Output the graph to dot file for png rendering support

cacheinvalidationindex/build.gradle.kts

@@ -19,6 +19,7 @@ gradlePlugin {
 dependencies {
     implementation(kotlin("stdlib-jdk8"))
     implementation(libs.jgrapht.core)
+    implementation(libs.jgrapht.io)
 
     testImplementation(libs.junit)
     testImplementation(libs.truth)

cacheinvalidationindex/src/main/java/com/ivanalvarado/cacheinvalidationindex/CacheInvalidationIndexPlugin.kt

@@ -3,6 +3,7 @@ package com.ivanalvarado.cacheinvalidationindex
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.AffectedSubgraphsImpl
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.BuildDagFromDependencyPairsImpl
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.FindDependencyPairsImpl
+import com.ivanalvarado.cacheinvalidationindex.writer.GraphVizWriter
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.internal.configuration.problems.taskPathFrom
@@ -20,7 +21,8 @@ class CacheInvalidationIndexPlugin : Plugin<Project> {
             CacheInvalidationIndexTask::class.java,
             FindDependencyPairsImpl(),
             BuildDagFromDependencyPairsImpl(),
-            AffectedSubgraphsImpl()
+            AffectedSubgraphsImpl(),
+            GraphVizWriter()
         )
         cacheInvalidationIndexTaskProvider.configure { task ->
             task.configurationToAnalyze.set(extension.configurationToAnalyze)

cacheinvalidationindex/src/main/java/com/ivanalvarado/cacheinvalidationindex/CacheInvalidationIndexTask.kt

@@ -3,6 +3,7 @@ package com.ivanalvarado.cacheinvalidationindex
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.AffectedSubgraphs
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.BuildDagFromDependencyPairs
 import com.ivanalvarado.cacheinvalidationindex.domain.usecase.FindDependencyPairs
+import com.ivanalvarado.cacheinvalidationindex.writer.GraphVizWriter
 import org.gradle.api.DefaultTask
 import org.gradle.api.provider.SetProperty
 import org.gradle.api.tasks.Input
@@ -12,7 +13,8 @@ import javax.inject.Inject
 abstract class CacheInvalidationIndexTask @Inject constructor(
     private val findDependencyPairs: FindDependencyPairs,
     private val buildDagFromDependencyPairs: BuildDagFromDependencyPairs,
-    private val affectedSubgraphs: AffectedSubgraphs
+    private val affectedSubgraphs: AffectedSubgraphs,
+    private val graphVizWriter: GraphVizWriter
 ) : DefaultTask() {
 
     @get:Input
@@ -23,10 +25,11 @@ abstract class CacheInvalidationIndexTask @Inject constructor(
         val rootProject = project.rootProject
         val configurationsToAnalyze = configurationToAnalyze.get()
         val sampleList = findDependencyPairs(rootProject, configurationsToAnalyze)
-        println("Dependency Pairs: $sampleList")
         val dag = buildDagFromDependencyPairs(sampleList)
-        println("DAG: $dag")
         val affectedSubgraphs = affectedSubgraphs(dag)
-        println("Affected Subgraphs: $affectedSubgraphs")
+        graphVizWriter.writeGraph(
+            graph = affectedSubgraphs.find { it.node == project.path }!!.affectedDag,
+            file = project.file("build/graph.dot")
+        )
     }
 }

cacheinvalidationindex/src/main/java/com/ivanalvarado/cacheinvalidationindex/writer/GraphVizWriter.kt

@@ -0,0 +1,37 @@
+package com.ivanalvarado.cacheinvalidationindex.writer
+
+import com.ivanalvarado.cacheinvalidationindex.domain.model.DependencyEdge
+import org.jgrapht.graph.AbstractGraph
+import org.jgrapht.nio.DefaultAttribute
+import org.jgrapht.nio.dot.DOTExporter
+import java.io.File
+
+class GraphVizWriter {
+
+    fun writeGraph(graph: AbstractGraph<String, DependencyEdge>, file: File) {
+        val exporter = DOTExporter<String, DependencyEdge> { vertex ->
+            vertex.sanitize()
+        }
+
+        exporter.setVertexAttributeProvider { vertex ->
+            buildMap {
+                put("label", DefaultAttribute.createAttribute(vertex))
+            }
+        }
+
+        exporter.setEdgeAttributeProvider { edge ->
+            buildMap {
+                put("label", DefaultAttribute.createAttribute(edge.configuration))
+            }
+        }
+
+        file.delete()
+        exporter.exportGraph(graph, file)
+    }
+
+    private fun String.sanitize(): String {
+        return this.replace("-", "_")
+            .replace(".", "_")
+            .replace(":", "_")
+    }
+}

gradle/libs.versions.toml

@@ -6,6 +6,7 @@ truth = "1.4.4"
 
 [libraries]
 jgrapht-core = { group = "org.jgrapht", name = "jgrapht-core", version.ref = "jgrapht" }
+jgrapht-io = { group = "org.jgrapht", name = "jgrapht-io", version.ref = "jgrapht" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
 truth = { group = "com.google.truth", name = "truth", version.ref = "truth" }