Konsist integration

While katachi’s core API focuses on validating directory structure and file location, "...".konsist { } lets you use the Konsist API to validate the declarations inside a file.

Installation

"...".konsist { } lives in a separate artifact, me.tbsten.katachi:katachi-konsist, so add it to the dependencies in build.gradle.kts.

build.gradle.kts

dependencies {
    testImplementation("me.tbsten.katachi:katachi-konsist:<version>")
}

Next, pass FileConstraintCheck() to projectArchitecture.assert() to run the Konsist checks.

@Test
fun `files are placed according to the architecture`() {
  projectArchitecture.assert()
  projectArchitecture.assert(FileConstraintCheck())
}

Basic usage

Inside a Role, you define what declarations that Role’s files should have.

architecture {
  "UseCase" {
    layout {
      "src/main/kotlin/com/example/useCase" / "*UseCase".ktFile()
    }

    "has exactly one invoke function".konsist {
        classes().must { it.functions().map { f -> f.name } == listOf("invoke") }
    }
  }
}

A constraint applies to the files that matched the Role’s layout { }. A Role with no layout { } can’t have constraints.

Example error

When a constraint violation is detected, the error message looks like this.

Katachi check failed: 1 violation (FileConstraint: 1)

[UnsatisfiedFileConstraint] file:///path/to/project/src/main/kotlin/com/example/useCase/GetUserUseCase.kt
  Role: UseCase / FileConstraint: "has exactly one invoke function"
  Declaration: GetUserUseCase (line 3)
  Declared at: ProjectArchitecture.kt:12

The name you gave the constraint appears exactly as written. When there are multiple constraints, this single line tells you which one failed, so write the name in the form of what must be satisfied.

Konsist API

Inside a "...".konsist { } block, you can use the regular Konsist API.

Konsist documentation

katachi adds three things — must, mustNot, and mustBeEmpty — and blocks Konsist’s assertions such as assertTrue with compile errors. Everything up to narrowing down the target uses Konsist’s syntax as-is.

Summary

• layout { } handles where files may be placed, and konsist { } handles what their contents should look like.
• katachi-konsist is an optional module. It requires adding the dependency and setting up assert(FileConstraintCheck()).
• The constraint name appears directly in the violation report. Write the name in the form of what must be satisfied.
• Konsist’s assertTrue family can’t be used inside konsist { } (it causes a compile error). Write must / mustNot / mustBeEmpty instead.

Next steps

• See the various recipes for real examples that use the Konsist API.
• Role … Learn how to write a Role’s description, placement, and grouping — the place where you write constraints.
• ArchitectureProcessor and customizing it … Learn how to pull your own information out of the definition, using the same interface as FileConstraintCheck.