Kotlin Multiplatform in Production

Update on the state of the Kotlin Multiplatform universe, current libraries, and how to get started.

Transcript

1. Kotlin Multiplatform In Production Kevin Galligan
3. Touchlab
4. Community community!
6. What is Kotlin Multiplatform?
7. kot·lin mul·ti·plat·form /ˌkätˈlin məltiˈplatfôrm,ˌkätˈlin məltīˈplatfôrm/ noun noun: kotlin multiplatform 1.optional, natively-integrated, open-source, code sharing platform, based on the popular, modern language kotlin. facilitates non-ui logic availability on many platforms.
8. Optional Sharing Low risk. No Big Decisions.
9. Natively Integrated smooth interop
10. open source
11. Code Sharing not “cross platform”
12. popular
13. popular
14. popular
15. language & tools
16. modern
17. Not UI well, not necessarily UI
18. Shared UI == Failure!
19. Shared Logic == Computers
20. Many Platforms
21. Kotlin
22. Kotlin JVM
23. Kotlin JVM JS
24. Kotlin JVM JS Native
25. Kotlin JVM JS Native iOS Mac Linux Windows Android/NDK Others…
26. Kotlin JVM JS Native iOS Mac Linux Windows Android/NDK Others… Webassembly
27. Kotlin JVM JS Native iOS Mac Linux Windows Android/NDK Others… Webassembly Many Platforms
28. Why Kotlin? High Efficiency Low Risk Modern Language/Tools Highly Engaged Community
29. mobile is easy
30. mobile is easy
31. Status
32. Q3 Q2 Q4 Q1 Q2 2018 2019 0 .6 v0.7 v0.8 v0.8.2 v0.9.3 IDE tooling! Coroutines?
33. Q3 Q2 Q4 Q1 Q2 2018 2019 0 .6 v0.7 v0.8 v0.8.2 v0.9.3 IDE tooling! Coroutines? K/N 1.0, Kotlin 1.3 Gradle 4.10+ Android Studio
34. Q3 Q2 Q4 Q1 Q2 2018 2019 0 .6 v0.7 v0.8 v0.8.2 v0.9.3 IDE tooling! Coroutines? K/N 1.0, Kotlin 1.3 Gradle 4.10+ Android Studio Other samples/libraries Production deployments Compiler plugins! MT Coroutines!
35. Q3 Q2 Q4 Q1 Q2 2018 2019 0 .6 v0.7 v0.8 v0.8.2 v0.9.3 IDE tooling! Coroutines? K/N 1.0, Kotlin 1.3 Gradle 4.10+ Android Studio Compiler plugins! Other samples/libraries Production deployments Paid license/debugger Reactive Library Big Production Apps Webassembly stuff? MT Coroutines!
36. TL;DR March start getting real end of Q1
37. SHARED CODE FOR ANDROID & IOS
38. Common
39. Common mainThread?
40. expect val mainThread:Boolean
41. expect val mainThread:Boolean actual val mainThread: Boolean get() = Looper.myLooper() === Looper.getMainLooper()
42. expect val mainThread:Boolean actual val mainThread: Boolean get() = Looper.myLooper() === Looper.getMainLooper() actual val mainThread: Boolean get() = NSThread.isMainThread()
43. expect val mainThread:Boolean actual val mainThread: Boolean get() = Looper.myLooper() === Looper.getMainLooper() actual val mainThread: Boolean get() = NSThread.isMainThread() actual val mainThread: Boolean = true
44. expect fun currentTimeMillis():Long expect fun <B> backgroundTask(backJob:()-> B, mainJob:(B) -> Unit) expect fun backgroundTask(backJob:()->Unit) expect fun networkBackgroundTask(backJob:()->Unit) expect fun initContext():NativeOpenHelperFactory expect fun <T> goFreeze(a:T):T expect fun <T> T.freeze2(): T expect fun simpleGet(url:String):String expect fun logException(t:Throwable) expect fun settingsFactory(): Settings.Factory expect fun createUuid():String
45. expect class Date { fun toLongMillis():Long } expect class DateFormatHelper(format:String){ fun toDate(s:String):Date fun format(d:Date):String }
46. actual class Date(val date:java.util.Date) { actual fun toLongMillis(): Long = date.time } actual class DateFormatHelper actual constructor(format: String) { val dateFormatter = object : ThreadLocal<DateFormat>(){ override fun initialValue(): DateFormat = SimpleDateFormat(format) } actual fun toDate(s: String): Date = Date(dateFormatter.get()!!.parse(s)) actual fun format(d: Date): String = dateFormatter.get()!!.format(d.date) }
47. fun initPlatformClient( staticFileLoader: (filePrefix: String, fileType: String) -> String?, analyticsCallback: (name: String, params: Map<String, Any>) -> Unit, clLogCallback: (s: String) -> Unit) {
48. fun initPlatformClient( staticFileLoader: (filePrefix: String, fileType: String) -> String?, analyticsCallback: (name: String, params: Map<String, Any>) -> Unit, clLogCallback: (s: String) -> Unit) { AppContext.initPlatformClient ({filePrefix, fileType -> loadAsset("${filePrefix}.${fileType}")}, {name: String, params: Map<String, Any> -> val event = CustomEvent(name) //Loop Answers.getInstance().logCustom(event) }, { Log.w("MainApp", it) })
49. let appContext = AppContext() appContext.doInitPlatformClient(staticFileLoader: loadAsset, analyticsCallback: analyticsCallback, clLogCallback: csLog) func loadAsset(filePrefix:String, fileType:String) -> String?{ do{ let bundleFile = Bundle.main.path(forResource: filePrefix, ofType: fileType) return try String(contentsOfFile: bundleFile!) } catch { return nil } }
50. Common
51. JVM Native Common
52. JVM Native Common Framework
53. JVM Native Common Framework
54. JVM Native Common Android Stuff Framework iOS Stuff
55. Libraries!
56. Jetbrains • Ktor • Kotlinx.Coroutines • Kotlinx.io • Kotlinx.serialization • Atomic-fu (maybe?)
57. Community • Sqldelight • Knarch.db • Multiplatform Settings • Stately • OKIO2 (developing) • Timber (sort of)
58. Community • Sqldelight • Knarch.db • Multiplatform Settings • Stately • OKIO2 (developing) • Timber (sort of)
60. SQLiter trim, lightly opinionated SQLite driver
61. SQLit trim, lightly opinionated SQLite driver
62. Targets Native SQLite
63. Targets Native SQLite Native SQL Encrypted
64. Targets Native SQLite Native SQL Encrypted Android SQLite
65. Targets Native SQLite Native SQL Encrypted Android SQLite Android SQL Encrypted
66. Targets Native SQLite Native SQL Encrypted Android SQLite Android SQL Encrypted JS?
69. Public Service Announcement if you understand anything about native…
70. STATE
71. 3 Ecosystems JVM, JS, and Native
72. Kotlin/Native State Rules
73. Rule #1 Live state belongs to 1 thread
74. Rule #2 Frozen state can be shared by threads
75. No threading primitives No “synchronized”, “volatile”, etc
76. Runtime Safety Kotlin/Native can verify safe mutability
77. JVM/JS? See Kotlinconf keynote
78. Short term pain Tradeoff for future
79. How does Kotlin know?!
80. FROZEN!
81. FROZEN!
82. Runtime Designation AKA a flag
83. Call freeze()
84. One-way operation No unfreeze()
85. class TalkExamples{ var justCountingStuff:Int = 0 init { backgroundCall { //do something justCountingStuff++ }.freeze() } }
86. class TalkExamples{ var justCountingStuff:Int = 0 init { backgroundCall { //do something justCountingStuff++ }.freeze() } }
87. Usually OK Data objects should be immutable
88. Global state more difficult Service object, large memory state
89. Passing State
90. DetachedObjectGraph(TransferMode.SAFE) { ListData("asdf") }
91. val data = ListData("asdf") DetachedObjectGraph(TransferMode.SAFE) { data }
92. private val stateBox: AtomicReference<DetachedObjectGraph<Any>> = AtomicReference( DetachedObjectGraph(mode = TransferMode.SAFE, producer = { mutableListOf<E>() as Any }) ) private val lock = NSLock() internal fun withLockDetached(proc: (MutableList<E>) -> MutableList<E>) { lock.lock() try { stateBox.value = DetachedObjectGraph(mode = TransferMode.SAFE, producer = { val dataList = stateBox.value.attach() as MutableList<E> proc(dataList) as Any }) } finally { lock.unlock() } }
93. Detaching Time must visit whole graph
97. Atomics! Mutable immutable
98. AtomicInt/AtomicLong
99. AtomicReference Update with frozen objects
100. val lambdas = AtomicReference<PlatformLambdas?>(null) fun initPlatformClient( staticFileLoader: (filePrefix: String, fileType: String) -> String?, analyticsCallback: (name: String, params: Map<String, Any>) -> Unit, clLogCallback: (s: String) -> Unit) { lambdas.value = PlatformLambdas( staticFileLoader, analyticsCallback, clLogCallback).freeze() }
101. Stately! v0.3.1~ish
102. Multiplatform Definitions • freeze() method and frozen info • Atomics (Int, Long, Reference) • K/N state-related annotations (@ThreadLocal/ @SharedImmutable) • Shared Collections!
103. More Info and Tutorials https://github.com/touchlab/KotlinMultiplatformStuff
104. Making a Library! a very small library
105. Download Intellij EAP https://www.jetbrains.com/idea/nextversion/
110. targets { fromPreset(presets.jvm, 'jvm') // This preset is for iPhone emulator // Switch here to presets.iosArm64 to build library for iPhone device fromPreset(presets.iosX64, 'ios') { compilations.main.outputKinds('FRAMEWORK') } }
111. targets { fromPreset(presets.jvm, 'jvm') // This preset is for iPhone emulator // Switch here to presets.iosArm64 to build library for iPhone device fromPreset(presets.macosX64, 'ios') /*{ compilations.main.outputKinds('FRAMEWORK') }*/ }
112. targets { fromPreset(presets.jvm, 'jvm') fromPreset(presets.js, 'js') fromPreset(presets.macosX64, 'macos') fromPreset(presets.iosX64, 'iosX64') fromPreset(presets.iosArm32, 'iosArm32') fromPreset(presets.iosArm64, 'iosArm64') }
113. Live Coding is a Bad Idea don’t be a hero
114. Go to Github https://github.com/kpgalligan/MyNewLibrary
115. Much More obviously
116. Libraries Needed • File Access • Date (310 port) • Mocking (and other test support) • Reactive • UI State
117. Getting Started
118. Join Kotlin Slack https://slack.kotlinlang.org
119. Sample Apps the conference apps
120. https://github.com/touchlab/DroidconKotlin/
121. Sample Libraries Stately SQLDelight
122. Office Hours - Kotlin Multiplatform 2pm in Coblenz
124. kevin@touchlab.co @kpgalligan
125. kevin@touchlab.co @kpgalligan Join the team !