Refactor: Detangle GitHub rendering from extraction

- Extracted `DependencyGraphRenderer` interface with single GitHub implementation
- Abstract plugin allows renderer classname to be specified

This should make it possible to implement support for other output formats.

plugin/src/main/kotlin/org/gradle/github/dependencygraph/AbstractDependencyExtractorPlugin.kt

@@ -0,0 +1,127 @@
+package org.gradle.github.dependencygraph
+
+import org.gradle.api.Plugin
+import org.gradle.api.invocation.Gradle
+import org.gradle.api.provider.Provider
+import org.gradle.github.dependencygraph.internal.DependencyExtractor
+import org.gradle.github.dependencygraph.internal.DependencyExtractorBuildService
+import org.gradle.github.dependencygraph.internal.LegacyDependencyExtractor
+import org.gradle.github.dependencygraph.internal.util.GradleExtensions
+import org.gradle.github.dependencygraph.internal.util.service
+import org.gradle.internal.build.event.BuildEventListenerRegistryInternal
+import org.gradle.util.GradleVersion
+
+abstract class AbstractDependencyExtractorPlugin : Plugin<Gradle> {
+    // Register extension functions on `Gradle` type
+    private companion object : GradleExtensions()
+
+    abstract fun getRendererClassName(): String
+
+    internal lateinit var dependencyExtractorProvider: Provider<out DependencyExtractor>
+
+    override fun apply(gradle: Gradle) {
+        val gradleVersion = GradleVersion.current()
+        // Create the adapter based upon the version of Gradle
+        val applicatorStrategy = when {
+            gradleVersion < GradleVersion.version("8.0") -> PluginApplicatorStrategy.LegacyPluginApplicatorStrategy
+            else -> PluginApplicatorStrategy.DefaultPluginApplicatorStrategy
+        }
+
+        // Create the service
+        dependencyExtractorProvider = applicatorStrategy.createExtractorService(gradle, getRendererClassName())
+
+        gradle.rootProject { project ->
+            dependencyExtractorProvider
+                .get()
+                .rootProjectBuildDirectory = project.buildDir
+        }
+
+        // Register the service to listen for Build Events
+        applicatorStrategy.registerExtractorListener(gradle, dependencyExtractorProvider)
+
+        // Register the shutdown hook that should execute at the completion of the Gradle build.
+        applicatorStrategy.registerExtractorServiceShutdown(gradle, dependencyExtractorProvider)
+    }
+
+    /**
+     * Adapters for creating the [DependencyExtractor] and installing it into [Gradle] based upon the Gradle version.
+     */
+    private interface PluginApplicatorStrategy {
+
+        fun createExtractorService(
+            gradle: Gradle,
+            rendererClassName: String
+        ): Provider<out DependencyExtractor>
+
+        fun registerExtractorListener(
+            gradle: Gradle,
+            extractorServiceProvider: Provider<out DependencyExtractor>
+        )
+
+        fun registerExtractorServiceShutdown(
+            gradle: Gradle,
+            extractorServiceProvider: Provider<out DependencyExtractor>
+        )
+
+        object LegacyPluginApplicatorStrategy : PluginApplicatorStrategy {
+
+            override fun createExtractorService(
+                gradle: Gradle,
+                rendererClassName: String
+            ): Provider<out DependencyExtractor> {
+                val dependencyExtractor = LegacyDependencyExtractor(rendererClassName)
+                return gradle.providerFactory.provider { dependencyExtractor }
+            }
+
+            override fun registerExtractorListener(
+                gradle: Gradle,
+                extractorServiceProvider: Provider<out DependencyExtractor>
+            ) {
+                gradle.buildOperationListenerManager
+                    .addListener(extractorServiceProvider.get())
+            }
+
+            override fun registerExtractorServiceShutdown(
+                gradle: Gradle,
+                extractorServiceProvider: Provider<out DependencyExtractor>
+            ) {
+                gradle.buildFinished {
+                    extractorServiceProvider.get().close()
+                    gradle.buildOperationListenerManager
+                        .removeListener(extractorServiceProvider.get())
+                }
+            }
+        }
+
+        object DefaultPluginApplicatorStrategy : PluginApplicatorStrategy {
+            private const val SERVICE_NAME = "gitHubDependencyExtractorService"
+
+            override fun createExtractorService(
+                gradle: Gradle,
+                rendererClassName: String
+            ): Provider<out DependencyExtractor> {
+                return gradle.sharedServices.registerIfAbsent(
+                    SERVICE_NAME,
+                    DependencyExtractorBuildService::class.java
+                ) {
+                    it.parameters.rendererClassName.set(rendererClassName)
+                }
+            }
+
+            override fun registerExtractorListener(
+                gradle: Gradle,
+                extractorServiceProvider: Provider<out DependencyExtractor>
+            ) {
+                gradle.service<BuildEventListenerRegistryInternal>()
+                    .onOperationCompletion(extractorServiceProvider)
+            }
+
+            override fun registerExtractorServiceShutdown(
+                gradle: Gradle,
+                extractorServiceProvider: Provider<out DependencyExtractor>
+            ) {
+                // No-op as DependencyExtractorService is Auto-Closable
+            }
+        }
+    }
+}

plugin/src/main/kotlin/org/gradle/github/dependencygraph/GitHubDependencyExtractorPlugin.kt

@@ -1,123 +1,12 @@
 package org.gradle.github.dependencygraph
 
-import org.gradle.api.Plugin
-import org.gradle.api.invocation.Gradle
-import org.gradle.api.provider.Provider
-import org.gradle.github.dependencygraph.internal.DependencyExtractor
-import org.gradle.github.dependencygraph.internal.DependencyExtractorBuildService
-import org.gradle.github.dependencygraph.internal.LegacyDependencyExtractor
-import org.gradle.github.dependencygraph.internal.util.GradleExtensions
-import org.gradle.github.dependencygraph.internal.util.service
-import org.gradle.internal.build.event.BuildEventListenerRegistryInternal
-import org.gradle.util.GradleVersion
+import org.gradle.github.dependencygraph.internal.github.GitHubDependencyGraphRenderer
 
 /**
  * A plugin that collects all resolved dependencies in a Gradle build and exports it using the GitHub API format.
  */
-class GitHubDependencyExtractorPlugin : Plugin<Gradle> {
-    // Register extension functions on `Gradle` type
-    private companion object : GradleExtensions()
-
-    internal lateinit var dependencyExtractorProvider: Provider<out DependencyExtractor>
-
-    override fun apply(gradle: Gradle) {
-        val gradleVersion = GradleVersion.current()
-        // Create the adapter based upon the version of Gradle
-        val applicatorStrategy = when {
-            gradleVersion < GradleVersion.version("8.0") -> PluginApplicatorStrategy.LegacyPluginApplicatorStrategy
-            else -> PluginApplicatorStrategy.DefaultPluginApplicatorStrategy
-        }
-
-        // Create the service
-        dependencyExtractorProvider = applicatorStrategy.createExtractorService(gradle)
-
-        gradle.rootProject { project ->
-            dependencyExtractorProvider
-                .get()
-                .rootProjectBuildDirectory = project.buildDir
-        }
-
-        // Register the service to listen for Build Events
-        applicatorStrategy.registerExtractorListener(gradle, dependencyExtractorProvider)
-
-        // Register the shutdown hook that should execute at the completion of the Gradle build.
-        applicatorStrategy.registerExtractorServiceShutdown(gradle, dependencyExtractorProvider)
-    }
-
-    /**
-     * Adapters for creating the [DependencyExtractor] and installing it into [Gradle] based upon the Gradle version.
-     */
-    private interface PluginApplicatorStrategy {
-
-        fun createExtractorService(
-            gradle: Gradle
-        ): Provider<out DependencyExtractor>
-
-        fun registerExtractorListener(
-            gradle: Gradle,
-            extractorServiceProvider: Provider<out DependencyExtractor>
-        )
-
-        fun registerExtractorServiceShutdown(
-            gradle: Gradle,
-            extractorServiceProvider: Provider<out DependencyExtractor>
-        )
-
-        object LegacyPluginApplicatorStrategy : PluginApplicatorStrategy {
-
-            override fun createExtractorService(
-                gradle: Gradle
-            ): Provider<out DependencyExtractor> {
-                val dependencyExtractor = LegacyDependencyExtractor()
-                return gradle.providerFactory.provider { dependencyExtractor }
-            }
-
-            override fun registerExtractorListener(
-                gradle: Gradle,
-                extractorServiceProvider: Provider<out DependencyExtractor>
-            ) {
-                gradle.buildOperationListenerManager
-                    .addListener(extractorServiceProvider.get())
-            }
-
-            override fun registerExtractorServiceShutdown(
-                gradle: Gradle,
-                extractorServiceProvider: Provider<out DependencyExtractor>
-            ) {
-                gradle.buildFinished {
-                    extractorServiceProvider.get().close()
-                    gradle.buildOperationListenerManager
-                        .removeListener(extractorServiceProvider.get())
-                }
-            }
-        }
-
-        object DefaultPluginApplicatorStrategy : PluginApplicatorStrategy {
-            private const val SERVICE_NAME = "gitHubDependencyExtractorService"
-
-            override fun createExtractorService(
-                gradle: Gradle
-            ): Provider<out DependencyExtractor> {
-                return gradle.sharedServices.registerIfAbsent(
-                    SERVICE_NAME,
-                    DependencyExtractorBuildService::class.java
-                ) {}
-            }
-
-            override fun registerExtractorListener(
-                gradle: Gradle,
-                extractorServiceProvider: Provider<out DependencyExtractor>
-            ) {
-                gradle.service<BuildEventListenerRegistryInternal>()
-                    .onOperationCompletion(extractorServiceProvider)
-            }
-
-            override fun registerExtractorServiceShutdown(
-                gradle: Gradle,
-                extractorServiceProvider: Provider<out DependencyExtractor>
-            ) {
-                // No-op as DependencyExtractorService is Auto-Closable
-            }
-        }
+class GitHubDependencyExtractorPlugin : AbstractDependencyExtractorPlugin() {
+    override fun getRendererClassName(): String {
+        return GitHubDependencyGraphRenderer::class.java.name
     }
 }

plugin/src/main/kotlin/org/gradle/github/dependencygraph/internal/DependencyExtractor.kt

@@ -5,9 +5,8 @@ import org.gradle.api.artifacts.result.ResolvedComponentResult
 import org.gradle.api.artifacts.result.ResolvedDependencyResult
 import org.gradle.api.internal.artifacts.DefaultProjectComponentIdentifier
 import org.gradle.api.internal.artifacts.configurations.ResolveConfigurationDependenciesBuildOperationType
+import org.gradle.api.logging.Logging
 import org.gradle.github.GitHubDependencyGraphPlugin
-import org.gradle.github.dependencygraph.internal.github.GitHubDependencyGraphOutput
-import org.gradle.github.dependencygraph.internal.github.GitHubSnapshotParams
 import org.gradle.github.dependencygraph.internal.model.*
 import org.gradle.github.dependencygraph.internal.util.*
 import org.gradle.initialization.EvaluateSettingsBuildOperationType
@@ -50,14 +49,7 @@ abstract class DependencyExtractor :
         pluginParameters.loadOptional(PARAM_REPORT_DIR)
     }
 
-    private val gitHubSnapshotParams by lazy {
-        GitHubSnapshotParams(
-            pluginParameters.load(PARAM_JOB_CORRELATOR),
-            pluginParameters.load(PARAM_JOB_ID),
-            pluginParameters.load(PARAM_GITHUB_SHA),
-            pluginParameters.load(PARAM_GITHUB_REF)
-        )
-    }
+    abstract fun getRendererClassName(): String
 
     override fun started(buildOperation: BuildOperationDescriptor, startEvent: OperationStartEvent) {
         // This method will never be called when registered in a `BuildServiceRegistry` (ie. Gradle 6.1 & higher)
@@ -239,8 +231,12 @@ abstract class DependencyExtractor :
     }
 
     private fun writeDependencyGraph() {
-        val builder = GitHubDependencyGraphOutput(gitHubSnapshotParams, getOutputDir())
-        builder.outputDependencyGraph(resolvedConfigurations, buildLayout)
+        createRenderer().outputDependencyGraph(pluginParameters, buildLayout, resolvedConfigurations, getOutputDir())
+    }
+
+    private fun createRenderer(): DependencyGraphRenderer {
+        LOGGER.lifecycle("Constructing renderer: ${getRendererClassName()}")
+        return Class.forName(getRendererClassName()).getDeclaredConstructor().newInstance() as DependencyGraphRenderer
     }
 
     private fun getOutputDir(): File {
@@ -275,6 +271,10 @@ abstract class DependencyExtractor :
             )
         }
     }
+
+    companion object {
+        private val LOGGER = Logging.getLogger(DependencyExtractor::class.java)
+    }
 }
 
 private inline fun <reified D, reified R> handleBuildOperationTypeRaw(

plugin/src/main/kotlin/org/gradle/github/dependencygraph/internal/DependencyExtractorBuildService.kt

@@ -1,8 +1,19 @@
 package org.gradle.github.dependencygraph.internal
 
+import org.gradle.api.provider.Property
 import org.gradle.api.services.BuildService
 import org.gradle.api.services.BuildServiceParameters
 
 abstract class DependencyExtractorBuildService :
     DependencyExtractor(),
-    BuildService<BuildServiceParameters.None>
+    BuildService<DependencyExtractorBuildService.Params>
+{
+    // Some parameters for the web server
+    internal interface Params : BuildServiceParameters {
+        val rendererClassName: Property<String>
+    }
+
+    override fun getRendererClassName(): String {
+        return parameters.rendererClassName.get()
+    }
+}

plugin/src/main/kotlin/org/gradle/github/dependencygraph/internal/DependencyGraphRenderer.kt

@@ -0,0 +1,14 @@
+package org.gradle.github.dependencygraph.internal
+
+import org.gradle.github.dependencygraph.internal.model.BuildLayout
+import org.gradle.github.dependencygraph.internal.model.ResolvedConfiguration
+import org.gradle.github.dependencygraph.internal.util.PluginParameters
+import java.io.File
+
+interface DependencyGraphRenderer {
+    fun outputDependencyGraph(pluginParameters: PluginParameters,
+                              buildLayout: BuildLayout,
+                              resolvedConfigurations: MutableList<ResolvedConfiguration>,
+                              outputDirectory: File
+    )
+}

plugin/src/main/kotlin/org/gradle/github/dependencygraph/internal/LegacyDependencyExtractor.kt

@@ -2,7 +2,11 @@ package org.gradle.github.dependencygraph.internal
 
 import org.gradle.initialization.EvaluateSettingsBuildOperationType
 
-class LegacyDependencyExtractor : DependencyExtractor() {
+class LegacyDependencyExtractor(private val rendererClassName: String) : DependencyExtractor() {
+    override fun getRendererClassName(): String {
+        return rendererClassName
+    }
+
     override fun extractSettings(details: EvaluateSettingsBuildOperationType.Details) {
         // Extraction fails for included builds on Gradle 5.x.
         // It's OK to ignore these events since we only care about the root build settings file at this stage.