Building SDKs - The Kotlin Way

Talk from Droidcon Berlin 2019.

Transcript

4. Project Manager Developer Hey could you ship the new SDK version?
5. Project Manager Developer Hey could you ship the new SDK version? S-s-sure…
6. $ gradlew sdk:assembleRelease $ building… $ … $ # 10 hours later
7. 3. Blah blah bla 2. Bla blah bla 1. Blah blah blah RELEASE NOTES
8. 4. EXPERIMENTAL APIs. They are subject to change and not final!!! 3. Blah blah bla 2. Bla blah bla 1. Blah blah blah RELEASE NOTES
9. Project Manager Developer Cool, thanks Here’s the new Version! SDK
10. 4. APIs have been removed. 3. Blah blah bla 2. Bla blah bla 1. Blah blah blah RELEASE NOTES
11. Project Manager Developer Cool, thanks Here’s the new Version! SDK
12. Slack Message PROJECT MANAGER $CUSTOMER JUST CALLED THEY HAVE A BUILD ERROR WITH THE NEW SDK VERSION CAN YOU FIX THAT NOW PLS Friday, 9PM
13. You: Have they read the release notes? PM: I’ll ask ... PM: No
14. @Experimental @Deprecated
15. @Target(ANNOTATION_CLASS) public annotation class Experimental(val level: Level = Level.ERROR) { public enum class Level { WARNING, ERROR, } }
16. @Target(ANNOTATION_CLASS) public annotation class Experimental(val level: Level = Level.ERROR) { public enum class Level { WARNING, ERROR, } }
17. @Target(ANNOTATION_CLASS) public annotation class Experimental(val level: Level = Level.ERROR) { public enum class Level { WARNING, ERROR, } }
18. @Experimental annotation class ExperimentalCatPicturesAPI
19. class CatPicturesAPI { /** * Experimental in case cats overtake the planet and * demand pets and treats in exchange for cat pictures */ @ExperimentalCatPicturesAPI fun getCatPicture(): CatPicture = CatPicture() }
20. fun doCatPictureAPIStuff() { val catPicturesAPI = CatPicturesAPI() catPicturesAPI.getCatPicture() } This API is experimental and its usage must be marked with @UseExperimental.
21. @ExperimentalCatPicturesAPI fun doCatPictureAPIStuff() { val catPicturesAPI = CatPicturesAPI() catPicturesAPI.getCatPicture() }
22. @UseExperimental(ExperimentalCatPicturesAPI::class) fun doCatPictureAPIStuff() { val catPicturesAPI = CatPicturesAPI() catPicturesAPI.getCatPicture() }
23. Productive Developer
24. Project Man Developer
25. Project Manager Developer
26. Project Manager Developer
27. Project Manager Developer
28. Project Manager Developer Hey could you ship the new SDK version?
29. Project Manager Developer Hey could you ship the new SDK version? S-s-sure…
30. 4. APIs have been deprecated. 3. Blah blah bla 2. Bla blah bla 1. Blah blah blah RELEASE NOTES
31. Project Manager Developer Cool, thanks Here’s the new Version! SDK Contains deprecated APIs
32. Project Manager Cool, thanks SDK User Here’s the new Version! SDK Contains deprecated APIs
33. BUILD ERROR SDK User SDK *updates SDK version* *runs Gradle build*
34. /** * Marks the annotated declaration as deprecated. */ TYPEALIAS) annotation class Deprecated( val message: String, val replaceWith: ReplaceWith = ReplaceWith(""), val level: DeprecationLevel = DeprecationLevel.WARNING )
35. @Deprecated(“This is a legacy API. Please use the new CatPicturesAPI instead.") class LegacyCatPictureAPI { fun getCatPicture(): CatPicture = CatPicture() }
36. val api = LegacyCatPictureAPI()
37. /** * Marks the annotated declaration as deprecated. */ TYPEALIAS) annotation class Deprecated( val message: String, val replaceWith: ReplaceWith = ReplaceWith(""), val level: DeprecationLevel = DeprecationLevel.WARNING )
38. annotation class ReplaceWith( val expression: String, vararg val imports: String )
39. @Deprecated( "This is a legacy API. Please use the new CatPicturesAPI instead.", ReplaceWith("CatPicturesAPI") ) class LegacyCatPictureAPI { fun getCatPicture(): CatPicture = CatPicture() }
40. @Deprecated( "This is a legacy API. Please use the new CatPicturesAPI instead.", ReplaceWith("CatPicturesAPI") ) class LegacyCatPictureAPI { fun getCatPicture(): CatPicture = CatPicture() }
41. val api = LegacyCatPictureAPI() Replace with ‘CatPicturesAPI’
42. val api = LegacyCatPictureAPI() Replace with ‘CatPicturesAPI’ Alt + Enter
43. val api = CatPicturesAPI() ✔Occurrence Replaced!
44. class Laboratory { fun getRandommChemical(): Chemical = randomExperiment + randomExperiment + explosive }
45. class Laboratory { @Deprecated( "Typo in here. Please use getRandomChemical instead.", ReplaceWith("getRandomChemical") ) fun getRandommChemical(): Chemical = randomExperiment + randomExperiment + explosive }
46. class Laboratory { @Deprecated( "Typo in here. Please use getRandomChemical instead.", ReplaceWith("getRandomChemical") ) fun getRandommChemical(): Chemical = randomExperiment + randomExperiment + explosive fun getRandomChemical(): Chemical = randomExperiment + randomExperiment + explosive }
47. class Laboratory { @Deprecated( "Typo in here. Please use getRandomChemical instead.", ReplaceWith("getRandomChemical") ) fun getRandommChemical(): Chemical = getRandomChemical() fun getRandomChemical(): Chemical = randomExperiment + randomExperiment + explosive }
48. class CatPicturesAPI { /** * Experimental in case cats overtake the planet and * demand pets and treats in exchange for cat pictures */ @ExperimentalCatPicturesAPI fun getCatPicture(): CatPicture = CatPicture() }
49. class CatPictureAPI { /** * Experimental in case cats overtake the planet and * demand pets and treats in exchange for cat pictures */ @ExperimentalCatPicturesAPI fun getCatPicture(): CatPicture = CatPicture() }
50. @Deprecated( message = "CatPicturesAPI has been renamed to CatPictureAPI“, replaceWith = ReplaceWith("CatPictureAPI") ) typealias CatPicturesAPI = CatPictureAPI
52. SDK
53. interface SDKCapabilities { ... } class ArtboardSDK: SDKCapabilities { //It'll become super bloated }
54. interface CanvasCapabilities interface SDKCapabilities: CanvasCapabilities class ArtboardSDK: SDKCapabilities { val canvasManager = CanvasManager() override fun draw() = canvasManager.draw() }
55. interface CanvasCapabilities interface SDKCapabilities: CanvasCapabilities class ArtboardSDK: SDKCapabilities { val canvasManager = CanvasManager() override fun draw() = canvasManager.draw() }
56. interface CanvasCapabilities interface SDKCapabilities: CanvasCapabilities class ArtboardSDK: SDKCapabilities { val canvasManager = CanvasManager() override fun draw() = canvasManager.draw() }
57. interface CanvasCapabilities interface SDKCapabilities: CanvasCapabilities class CanvasManager: CanvasCapabilities class ArtboardSDK: SDKCapabilities, CanvasCapabilities by CanvasManager()
58. interface CanvasCapabilities interface SDKCapabilities: CanvasCapabilities class CanvasManager: CanvasCapabilities class ArtboardSDK: SDKCapabilities, CanvasCapabilities by CanvasManager()