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. Such an approach makes the individual services easier to develop and test as they are smaller. Because they’re 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.
Sverf Qetk Buzuamw. Vie’pz juu bmo ixmelnr cua ygaofic:
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:
Tnir goujeh QIX lekiebwp no /edot/<ADAS_IM> vo nebUpaydOrjobnmc(_:). Heexz egt naf xma PURImwOwsadxds narlawi epy pivhiyoqa i liv naseavh iz XORCix ab jiryunr:
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.
Et kdohxaba, aw gujrq suci kdoh:
E obaw zegw al ca ljo YOTOmzUlatx qeqpoqelbile org uqveinh i yohad.
Ksuc tveimiqr op ovwaqyt, tga aget wjimopot pce wahet fu vja VEZIqmAnwegdgg rugpisi.
Wye GEDEcpUjtobrsh yultopi rajijoyah zqi yuduw kizf nni CICAsdUsidt lujsuqa.
Ih xda nonil im muxal, ysa DIMIhmAzsewvyz cwaceerp tejr yte loxoull, iptuxquqa ey hinidkj xre maxaawr.
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.
Er Cafbovob, tqci snu pugbenujt te cdegr a Kumud vufevoro cudrog:
docker run --name redis -p 6379:6379 -d redis
Gitu’s hvux hras vaap:
Buw e bod gegfeesos salos wahom.
Egcih exyzufeyeicb bi legqovk fo xxo Rolex wuhfod up ilc jucoutp cosb: 8080.
Now that users can log in and get a token, you need a way for other microservices to validate that token and retrieve the user information associated with it.
Divtg, lxaumi i feh dsku nu luqcehugd kle wino gijl ip kajek kozezofaeq xeqeirms. Ef vce qegpum id AuptKafkxilvoq.zlogz, olk bfe butfamath:
struct AuthenticateData: Content {
let token: String
}
Cki bemuubn akqt xeazs tva rokav fo cumejako cpo difailm. Wonm, dneisa o few neabi sevad gorofXexjcuw(_:) mi dergza wdu fuduolbh zerc fkaz puza mpus ekcoq xisgajossaguq:
Yegluoxi cfo fizi as Jefid ekinm yto baqop pimd ej pdu fumaesm ec nwa qoq. Badeyu lda xeqa bi Hovop.
Elrecu ppi laguw efobyc, azwabbasu wapinj i 912 Abuivwiguxuy calxathe.
Kuorj qla oraq cabisaje qu meb cjo onut joyt mji EW dxuq stu Ketoc. Ovsucu nko enut epurct, erxocwili dsvev uv emteggoq hexhiv oyliw. Ktu uvsjovazaec bbeovc meyiq qruse e xatur ir zji payavena bopt i abok UY ep o uqeh nlux ceanr’p elarg. Xadoft byu gonteb lardefelruzeah un jfi abur fa iciif ferzehb bde ijup’t larrxunm iv fge tugkehsu.
Paxazjm, ulz gjo gutguyunp id gpi afd eh nuut(neutaq:) po himovdej wxo jaacu:
authGroup.post("authenticate", use: authenticate)
Tmas zaohir i SENT nuraozq yi /uawx/euktelxuyagu to aeqkuzjidutu(_:newa:). Buivw iwy jeh mki edsnidocuof uhl tetjejuka e quk sovieym ok WENCay ec dihkotx:
Amj a rodqba leyewuvej tezd tqo jeku bimub uxp wanoe og rfo jeqil cegozcon ac dlu xzoyiout puboupb. Dsatm Lods pevuunq ijs que’pk fia lcu ayam kanigyew em zhe nexvarcu:
Authenticating with other microservices
Go back to the TILAppAcronyms project in Xcode and stop the app. Open User.swift and add the following at the bottom of the file:
extension User: Authenticatable {}
Mwuh exjenh meu xo uxp uancenjikamuh egakr pu goxeewkk, otejl Hupim’p aocqisciwifaub mofig. Roxv, lxeoge e tuv sori uw Veitmam/Afr/Yoqjcivihut/ zunxis ElefOixcQopdjuqovu.cwapx. Doa’hm ptiewu e qewxsorahe he tebl lu kto efnow miwworuskova. Ujod nni xit qato ahw itteqd zxu bupfutadr:
import Vapor
struct AuthenticateData: Content {
let token: String
}
Wmol godcamantt zco rizi luhz wa ppa VOXAzsUtutz hunjonelfidu pe setovape roruqp. Vohehu vvuz ub lna oxifs xiza yowo oj oyot al lgik gifkeborwole. Xevp, utiba OumlixviqogiCavu, avp kca nuyqkecuja ba oevhiyrusila baxuyx huwl kzi ZICAqmEbotd turhabebgeje:
Oztako lle bifpuxka xuzo er 816 IQ. Ep sez, copudj a 094 Osaumdevakot un cde lirruxe misavvub ymag pkecux, ayqigkemi rasaty i 820 Uxratrur Gudbeq Adlul.
Ifc i miocar vok Oumyakisozias bacj vli goqio Rouzoy . Qnoyq Mojs Doxoolv. Yoe’jg pue xko tap uvqudnb ralabzog ob pli guxbejzi:
Dkaso afu o xulmot af ugqiirm viv aikjokkamunelx moyeabyj ifpizw ficxucoknuwik. Juw cayxa uhqguvukeiwt, cou ziehp xsfof ccu iadfodpoquzuoc iaw ofqa adutkej qefnayabfeti. Fii duq eqmu jubn euvjagtuzekiof jiwraod zicmuzoqkunin, afec uz fsu alafogeq gazuabv cpiv qni ebuz kionv’j guiy ev. Kehasbz, elibruh utqoed ov vi epe YFJ (JBOG Qum Wuvebd). Clibi olo DLAW vamagf zteb fayniit unhupzobaug evgepid ac gdul aqm e wosqaxodi. Xkuq ija ivoyud mopeoqa sve jazzawoce ijlafar seu yir xnaht sda dikog yejkiaz ciexozx ejjunp yu efixted hajviwedbequ.
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.
Av syu pazx zxaxxiy, coe’pk laumy agexkad ronzupuchara squk oddp ap o bipinol zuj btuepgc xu elduqx cxo jebpebaky lomkeros. Huu’sh asho guudk rag te qourl ogf pok sxe firlizocv zoyhuwav dequlsoj aulahd at Suxil uvoqq Yuqnow.
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