Add support to Android using Kotlin code generation

.github/workflows/kotlin-tests.yml

@@ -0,0 +1,27 @@
+name: Kotlin Tests
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest # Assuming Kotlin projects can be built on Linux
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 11
+      uses: actions/setup-java@v2
+      with:
+        java-version: '11'
+        distribution: 'adopt'
+    - name: Cache Gradle packages
+      uses: actions/cache@v2
+      with:
+        path: |
+          ~/.gradle/caches
+          ~/.gradle/wrapper
+        key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
+        restore-keys: |
+          ${{ runner.os }}-gradle-
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.2'
+        bundler-cache: true # Runs 'bundle install' and caches installed gems automatically
+    - name: Generate Kotlin Code & Run Tests
+      run: bundle exec rake test_kotlin

.gitignore

@@ -7,8 +7,18 @@
 /spec/reports/
 /tmp/
 
-# rspec failure tracking
+# Rspec failure tracking
 .rspec_status
 coverage
 *.gem
 **/.DS_Store
+
+# Compiled Kotlin/Java class files
+*.class
+
+# IntelliJ IDEA files
+.idea/
+
+# Gradle files
+.gradle/
+build/

README.md

@@ -37,29 +37,73 @@
 
 # Requirements
 
+## Android
+
+Your project must be using the Gradle Build Tool.
+
 ## iOS
 
 Your project must be using Swift Package Manager or CocoaPods as dependency manager (or both). No support for Carthage.
 
 <sub>Note: this gem was only tested in macOS environments.</sub>
 
-## Android
+## Preview
 
-The Java/Kotlin code generator hasn't been implemented yet. Star and "watch" this project and check back in the future, or help us build it [here](https://github.com/rogerluan/arkana/issues/1).
+### Kotlin
 
-<img width="200" alt="image" src="https://user-images.githubusercontent.com/8419048/177968055-6774ad8e-2ef3-45ed-9e26-fbe73a783083.png">
+<details><summary>Click here to see the Kotlin preview</summary>
+<p>
 
-## Preview
+The image below shows how the auto-generated file looks like.
+
+<div align="center">
+  <img src="docs/kotlin-demo.png">
+</div>
+
+Usage using the example code above:
 
-<details><summary>Click here to show an image with the preview!</summary>
+```kotlin
+import com.arkanakeys.MySecrets
+
+// Designed with testability and DI in mind
+println(MySecrets.Global.someBooleanSecret)
+println(MySecrets.Global.someIntSecret)
+println(MySecrets.Global.mySecretAPIKey)
+
+// Simulating environment selection using a random boolean value
+val keys = if (Math.random() < 0.5) MySecrets.Dev else MySecrets.Staging
+println(keys.serviceKey)
+```
+
+</p>
+</details>
+
+### Swift
+
+<details><summary>Click here to see the Swift preview</summary>
 <p>
 
-The image below shows how the auto-generated file looks like. At the bottom of it you can see how you'll consume the code generated.
+The image below shows how the auto-generated file looks like.
 
 <div align="center">
   <img src="docs/swift-demo.png">
 </div>
 
+Usage using the example code above:
+
+```swift
+import ArkanaKeys
+
+// Designed with testability and DI in mind
+print(MySecrets.Global().someBooleanSecret)
+print(MySecrets.Global().someIntSecret)
+print(MySecrets.Global().mySecretAPIKey)
+
+// This is a demo, so we are using Bool.random() to simulate the environment
+let keys: MySecretsEnvironmentProtocol = Bool.random() ? MySecrets.Dev() : MySecrets.Staging()
+print(keys.serviceKey)
+```
+
 </p>
 </details>
 
@@ -87,18 +131,21 @@ Once you have create your config file, you can run Arkana:
 
 ```sh
 Usage: arkana [options]
-    -c /path/to/your/.arkana.yml,         Path to your config file. Defaults to '.arkana.yml'
+    -c /path/to/your/.arkana.yml,    Path to your config file. Defaults to '.arkana.yml'
         --config-filepath
-    -e /path/to/your/.env,                Path to your dotenv file. Defaults to '.env' if one exists.
+    -e /path/to/your/.env,           Path to your dotenv file. Defaults to '.env' if one exists.
         --dotenv-filepath
     -f, --flavor FrostedFlakes       Flavors are useful, for instance, when generating secrets for white-label projects. See the README for more information
+    -i debug,release,                Optionally pass the environments that you want Arkana to generate secrets for. Useful if you only want to build a certain environment, e.g. just Debug in local machines, while only building Staging and Release in CI. Separate the keys using a comma, without spaces. When omitted, Arkana generate secrets for all environments.
+        --include-environments
+    -l, --lang kotlin                Language to produce keys for, e.g. kotlin, swift. Defaults to 'swift'. See the README for more information
 ```
 
 Note that you have to prepend `bundle exec` before `arkana` if you manage your dependencies via bundler, as recommended.
 
 Arkana only has one command, which parses your config file and env vars, generating all the code needed. Arkana should always be run before attempting to build your project, to make sure the files exist _and_ are up-to-date (according to the current config file). This means you might need to add the Arkana run command in your CI/CD scripts, _fastlane_, Xcode Build Phases, or something similar.
 
-## Importing Arkana into your project
+## Importing Arkana into your iOS project
 
 Once the Arkana has been run, its files will be created according to the `package_manager` setting defined in your config file, so update that setting according to your project needs.
 
@@ -145,12 +192,48 @@ After adding its dependency, you should be able to `import ArkanaKeys` (or the `
 
 We recommend you to add your ArkanaKeys directory to your `.gitignore` since it's an auto-generated code that will change every time you run Arkana (since its salt gets generated on each run). For more information, see [How does it work?](#how-does-it-work)
 
+## Importing Arkana into your Android project
+
+When importing Arkana into your project, you have two options: generating its files within a new Gradle module created by Arkana, or adding them to an existing module. The choice depends on the settings in your config file, so ensure these are updated to reflect your project's requirements.
+
+### Creating a New Arkana Gradle Module
+
+To generate a new Gradle module containing Arkana files, follow these steps:
+
+1. In your config file, set the `result_path` to the desired name for the new Arkana module.
+2. Update your project's `settings.gradle` file to include this newly created Arkana module.
+
+### Adding Arkana to an Existing Gradle Module
+
+If you prefer to add Arkana files to an existing Gradle module, follow these steps:
+
+1. Adjust the `result_path` in your config file to specify the existing Gradle module where you want to include the Arkana files.
+2. Change `should_generate_gradle_build_file` to `false`. This prevents the overwriting of your existing module's `build.gradle` file.
+
+### Automating Arkana Execution During Gradle Sync
+
+For automatic execution of Arkana during Gradle sync, modify your `settings.gradle` file by adding the following code:
+
+```kotlin
+exec {
+    commandLine("arkana", "--lang", "kotlin")
+}
+```
+
 ## Options
 
 ### `--help`
 
 Will display a list of the available options.
 
+### `--lang`
+
+Usage: `--lang kotlin`
+
+Indicates the language to produce keys for, e.g. kotlin, swift.
+
+Defaults to `swift`.
+
 ### `--config-file-path`
 
 Usage: `--config-file-path /path/to/your/.arkana.yml`

Rakefile

@@ -21,6 +21,16 @@ task :test_swift do
   FileUtils.rm_rf("tests")
 end
 
+desc "Generates Kotlin source code and run its unit tests."
+task :test_kotlin do
+  FileUtils.copy_entry("spec/fixtures/kotlin", "tests")
+  sh("ARKANA_RUNNING_CI_INTEGRATION_TESTS=true bin/arkana --lang kotlin --config-filepath spec/fixtures/kotlin-tests.yml --dotenv-filepath spec/fixtures/.env.fruitloops --include-environments dev,staging")
+  Dir.chdir("tests") do
+    sh("./gradlew test")
+  end
+  FileUtils.rm_rf("tests")
+end
+
 desc "Sets lib version to the semantic version given, and push it to remote."
 task :bump, [:v] do |_t, args|
   version = args[:v] || raise("A version is required. Pass it like `rake bump[1.2.3]`")

docs/demo-used-to-gen-image.kt

@@ -0,0 +1,58 @@
+// DO NOT MODIFY
+// Automatically generated by Arkana (https://github.com/rogerluan/arkana)
+package com.arkanakeys
+
+object MySecrets {
+    private val salt = listOf(0x3f, 0xb6, 0x2, 0x3, 0xbf, 0x54, 0xf5, 0x67, 0x95, 0xc, 0x56, 0x47, 0x87, 0x55, 0x60, 0x74, 0x6, 0x77, 0x8b, 0xd6, 0x88, 0x41, 0x99, 0xe2, 0x97, 0x92, 0x9f, 0x68, 0x7d, 0x6c, 0x39, 0x64, 0xca, 0x98, 0xe7, 0x8d, 0xe8, 0x9e, 0x1f, 0xe5, 0xad, 0x45, 0x32, 0xac, 0xc5, 0xe1, 0xf6, 0x4f, 0x67, 0xcc, 0x6a, 0xee, 0x66, 0xac, 0x80, 0xea, 0x78, 0x1b, 0xd6, 0x78, 0x4, 0x97, 0xfa, 0xcc)
+
+    internal fun decode(encoded: List<Int>, cipher: List<Int>): String {
+        val decoded = encoded.mapIndexed { index, item ->
+            (item xor cipher[(index % cipher.size)]).toByte()
+        }.toByteArray()
+        return decoded.toString(Charsets.UTF_8)
+    }
+
+    internal fun decodeInt(encoded: List<Int>, cipher: List<Int>): Int {
+        return decode(encoded = encoded, cipher = cipher).toInt()
+    }
+
+    internal fun decodeBoolean(encoded: List<Int>, cipher: List<Int>): Boolean {
+        return decode(encoded = encoded, cipher = cipher).toBoolean()
+    }
+
+    object Global {
+        val someBooleanSecret: Boolean
+            get() {
+                val encoded = listOf(0x4b, 0xc4, 0x77, 0x66)
+                return decodeBoolean(encoded = encoded, cipher = salt)
+            }
+
+        val someIntSecret: Int
+            get() {
+                val encoded = listOf(0xb, 0x84)
+                return decodeInt(encoded = encoded, cipher = salt)
+            }
+
+        val mySecretAPIKey: String
+            get() {
+                val encoded = listOf(0x6, 0x84, 0x30, 0x30, 0x8c, 0x63, 0xc7, 0x57, 0xa6, 0x3a, 0x6e, 0x72, 0xb3, 0x62, 0x57, 0x41, 0x3e, 0x47, 0xbc, 0xef, 0xba, 0x73, 0xaa, 0xd1, 0xa0, 0xa0, 0xaf, 0x5b, 0x4b, 0x54, 0xc, 0x50, 0xfd, 0xaf, 0xd2, 0xb5, 0xd8, 0xa9)
+                return decode(encoded = encoded, cipher = salt)
+            }
+    }
+
+    object Dev : MySecretsEnvironment {
+        override val serviceKey: String
+            get() {
+                val encoded = listOf(0x4b, 0xde, 0x6b, 0x70, 0x9f, 0x30, 0x90, 0x11, 0xb5, 0x67, 0x33, 0x3e, 0xa7, 0x3c, 0x13, 0x54, 0x75, 0x12, 0xe8, 0xa4, 0xed, 0x35)
+                return decode(encoded = encoded, cipher = salt)
+            }
+    }
+
+    object Staging : MySecretsEnvironment {
+        override val serviceKey: String
+            get() {
+                val encoded = listOf(0x4b, 0xde, 0x6b, 0x70, 0x9f, 0x27, 0x81, 0x6, 0xf2, 0x65, 0x38, 0x20, 0xa7, 0x3e, 0x5, 0xd, 0x26, 0x1e, 0xf8, 0xf6, 0xfb, 0x24, 0xfa, 0x90, 0xf2, 0xe6)
+                return decode(encoded = encoded, cipher = salt)
+            }
+    }
+}

docs/demo-used-to-gen-image.swift

@@ -0,0 +1,86 @@
+// DO NOT MODIFY
+// Automatically generated by Arkana (https://github.com/rogerluan/arkana)
+
+import Foundation
+import MySecretsInterfaces
+
+public enum MySecrets {
+    @inline(__always)
+    fileprivate static let salt: [UInt8] = [
+        0x47, 0x7c, 0xe3, 0x7f, 0x80, 0xa8, 0x41, 0x6c, 0x2, 0xc3, 0x7f, 0x3f, 0x63, 0xd9, 0xb6, 0x57, 0x3a, 0x33, 0x98, 0xed, 0xfa, 0x71, 0xcb, 0x9a, 0x55, 0x23, 0x52, 0x1c, 0x31, 0xc0, 0x74, 0xd4, 0x7e, 0x6e, 0xf5, 0xca, 0xbc, 0x25, 0x69, 0xcd, 0x9, 0, 0xcb, 0x70, 0xd3, 0x5e, 0xa5, 0x92, 0xe7, 0x6b, 0x2, 0x90, 0x29, 0xc2, 0x44, 0xc8, 0x5a, 0xc2, 0xc0, 0xc7, 0x42, 0x30, 0x40, 0xa3
+    ]
+
+    static func decode(encoded: [UInt8], cipher: [UInt8]) -> String {
+        return String(decoding: encoded.enumerated().map { offset, element in
+            element ^ cipher[offset % cipher.count]
+        }, as: UTF8.self)
+    }
+
+    static func decode(encoded: [UInt8], cipher: [UInt8]) -> Bool {
+        let stringValue: String = Self.decode(encoded: encoded, cipher: cipher)
+        return Bool(stringValue)!
+    }
+
+    static func decode(encoded: [UInt8], cipher: [UInt8]) -> Int {
+        let stringValue: String = Self.decode(encoded: encoded, cipher: cipher)
+        return Int(stringValue)!
+    }
+}
+
+public extension MySecrets {
+    struct Global: MySecretsGlobalProtocol {
+        public init() {}
+
+        @inline(__always)
+        public lazy var someBooleanSecret: Bool = {
+            let encoded: [UInt8] = [
+                0x33, 0xe, 0x96, 0x1a
+            ]
+            return MySecrets.decode(encoded: encoded, cipher: MySecrets.salt)
+        }()
+
+        @inline(__always)
+        public lazy var someIntSecret: Int = {
+            let encoded: [UInt8] = [
+                0x73, 0x4e
+            ]
+            return MySecrets.decode(encoded: encoded, cipher: MySecrets.salt)
+        }()
+
+        @inline(__always)
+        public lazy var mySecretAPIKey: String = {
+            let encoded: [UInt8] = [
+                0x7e, 0x4e, 0xd1, 0x4c, 0xb3, 0x9f, 0x73, 0x5c, 0x31, 0xf5, 0x47, 0xa, 0x57, 0xee, 0x81, 0x62, 0x2, 0x3, 0xaf, 0xd4, 0xc8, 0x43, 0xf8, 0xa9, 0x62, 0x11, 0x62, 0x2f, 0x7, 0xf8, 0x41, 0xe0, 0x49, 0x59, 0xc0, 0xf2, 0x8c, 0x12
+            ]
+            return MySecrets.decode(encoded: encoded, cipher: MySecrets.salt)
+        }()
+    }
+}
+
+public extension MySecrets {
+    struct Dev: MySecretsEnvironmentProtocol {
+        public init() {}
+
+        @inline(__always)
+        public lazy var serviceKey: String = {
+            let encoded: [UInt8] = [
+                0x33, 0x14, 0x8a, 0xc, 0xa0, 0xcc, 0x24, 0x1a, 0x22, 0xa8, 0x1a, 0x46, 0x43, 0xb0, 0xc5, 0x77, 0x49, 0x56, 0xfb, 0x9f, 0x9f, 0x5
+            ]
+            return MySecrets.decode(encoded: encoded, cipher: MySecrets.salt)
+        }()
+    }
+}
+
+public extension MySecrets {
+    struct Staging: MySecretsEnvironmentProtocol {
+        public init() {}
+
+        @inline(__always)
+        public lazy var serviceKey: String = {
+            let encoded: [UInt8] = [
+                0x33, 0x14, 0x8a, 0xc, 0xa0, 0xdb, 0x35, 0xd, 0x65, 0xaa, 0x11, 0x58, 0x43, 0xb2, 0xd3, 0x2e, 0x1a, 0x5a, 0xeb, 0xcd, 0x89, 0x14, 0xa8, 0xe8, 0x30, 0x57
+            ]
+            return MySecrets.decode(encoded: encoded, cipher: MySecrets.salt)
+        }()
+    }
+}

lib/arkana.rb

@@ -7,6 +7,7 @@
 require_relative "arkana/models/template_arguments"
 require_relative "arkana/salt_generator"
 require_relative "arkana/swift_code_generator"
+require_relative "arkana/kotlin_code_generator"
 require_relative "arkana/version"
 
 # Top-level namespace for Arkana's execution entry point. When ran from CLI, `Arkana.run` is what is invoked.
@@ -43,7 +44,14 @@ def self.run(arguments)
       config: config,
       salt: salt,
     )
-    SwiftCodeGenerator.generate(
+
+    generator = case config.current_lang.downcase
+      when "swift" then SwiftCodeGenerator
+      when "kotlin" then KotlinCodeGenerator
+      else UI.crash("Unknown output lang selected: #{config.current_lang}")
+    end
+
+    generator.method(:generate).call(
       template_arguments: template_arguments,
       config: config,
     )

lib/arkana/config_parser.rb

@@ -14,6 +14,7 @@ def self.parse(arguments)
     config = Config.new(yaml)
     config.include_environments(arguments.include_environments)
     config.current_flavor = arguments.flavor
+    config.current_lang = arguments.lang
     config.dotenv_filepath = arguments.dotenv_filepath
     UI.warn("Dotenv file was specified but couldn't be found at '#{config.dotenv_filepath}'") if config.dotenv_filepath && !File.exist?(config.dotenv_filepath)
     config