Scripting in Swift For a Testable Build - iOS Conf SG, Singapore, January 2020

Abstract:

Underlying many large iOS projects is a tangled nest of bash scripts that developers are often afraid to touch for fear of breaking something, and which is littered with print statements from generations of developers trying to figure out how on earth it works. How can we move away from this mess and to something more sustainable? Ellen will discuss moving a codebase like this to a command line tool that can be called from a Swift script, and which can be tested and breakpointed, and just might save a tiny bit of your sanity.

Transcript

1. SCRIPTING IN SWIFT FOR A TESTABLE BUILD IOS CONF SG | SINGAPORE | JANUARY 2020 ELLEN SHAPIRO | @DESIGNATEDNERD | APOLLOGRAPHQL.COM
3. SINGAPORE NOW @CARROT_App
4. MADISON NOW @CARROT_App
5. YOUR IOS PROJECT HAS A NEST OF BASH SCRIPTS @DesignatedNerd
6. YOUR IOS PROJECT HAS A NEST OF BASH SCRIPTS (IT'S OKAY, MY PROJECTS DO TOO) @DesignatedNerd
7. @DesignatedNerd
9. SPOILER: THERE IS A BETTER WAY @DesignatedNerd
10. SCRIPTING WITH ✨ SWIFT @DesignatedNerd
11. @DesignatedNerd
12. ! HOW DOES APOLLO WORK? @DesignatedNerd
13. ! HOW DOES APOLLO WORK? (THE SHORT VERSION) @DesignatedNerd
14. GraphQL @DesignatedNerd
15. SCHEMA + QUERIES = CODE @DesignatedNerd
16. SCHEMA + QUERIES = CODE @DesignatedNerd
17. SCHEMA + QUERIES = CODE WHAT IS POSSIBLE? @DesignatedNerd
18. SCHEMA + QUERIES = CODE @DesignatedNerd
19. SCHEMA + QUERIES = CODE WHAT AM I ASKING FOR? @DesignatedNerd
20. SCHEMA + QUERIES = CODE @DesignatedNerd
21. SCHEMA + QUERIES = CODE IS WHAT I'M ASKING FOR POSSIBLE? @DesignatedNerd
22. ! @DesignatedNerd
24. ! @DesignatedNerd
25. SCHEMA + QUERIES = CODE @DesignatedNerd
26. SCHEMA + QUERIES = CODE HAVE SOME TYPE-SAFE CODE! @DesignatedNerd
27. JAVASCRIPT + NODE @DesignatedNerd
28. TYPESCRIPT + NODE @DesignatedNerd
29. via Webcomic Name and Alex Norris
30. npm = @DesignatedNerd
32. HOW DO WE MAKE THIS BETTER? @DesignatedNerd
33. !!!! @DesignatedNerd
34. HOW DO WE MAKE THIS LESS TERRIBLE AS QUICKLY AS POSSIBLE? @DesignatedNerd
35. BUNDLING EVERYTHING @DesignatedNerd
36. BUNDLING EVERYTHING A SMALLER @DesignatedNerd
37. BEFORE LOTS OF BASH YOU HAD TO WRITE @DesignatedNerd
38. AFTER LOTS OF BASH I HAD TO WRITE @DesignatedNerd
39. @DesignatedNerd
40. I HATE BASH @DesignatedNerd
41. I HATE SUCK AT BASH @DesignatedNerd
42. TESTING AND DEBUGGING BASH: ¯\_(ϑ)_/¯ @DesignatedNerd
43. echo "Variable: ${VARIABLE}" @DesignatedNerd
44. FIGURING OUT WHAT WENT WRONG IN BASH: ¯\_(ϑ)_/¯ @DesignatedNerd
45. ! @DesignatedNerd
46. DON'T IT ALWAYS SEEM TO GO THAT YOU DON'T KNOW WHAT YOU GOT 'TIL IT'S GONE - JONI MITCHELL @DesignatedNerd
47. LET'S DO THIS! @DesignatedNerd
48. 1. BUILD A SWIFT FRAMEWORK THAT DOES WHAT YOUR SCRIPT CURRENTLY DOES @DesignatedNerd
49. IDENTIFY WHAT YOUR SCRIPT DOES @DesignatedNerd
50. IDENTIFY WHAT YOUR SCRIPT DOES (THIS SOUNDS MUCH EASIER THAN IT IS) @DesignatedNerd
51. run_bundled_codegen.sh @DesignatedNerd
52. WHAT APOLLO'S SCRIPT DOES @DesignatedNerd
53. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? @DesignatedNerd
54. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? NO @DesignatedNerd
55. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? NO Download and unzip current version of CLI. @DesignatedNerd
56. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES @DesignatedNerd
57. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES Does the zipped version of the CLI have the correct hash for this version of the iOS SDK? @DesignatedNerd
58. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES Does the zipped version of the CLI have the correct hash for this version of the iOS SDK? NO @DesignatedNerd
59. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES Does the zipped version of the CLI have the correct hash for this version of the iOS SDK? NO Download and unzip current version of CLI. @DesignatedNerd
60. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES Does the zipped version of the CLI have the correct hash for this version of the iOS SDK? YES @DesignatedNerd
61. WHAT APOLLO'S SCRIPT DOES Is there a zipped version of the CLI? YES Does the zipped version of the CLI have the correct hash for this version of the iOS SDK? YES Unzip if needed @DesignatedNerd
62. RUN THE CLI WITH THE PASSED IN INFORMATION ⬇ GENERATE CODE @DesignatedNerd
63. codegen:generate --target=swift --localSchemaFile="schema.json" --includes=./**/*.graphql --operationIdsPath=operationIdsPath.json --suppressSwiftMultilineStringLiterals ⬇ ApolloCodegenOptions @DesignatedNerd
64. if [ -f "${ZIP_FILE}" ] ⬇ FileManager @DesignatedNerd
65. curl ⬇ URLSession @DesignatedNerd
66. /usr/bin/shasum ⬇ CommonCrypto @DesignatedNerd
67. SEPARATION OF CONCERNS @DesignatedNerd
68. ! DEPENDENCY INJECTION @DesignatedNerd
69. CODE COVERAGE @DesignatedNerd
70. @DesignatedNerd
71. @DesignatedNerd
72. @DesignatedNerd
73. ! BEST PRACTICES, DUH @DesignatedNerd
74. YOUR SCRIPTS DESERVE TO BE FIRST-CLASS CITIZENS @DesignatedNerd
75. IF YOU CAN'T RELEASE YOUR APP WITHOUT IT TEST IT @DesignatedNerd
76. IF YOU CAN'T RELEASE YOUR APP WITHOUT IT TEST IT (AND IT'S A LOT EASIER TO TEST IT IN SWIFT) @DesignatedNerd
77. 2. USE THE LIBRARY IN A SPM EXECUTABLE @DesignatedNerd
78. #! /usr/bin/env xcrun swift -F ../build/Debug @DesignatedNerd
79. chmod +x main.swift @DesignatedNerd
80. @DesignatedNerd
81. @DesignatedNerd
82. @DesignatedNerd
83. swift run @DesignatedNerd
84. DON'T DO THIS @DesignatedNerd
85. CREATE IT WITH SWIFT PACKAGE MANAGER $ mkdir Codegen $ cd Codegen $ swift package init --type executable @DesignatedNerd
86. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
87. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
88. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
89. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
90. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
91. Package.swift // swift-tools-version:5.1 import PackageDescription let package = Package( name: "Codegen", products: [ .executable(name: "Codegen", targets: ["Codegen"]), ], dependencies: [ .package(url: "https://github.com/apollographql/apollo-ios.git", .branch("swift-codegen")) ], targets: [ .target(name: "Codegen", dependencies: ["ApolloCodegenLib"]), .testTarget(name: "CodegenTests", dependencies: ["Codegen"]), ] ) @DesignatedNerd
92. @DesignatedNerd
93. $SRCROOT @DesignatedNerd
94. @DesignatedNerd
95. main.swift print("Hello, world!") @DesignatedNerd
96. main.swift import Foundation enum MyCodegenError: Error { case sourceRootNotProvided case sourceRootNotADirectory case targetDoesntExist } guard let sourceRootPath = ProcessInfo.processInfo.environment["SRCROOT"] else { throw MyCodegenError.sourceRootNotProvided } @DesignatedNerd
97. main.swift import Foundation import ApolloCodegenLib enum MyCodegenError: Error { case sourceRootNotProvided case sourceRootNotADirectory case targetDoesntExist } guard let sourceRootPath = ProcessInfo.processInfo.environment["SRCROOT"] else { throw MyCodegenError.sourceRootNotProvided } guard FileManager.default.apollo_folderExists(at: sourceRootPath) else { throw MyCodegenError.sourceRootNotADirectory } @DesignatedNerd
98. main.swift (pt. 2) let applicationTargetFolderURL = sourceRootURL .appendingPathComponent("SwiftScriptTestSPM") guard FileManager.default.apollo_folderExists(at: applicationTarget) else { throw MyCodegenError.targetDoesntExist } let scriptFolderURL = sourceRootURL.appendingPathComponent("scripts") let options = ApolloCodegenOptions(targetRootURL: applicationTargetFolderURL) do { try ApolloCodegen.run(from: applicationTargetFolderURL, with: scriptsFolderURL, options: options) } catch { CodegenLogger.log("ERROR: \(error.localizedDescription)") exit(1) } @DesignatedNerd
99. main.swift (pt. 2) let applicationTargetFolderURL = sourceRootURL .appendingPathComponent("SwiftScriptTestSPM") guard FileManager.default.apollo_folderExists(at: applicationTarget) else { throw MyCodegenError.targetDoesntExist } let scriptFolderURL = sourceRootURL.appendingPathComponent("scripts") let options = ApolloCodegenOptions(targetRootURL: applicationTargetFolderURL) do { try ApolloCodegen.run(from: applicationTargetFolderURL, with: scriptsFolderURL, options: options) } catch { CodegenLogger.log("ERROR: \(error.localizedDescription)") exit(1) } @DesignatedNerd
100. main.swift (pt. 2) let applicationTargetFolderURL = sourceRootURL .appendingPathComponent("SwiftScriptTestSPM") guard FileManager.default.apollo_folderExists(at: applicationTarget) else { throw MyCodegenError.targetDoesntExist } let scriptFolderURL = sourceRootURL.appendingPathComponent("scripts") let options = ApolloCodegenOptions(targetRootURL: applicationTargetFolderURL) do { try ApolloCodegen.run(from: applicationTargetFolderURL, with: scriptsFolderURL, options: options) } catch { CodegenLogger.log("ERROR: \(error.localizedDescription)") exit(1) } @DesignatedNerd
101. main.swift (pt. 2) let applicationTargetFolderURL = sourceRootURL .appendingPathComponent("SwiftScriptTestSPM") guard FileManager.default.apollo_folderExists(at: applicationTarget) else { throw MyCodegenError.targetDoesntExist } let scriptFolderURL = sourceRootURL.appendingPathComponent("scripts") let options = ApolloCodegenOptions(targetRootURL: applicationTargetFolderURL) do { try ApolloCodegen.run(from: applicationTargetFolderURL, with: scriptsFolderURL, options: options) } catch { CodegenLogger.log("ERROR: \(error.localizedDescription)") exit(1) } @DesignatedNerd
102. main.swift (pt. 2) let applicationTargetFolderURL = sourceRootURL .appendingPathComponent("SwiftScriptTestSPM") guard FileManager.default.apollo_folderExists(at: applicationTarget) else { throw MyCodegenError.targetDoesntExist } let scriptFolderURL = sourceRootURL.appendingPathComponent("scripts") let options = ApolloCodegenOptions(targetRootURL: applicationTargetFolderURL) do { try ApolloCodegen.run(from: applicationTargetFolderURL, with: scriptsFolderURL, options: options) } catch { CodegenLogger.log("ERROR: \(error.localizedDescription)") exit(1) } @DesignatedNerd
103. IN YOUR APPLICATION PROJECT @DesignatedNerd
104. 3. ! PROFIT! @DesignatedNerd
105. 3. ! PROFIT!* * - BY WASTING LESS OF YOUR TIME FAFFING AROUND WITH BASH @DesignatedNerd
106. A CAVEAT @DesignatedNerd
107. DEVELOPERS ARE NOT USED TO SCRIPTING IN SWIFT @DesignatedNerd
108. ! " @DesignatedNerd
109. WRITE THE DOCS @DesignatedNerd
110. COMING SOON TO AN APOLLO IOS SDK NEAR YOU! @DesignatedNerd
111. OBLIGATORY SUMMARY SLIDE @DesignatedNerd
112. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code @DesignatedNerd
113. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when stuff breaks @DesignatedNerd
114. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks @DesignatedNerd
115. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks > Dissect your old scripts, rebuild in a Swift Framework @DesignatedNerd
116. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks > Dissect your old scripts, rebuild in a Swift Framework > Test everything you can't release your app without @DesignatedNerd
117. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks > Dissect your old scripts, rebuild in a Swift Framework > Test everything you can't release your app without > Use Swift Package Manager to build an executable @DesignatedNerd
118. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks > Dissect your old scripts, rebuild in a Swift Framework > Test everything you can't release your app without > Use Swift Package Manager to build an executable > Run that from a build script run phase in your main app @DesignatedNerd
119. OBLIGATORY SUMMARY SLIDE > Use swift to write testable script code > Know what broke when (not if) stuff breaks > Dissect your old scripts, rebuild in a Swift Framework > Test everything you can't release your app without > Use Swift Package Manager to build an executable > Run that from a build script run phase in your main app > Document the crap out of everything @DesignatedNerd
120. ! THANK YOU! @DesignatedNerd
121. LINKS! ADOPTING SWIFT PACKAGES IN XCODE https://developer.apple.com/videos/play/wwdc2019/408/ CREATING SWIFT PACKAGES https://developer.apple.com/videos/play/wwdc2019/410/ @DesignatedNerd