build: Flatten project structure

This change updates the project structure to become flattened. 
Previously, the simulator, frontend and API each lived into their own directory. 

With this change, all modules of the project live in the top-level directory of 
the repository.

9 files changed, 455 insertions, 0 deletions

diff --git a/buildSrc/src/main/kotlin/ProjectExtensions.kt b/buildSrc/src/main/kotlin/ProjectExtensions.kt
new file mode 100644
index 00000000..ddf643f6
--- /dev/null
+++ b/buildSrc/src/main/kotlin/ProjectExtensions.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.extra
+import org.gradle.kotlin.dsl.provideDelegate
+
+/**
+ * Obtain the [Versions] object for the specified [Project] instance.
+ */
+val Project.versions: Versions
+    get() {
+        var versions: Versions? by rootProject.extra
+        return versions ?: Versions(rootProject).also { versions = it }
+    }
diff --git a/buildSrc/src/main/kotlin/Versions.kt b/buildSrc/src/main/kotlin/Versions.kt
new file mode 100644
index 00000000..6aa9260b
--- /dev/null
+++ b/buildSrc/src/main/kotlin/Versions.kt
@@ -0,0 +1,69 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2019 atlarge-research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import org.gradle.api.JavaVersion
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.extra
+import kotlin.properties.ReadOnlyProperty
+import kotlin.reflect.KProperty
+
+/**
+ * This class contains the versions of the dependencies shared by the different
+ * subprojects.
+ */
+public class Versions(private val project: Project) {
+    /**
+     * A delegate for obtaining configuration values from a [Project] instance.
+     */
+    private fun version(name: String? = null): ReadOnlyProperty<Versions, String> =
+        ReadOnlyProperty { _, property -> get(name ?: property.name) }
+
+    val junitJupiter by version(name = "junit-jupiter")
+    val junitPlatform by version(name = "junit-platform")
+    val mockk by version()
+
+    val slf4j by version()
+    val kotlinLogging by version(name = "kotlin-logging")
+    val log4j by version()
+
+    val kotlinxCoroutines by version(name = "kotlinx-coroutines")
+
+    val otelApi by version(name = "opentelemetry-api")
+    val otelApiMetrics by version(name = "opentelemetry-api-metrics")
+    val otelSdk by version(name = "opentelemetry-sdk")
+    val otelSdkMetrics by version(name = "opentelemetry-sdk-metrics")
+
+
+    /**
+     * Obtain the version for the specified [dependency][name].
+     */
+    operator fun get(name: String) = project.extra.get("$name.version") as String
+
+    companion object {
+        /**
+         * The JVM version to target.
+         */
+        val jvmTarget = JavaVersion.VERSION_1_8
+    }
+}
diff --git a/buildSrc/src/main/kotlin/benchmark-conventions.gradle.kts b/buildSrc/src/main/kotlin/benchmark-conventions.gradle.kts
new file mode 100644
index 00000000..8623e8da
--- /dev/null
+++ b/buildSrc/src/main/kotlin/benchmark-conventions.gradle.kts
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import kotlinx.benchmark.gradle.*
+import org.jetbrains.kotlin.allopen.gradle.*
+
+plugins {
+    id("org.jetbrains.kotlinx.benchmark")
+    `java-library`
+    kotlin("plugin.allopen")
+}
+
+sourceSets {
+    register("jmh") {
+        compileClasspath += sourceSets["main"].output
+        runtimeClasspath += sourceSets["main"].output
+    }
+}
+
+configurations {
+    named("jmhImplementation") {
+        extendsFrom(configurations["implementation"])
+    }
+}
+
+configure<AllOpenExtension> {
+    annotation("org.openjdk.jmh.annotations.State")
+}
+
+benchmark {
+    targets {
+        register("jmh") {
+            this as JvmBenchmarkTarget
+            jmhVersion = "1.21"
+        }
+    }
+}
+
+// Workaround for https://github.com/Kotlin/kotlinx-benchmark/issues/39
+afterEvaluate {
+    tasks.named<org.gradle.jvm.tasks.Jar>("jmhBenchmarkJar") {
+        duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    }
+}
+
+dependencies {
+    implementation("org.jetbrains.kotlinx:kotlinx-benchmark-runtime-jvm:0.3.0")
+}
diff --git a/buildSrc/src/main/kotlin/dokka-conventions.gradle.kts b/buildSrc/src/main/kotlin/dokka-conventions.gradle.kts
new file mode 100644
index 00000000..91156cbf
--- /dev/null
+++ b/buildSrc/src/main/kotlin/dokka-conventions.gradle.kts
@@ -0,0 +1,33 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2021 atlarge-research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import org.jetbrains.dokka.gradle.DokkaTask
+
+plugins {
+    id("org.jetbrains.dokka")
+}
+
+tasks.getting(DokkaTask::class) {
+    outputFormat = "html"
+}
diff --git a/buildSrc/src/main/kotlin/experiment-conventions.gradle.kts b/buildSrc/src/main/kotlin/experiment-conventions.gradle.kts
new file mode 100644
index 00000000..4745ff1a
--- /dev/null
+++ b/buildSrc/src/main/kotlin/experiment-conventions.gradle.kts
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+plugins {
+    `java-library`
+}
+
+dependencies {
+    implementation(project(":opendc-harness"))
+}
+
+tasks.register<Test>("experiment") {
+    // Ensure JUnit Platform is used for resolving tests
+    useJUnitPlatform()
+
+    description = "Runs OpenDC experiments"
+    group = "application"
+
+    testClassesDirs = sourceSets["main"].output.classesDirs
+    classpath = sourceSets["main"].runtimeClasspath
+}
diff --git a/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts b/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts
new file mode 100644
index 00000000..3e8aa741
--- /dev/null
+++ b/buildSrc/src/main/kotlin/jacoco-aggregation.gradle.kts
@@ -0,0 +1,56 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2019 atlarge-research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+
+plugins {
+    jacoco
+}
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
+
+tasks.register<JacocoReport>("codeCoverageReport") {
+    group = "Coverage reports"
+    description = "Generates an aggregate report based on all subprojects"
+
+    reports {
+        xml.isEnabled = true
+        xml.destination = file("${buildDir}/reports/jacoco/report.xml")
+
+        html.isEnabled = true
+    }
+
+    subprojects {
+        this@subprojects.plugins.withType<JacocoPlugin>().configureEach {
+            this@subprojects.tasks.matching {
+                it.extensions.findByType<JacocoTaskExtension>() != null }
+                .configureEach {
+                    sourceSets(this@subprojects.the<SourceSetContainer>().named("main").get())
+                    executionData(this)
+                }
+        }
+    }
+}
diff --git a/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts b/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts
new file mode 100644
index 00000000..d0534d4f
--- /dev/null
+++ b/buildSrc/src/main/kotlin/jacoco-conventions.gradle.kts
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+plugins {
+    `java-library`
+    jacoco
+}
+
+tasks.jacocoTestReport {
+    reports {
+        html.isEnabled = true
+    }
+}
+
+/* Share sources folder with other projects for aggregated JaCoCo reports */
+configurations.create("transitiveSourcesElements") {
+    isVisible = false
+    isCanBeResolved = false
+    isCanBeConsumed = true
+    extendsFrom(configurations.implementation.get())
+    attributes {
+        attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+        attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.DOCUMENTATION))
+        attribute(DocsType.DOCS_TYPE_ATTRIBUTE, objects.named("source-folders"))
+    }
+    sourceSets.main.get().java.srcDirs.forEach {
+        outgoing.artifact(it)
+    }
+}
+
+/* Share the coverage data to be aggregated for the whole product */
+configurations.create("coverageDataElements") {
+    isVisible = false
+    isCanBeResolved = false
+    isCanBeConsumed = true
+    extendsFrom(configurations.implementation.get())
+    attributes {
+        attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
+        attribute(Category.CATEGORY_ATTRIBUTE, objects.named(Category.DOCUMENTATION))
+        attribute(DocsType.DOCS_TYPE_ATTRIBUTE, objects.named("jacoco-coverage-data"))
+    }
+    // This will cause the test task to run if the coverage data is requested by the aggregation task
+    outgoing.artifact(tasks.test.map { task ->
+        task.extensions.getByType<JacocoTaskExtension>().destinationFile!!
+    })
+}
diff --git a/buildSrc/src/main/kotlin/kotlin-library-conventions.gradle.kts b/buildSrc/src/main/kotlin/kotlin-library-conventions.gradle.kts
new file mode 100644
index 00000000..cf3f2569
--- /dev/null
+++ b/buildSrc/src/main/kotlin/kotlin-library-conventions.gradle.kts
@@ -0,0 +1,50 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2019 atlarge-research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+plugins {
+    `java-library`
+    kotlin("jvm")
+    id("org.jlleitschuh.gradle.ktlint")
+}
+
+/* Project configuration */
+repositories {
+    mavenCentral()
+}
+
+java {
+    sourceCompatibility = Versions.jvmTarget
+}
+
+kotlin {
+    explicitApi()
+}
+
+tasks.withType<KotlinCompile>().configureEach {
+    kotlinOptions.jvmTarget = Versions.jvmTarget.toString()
+    kotlinOptions.useIR = true
+    kotlinOptions.freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
+}
diff --git a/buildSrc/src/main/kotlin/testing-conventions.gradle.kts b/buildSrc/src/main/kotlin/testing-conventions.gradle.kts
new file mode 100644
index 00000000..f129c282
--- /dev/null
+++ b/buildSrc/src/main/kotlin/testing-conventions.gradle.kts
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2021 AtLarge Research
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+plugins {
+    `java-library`
+}
+
+tasks.test {
+    useJUnitPlatform()
+
+    reports {
+        html.isEnabled = true
+        junitXml.isEnabled = true
+    }
+}
+
+dependencies {
+    testImplementation("org.junit.jupiter:junit-jupiter-api:${versions.junitJupiter}")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:${versions.junitJupiter}")
+    testImplementation("org.junit.jupiter:junit-jupiter-params:${versions.junitJupiter}")
+    testImplementation("io.mockk:mockk:${versions.mockk}")
+}