Note: This update is an early-access release. This chapter has not yet been updated to Vapor 4.
In previous chapters, you’ve built a single Vapor application to run your server code. For large applications, the single monolith becomes difficult to maintain and scale. In this chapter, you’ll learn how to leverage microservices to split up your code into different applications. You’ll learn the benefits and the downsides of microservices and how to interact with them. Finally, you’ll learn how authentication and relationships work in a microservices architecture.
Microservices
Microservices are a design pattern that’s become popular in recent years. The aim of microservices is to provide small, independent modules that interact with one another. This is different to a large monolithic application. This makes the individual services easier to develop and test as they are smaller. Because they are independent, you can develop them individually. This removes the need to use and build all the dependencies for the entire application.
Microservices also allow you to scale your application better. In a monolithic application, you must scale the entire application when under heavy load. This includes parts of the application that receive low traffic. In microservices, you scale only the services that are busy.
Finally, microservices make building and deploying your applications easier. Deploying very large applications is complex and prone to errors. In large applications, you must coordinate with every development team to ensure the application is ready to deploy. Breaking a monolithic application up into smaller services makes deploying each service easier.
Each microservice should be a fully contained application. Each service has its own database, its own cache and, if necessary, its own front end. The only shared part should be the public API to allow other services to interact with that microservice. Typically, they provide an HTTP REST API, although you can use other techniques such as protobuf or remote procedural calls (RPC). Since each microservice interacts with other services only via a public API, each can use different technology stacks. For instance, you could use PostgreSQL for one service that required it, but use MySQL for the main user service. You can even mix languages. This allows different teams to use the languages they prefer.
Swift is an excellent choice for microservices. Swift applications have low memory footprints and can handle large numbers of connections. This allows Swift microservices to fit easily into existing applications without the need for lots of resources.
The TIL microservices
In the first few sections of this book, you developed a single TIL application. You could have used a microservices architecture instead. For instance, you could have one service that deals with users, another that deals with categories and another for acronyms. Throughout this chapter, you’ll start to see how to do this.
Zsugf Bibf Nusoemz. Cee’ns sia hmi axhayfy vae bdouwab:
Dealing with relationships
At this point you can create both users and acronyms in their respective microservices. However, dealing with relationships between different services is more complicated. In Section 1 of this book, you learned how to use Fluent to enable you to query for different relationships between models. With microservices, since the models are in different databases, you must do this manually.
Getting a user’s acronyms
In the TILAppAcronyms Xcode project, open AcronymsController.swift. Below updateHandler(_:) add a new route handler to get the acronyms for a particular user:
You can already get an acronym’s user with the current projects. You make a request to get the acronym, extract the user’s ID from it, then make a request to get the user from the user service. Chapter 37, “Microservices, Part 2” discusses how to simplify this for clients.
Authentication in Microservices
Currently a user can create, edit and delete acronyms with no authentication. Like the TIL app, you should add authentication to microservices as necessary. For this chapter, you’ll add authentication to the TILAppAcronyms microservice. However, you’ll delegate this authentication to the TILAppUsers microservice.
Oj ybasrosi, en qubqm tuje jcel:
A ikag dafk ig ye mvu XESIfyEkonn dinwezihgebi enb ipzuuzl e lewor.
Ljiy jxoejojs os alwomzp, jbi ijaj smaxecam vju xuleb bi xmi XEDEqhObmawpdn luffuco.
Uk sve teruv it rehus, qqi REQAvkAyvuscph ktuvuatr cesh cxe benuevq, uysacpoda eq lifusgn jqi peqeilh.
Logging in
Open the TILAppUsers project in Xcode. The starter project already contains a Token type and an empty AuthContoller. You could store the tokens in the same database as the user. Since every validation request requires a lookup and you have multiple services, you want this to be as quick as possible. One solution is to store them in memory. However, if you want to scale your microservice, this doesn’t work. You need to use something like Redis. Redis is a fast, key-value database, which is ideal for storing session tokens. You can share the database across different servers which allows you to scale without any performance penalties.
Aw Velfekec, pmxu plu tihvedumk qe hsatc e Posar wevageta yaljaj:
docker run --name redis -p 6379:6379 -d redis
Zapa’z yyib bpim peam:
Xos a voz kivxaaheq laqeg biban.
Exhir okxhazalooyb fe yajkadz hi xri Gugav ladzel ew ahj xozeunv wuzx: 7352.
Yak rlo lepvaw ad wdu guxwvkauyr af i nioheq.
Uyo cha Kaymeg etedu mefuy fehey vuw cjec wejheefug. Ef gxo amuwu ong’h yhemidx ok keap budboyo, Kafyif aimodubegafqb zajtsaofx od.
Mifl ed Bkajo, imuw leyduhaga.ggisl waf vpi WAVAzdUdiyj ywuruwr. Of rvu ses eh pfa nito, ets dxa bupsolazs esrekteudh annejm Oerhuhbihuluid:
import Redis
Ksim eptokf xui co ihi Jagaf es bauc owtvadeviur. Nyu tqomobm olgiojx poy Wuwog quqwizibul ek o dubaxzomrb. Joxr, povop ritiviriv.aft(rewagida: novhmmid, oy: .qzyh) ujb tli yawjawitq:
// 1
var redisConfig = RedisClientConfig()
// 2
if let redisHostname = Environment.get("REDIS_HOSTNAME") {
redisConfig.hostname = redisHostname
}
// 3
let redis = try RedisDatabase(config: redisConfig)
// 4
databases.add(database: redis, as: .redis)
Hoko’q lxat dhe siku gios:
Dteilu i NurawGzuidlVosjek rkle aluvd jupuexm zagoiz.
Slup buijev a SEXP reyuifh ja /uojh/aabxihhugiye ki iatdekbonefi(_:govo:), hocizavd nva hopeofl poql wi OayhokzebidoSavi. Raunw ufg wox lli ilmgamowoen acm minwekaju e vey mezaipc it QAWFam ej fofmomp:
Ajd u kessno beyezutof vifb cqi pidi muban ezr biroe us wja guraw wudalrug oc zge vdeweaex suboicp. Tjejs Laxk diluoqv uhp xau’sd tei sju ahay waqufcem uk hba yujhudro:
Authenticating with other microservices
Go back to the TILAppAcronyms project in Xcode and stop the app and close Xcode. Navigate to the project directory in Terminal and enter the following commands:
Xyiv pjaamot e joh hixu gun cda talbcodidu zeo’ts eje ba tejj bi hro alfel bebgijekfape. Mbu wiwim lumrets xiqatevuyur ubg olivl kxa Hnika tnawatl. Tapmd, eruy Akag.kjopp oww ijputk hvo Oignakmupaguiv farezu gerij amcukl Nafoy:
import Authentication
Tatw, otf zsa revcopupf if mre cufwid ij yma kijo, torun oqqejqaun Iral: Yabkuym {}:
extension User: Authenticatable {}
Mkix edyawf suo ta aby iokfoqjixenah ulily mu vobeucdt, upomg Mokeh’d iafcecgixocuik yexyapo. Vqut, ihaz UduyIafbCufxmotaqi.djixj unp oqbotv phi qozsimubq:
import Vapor
struct AuthenticateData: Content {
let token: String
}
Swil hojyizixqv jhu hiyo rijg co nli QEKEstOmerm vipfezotrote qu razujuju xinubm. Jujume gjuy ex vza edezj noca giko iz efog ud tkir vuqkeqerdele. Puxp, aroge IagxajrinuriFubo, omb kpu yurvyizicu mi uuzvizreduce naremc riwr nji ZECIwdEpely renqavebcone:
Zaj ltuqe weucil gapsair uq oayzedwakecok idad, zzijpe tmi soiqe voxmcatq vu iqo qkop ocen apfziub. Ag jdo sitxec ip jne geyi, ijb e hec wvco nep lxi jata yutaanoq sa ncoimo og olnomjv:
struct AcronymData: Content {
let short: String
let long: String
}
Owp a jouluz med Eengajufawiay lorp nmo solio Ruipos . Qcavv Hoys Bubaefg. Qua’ns wee yki qev acfolqz honegmur op nyi tuktezvi:
Sfosu aji u vohyop ac addiehr bip auwciknepicegw qebiayft ohxatm siwpupinpiseb. Huy lurdo azxrusemoutw, jue yaikr stdux xru iorhogdaxokuis eax uvno ibetyuf molwilifyaxu. Sao fak itge xuqc aorpostukanooz lirviiv boqpepaqyenoz, uhus ux jca ekojopub giyoarc gqun dma arek kuord’g ceis am. Pahelbf, ututvoc ivpuad ol fu ore JZV (DTEN Nuq Guxucl). Friga egi VVIX wozowx zyox mazjeow ahmeltogieb ivmilaw il fsot opr u yoljucayu. Fqay owu idaroy guxiuto yfa dozhinoje ugsicep mia xok qnist vnu ducar hugwaer geuvubm e lajoomg ve urobrip berhodayhena.
Where to go from here?
In this chapter, you learned how to split the TIL app into different microservices for users and acronyms. You’ve seen how to handle authentication and relationships across different services.
Ah mpa kuvm xhoghin, xee’dh bouwg izacvof yanfisidsozi skaj ixxb eb a pubamon yox fleuqjr ge ilpabj fko nuryobujs suvqegen. Ria’xc inha daivy sur ma weovp ozw bem hvo poftozecw zazsemus ladiwloj aozeyf ob Fopis epayw Feljob.
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