spotless-kotlin

A template Kotlin (Java) project configured with Gradle and Spotless plugin for Klean Kotlin Kode.

The template comes with a ktlint, logging, gitignore, gradle and junit preconfigured. See here for more information.

The template was designed and tested in Intellij Idea, but should be useable in other IDEs.

How to use

1. In the parent directory you want your in project run:
   1. git clone https://github.com/iikirilov/spotless-kotlin <you_project_name>
   2. cd <you_project_name>
   3. rm -rf .git
   4. git init
   5. Add your rootProject.name name to settings.gradle
   6. Edit gradle/spotless.kotlin.license to inclide your company name
   7. Edit README.md
   8. git add -A
   9. git remote add origin <your_remote_repo_url>
   10. git commit -m "Initial commit"
2. Open your newly created project in you IDE of choice.
3. Create your modules. [Optional]
4. Set-up logging. [TODO]
5. Write some kotlin.
6. Run ./gradlew spotlessApply to automatically klean up you kode.
7. Commit, push and repeat from 5.

Modules

Modular code is awesome!! It makes it easier to build, maintain and re-use code. The root directory is already a module. You do not need to create modules if you feel your project does not need them, instead you can put your src folder directly in the project root.

Module structure:

└── <module_name>
    └── src
        ├── main
        │   ├── kotlin
        │   └── resources
        └── test
            ├── kotlin
            └── resources

Adding a module:

Add a new line to settings.gradle in the format include '<module_name>'. Then create the folder structure in the project root as decribed in module structure.

Adding a nested module:

include '<parent_module>:<child_module>'
include `<parent_module>:<child_module_1>`

Then create the parnet_module folder in the project root and then the folder structure described in module structure in the parnet_module folder.

The following is an example settings.gradle file. The file includes the root project name.

rootProject.name = 'spotless-kotlin'

include 'module1'
include 'module2:module2a'
include 'module2:module2b'

Logging

Logging is set up using kotlin-logging and logback.

Declare a logger wherever you need it like this: val logger = KotlinLogging.logger {}

Logback configuration should be located in src/main/resources/logback.xml. Logback configuration for tests should be located in src/test/resources/logback-test.xml. The following is a minimal configuration of a logback config file.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="INFO">
        <appender-ref ref="STDOUT" />
    </root>
</configuration>

Steps used to create this template

1. Created a new Gradle project in Intellij checking the Kotlin (Java) checkbox in the "Additional Libraries and Frameworks" section
2. Set up git - in the project directory
   1. git init
   2. git remote add origin https://github.com/iikirilov/spotless-kotlin.git
3. Modify build.gradle
   1. Removed the version label
   2. Adding spotless gradle plugin
   3. Configured Spotless Defaults
   4. Added kotlin-logging and logback for logging
4. Added Apache License v2 in gradle/spotless.kotlin.license
   Remember to change <insert-company-name-here> to your company name.
5. Set up modules in settings.gradle
6. Generate .gitignore for Kotlin, JetBrains and Gradle using Intellij plugin

Spotless Defaults

Kotlin

Uses ktlint behind the scenes. By default:

1. Max Line Length = 100
2. Inserts new line at the end of every .kt file
3. Puts an Apache License v2 at the top of every .kt file. You can change the license by modifying gradle/spotless.kotlin.license

Gradle

Uses groovy eclipse with the config file specified in gradle/formatter.properties. By default:

1. Uses 4 space as the indentation
2. Indentations are not inserted in empty lines
3. Inserts new line at the end of every .gradle file