What's In Store: KotlinConf19 Mike Nakhimovich Yigit Boyar

Transcript

1. Copenhagen Denmark WHAT’S IN STORE YIGIT BOYAR MIKE NAKHIMOVICH @yigitboyar @friendlyMikhail
2. We love Android
3. We love how easy Android is
4. Working with Data on Android is easier than ever
5. We stand on shoulders of giant (libraries)
6. We stand on shoulders of giant (libraries) • Fetch Data - Retrofit, Okhttp, Apollo, Firebase
7. We stand on shoulders of giant (libraries) • Fetch Data - Retrofit, Okhttp, Apollo, Firebase • Cache - Room, SQLDelight, Okio
8. We stand on shoulders of giant (libraries) • Fetch Data - Retrofit, Okhttp, Apollo, Firebase • Cache - Room, SQLDelight, Okio • Transmitting - Rxjava, LiveData, Flow
9. HOW DO YOU PUT IT ALL TOGETHER ?
10. https://developer.android.com/jetpack/docs/guide
11. https://developer.android.com/jetpack/docs/guide
12. https://developer.android.com/jetpack/docs/guide Fragment/ Activity
13. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData
14. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository
15. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source
16. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source
17. What does android ecosystem give us?
18. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source
19. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source Jetpack
20. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source Jetpack Jetpack
21. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source Jetpack Jetpack Jetpack
22. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source Jetpack Jetpack Jetpack Square
23. https://developer.android.com/jetpack/docs/guide Fragment/ Activity ViewModel LiveData Repository Local Source Remote Data Source Jetpack Jetpack Jetpack Square Figure it out yourself lolz https://developer.android.com/jetpack/docs/guide
24. Repository Let’s figure it out (together)
25. The Repository Pattern Repositories are classes or components that encapsulate the logic required to access data sources. https://docs.microsoft.com/en-us/dotnet/architecture/microservices/microservice-ddd-cqrs-patterns/infrastructure-persistence-layer-design
26. What does repository do ?
27. What does repository do ? • Centralize logic to manage data
28. What does repository do ? • Centralize logic to manage data • Remove data retrieval burden from UI code
29. What does repository do ? • Centralize logic to manage data • Remove data retrieval burden from UI code • Enable Data Driven UI’s
30. Few years back…. Younger/More Handsome Friendly Mike NY Times made Store
31. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN Why NY Times made Store
32. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN get() Why NY Times made Store
33. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN get() get() get() get() Why NY Times made Store
34. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN get() get() get() get() get() get() get() get() Why NY Times made Store
35. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN get() get() get() get() Why NY Times made Store
36. Sharing of responses was important Fragment1 ConfigApi Fragment2 Fragment3 FragmentN Users Wallet get() get() get() get() Why NY Times made Store
37. Why NY Times released Store
38. RxJava was new & we wanted abstractions switchIfEmpty concat first Maybe Single Observable cache onErrorResumeNext empty map filter doOnSuccess error doAfterTerminate PublishSubject hide startWith repeatWhen Why NY Times released Store
39. How we used Store
40. Build a simple Store
41. Store<Article, Integer> store = StoreBuilder.<Integer, Article>builder() Build a simple Store
42. Store<Article, Integer> store = StoreBuilder.<Integer, Article>builder() .fetcher(articleId -> api.getArticles(articleId)) Build a simple Store
43. Store<Article, Integer> store = StoreBuilder.<Integer, Article>builder() .fetcher(articleId -> api.getArticles(articleId)) .open(); Build a simple Store
44. Fresh request
45. Fresh request disposable = store.fresh(path) .subscribe( handleSuccess(), handleError() )
46. Fresh request Store returns Single<T> skipping memory & disk
47. Get request
48. Get request disposable = store.get(path) .subscribe( handleSuccess(), handleError() )
49. Store returns Single<T> from memory or get fresh Get request
50. Building an offline Store
51. StoreBuilder.<Integer, BufferedSource, ArticleAsset>builder() Building an offline Store
52. StoreBuilder.<Integer, BufferedSource, ArticleAsset>builder() .fetcher(articleId -> api.getArticleAsBufferedSource(articleId)) Building an offline Store
53. StoreBuilder.<Integer, BufferedSource, ArticleAsset>builder() .fetcher(articleId -> api.getArticleAsBufferedSource(articleId)) .persister(FileSystemPersister.create(folder) Building an offline Store
54. StoreBuilder.<Integer, BufferedSource, ArticleAsset>builder() .fetcher(articleId -> api.getArticleAsBufferedSource(articleId)) .persister(FileSystemPersister.create(folder) .parser(GsonParserFactory.createSourceParser(gson, ArticleAsset.Article.class)) Building an offline Store
55. StoreBuilder.<Integer, BufferedSource, ArticleAsset>builder() .fetcher(articleId -> api.getArticleAsBufferedSource(articleId)) .persister(FileSystemPersister.create(folder) .parser(GsonParserFactory.createSourceParser(gson, ArticleAsset.Article.class)) .open(); Building an offline Store
56. Building an offline Store
57. Building an offline Store
58. Building an offline Store tl;dr; IT IS COMPLICATED!
59. Building an offline Store
60. Store gave consistent apis for all requests
61. Store gave consistent apis for all requests Get = I want data don’t care source
62. Store gave consistent apis for all requests Get = I want data don’t care source Fresh = I want new data
63. Fast forward 3 years, Store is showing its age
64. Fast forward 3 years Biggest issue: observable sources public interface Store<T, V> { Single<T> get(V key); Single<T> fetch(V key); // returns an Observable that emits “fresh" any response // from the store that hit the fetcher Observable<T> stream(); }
65. public interface Store<T, V> { Single<T> get(V key); Single<T> fetch(V key); // returns an Observable that emits “fresh" any response // from the store that hit the fetcher Observable<T> stream(); } Fast forward 3 years Biggest issue: observable sources
66. Today We’d like to introduce
67. STORE 4 Today We’d like to introduce
68. 100% kotlin Today We’d like to introduce
69. No Rxjava dependency Today We’d like to introduce
70. Support for observable network & databases Today We’d like to introduce
71. Thanks in big part to Kotlin & Flow Today We’d like to introduce
72. Why Kotlin Coroutines?
73. Why Kotlin Coroutines? Structured Concurrency
74. Rxjava - warns you when you might leak 
 Structured Concurrency
75. Rxjava - warns you when you might leak 
 // Flowable.java @CheckReturnValue public final Disposable subscribe(Consumer<? super T> onNext) { } Structured Concurrency
76. Rxjava - warns you when you might leak 
 // Flowable.java @CheckReturnValue public final Disposable subscribe(Consumer<? super T> onNext) { } Structured Concurrency
77. Coroutines - forces you to not leak 
 Structured Concurrency
78. Coroutines - forces you to not leak 
 public fun CoroutineScope.launch(...) Structured Concurrency
79. Coroutines - forces you to not leak 
 public fun CoroutineScope.launch(...) lifecycleScope.launch { Structured Concurrency
80. Coroutines - forces you to not leak 
 public fun CoroutineScope.launch(...) lifecycleScope.launch { // scoped to the lifecycle } Structured Concurrency
81. AndroidX loves Kotlin Why Kotlin?
82. The future is Kotlin Native/JS Why Kotlin?
83. USING STORE 4
84. Building a Store
85. Building a Store StoreBuilder
86. Building a Store StoreBuilder .fromNonFlow(api::listFiles)
87. Building a Store StoreBuilder .fromNonFlow(api::listFiles) suspend fun listFiles(path: String) : List<File>
88. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister(
89. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read,
90. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read, fun read(path: String): Flow<List<File>?>
91. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read, writer = dao::write)
92. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read, writer = dao::write) suspend fun write(path: String, files: List<File>)
93. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read, writer = dao::write) .cachePolicy(MemoryPolicy)
94. Building a Store StoreBuilder .fromNonFlow(api::listFiles) .persister( reader = dao::read, writer = dao::write) .cachePolicy(MemoryPolicy) .build()
95. Store Stream as First Class Citizen fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>>
96. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>>
97. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> StoreRequest
98. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> StoreRequest Key
99. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> StoreRequest Key Skipped Sources
100. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> StoreRequest Key Skipped Sources Refresh
101. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>>
102. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading
103. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin
104. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Data
105. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Data ResponseOrigin
106. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Data ResponseOrigin Value
107. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Error Data ResponseOrigin Value
108. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Error ResponseOrigin Data ResponseOrigin Value
109. Store stream API fun stream(request: StoreRequest<Key>): Flow<StoreResponse<Key, Value>> Loading ResponseOrigin Error ResponseOrigin Throwable Data ResponseOrigin Value
110. STREAM CACHED
111. Simple case: I want data & updates
112. Simple case: I want data & updates val store = StoreBuilder
113. Simple case: I want data & updates val store = StoreBuilder .from(api::listFiles)
114. Simple case: I want data & updates val store = StoreBuilder .from(api::listFiles) .withPersister(
115. Simple case: I want data & updates val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load,
116. Simple case: I want data & updates val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert
117. Simple case: I want data & updates val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build()
118. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() Simple case: I want data & updates
119. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( Simple case: I want data & updates
120. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( path, Simple case: I want data & updates
121. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( path, refresh = false Simple case: I want data & updates
122. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( path, refresh = false ).collect { Simple case: I want data & updates
123. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( path, refresh = false ).collect { updateUI(it) Simple case: I want data & updates
124. val store = StoreBuilder .from(api::listFiles) .withPersister( reader = dao::load, writer = dao::insert ).build() store.get( path, refresh = false ).collect { updateUI(it) } Simple case: I want data & updates
125. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) }
126. Memory Disk Network Store StoreRequest: Path, Refresh store.get( path, refresh = false ).collect { updateUI(it) }
127. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) }
128. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) }
129. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) }
130. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } LOADING
131. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) }
132. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1
133. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1
134. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 1
135. Memory Disk Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 1
136. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1
137. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1
138. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh
139. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1 1 Flow
140. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1 Flow
141. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1 Flow
142. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1
143. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1
144. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Refresh Flow
145. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh Flow 1
146. Memory Disk Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Refresh Flow 1
147. STREAM CACHED + REFRESH
148. Memory Disk Network Store store.get( path, refresh = true ).collect { updateUI(it) } 1 1 1
149. Memory Disk Network Store store.get( path, refresh = true ).collect { updateUI(it) } 1 1 1 StoreRequest: Path, Refresh
150. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 1 StoreRequest: Path, Refresh
151. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh 1
152. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh 1
153. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh 1 LOADING
154. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 StoreRequest: Path, Refresh 1
155. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 1
156. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 2 1
157. Memory Disk Network Store Flow store.get( path, refresh = true ).collect { updateUI(it) } 1 1 2 2
158. STREAM SKIP CACHE
159. Memory Disk Network Store store.fresh( path ).collect { updateUI(it) } 1 1
160. Memory Disk Network Store store.fresh( path ).collect { updateUI(it) } 1 1 StoreRequest: Path, Fresh
161. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 StoreRequest: Path, Fresh
162. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 StoreRequest: Path, Fresh LOADING
163. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 StoreRequest: Path, Fresh
164. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 StoreRequest: Path, Fresh
165. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1
166. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 2
167. Memory Disk Network Store Flow store.fresh( path ).collect { updateUI(it) } 1 1 2 2
168. STREAM NOW WITH OBSERVABLE LOCAL DATA
169. Memory Source Of Truth Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1
170. Memory Source Of Truth Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1
171. Memory Source Of Truth Network Store store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Cached
172. Memory Source Of Truth Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Cached
173. Memory Source Of Truth Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 1 StoreRequest: Path, Cached 1
174. Memory Source Of Truth Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Cached 1
175. Memory Source Of Truth Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Cached 2
176. Memory Source Of Truth Network Store Flow store.get( path, refresh = false ).collect { updateUI(it) } 1 StoreRequest: Path, Cached 2 2
177. Source of Truth Documents Images Code
178. Source of Truth Enter Folder Name Save
179. Source of Truth Enter Folder Name Save Kotlin Conf
180. Source of Truth Documents Images Code
181. Source of Truth Documents Images Code
182. Source of Truth Documents Images Code Kotlin Conf
183. Source of Truth Documents Images Code Kotlin Conf Bad UX
184. List Files Screen
185. List Files Screen fetch files
186. List Files Screen fetch files Add Folder Screen Screen
187. List Files Screen fetch files Add Folder Screen Screen add new folder
188. Add Folder Screen Screen add new folder List Updated Files Screen
189. Add Folder Screen Screen add new folder List Updated Files Screen fetch files
190. List Files Screen fetch files Add Folder Screen Screen add new folder List Updated Files Screen fetch files
191. List Files Screen fetch files Add Folder Screen Screen add new folder List Updated Files Screen fetch files Local Source of Truth
192. List Files Screen fetch files Add Folder Screen Screen add new folder List Updated Files Screen fetch files Local Source of Truth Is this Store ?
193. Should Store be The Source of Truth?
194. Should Store be The Source of Truth? Local Storage Store put(Key, Value) load(Key): Value?
195. Should Store be The Source of Truth? VS Local Storage Store put(Key, Value) load(Key): Value? Local Storage Store put(Key, Value) load(Key): Flow<Value?>
196. Should Store be The Source of Truth? VS Local Storage Store put(Key, Value) load(Key): Value? Local Storage Store put(Key, Value) load(Key): Flow<Value?>
197. Should Store be The Source of Truth?
198. Should Store be The Source of Truth? • PRO
199. Should Store be The Source of Truth? • PRO • Easy for Store to track invalidations
200. Should Store be The Source of Truth? • PRO • Easy for Store to track invalidations • CON
201. Should Store be The Source of Truth? • PRO • Easy for Store to track invalidations • CON • Hard to migrate
202. Should Store be The Source of Truth? • PRO • Easy for Store to track invalidations • CON • Hard to migrate • Developer needs to “report back” to Store
203. Reporting Back to Store
204. Reporting Back to Store database.deleteDraftChanges()
205. Reporting Back to Store database.deleteDraftChanges() CANT DO “JUST” THIS!
206. Reporting Back to Store database.deleteDraftChanges() CANT DO “JUST” THIS! store.invalidateKey(Comments)
207. Reporting Back to Store database.deleteDraftChanges() CANT DO “JUST” THIS! store.invalidateKey(Comments) REPORTING BACK TO STORE
208. We stand on shoulders of giant (libraries) • Both Room and SQLDelight supports observable streams!
209. Local Source of Truth Is this Store ?
210. Local Source of Truth Store
211. Local Source of Truth Store
212. Local Source of Truth Store Repository Local Source Remote Data Source
213. Supporting source of truth
214. Supporting source of truth • Fits architecture recommendation -> Easy migrations
215. Supporting source of truth • Fits architecture recommendation -> Easy migrations • Allows out of band updates
216. Supporting source of truth • Fits architecture recommendation -> Easy migrations • Allows out of band updates • Simplifies user code -> No tracking, no reporting back
217. Supporting source of truth • Fits architecture recommendation -> Easy migrations • Allows out of band updates • Simplifies user code -> No tracking, no reporting back • Enables partial migration
218. Source of truth gotchas sealed class StoreResponse<T> { abstract val origin: ResponseOrigin data class Loading<T>(...) : StoreResponse<T>() data class Data<T>(...) : StoreResponse<T>() data class Error<T>(...) : StoreResponse<T>() }
219. Source of truth gotchas sealed class StoreResponse<T> { abstract val origin: ResponseOrigin data class Loading<T>(...) : StoreResponse<T>() data class Data<T>(...) : StoreResponse<T>() data class Error<T>(...) : StoreResponse<T>() }
220. Source of truth gotchas sealed class StoreResponse<T> { abstract val origin: ResponseOrigin data class Loading<T>(...) : StoreResponse<T>() data class Data<T>(...) : StoreResponse<T>() data class Error<T>(...) : StoreResponse<T>() } cache | persister | fetcher
221. Source of Truth Store
222. Source of Truth Store StoreResponse<T>
223. Source of Truth Store StoreResponse<T>
224. Source of Truth Store StoreResponse<T> 1
225. Source of Truth Store StoreResponse<T> 1
226. Source of Truth Store StoreResponse<T> 1
227. Source of Truth Store StoreResponse<T> 1 2
228. Source of Truth Store StoreResponse<T> 1 2
229. Source of Truth Store StoreResponse<T> 1 2
230. Source of Truth Store StoreResponse<T> 1 2 Violates source of truth
231. Source of Truth Store StoreResponse<T> 1
232. Source of Truth Store StoreResponse<T> 1 2
233. Source of Truth Store StoreResponse<T> 1 2
234. Source of Truth Store StoreResponse<T> 1 2
235. Source of Truth Store StoreResponse<T> 1 2`
236. Source of Truth Store StoreResponse<T> 1 2`
237. Source of Truth Store StoreResponse<T> 1 2`
238. Source of Truth Store StoreResponse<T> 1 2`
239. Source of Truth Store
240. Source of Truth Store 2
241. Source of Truth Store 2 sourceOfTruth.put(ITEM_2) markNextItemAsFetcher()
242. Source of Truth Store 2 sourceOfTruth.put(ITEM_2) markNextItemAsFetcher()
243. Source of Truth Store 2 sourceOfTruth.put(ITEM_2) markNextItemAsFetcher()
244. Source of Truth Store 2` sourceOfTruth.put(ITEM_2) markNextItemAsFetcher()
245. Source of Truth Store 2` sourceOfTruth.put(ITEM_2) markNextItemAsFetcher()
246. Source of Truth Store 2` sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() Wrong origin
247. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
248. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
249. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
250. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
251. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
252. Source of Truth Store 2 stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
253. Source of Truth Store 2` stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
254. Source of Truth Store 2` stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY)
255. Source of Truth Store stopFlow(KEY) sourceOfTruth.put(ITEM_2) markNextItemAsFetcher() startFlow(KEY) 2`
256. Source of Truth Store StoreResponse<T> 2`
257. Source of Truth Store StoreResponse<T> error 2`
258. Source of Truth Store StoreResponse<T> error 2`
259. Source of Truth Store StoreResponse<T> error 2`
260. CONCURRENT REQUESTS
261. Memory Source Of Truth Network Store store.get( path, refresh = true ).collect { updateUI(it) }
262. Memory Source Of Truth Network Store StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) }
263. Memory Source Of Truth Network Store StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow
264. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow
265. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow
266. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow LOADING
267. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow LOADING
268. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow LOADING LOADING LOADING
269. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow
270. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow
271. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow 1
272. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow 1 1
273. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow 1 1 1
274. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow 1 1 1 1 1
275. Memory Source Of Truth Network Store StoreRequest: Path, Cached StoreRequest: Path, Cached StoreRequest: Path, Cached store.get( path, refresh = true ).collect { updateUI(it) } Flow Flow Flow 1 1
276. SHARING FLOWS
277. Sharing in RxJava val flowable:Flowable<Value> = ... flowable.share()
278. Sharing in Flow val flow:Flow<Value> = ... flow.share()
279. Sharing in Flow val flow:Flow<Value> = ... flow.share()
280. Sharing in Flow val flow:Flow<Value> = ... flow.share() ¯\_(ツ)_/¯
281. Sharing in Flow fun <T> Flow<T>.share() = flow { ... }
282. Sharing in Flow fun <T> Flow<T>.share() = flow { ... } (╯°□°)╯︵ ┻━┻
283. Context Preservation https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/index.html
284. Context Preservation https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines.flow/-flow/index.html
285. Context Preservation val flow:Flow<Value> = …. val shared = flow.share() val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION)
286. Context Preservation val flow:Flow<Value> = …. val shared = flow.share() val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION)
287. Context Preservation val flow:Flow<Value> = …. val shared = flow.share() val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION)
288. Context Preservation val flow:Flow<Value> = …. val shared = flow.share() val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION) WHICH SCOPE DO WE EMIT IN?
289. Context Preservation val flow:Flow<Value> = …. val shared = flow.share( ) val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION)
290. Context Preservation val flow:Flow<Value> = …. val shared = flow.share( ) val collector1 = shared.onEach { ... }.launchIn(IO) val collector2 = shared.onEach { ... }.launchIn(COMPUTATION) upstreamScope
291. Store Multicast
292. Store Multicast Multicaster
293. Store Multicast ChannelManager Multicaster
294. Store Multicast Producer ChannelManager Multicaster
295. Store Multicast Producer ChannelManager Multicaster
296. Store Multicast Producer ChannelManager Multicaster Entry point
297. Store Multicast Producer ChannelManager Multicaster Entry point Core of the implementation - An Actor
298. Store Multicast Producer ChannelManager Multicaster Entry point Core of the implementation - An Actor Upstream wrapper to work with ChannelManager
299. Store Multicast Multicaster
300. Store Multicast Multicaster create()
301. Store Multicast Multicaster Downstream Flow 1 create()
302. Store Multicast Multicaster Downstream Flow 1 create() collect()
303. Store Multicast Multicaster Downstream Flow 1 create() collect() ChannelManager
304. Store Multicast ChannelManager Downstream Flow 1
305. Store Multicast ChannelManager Downstream Flow 1 addChannel
306. Store Multicast ChannelManager Downstream Flow 1 addChannel Create producer
307. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer
308. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer 1 ack 1
309. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer 1 ack 1
310. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer 1 ack 1
311. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer ack 1
312. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer
313. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2
314. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel
315. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel Receive 1 if buffering is enabled
316. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel
317. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel 2 ack 2
318. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel 2 ack 2
319. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel 2 2 ack 2 ack 2
320. Store Multicast ChannelManager Producer Downstream Flow 1 addChannel Create producer Downstream Flow 2 addChannel 2 ack 2 ack 2
321. Store Multicast ChannelManager Producer Downstream Flow 2 Downstream Flow 1 2 ack 2
322. Store Multicast ChannelManager Producer Downstream Flow 2 Downstream Flow 1 2 ack 2 Downstream Flow 3 addChannel
323. Store Multicast ChannelManager Producer Downstream Flow 2 Downstream Flow 1 2 ack 2 Downstream Flow 3 addChannel finish
324. Store Multicast ChannelManager Downstream Flow 2 Downstream Flow 1 2 ack 2 Downstream Flow 3 addChannel cancel cancel
325. Store Multicast ChannelManager Downstream Flow 2 Downstream Flow 1 2 ack 2 Downstream Flow 3 addChannel cancel cancel didn’t receive any value
326. Store Multicast ChannelManager Downstream Flow 3 addChannel Downstream Flow 2 Downstream Flow 1 2 ack 2 cancel cancel didn’t receive any value
327. Store Multicast ChannelManager Downstream Flow 3 addChannel didn’t receive any value
328. Store Multicast ChannelManager Downstream Flow 3 addChannel didn’t receive any value Producer 2 Create producer
329. Store Multicast ChannelManager Downstream Flow 3 Producer 2
330. Store Multicast ChannelManager Downstream Flow 3 Producer 2 3 ack 3
331. Store Multicast ChannelManager Downstream Flow 3 Producer 2 3 ack 3
332. Store Multicast ChannelManager Downstream Flow 3 Producer 2 3 ack 3
333. Store Multicast ChannelManager Downstream Flow 3 Producer 2 ack 3
334. Store Multicast ChannelManager Downstream Flow 3 Producer 2
335. Store Multicast ChannelManager Downstream Flow 3 Producer 2 Downstream Flow 4 addChannel
336. Store Multicast ChannelManager Downstream Flow 3 Downstream Flow 4 error
337. Store Multicast ChannelManager Downstream Flow 3 Downstream Flow 4 error cancel cancel error
338. MIGRATING STORE TESTS
339. Migrating Store tests Test Configure Store Run Test
340. Migrating Store tests Test Configure Store Run Test Common Builder for Store 3 / 4
341. Migrating Store tests Test Configure Run Test Common Builder for Store 3 / 4
342. Migrating Store tests Test Configure Run Test Common Builder for Store 3 / 4 @Paramterized
343. We ❤ TestCoroutineScope
344. TestCoroutineScope • kotlinx-coroutines-test
345. TestCoroutineScope • Scope for testing coroutines • kotlinx-coroutines-test
346. TestCoroutineScope • Scope for testing coroutines • Very good at catching unnecessary work • kotlinx-coroutines-test
347. TestCoroutineScope • Scope for testing coroutines • Very good at catching unnecessary work • Easy to produce control parallel work order • kotlinx-coroutines-test
348. Catching work leaks
349. Catching work leaks val flow = channelFlow {
350. Catching work leaks val flow = channelFlow { myScope.launch {
351. Catching work leaks val flow = channelFlow { myScope.launch { send(1)
352. Catching work leaks val flow = channelFlow { myScope.launch { send(1) delay(1000)
353. Catching work leaks val flow = channelFlow { myScope.launch { send(1) delay(1000) send(2)
354. Catching work leaks val flow = channelFlow { myScope.launch { send(1) delay(1000) send(2) }.join() }
355. Catching work leaks
356. private val testScope = TestCoroutineScope() Catching work leaks
357. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { Catching work leaks
358. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( Catching work leaks
359. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() Catching work leaks
360. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } Catching work leaks
361. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } Catching work leaks
362. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } java.lang.IllegalStateException: This job has not completed yet Catching work leaks
363. val flow = channelFlow { myScope.launch { send(1) delay(1000) send(2) }.join() } Catching work leaks
364. val flow = channelFlow { myScope.launch { send(1) delay(1000) send(2) }.join() } Catching work leaks
365. val flow = channelFlow { myScope.launch { send(1) delay(1000) send(2) }.join() } Will only cancel here Catching work leaks
366. val flow = channelFlow { launch { send(1) delay(1000) send(2) }.join() } Catching work leaks
367. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } Catching work leaks
368. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } Catching work leaks
369. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } ✅ 100 ms Catching work leaks
370. private val testScope = TestCoroutineScope() @Test fun test() = testScope.runBlockingTest { assertThat( flow.take(2).toList() ).contains(1, 2) } ✅ 100 ms Delays are fake! :) Catching work leaks
371. Predictable parallel work Test Subject
372. Predictable parallel work Test Subject Flow A
373. Predictable parallel work Test Subject Flow A Flow B
374. Predictable parallel work
375. val flowA = flowOf(1, 2, 3) Predictable parallel work
376. val flowA = flowOf(1, 2, 3) val flowB = flowOf(7, 8, 9) Predictable parallel work
377. val flowA = flowOf(1, 2, 3) val flowB = flowOf(7, 8, 9) val subject = TestSubject(flowA.merge(flowB)) Predictable parallel work
378. val flowA = flowOf(1, 2, 3) val flowB = flowOf(7, 8, 9) val subject = TestSubject(flowA.merge(flowB)) Predictable parallel work 1 2 3 7 9 8
379. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(1) } val flowB = flowOf(7, 8, 9) val subject = TestSubject(flowA.merge(flowB))
380. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(1) } val flowB = flowOf(7, 8, 9) val subject = TestSubject(flowA.merge(flowB)) 7 9 8
381. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(1) } val flowB = flowOf(7, 8, 9) val subject = TestSubject(flowA.merge(flowB)) 1 2 3 7 9 8
382. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(2) } val flowB = flowOf(7, 8, 9).onEach { delay(5) } val subject = TestSubject(flowA.merge(flowB))
383. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(2) } val flowB = flowOf(7, 8, 9).onEach { delay(5) } val subject = TestSubject(flowA.merge(flowB)) 1 2
384. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(2) } val flowB = flowOf(7, 8, 9).onEach { delay(5) } val subject = TestSubject(flowA.merge(flowB)) 1 2 7
385. Predictable parallel work val flowA = flowOf(1, 2, 3).onEach { delay(2) } val flowB = flowOf(7, 8, 9).onEach { delay(5) } val subject = TestSubject(flowA.merge(flowB)) 1 2 3 7 9 8
386. YES: I JUST RECOMMENDED “DELAY” FOR TESTING :)
387. WHAT IS NEXT?
388. WHAT IS NEXT? Store3 github.com/nytimes/store
389. WHAT IS NEXT? Store4 github.com/dropbox/store
390. #KotlinConf THANK YOU AND REMEMBER TO VOTE yigitboyar@ friendlyMikhail@