Support gradle versions api url customization (#807)

Co-authored-by: Marcel Sebek <marcel.sebek@deutsche-boerse.com>

README.md

@@ -272,6 +272,12 @@ The default is `release-candidate`. The value can be changed as shown below:
 dependencyUpdates.gradleReleaseChannel="current"
 ```
 
+#### Gradle Versions Api Base URL
+
+The `gradleVersionsApiBaseUrl` task property provides an option for customization of the Gradle versions service URL.
+If not specified, the default value https://services.gradle.org/versions/ is used.
+The customization can be useful in restricted environments without direct internet access and proxy availability.
+
 #### Constraints
 
 If you use constraints, for example to define a BOM using the [`java-platform`](https://docs.gradle.org/current/userguide/java_platform_plugin.html)

gradle-versions-plugin/src/main/kotlin/com/github/benmanes/gradle/versions/updates/DependencyUpdates.kt

@@ -26,6 +26,7 @@ class DependencyUpdates @JvmOverloads constructor(
   val outputDir: String,
   val reportfileName: String?,
   val checkForGradleUpdate: Boolean,
+  val gradleVersionsApiBaseUrl: String,
   val gradleReleaseChannel: String,
   val checkConstraints: Boolean = false,
   val checkBuildEnvironmentConstraints: Boolean = false,
@@ -107,7 +108,7 @@ class DependencyUpdates @JvmOverloads constructor(
     val upgradeVersions = toMap(versions.upgrade)
 
     // Check for Gradle updates.
-    val gradleUpdateChecker = GradleUpdateChecker(checkForGradleUpdate)
+    val gradleUpdateChecker = GradleUpdateChecker(checkForGradleUpdate, gradleVersionsApiBaseUrl)
 
     return DependencyUpdatesReporter(
       project, revision, outputFormatterArgument, outputDir,

gradle-versions-plugin/src/main/kotlin/com/github/benmanes/gradle/versions/updates/DependencyUpdatesTask.kt

@@ -92,6 +92,9 @@ open class DependencyUpdatesTask : DefaultTask() { // tasks can't be final
   @Input
   var checkForGradleUpdate: Boolean = true
 
+  @Input
+  var gradleVersionsApiBaseUrl: String = "https://services.gradle.org/versions/"
+
   @Input
   var checkConstraints: Boolean = false
 
@@ -128,7 +131,7 @@ open class DependencyUpdatesTask : DefaultTask() { // tasks can't be final
     }
     val evaluator = DependencyUpdates(
       project, resolutionStrategyAction, revision,
-      outputFormatter(), outputDir, reportfileName, checkForGradleUpdate,
+      outputFormatter(), outputDir, reportfileName, checkForGradleUpdate, gradleVersionsApiBaseUrl,
       gradleReleaseChannel, checkConstraints, checkBuildEnvironmentConstraints,
       filterConfigurations
     )

gradle-versions-plugin/src/main/kotlin/com/github/benmanes/gradle/versions/updates/gradle/GradleUpdateChecker.kt

@@ -18,11 +18,12 @@ import java.util.concurrent.TimeUnit
  */
 class GradleUpdateChecker(
   val enabled: Boolean = true,
+  private val gradleVersionsApiBaseUrl: String,
 ) {
 
   init {
     if (enabled) {
-      fetch()
+      fetch(gradleVersionsApiBaseUrl)
     }
   }
 
@@ -84,7 +85,6 @@ class GradleUpdateChecker(
     private val cacheMap = EnumMap<GradleReleaseChannel, ReleaseStatus>(
       GradleReleaseChannel::class.java
     )
-    private const val API_BASE_URL = "https://services.gradle.org/versions/"
     private const val CLIENT_TIME_OUT = 15_000L
     private val client: OkHttpClient = OkHttpClient.Builder()
       .connectTimeout(CLIENT_TIME_OUT, TimeUnit.SECONDS)
@@ -95,17 +95,17 @@ class GradleUpdateChecker(
       .addLast(KotlinJsonAdapterFactory())
       .build()
 
-    /** Represents the XML from [API_BASE_URL] */
+    /** Represents the XML from [gradleVersionsApiBaseUrl] */
     private class VersionSite {
       var version: String? = null
     }
 
-    private fun fetch() {
+    private fun fetch(gradleVersionsApiBaseUrl: String) {
       for (it in GradleReleaseChannel.values()) {
         try {
           client.newCall(
             Request.Builder()
-              .url(API_BASE_URL + it.id)
+              .url(gradleVersionsApiBaseUrl + it.id)
               .build()
           ).execute().use { response ->
             response.body?.source()?.let { body ->

gradle-versions-plugin/src/test/groovy/com/github/benmanes/gradle/versions/DependencyUpdatesSpec.groovy

@@ -582,7 +582,7 @@ final class DependencyUpdatesSpec extends Specification {
     }
 
     when:
-    def reporter = evaluate(project, 'milestone', 'plain', 'build', null, null, true, CURRENT.id)
+    def reporter = evaluate(project, 'milestone', 'plain', 'build', null, null, true, "", CURRENT.id)
     reporter.write()
 
     then:
@@ -619,7 +619,7 @@ final class DependencyUpdatesSpec extends Specification {
     addRepositoryTo(project)
 
     when:
-    def reporter = evaluate(project, 'milestone', null, 'build', null,null, false, RELEASE_CANDIDATE.id, {config -> config.name.equals("upgradesFound")})
+    def reporter = evaluate(project, 'milestone', null, 'build', null,null, false, "", RELEASE_CANDIDATE.id, {config -> config.name.equals("upgradesFound")})
     reporter.write()
 
     then:
@@ -645,10 +645,10 @@ final class DependencyUpdatesSpec extends Specification {
 
   private static def evaluate(project, revision = 'milestone', outputFormatter = null,
     outputDir = 'build', resolutionStrategy = null, reportfileName = null,
-    checkForGradleUpdate = true, gradleReleaseChannel = RELEASE_CANDIDATE.id,
+    checkForGradleUpdate = true, gradleVersionsApiBaseUrl = "", gradleReleaseChannel = RELEASE_CANDIDATE.id,
     configurationFilter = { true }) {
     new DependencyUpdates(project, resolutionStrategy, revision, buildOutputFormatter(outputFormatter), outputDir,
-      reportfileName, checkForGradleUpdate, gradleReleaseChannel, false, false, configurationFilter).run()
+      reportfileName, checkForGradleUpdate, gradleVersionsApiBaseUrl, gradleReleaseChannel, false, false, configurationFilter).run()
   }
 
   private static OutputFormatterArgument buildOutputFormatter(outputFormatter) {