Use Gradle Tooling API

app/build.gradle.kts

@@ -14,9 +14,17 @@ repositories {
 }
 
 dependencies {
+    implementation(project(":model"))
     implementation(kotlin("stdlib-jdk8"))
+    implementation(kotlin("reflect"))
     implementation("org.gradle:gradle-tooling-api:${gradle.gradleVersion}")
     implementation("com.github.ajalt:clikt:2.0.0")
+    implementation("org.slf4j:slf4j-api:1.7.26")
+    runtimeOnly("org.slf4j:slf4j-simple:1.7.26")
+    implementation("com.squareup.moshi:moshi:1.8.0")
+    implementation("com.squareup.moshi:moshi-adapters:1.8.0")
+    implementation("com.squareup.moshi:moshi-kotlin:1.8.0")
+    implementation("com.squareup.okio:okio:2.2.2")
 }
 
 application {

app/gradle/dependency-locks/compileClasspath.lockfile

@@ -0,0 +1,16 @@
+# This is a Gradle generated file for dependency locking.
+# Manual edits can break the build and are not advised.
+# This file is expected to be part of source control.
+com.github.ajalt:clikt:2.0.0
+com.squareup.moshi:moshi-adapters:1.8.0
+com.squareup.moshi:moshi-kotlin:1.8.0
+com.squareup.moshi:moshi:1.8.0
+com.squareup.okio:okio:2.2.2
+org.gradle:gradle-tooling-api:5.4.1
+org.jetbrains.kotlin:kotlin-reflect:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-common:1.3.31
+org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib:1.3.31
+org.jetbrains:annotations:13.0
+org.slf4j:slf4j-api:1.7.26

app/gradle/dependency-locks/runtimeClasspath.lockfile

@@ -0,0 +1,17 @@
+# This is a Gradle generated file for dependency locking.
+# Manual edits can break the build and are not advised.
+# This file is expected to be part of source control.
+com.github.ajalt:clikt:2.0.0
+com.squareup.moshi:moshi-adapters:1.8.0
+com.squareup.moshi:moshi-kotlin:1.8.0
+com.squareup.moshi:moshi:1.8.0
+com.squareup.okio:okio:2.2.2
+org.gradle:gradle-tooling-api:5.4.1
+org.jetbrains.kotlin:kotlin-reflect:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-common:1.3.31
+org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib:1.3.31
+org.jetbrains:annotations:13.0
+org.slf4j:slf4j-api:1.7.26
+org.slf4j:slf4j-simple:1.7.26

app/gradle/dependency-locks/testCompileClasspath.lockfile

@@ -0,0 +1,16 @@
+# This is a Gradle generated file for dependency locking.
+# Manual edits can break the build and are not advised.
+# This file is expected to be part of source control.
+com.github.ajalt:clikt:2.0.0
+com.squareup.moshi:moshi-adapters:1.8.0
+com.squareup.moshi:moshi-kotlin:1.8.0
+com.squareup.moshi:moshi:1.8.0
+com.squareup.okio:okio:2.2.2
+org.gradle:gradle-tooling-api:5.4.1
+org.jetbrains.kotlin:kotlin-reflect:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-common:1.3.31
+org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib:1.3.31
+org.jetbrains:annotations:13.0
+org.slf4j:slf4j-api:1.7.26

app/gradle/dependency-locks/testRuntimeClasspath.lockfile

@@ -0,0 +1,17 @@
+# This is a Gradle generated file for dependency locking.
+# Manual edits can break the build and are not advised.
+# This file is expected to be part of source control.
+com.github.ajalt:clikt:2.0.0
+com.squareup.moshi:moshi-adapters:1.8.0
+com.squareup.moshi:moshi-kotlin:1.8.0
+com.squareup.moshi:moshi:1.8.0
+com.squareup.okio:okio:2.2.2
+org.gradle:gradle-tooling-api:5.4.1
+org.jetbrains.kotlin:kotlin-reflect:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-common:1.3.31
+org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.3.21
+org.jetbrains.kotlin:kotlin-stdlib:1.3.31
+org.jetbrains:annotations:13.0
+org.slf4j:slf4j-api:1.7.26
+org.slf4j:slf4j-simple:1.7.26

app/src/main/kotlin/org/nixos/gradle2nix/GradleRunner.kt

@@ -1,45 +1,40 @@
 package org.nixos.gradle2nix
 
 import org.gradle.tooling.GradleConnector
-import java.io.File
+import org.gradle.tooling.ProjectConnection
 
-class GradleRunner(
-    private val projectDir: File,
-    private val useWrapper: Boolean,
-    private val gradleVersion: String?,
-    private val configurations: List<String>
-) {
-    companion object {
-        val initScript: String = System.getProperty("org.nixos.gradle2nix.initScript")
+private val initScript: String = System.getProperty("org.nixos.gradle2nix.initScript")
+
+fun connect(config: Config): ProjectConnection =
+    GradleConnector.newConnector()
+        .apply {
+            if (config.wrapper) {
+                useBuildDistribution()
+            } else if (config.gradleVersion != null) {
+                useGradleVersion(config.gradleVersion)
+            }
+        }
+        .forProjectDirectory(config.projectDir)
+        .connect()
+
+fun ProjectConnection.getBuildModel(config: Config, path: String): DefaultBuild {
+    val arguments = mutableListOf(
+        "--init-script=$initScript",
+        "-Dorg.nixos.gradle2nix.configurations='${config.configurations.joinToString(",")}'"
+    )
+
+    if (path.isNotEmpty()) {
+        arguments += "--project-dir=$path"
     }
 
-    fun runGradle() {
-        GradleConnector.newConnector()
-            .apply {
-                if (useWrapper) {
-                    useBuildDistribution()
-                } else if (gradleVersion != null) {
-                    useGradleVersion(gradleVersion)
-                }
+    return model(Build::class.java)
+        .withArguments(arguments)
+        .apply {
+            if (config.verbose) {
+                setStandardOutput(System.out)
+                setStandardError(System.err)
             }
-            .forProjectDirectory(projectDir)
-            .connect()
-            .use { connection ->
-                connection.newBuild()
-                    .withArguments("--init-script", initScript)
-                    .apply {
-                        if (configurations.isNotEmpty()) {
-                            withArguments(
-                                "-Dorg.nixos.gradle2nix.configurations=${configurations.joinToString(
-                                    ","
-                                )}"
-                            )
-                        }
-                    }
-                    .forTasks("nixGradleEnv")
-                    .setStandardOutput(System.out)
-                    .setStandardError(System.err)
-                    .run()
-            }
-    }
-}
+        }
+        .get()
+        .let { DefaultBuild(it) }
+}

app/src/main/kotlin/org/nixos/gradle2nix/Logger.kt

@@ -0,0 +1,19 @@
+package org.nixos.gradle2nix
+
+import java.io.PrintStream
+
+class Logger(
+    val out: PrintStream = System.err,
+    val verbose: Boolean) {
+
+    val log: (String) -> Unit = { if (verbose) out.println(it) }
+    val warn: (String) -> Unit = { out.println("Warning: $it")}
+    val error: (String) -> Unit = {
+        out.println("Error: $it")
+        System.exit(1)
+    }
+
+    operator fun component1() = log
+    operator fun component2() = warn
+    operator fun component3() = error
+}

app/src/main/kotlin/org/nixos/gradle2nix/Main.kt

@@ -1,25 +1,103 @@
 package org.nixos.gradle2nix
 
+import com.github.ajalt.clikt.completion.CompletionCandidates
 import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.parameters.arguments.ProcessedArgument
 import com.github.ajalt.clikt.parameters.arguments.argument
-import com.github.ajalt.clikt.parameters.arguments.defaultLazy
-import com.github.ajalt.clikt.parameters.options.flag
-import com.github.ajalt.clikt.parameters.options.multiple
-import com.github.ajalt.clikt.parameters.options.option
+import com.github.ajalt.clikt.parameters.arguments.convert
+import com.github.ajalt.clikt.parameters.arguments.default
+import com.github.ajalt.clikt.parameters.options.*
 import com.github.ajalt.clikt.parameters.types.file
+import com.squareup.moshi.Moshi
+import okio.buffer
+import okio.sink
 import java.io.File
 
+data class Config(
+    val wrapper: Boolean,
+    val gradleVersion: String?,
+    val configurations: List<String>,
+    val projectDir: File,
+    val includes: List<File>,
+    val buildSrc: Boolean,
+    val verbose: Boolean
+) {
+    val allProjects = listOf(projectDir) + includes
+}
+
 class Main : CliktCommand() {
-    val wrapper: Boolean by option(help = "Use the project's gradle wrapper for building").flag()
-    val gradleVersion: String? by option(help = "Use a specific Gradle version")
+    val wrapper: Boolean by option("--gradle-wrapper", "-w",
+        help = "Use the project's gradle wrapper for building")
+        .flag()
+
+    val gradleVersion: String? by option("--gradle-version", "-g",
+        help = "Use a specific Gradle version")
+
     val configurations: List<String> by option(help = "Project configuration(s)").multiple()
+
     val projectDir: File by argument(help = "Path to the project root")
+        .projectDir()
+        .default(File("."))
+
+    val outputDir: File by option("--out", "-o",
+        help = "Path to write Nix environment files")
+        .file(fileOkay = false, folderOkay = true)
+        .default(File("."))
+
+    val includes: List<File> by option("--include", "-i",
+        help = "Path to included build(s)",
+        metavar = "DIR")
         .file(exists = true, fileOkay = false, folderOkay = true, readable = true)
-        .defaultLazy { File(".") }
+        .multiple()
+        .validate { files ->
+            val failures = files.filterNot { it.isProjectRoot() }
+            if (failures.isNotEmpty()) {
+                val message = failures.joinToString("\n    ")
+                fail("Included builds are not Gradle projects:\n$message\n" +
+                        "Gradle projects must contain a settings.gradle or settings.gradle.kts script.")
+            }
+        }
+
+    val buildSrc: Boolean by option("--enableBuildSrc", help = "Include buildSrc project")
+        .flag("--disableBuildSrc", default = true)
+
+    val verbose: Boolean by option("--verbose", "-v", help = "Enable verbose logging")
+        .flag(default = false)
 
     override fun run() {
-        GradleRunner(projectDir, wrapper, gradleVersion, configurations).runGradle()
+        val config = Config(wrapper, gradleVersion, configurations, projectDir, includes, buildSrc, verbose)
+        val (log, warn, error) = Logger(verbose = config.verbose)
+
+        val json by lazy { Moshi.Builder().build().adapter(DefaultBuild::class.java).indent("  ") }
+        val out by lazy { outputDir.also { it.mkdirs() }}
+
+        val paths = resolveProjects(config).map { p ->
+            p.toRelativeString(config.projectDir)
+        }
+
+        connect(config).use { connection ->
+            for (project in paths) {
+                log("Resolving project model: ${project.takeIf { it.isNotEmpty() } ?: "root project"}")
+                val build = connection.getBuildModel(config, project)
+                val filename = build.rootProject.name + ".json"
+                val file = out.resolve(filename)
+                file.sink().buffer().use { sink -> json.toJson(sink, build) }
+                log("  --> $file")
+            }
+        }
     }
 }
 
-fun main(args: Array<String>) = Main().main(args)
+fun ProcessedArgument<String, String>.projectDir(): ProcessedArgument<File, File> {
+    return convert(completionCandidates = CompletionCandidates.Path) {
+        File(it).also { file ->
+            if (!file.exists()) fail("Directory \"$file\" does not exist.")
+            if (file.isFile) fail("Directory \"$file\" is a file.")
+            if (!file.canRead()) fail("Directory \"$file\" is not readable.")
+            if (!file.isProjectRoot()) fail("Directory \"$file\" is not a Gradle project.")
+        }
+    }
+}
+
+fun main(args: Array<String>) = Main().main(args)
+

app/src/main/kotlin/org/nixos/gradle2nix/Projects.kt

@@ -0,0 +1,17 @@
+package org.nixos.gradle2nix
+
+import java.io.File
+
+fun resolveProjects(config: Config) = config.allProjects.run {
+    if (config.buildSrc) {
+        flatMap { listOfNotNull(it, it.findBuildSrc()) }
+    } else {
+        this
+    }
+}
+
+fun File.findBuildSrc(): File? =
+    resolve("buildSrc").takeIf { it.isDirectory }
+
+fun File.isProjectRoot(): Boolean =
+    isDirectory && (resolve("settings.gradle").isFile || resolve("settings.gradle.kts").isFile)