Gradlik

Gradlik is a toy build tool that allows its users to declare various tasks using neat Gradlik-DSL and execute any desirable Kotlin code.

Running

Console

To run Gradlik on a configuration file, execute the following command from the command line:

./gradlew gradlik-dsl:run --args="path-to-file/relative/to/gradlik-dsl/subdirectory"

For example:

./gradlew gradlik-dsl:run --args="../examples/cpp.gradlik.kts"

Output files will be created in the gradlik-dsl directory.

Idea

However, you may want to run Gradlik from IntelliJ to control the process more comfortably and to enable syntax highlighting in the scripts configuration files.

To do this, create new configuration for Kotlin with main class HostKt and configure it as shown on the screenshot below:

Configuration

To start using Gradlik you will need to create a configuration script -- a file with gradlik.kts extension.

Note, that for IntelliJ syntax highlighting to work correctly, this script must be able to see its base configuration class by either being in the same module or in a module with dependency declared as implementation(project(':gradlik-dsl')). You may also need to accept some hints from IntelliJ and restart the IDE.

Syntax

Gradlik uses Kotlin-based DSL to provide neat and comfortable syntax for project description. Its main entity is a task -- a program that accepts files as inputs, executes some Kotlin code or bash commands and produces some files as outputs.

To declare a task, simply write the following in your configuration script:

task("<name>") {

}

Inside the curly braces you will be able to configure it as you need! The following are functions that you may call inside the task builder.

dependsOn

Declare a block of dependencies for current task. Dependency insures that this task will be executed after all its dependencies, but their input will not be used.

task("dependent") {
    dependsOn {
        task("dependency")
    }
}

outputs

Declare a block of output files that are produced by this task. Files listed in this block are visible to other tasks and will be passed to them via inputs section.

task("I love outputs") {
    outputs {
        file("notMyFile.kts")
    }
}

inputs

Declare a block of inputs which will be available in all executable blocks of the task. Inputs can be either task's or file's: task inputs will create a dependency on the task and use all its output's as inputs, while file's inputs will be used directly.

task("I love inputs") {
    inputs {
        file("myFile.kts")
        task("I love outputs")
    }
}

In the example above, the "I love outputs" task will use two files as inputs -- myFile.kts and notMyFile.kts (from the outputs example) -- and it will execute strictly after the "I love outputs" task.

runProcess

Declare a shell command to be executed. Additional arguments can be declared via arg in the builder block. All inputs from inputs section will be passed to the process in the order of their declaration.

task("C++ enjoyer") {
    inputs {
        file("a.cpp")
        file("b.cpp")
    }

    runProcess("g++") {
        arg("-ocpp_cool_program.out")
    }
}

runCode

Declare a Kotlin function to be executed. This function accepts List<java.io.File> as a parameter -- this is a list of all inputs from inputs section in the order of their declaration.

task("Kotlin enthusiast") {
    runCode {
        val message = "Bazel"
        when (message) {
            "Gradle" -> println("Meow")
            "CMake" -> println("Woof")
            "Bazel" -> println("Quack")
        }
    }
}

A task can have multiple run... sections -- in this case they will be executed in the order of their declaration.

Misc

Gradlik also provides basic checks for the contents of the project: for example, it will notify you if you declared a cyclic dependency within your tasks or used an input that was not declared in inputs section.

Execution process is also verbose and will output some information as logs into stdin. To control the level of log messages, you may refer to this question on StackOverflow.

Examples

You can find some examples in examples module:

• cpp.gradlik.kts: write cpp source code into file via Kotlin, compile it and execute
• cycle.gradlik.kts: graph with cyclic dependency, which will be found during evaluation
• diamond.gradlik.kta: simple diamond-shaped graph
• tree.gradlik.kts: tree graph with node with several dependent nodes, where same files may be passed as arguments several times