State Functions Hardware Infrastructure Application X Functions IaaSCloud FaaSCloud
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Benefits ● Service price? (evangelists told us...) ● Efficiency: Performance? Speed? Latency? ● Easy to test, deploy, maintain? ● Security? Reliability? Flexibility? Quality? ● Quick development? ● Reduces development cost? ● Scalability?
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What we pay for? We pay for: ● lack of available professionals ● lack of competencies ● lack of available technologies ● lack of funding for our projects ● lack of time
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Cost Optimization Cases ● Small services, sometimes cold Can reduce cost x10 (great: $10 to $1) ● Highload >100k online, always warm Single bare metal can hold load Try to calculate serverless cost...
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Disadvantages ● High resource consumption ● Stateless nature and no application integrity ● Interactivity issue (separate solution needed) ● Development and debug issues ● Deploy and maintain issues ● Vendor lock, not open source ● Where is no promised simplicity
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Middleware Madness router.get('/user/:id', (req, res, next) => { const id = parseInt(req.params.id); const query = 'SELECT * FROM users WHERE id = $1'; pool.query(query, [id], (err, data) => { if (err) throw err; res.status(200).json(data.rows); next(); }); });
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Code Structure and Patterns exports.handler = (event, context, callback) => { const { Client } = require('pg'); const client = new Client(); client.connect(); const id = parseInt(event.pathParameters.id); const query = 'SELECT * FROM users WHERE id = $1'; client.query(query, [id], (err, data) => { callback(err, { statusCode: 200, body: JSON.stringify(data.rows)}); }); };
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? async (arg1, arg2, arg3) => { const [data1, data2] = await Promise.all( [getData(arg1), getData(arg2)] ); const data3 = await getData(arg3); if (!data3) throw new Error('Message'); return await processData(data1, data2, data3); }
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? async (arg1, arg2, arg3) => { const data1 = await getData(arg1); if (!data1) throw new Error('Message'); const [data2, data3] = await Promise.all( [getData(arg2), getData(arg3)] ); return await processData(data1, data2, data3); }
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Equivalent example id => application .database .select('users') .where({ id });
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Complex Query id => application.database .select('users') .where({ id }) .cache({ timeout: 30000, invalidate: { id }) .projection({ name: ['name', toUpperCase], age: ['birth', toAge], place: ['address', getCity, getGeocode], });
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Layered Architecture Server-side ● Layered ● Microservices ● Serverless Database Data Access Layer Business-logic API Network Client UI
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? ● Apps consolidation ● Stateful cloud applications ● Interactivity (Websockets, TCP, TLS support) ● No vendor lock ● Private clouds ● Do not overpay for clouds
● Architecture and layered approach ● Async I/O for business-logic parallelization ● Long-lived processes: in-memory, reuse ● Server inside application (not vice versa) ● Minimize IPC and serialization ● Open source ● But we need request isolation const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How do we achieve this?
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c SOA Architecture DB API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network SingleServer SOAArchitecture
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Microservices Architecture DB API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network DB DB DB SingleServer Microservices
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network SingleServer Serverless
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Vendor Lock Prevention Checklist ● Wrap vendor services ● Concentrate on architecture: layers ● Code quality and competencies ● Think twice before following hype and trends ● Remove dependencies if possible
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Vendor Loyalty Checklisk ● Use everything as a service ● Follow guidelines ● Сut risky developments ● Relax ● Share your income
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Metaserverless Experiments ● Application is not a separate functions, application has distributed in-memory state ● Functions can be executed sequentially and parallely in asynchronous style ● Applications have long life and structure ● Interactivity (Websockets, TCP, TLS support) ● No vendor lock, Private clouds, Open Source
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Node.js Starter Kit no dependencies, 20 kb with pg drivers + 1.2 mb and ws + 0.24 mb
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Starter Kit Key Ideas ● Минимум кода и зависимостей ● Минимизация I/O, отдача всего из памяти ● Безопасность и изоляция контекстов ● Структура и архитектура приложения ● Разделение системного и прикладного слоя ● Все на контрактах (interface) ● Балансировка, таймауты и очередь запросов
const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Starter Kit Feature List ● Автороутинг API и поддержка HTTP(S), WS(S) ● Подгрузка изменений на лету через fs.watch ● Загрузчик конфигурации и Graceful shutdown ● Утилизация CPU, кластеризация через потоки ● Слой доступа к данным DAL: Postgresql ● Сессии с сохраняемым состоянием ● Песочницы, потоки, масштабирование, тесты
Questions?
github.com/tshemsedinov https://youtube.com/TimurShemsedinov github.com/HowProgrammingWorks/Index Весь курс по ноде (>35.5 часов) https://habr.com/ru/post/485294/ t.me/HowProgrammingWorks t.me/NodeUA timur.shemsedinov@gmail.com

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Node.js in 2020 - part 3

  • 1. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Node.js in 2020 #3 Выйди и зайди нормально Timur Shemsedinov github.com/HowProgrammingWorks github.com/tshemsedinov Chief Technology Architect at Metarhia Lecturer at Kiev Polytechnic Institute
  • 2. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Limit сoncurrency to avoid resource starvation in high-intensive servers
  • 3. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to limit concurrency? ● Counter variable ● Array, Linked list ● Asynchronous Queue ● Counting Semaphore ● Event Stream ● External ballancer + monitoring ● It works somehow
  • 4. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Asynchronous Queue Usage const q1 = metasync.queue(3).priority() .process((item, cb) => {}); const q2 = metasync.queue(1).wait(100).timeout(200) .process((item, cb) => {}); q1.pipe(q2); q1.add({ id: 1 }, 0); q1.add({ id: 3 }, 1);
  • 5. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Counting Semaphore const semaphore = new CountingSemaphore(concurrency); const handler = async (req, res) => { await semaphore.enter(); ... semaphore.leave(); };
  • 6. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Reference implementations Асинхронная очередь https://github.com/metarhia/ metasync/blob/master/lib/queue.js Семафор со счетчиком https://github.com/HowProgrammingWorks/ NodejsStarterKit/blob/master/lib/semaphore.js
  • 7. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Graceful shutdown after fatal errors and for reload applications
  • 8. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c When we need to exit? ● On fatal errors, unhandled exceptions ● Update infrastructure or platform ● Scheduled restart, release leaks, etc. ● Manual stop or restart, maintenance
  • 9. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to shutdown graceful? ● Close server network ports ● Notify all clients with special events ● Wait for timeout ● Close all connections with socket.destroy() ● Save all data and release critical resources ● exit 0
  • 10. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) fs.watch fs.watchFile, fs.FSWatcher and live code reload
  • 11. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Counting Semaphore const fs = require('fs'); fs.watch(dirPath, (event, fileName) => { const filePath = path.join(dirPath, fileName); reloadFile(filePath); });
  • 12. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Tricks ● Wait for 3-5 sec. timeout after fs.watch event ● Put all changes to collection to reload ● Ignore temporary and unneeded files
  • 13. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Multi-cure support child_process, cluster and worker_threads
  • 14. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How to use workers_threads for net load ● Don’t run business-logic in main thread ● Spawn one thread per one network port ● Spawn os.cpus().length / 2 threads ● Stick client to certain thread/port ● Separate log file for each thread ● Use shared memory for cache (for example static files)
  • 15. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) FaaS Serverless Clouds and Node.js
  • 16. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Infrastructure Clouds vs App Clouds Hardware Infrastructure Application State Functions Hardware Infrastructure Application X Functions IaaSCloud FaaSCloud
  • 17. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Benefits ● Service price? (evangelists told us...) ● Efficiency: Performance? Speed? Latency? ● Easy to test, deploy, maintain? ● Security? Reliability? Flexibility? Quality? ● Quick development? ● Reduces development cost? ● Scalability?
  • 18. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What we pay for? We pay for: ● lack of available professionals ● lack of competencies ● lack of available technologies ● lack of funding for our projects ● lack of time
  • 19. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Cost Optimization Cases ● Small services, sometimes cold Can reduce cost x10 (great: $10 to $1) ● Highload >100k online, always warm Single bare metal can hold load Try to calculate serverless cost...
  • 20. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Disadvantages ● High resource consumption ● Stateless nature and no application integrity ● Interactivity issue (separate solution needed) ● Development and debug issues ● Deploy and maintain issues ● Vendor lock, not open source ● Where is no promised simplicity
  • 21. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Middleware Madness router.get('/user/:id', (req, res, next) => { const id = parseInt(req.params.id); const query = 'SELECT * FROM users WHERE id = $1'; pool.query(query, [id], (err, data) => { if (err) throw err; res.status(200).json(data.rows); next(); }); });
  • 22. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Code Structure and Patterns exports.handler = (event, context, callback) => { const { Client } = require('pg'); const client = new Client(); client.connect(); const id = parseInt(event.pathParameters.id); const query = 'SELECT * FROM users WHERE id = $1'; client.query(query, [id], (err, data) => { callback(err, { statusCode: 200, body: JSON.stringify(data.rows)}); }); };
  • 23. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? async (arg1, arg2, arg3) => { const [data1, data2] = await Promise.all( [getData(arg1), getData(arg2)] ); const data3 = await getData(arg3); if (!data3) throw new Error('Message'); return await processData(data1, data2, data3); }
  • 24. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? async (arg1, arg2, arg3) => { const data1 = await getData(arg1); if (!data1) throw new Error('Message'); const [data2, data3] = await Promise.all( [getData(arg2), getData(arg3)] ); return await processData(data1, data2, data3); }
  • 25. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Equivalent example id => application .database .select('users') .where({ id });
  • 26. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Complex Query id => application.database .select('users') .where({ id }) .cache({ timeout: 30000, invalidate: { id }) .projection({ name: ['name', toUpperCase], age: ['birth', toAge], place: ['address', getCity, getGeocode], });
  • 27. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Layered Architecture Server-side ● Layered ● Microservices ● Serverless Database Data Access Layer Business-logic API Network Client UI
  • 28. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c What do we want? ● Apps consolidation ● Stateful cloud applications ● Interactivity (Websockets, TCP, TLS support) ● No vendor lock ● Private clouds ● Do not overpay for clouds
  • 29. ● Architecture and layered approach ● Async I/O for business-logic parallelization ● Long-lived processes: in-memory, reuse ● Server inside application (not vice versa) ● Minimize IPC and serialization ● Open source ● But we need request isolation const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c How do we achieve this?
  • 30. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c SOA Architecture DB API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network SingleServer SOAArchitecture
  • 31. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Microservices Architecture DB API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network DB DB DB SingleServer Microservices
  • 32. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API + BL Network API + BL API + BL API + BL Database Data Access Layer Business-logic API Network SingleServer Serverless
  • 33. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
  • 34. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
  • 35. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Serverless Architecture Database API+BL Network Database Data Access Layer Business-logic API Network API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL API+BL SingleServer Serverless
  • 36. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Vendor Lock Prevention Checklist ● Wrap vendor services ● Concentrate on architecture: layers ● Code quality and competencies ● Think twice before following hype and trends ● Remove dependencies if possible
  • 37. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Vendor Loyalty Checklisk ● Use everything as a service ● Follow guidelines ● Сut risky developments ● Relax ● Share your income
  • 38. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Metaserverless Experiments ● Application is not a separate functions, application has distributed in-memory state ● Functions can be executed sequentially and parallely in asynchronous style ● Applications have long life and structure ● Interactivity (Websockets, TCP, TLS support) ● No vendor lock, Private clouds, Open Source
  • 39. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c toString().padStart(width) : cell.padEnd(width); }).join(''))).join }; const proportion = (max, val) => Math.round(val * 100 / max); co calcProportion = table => { table.sort((row1, row2) => row2[DENSITY row1[DENSITY_COL]); const maxDensity = table[0][DENSITY_COL]; table forEach(row => { row.push(proportion(maxDensity, row[DENSITY_COL])) return table; }; const getDataset = file => { const lines = fs.read FileSync(file, 'utf8').toString().split('n'); lines.shift(); lines return lines.map(line => line.split(',')); }; const main = compose (getDataset, calcProportion, renderTable); const fs = require('fs' compose = (...funcs) => x => funcs.reduce((x, fn) => fn(x), x); con DENSITY_COL = 3; const renderTable = table => { const cellWidth = [ 8, 8, 18, 6]; return table.map(row => (row.map((cell, i) => { const = cellWidth[i]; return i ? cell.toString().padStart(width) : cell.p (width); }).join(''))).join('n'); }; const proportion = (max, val) Node.js Starter Kit no dependencies, 20 kb with pg drivers + 1.2 mb and ws + 0.24 mb
  • 40. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Starter Kit Key Ideas ● Минимум кода и зависимостей ● Минимизация I/O, отдача всего из памяти ● Безопасность и изоляция контекстов ● Структура и архитектура прило��ения ● Разделение системного и прикладного слоя ● Все на контрактах (interface) ● Балансировка, таймауты и очередь запросов
  • 41. const fs = require('fs'); const compose = (...funcs) => x => funcs. reduce((x, fn) => fn(x), x); const DENSITY_COL = 3; const renderTab table => { const cellWidth = [18, 10, 8, 8, 18, 6]; return table.ma => (row.map((cell, i) => { const width = cellWidth[i]; return i ? c Starter Kit Feature List ● Автороутинг API и поддержка HTTP(S), WS(S) ● Подгрузка изменений на лету через fs.watch ● Загрузчик конфигурации и Graceful shutdown ● Утилизация CPU, кластеризация через потоки ● Слой доступа к данным DAL: Postgresql ● Сессии с сохраняемым состоянием ● Песочницы, потоки, масштабирование, тесты
  • 43. github.com/tshemsedinov https://youtube.com/TimurShemsedinov github.com/HowProgrammingWorks/Index Весь курс по ноде (>35.5 часов) https://habr.com/ru/post/485294/ t.me/HowProgrammingWorks t.me/NodeUA timur.shemsedinov@gmail.com