Patterns & Practices for Cloud-based Microservices
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This document discusses patterns and practices for building real-world, event-driven microservices. It recommends that microservices be built using the F# programming language to gain benefits like increased productivity, expanded feature sets with discriminated unions and type providers, and more readable and concise code. It provides guidelines for building microservices functionally by avoiding state changes and side effects, isolating side effects, and using an external service to control the microservices' lifecycles.
![The F# solution offers us an order of magnitude
increase in productivity and allows one developer to
perform the work [of] a team of dedicated
developers…
Yan Cui
Lead Server Engineer, Gamesys
“
“ “](https://image.slidesharecdn.com/untitled-160912101738/85/Patterns-Practices-for-Cloud-based-Microservices-22-320.jpg)
![F# way 37
type Year = int
type [<Measure>] percent
type Customer = Simple | Valuable | MostValuable
type AccountStatus =
| Registered of Customer * since:Year
| Unregistered
let customerDiscount = function
| Simple -> 1<percent>
| Valuable -> 3<percent>
| MostValuable -> 5<percent>
let yearsDiscount = function
| years when years > 5 -> 5<percent>
| years -> 1<percent> * years
let accountDiscount = function
| Registered (customer, years) ->
customerDiscount customer, yearsDiscount years
| Unregistered -> 0<percent>, 0<percent>
let asPercent p = decimal p / 100m
let reducePriceBy discount price =
price - price * (asPercent discount)
let calculateDiscountedPrice price account =
let custDiscount, yrsDiscount =
accountDiscount account
price
|> reducePriceBy custDiscount
|> reducePriceBy yrsDiscount](https://image.slidesharecdn.com/untitled-160912101738/85/Patterns-Practices-for-Cloud-based-Microservices-36-320.jpg)
Patterns & Practices for Cloud-based Microservices
- 1. Patterns and Practices for Real-world, Event-driven Microservices Rachel Reese | @rachelreese | rachelree.se Jet Technology | @JetTechnology | tech.jet.com
- 2. InfoQ.com: News & Community Site • 750,000 unique visitors/month • Published in 4 languages (English, Chinese, Japanese and Brazilian Portuguese) • Post content from our QCon conferences • News 15-20 / week • Articles 3-4 / week • Presentations (videos) 12-15 / week • Interviews 2-3 / week • Books 1 / month Watch the video with slide synchronization on InfoQ.com! https://www.infoq.com/presentations/ jet-microservices-cloud
- 3. Presented at QCon New York www.qconnewyork.com Purpose of QCon - to empower software development by facilitating the spread of knowledge and innovation Strategy - practitioner-driven conference designed for YOU: influencers of change and innovation in your teams - speakers and topics driving the evolution and innovation - connecting and catalyzing the influencers and innovators Highlights - attended by more than 12,000 delegates since 2007 - held in 9 cities worldwide
- 4. Real-world
- 5. We plan to be the new Amazon.com Launched July 22, 2015 • Both Apple & Android named our app as one of their tops for 2015 • Over 20k orders per day • Over 10.5 million SKUs • #4 marketplace worldwide • 700 microservices Stop by the power-up lounge!
- 6. Azure Web sites Cloud services VMs Service bus queues Services bus topics Blob storage Table storage Queues Hadoop DNS Active directory SQL Azure R F# Paket FSharp.Data Chessie Unquote SQLProvider Python Deedle FAKE FSharp.Async React Node Angular SAS Storm Elastic Search Xamarin Microservices Consul Kafka PDW Splunk Redis SQL Puppet Jenkins Apache Hive Apache Tez
- 8. Microservices An application of the single responsibility principle at the service level. Has an input, produces an output. Easy scalability Independent releasability More even distribution of complexity Benefits “A class should have one, and only one, reason to change.”
- 9. Event-driven
- 10. Event-driven The focus of your application code is to react to events (single or a stream).
- 11. Events Any significant change in state that has happened in your domain Past tense Immutable Contains only relevant data to transaction All events should be represented as verbs in the past tense such as CustomerRelocated, CargoShipped, or InventoryLossageRecorded. For those who speak French, it should be passé composé, they are things that have completed in the past. Greg Young
- 12. Event Consumer “Events” as the notification messages Event channelEvent Emitter
- 13. Event-sourced
- 14. Compare to relational model which captures only the latest state change. These sets are then related to each other. Event-sourced • Event-sourced is about how you model the domain. • An append-only sequence of events as data store. • Keep track of all state changes. • Can REPLAY these event streams.
- 15. Event Stream
- 16. How did Jet decide on microservices?
- 17. Why F#?
- 19. Why F#? <3
- 20. FP |> Programmers <3
- 22. The F# solution offers us an order of magnitude increase in productivity and allows one developer to perform the work [of] a team of dedicated developers… Yan Cui Lead Server Engineer, Gamesys “ “ “
- 23. Why F#? Expanded feature set
- 24. Expanded feature set: Option types
- 25. Expanded feature set: Discriminated unions public abstract class Transport{ } public abstract class Car : Transport { public string Make { get; private set; } public string Model { get; private set; } public Car (string make, string model) { this.Make = make; this.Model = model; } } public abstract class Bus : Transport { public int Route { get; private set; } public Bus (int route) { this.Route = route; } } public class Bicycle: Transport { public Bicycle() { } } type Transport = | Car of Make:string * Model:string | Bus of Route:int | Bicycle C# F# Trivial to pattern match on!
- 27. Concise & powerful code public abstract class Transport{ } public abstract class Car : Transport { public string Make { get; private set; } public string Model { get; private set; } public Car (string make, string model) { this.Make = make; this.Model = model; } } public abstract class Bus : Transport { public int Route { get; private set; } public Bus (int route) { this.Route = route; } } public class Bicycle: Transport { public Bicycle() { } } type Transport = | Car of Make:string * Model:string | Bus of Route:int | Bicycle | Train of Line:int let getThereVia (transport:Transport) = match transport with | Car (make,model) -> ... | Bus route -> ... | Bicycle -> ... Warning FS0025: Incomplete pattern matches on this expression. For example, the value ’Train' may indicate a case not covered by the pattern(s) C# F#
- 28. Expanded feature set: Type providers 920 pages! 31 lines!
- 30. Readability!
- 32. type Booking = | Basic of Plane | Combo of Combo | FullPack of Plane * Hotel * Car and Plane = {Outbound: DateTime; Return: DateTime; Destination: Country} and Combo = | ``With Hotel`` of Plane * Hotel | ``With Car`` of Plane * Car and Hotel = {Arrival: DateTime; Departure: DateTime; Location: Country} and Car = {From: DateTime; To: DateTime; Location: Country} and Country = {Name: String; ``ISO 3166-1``: char*char}
- 34. Original code
- 36. F# way 37 type Year = int type [<Measure>] percent type Customer = Simple | Valuable | MostValuable type AccountStatus = | Registered of Customer * since:Year | Unregistered let customerDiscount = function | Simple -> 1<percent> | Valuable -> 3<percent> | MostValuable -> 5<percent> let yearsDiscount = function | years when years > 5 -> 5<percent> | years -> 1<percent> * years let accountDiscount = function | Registered (customer, years) -> customerDiscount customer, yearsDiscount years | Unregistered -> 0<percent>, 0<percent> let asPercent p = decimal p / 100m let reducePriceBy discount price = price - price * (asPercent discount) let calculateDiscountedPrice price account = let custDiscount, yrsDiscount = accountDiscount account price |> reducePriceBy custDiscount |> reducePriceBy yrsDiscount
- 37. Why F#? You don’t need a Ph.D.
- 38. This is Sean.
- 39. When Sean was 8, he started speaking at large technical conferences. On F#.
- 40. Guidelines
- 41. Be functional! Prefer immutability Avoid state changes, side effects, and mutable data Use data in data out transformations Think about mapping inputs to outputs. Look at problems recursively Consider successively smaller chunks of the same problem Treat functions as unit of work Higher-order functions
- 42. Don’t abstract This one magical service could write to ALL of the following: …badly. Event store Nservice Bus MSMQ 0MQ SQL Server
- 43. Isolate side effects Submit order microservice Insert order to SQL microservice Send thank you email microservice Updates SQL Sends “Thank you for ordering” Email Updates SQL Sends “Thank you for ordering” Email
- 44. Use a backup service to replay events Service 1 runs in production as normal Backup service 1 replays events until up-to-date. Switch over. Instantly live with changes! Also stage a copy of any aggregate/data store until stream has completed replaying!
- 45. type Input = | Product of Product type Output = | ProductPriceNile of Product * decimal | ProductPriceCheckFailed of PriceCheckFailed let handle (input:Input) = async { return Some(ProductPriceNile({Sku="343434"; ProductId = 17; ProductDescription = "My amazing product"; CostPer=1.96M}, 3.96M)) } let interpret id output = match output with | Some (Output.ProductPriceNile (e, price)) -> async {()} // write to event store | Some (Output.ProductPriceCheckFailed e) -> async {()} // log failure | None -> async {{ }} // log failure let consume = EventStoreQueue.consume (decodeT Input.Product) handle interpret What do our services look like? Define inputs & outputs Define how input transforms to output Define what to do with output Read events, handle, & interpret
- 46. Microservices should not control own lifecycle Execution runtime Deployment Configuration Restarting Versioning Scaling Availability Grouping by subsystem Scheduling Input-output static analysis Dashboard Think IoC!
- 47. Torch YAML files torchVer: 2.0.0 subSystem: PriceCheck name: PriceCheck description: checks prices on nile ver: 0.0.1 autoStart: always compile: true ha: aa ##active-active. Could be ap for active-passive scriptPath: PriceCheckNilePriceCheckNile.fsx libPath: binrelease args: --jsonConfig=PriceCheckNile.json It used to mean “Yet Another Markup Language” but was backronymed to clarify its focus as data-oriented. YAML = “YAML Ain’t Markup Language”
- 48. Summary Don’t abstract Be functional Isolate side effects Use a backup service Use consistent formatting Use an outside product to control lifecycle
- 49. For more information 51 F# fsharp.org fsharpforfunandprofit.com NYC F# & Jet Tech Meetup Event sourcing Greg Young talks: http://www.infoq.com/news/2014/09/greg-young-event-sourcing https://www.youtube.com/watch?v=JHGkaShoyNs Microservices martinfowler.com microservices.io
- 50. Patterns and Practices for Real-world, Event-driven Microservices Rachel Reese | @rachelreese | rachelree.se Jet Technology | @JetTechnology | tech.jet.com
- 51. Watch the video with slide synchronization on InfoQ.com! https://www.infoq.com/presentations/jet- microservices-cloud