info-ci: Ability to plug in custom CI info providers

src/main/groovy/nebula/plugin/info/ci/ContinuousIntegrationInfoPlugin.groovy

@@ -2,21 +2,22 @@ package nebula.plugin.info.ci
 
 import nebula.plugin.info.InfoBrokerPlugin
 import nebula.plugin.info.InfoCollectorPlugin
+
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.internal.IConventionAware
 
 class ContinuousIntegrationInfoPlugin implements Plugin<Project>, InfoCollectorPlugin {
     protected Project project
-    List<ContinuousIntegrationInfoProvider> providers
+
+
     ContinuousIntegrationInfoProvider selectedProvider
     ContinuousIntegrationInfoExtension extension
 
     @Override
     void apply(Project project) {
         this.project = project
 
-        providers = [new JenkinsProvider(), new UnknownContinuousIntegrationProvider()]
         selectedProvider = findProvider()
 
         extension = project.extensions.create('ciinfo', ContinuousIntegrationInfoExtension)
@@ -37,11 +38,6 @@ class ContinuousIntegrationInfoPlugin implements Plugin<Project>, InfoCollectorP
     }
 
     ContinuousIntegrationInfoProvider findProvider() {
-        def provider = providers.find { it.supports(project) }
-        if (provider) {
-            return provider
-        } else {
-            throw new IllegalStateException('Unable to find a SCM provider, even the Unknown provider')
-        }
+		return new ContinuousIntegrationInfoProviderResolver().findProvider(project)
     }
 }

src/main/groovy/nebula/plugin/info/ci/ContinuousIntegrationInfoProviderResolver.groovy

@@ -0,0 +1,27 @@
+package nebula.plugin.info.ci;
+
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.ServiceLoader;
+
+public class ContinuousIntegrationInfoProviderResolver {
+
+	private static ServiceLoader<ContinuousIntegrationInfoProvider> continuousIntegrationInfoProviderServiceLoader = ServiceLoader
+			.load(ContinuousIntegrationInfoProvider.class);
+
+	def all () {
+		return continuousIntegrationInfoProviderServiceLoader.asList() << new UnknownContinuousIntegrationProvider();
+	}
+
+	ContinuousIntegrationInfoProvider findProvider(project) {
+
+		def provider = continuousIntegrationInfoProviderServiceLoader.find { it.supports(project) }
+
+        if (provider) {
+            return provider
+        } else {
+            return new UnknownContinuousIntegrationProvider()
+        }
+	}
+
+}

src/main/resources/META-INF/services/nebula.plugin.info.ci.ContinuousIntegrationInfoProvider

@@ -0,0 +1 @@
+nebula.plugin.info.ci.JenkinsProvider

src/test/groovy/nebula/plugin/info/ci/ContinuousIntegrationInfoProviderResolverSpec.groovy

@@ -0,0 +1,41 @@
+package nebula.plugin.info.ci
+
+import nebula.plugin.info.InfoBrokerPlugin
+import nebula.plugin.info.InfoBrokerPlugin.ManifestEntry
+import nebula.plugin.info.basic.BasicInfoPlugin
+import nebula.test.ProjectSpec
+
+import org.gradle.api.NamedDomainObjectContainer
+
+import spock.lang.Ignore
+
+import java.util.concurrent.atomic.AtomicBoolean
+
+class ContinuousIntegrationInfoProviderResolverSpec extends ProjectSpec {
+
+	def 'get all configured info providers'() {
+		when:
+		def resolver = new ContinuousIntegrationInfoProviderResolver()
+
+		then:
+		def providers = resolver.all()
+		providers != null
+		providers.size() == 2
+		providers[0].getClass().equals(JenkinsProvider.class)
+		providers[1].getClass().equals(UnknownContinuousIntegrationProvider.class)
+	}
+
+	def 'get Jenkins provider if running on Jenkins'() {
+		when:
+		def onJenkins = System.getenv('BUILD_NUMBER') && System.getenv('JOB_NAME')
+		def resolver = new ContinuousIntegrationInfoProviderResolver()
+
+		then:
+		def provider = resolver.findProvider(project)
+		if(onJenkins) {
+			provider.getClass().equals(JenkinsProvider.class)
+		} else {
+			provider.getClass().equals(UnknownContinuousIntegrationProvider.class)
+		}
+	}
+}