Paralelizando promesas

LimaJS 20/06/2018

Transcript

1. @lupomontero LimaJS 20/06/2018
2. Director de tecnología @Laboratoriala
4. Delete user auth.deleteUser(uid) .then(console.log) .catch(console.error);
5. Promise.all (todos a la vez!) Promise.all(users.map(user => auth.deleteUser(user.localId))) .then(console.log) .catch(console.error);
6. { Error: An internal error has occurred. Raw server response: "{"error":{"code":400,"message":"QUOTA_EXCEEDED : Exceeded quota for deleting accounts.","errors":[{"message":"QUOTA_EXCEEDED : Exceeded quota for deleting accounts.","domain":"global","reason":"invalid"}]}}" at FirebaseAuthError.FirebaseError [as constructor] (/Users/lupo/work/lupomontero/paralelizando-promesas/node_modules/firebase-admin/lib/utils/error.js:39:28) at FirebaseAuthError.PrefixedFirebaseError [as constructor] (/Users/lupo/work/lupomontero/paralelizando-promesas/node_modules/firebase-admin/lib/utils/error.js:85:28) at new FirebaseAuthError (/Users/lupo/work/lupomontero/paralelizando-promesas/node_modules/firebase-admin/lib/utils/error.js:143:16) at Function.FirebaseAuthError.fromServerError (/Users/lupo/work/lupomontero/paralelizando-promesas/node_modules/firebase-admin/lib/utils/error.js:173:16) at /Users/lupo/work/lupomontero/paralelizando-promesas/node_modules/firebase-admin/lib/auth/auth-api-request.js:723 :45 at process._tickCallback (internal/process/next_tick.js:68:7) errorInfo: { code: 'auth/internal-error', message: 'An internal error has occurred. Raw server response: "{"error":{"code":400,"message":"QUOTA_EXCEEDED : Exceeded quota for deleting accounts.","errors":[{"message":"QUOTA_EXCEEDED : Exceeded quota for deleting accounts.","domain":"global","reason":"invalid"}]}}"' }, codePrefix: 'auth' } QUOTA_EXCEEDED : Exceeded quota for deleting accounts.
8. Requerimientos • No más de 10 tareas (invocaciones a auth.deleteUser()) por segundo. • Batches (grupos) de 10 • Intervalo entre batches (1 seg) • Si una tarea falla las demás deben continuar
9. Tareas vs promesas const promises = users.map(user => auth.deleteUser(user.localId)) const tasks = users.map(user => () => auth.deleteUser(user.localId))
10. En serie vs en paralelo
11. Series const series = (tasks, results = []) => ( (!tasks.length) ? Promise.resolve(results) : tasks[0]().then(result => series(tasks.slice(1), [...results, result])) );
12. Concurrency
13. Dividiendo arreglo en “batches” (grupos?) const splitArrayIntoBatches = (arr, limit) => arr.reduce((memo, item) => { if (memo.length && memo[memo.length - 1].length < limit) { memo[memo. length - 1].push(item); return memo; } return [...memo, [item]] ; }, []);
14. const array = ['a', 'b', 'c', 'd', 'e']; splitArrayIntoBatches(array, 1); // => [['a'], ['b'], ['c'], ['d'], ['e']] splitArrayIntoBatches(array, 2); // => [['a', 'b'], ['c', 'd'], ['e']] splitArrayIntoBatches(array, 3); // => [['a', 'b', 'c'], ['d', 'e']] splitArrayIntoBatches(array, 4); // => [['a', 'b', 'c', 'd'], ['e']] splitArrayIntoBatches(array, 5); // => [['a', 'b', 'c', 'd', 'e']]
15. const batched = (tasks, concurrency) => { const processBatches = (batches, prevResults = []) => { if (!batches.length) { return Promise.resolve(prevResults) ; } return Promise.all(batches[0].map(fn => fn())).then((batchResults) => { const results = [...prevResults, ...batchResults] ; return (batches.length <= 1) ? results : processBatches(batches. slice(1), results); }); }; return processBatches(splitArrayIntoBatches(tasks, concurrency)) ; };
16. // ejecuta todas las tareas de 5 en 5 batched(tasks, 5) .then(console.log) .catch(console.error);
17. Throttling
18. Agregando tiempo de espera entre lotes // Antes processBatches(batches. slice(1), results).then(resolve, reject) // Después new Promise((resolve, reject) => setTimeout( () => processBatches(batches. slice(1), results) .then(resolve, reject), interval, ))
19. const throttled = (tasks, concurrency, interval = 0) => { const processBatches = (batches, prevResults = []) => { if (!batches.length) { return Promise.resolve(prevResults) ; } return Promise.all(batches[0].map(fn => fn())).then((batchResults) => { const results = [...prevResults, ...batchResults] ; return (batches.length <= 1) ? results : new Promise((resolve, reject) => setTimeout( () => processBatches(batches. slice(1), results).then(resolve, reject), interval, )); }); }; return processBatches(splitArrayIntoBatches(tasks, concurrency)) ; };
20. // ejecuta tareas de 5 en 5, // esperando 1s entre cada lote throttled(tasks, 5, 1000) .then(console.log) .catch(console.error);
21. Error handling
22. // así procesábamos las tareas de un batch (en parallelo) Promise.all( batches[0].map(fn => fn()), ) // agregamos la opción `failFast` y manejejamos errores cuando // `failFast` sea `false` Promise.all( batches[0].map(fn => (failFast ? fn() : fn(). catch(err => err))), )
23. const pact = (tasks, concurrency, interval = 0, failFast = true) => { const processBatches = (batches, prevResults = []) => { if (!batches.length) { return Promise.resolve(prevResults) ; } return Promise.all( batches[ 0].map(fn => (failFast ? fn() : fn(). catch(err => err))), ).then((batchResults) => { const results = [...prevResults, ...batchResults] ; return (batches.length <= 1) ? results : new Promise((resolve, reject) => setTimeout( () => processBatches(batches. slice(1), results).then(resolve, reject), interval, )); }); }; return processBatches(splitArrayIntoBatches(tasks, concurrency)) ; };
24. pact(tasks, 5, 1000, false) .then(console.log);
25. Material complementario Código fuente: https://github.com/lupomontero/pact Blog post: https://medium.com/laboratoria-how-to/paral elizando-promesas-372894c1d21f
26. … más Proyectos abiertos: • Currícula: https://github.com/Laboratoria/curricula-js • Foro: http://community.laboratoria.la/ Estamos contratando: lupo@laboratoria.la / mariana.gg@laboratoria.la
27. Gracias!