Extract checkLibVersions task to gradle plugin

buildSrc/build.gradle.kts

@@ -0,0 +1,16 @@
+plugins {
+    `kotlin-dsl`
+}
+
+repositories {
+    jcenter()
+}
+
+gradlePlugin {
+    plugins {
+        register("check-lib-versions") {
+            id = "check-lib-versions"
+            implementationClass = "CheckLibVersionsPlugin"
+        }
+    }
+}

buildSrc/src/main/kotlin/CheckLibVersionsPlugin.kt

@@ -0,0 +1,39 @@
+import groovy.util.XmlSlurper
+import groovy.util.slurpersupport.GPathResult
+import org.codehaus.groovy.runtime.ResourceGroovyMethods
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.Task
+import org.gradle.api.artifacts.Dependency
+
+class CheckLibVersionsPlugin : Plugin<Project> {
+    override fun apply(project: Project) {
+        project.task("checkLibVersions") {
+            description = "Find any 3rd party libraries which have released new versions to the central Maven repo since we last upgraded."
+            doLast {
+                project.configurations.flatMap { it.allDependencies }
+                        .toSet()
+                        .forEach { checkDependency(it) }
+            }
+        }
+    }
+
+    private fun Task.checkDependency(dependency: Dependency) {
+        val version = dependency.version
+        val group = dependency.group
+        val path = group?.replace(".", "/") ?: ""
+        val name = dependency.name
+        val metaDataUrl = "https://repo1.maven.org/maven2/$path/$name/maven-metadata.xml"
+        try {
+            val url = ResourceGroovyMethods.toURL(metaDataUrl)
+            val metaDataText = ResourceGroovyMethods.getText(url)
+            val metadata = XmlSlurper().parseText(metaDataText)
+            val newest = (metadata.getProperty("versioning") as GPathResult).getProperty("latest")
+            if (version != newest.toString()) {
+                println("UPGRADE {\"group\": \"$group\", \"name\": \"$name\", \"current\": \"$version\", \"latest\": \"$newest\"}")
+            }
+        } catch (e: Throwable) {
+            logger.debug("Unable to download or parse $metaDataUrl: $e.message")
+        }
+    }
+}