Initial spirng-session-data-geode setup.

(cherry picked from commit c5a1ee021016d37dda5e5eb96320ee1be9869314)
Signed-off-by: John Blum <jblum@pivotal.io>

buildSrc/src/main/groovy/build/GemFireServerPlugin.groovy

@@ -0,0 +1,70 @@
+package build;
+
+import org.gradle.api.plugins.JavaPlugin
+import org.gradle.api.tasks.bundling.Zip
+import org.gradle.api.DefaultTask
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.tasks.TaskAction
+
+public class GemFireServerPlugin implements Plugin<Project> {
+
+	@Override
+	public void apply(Project project) {
+		project.tasks.create('gemFireServer', GemFireServerTask)
+
+		project.tasks.integrationTest.doLast {
+			println 'Stopping GemFire Server...'
+			project.tasks.gemFireServer.process?.destroyForcibly()
+		}
+
+		project.tasks.prepareAppServerForIntegrationTests {
+			dependsOn project.tasks.gemFireServer
+			doFirst {
+				project.gretty {
+					jvmArgs = ["-Dspring.session.data.gemfire.port=${project.tasks.gemFireServer.port}"]
+				}
+			}
+		}
+	}
+
+	static int availablePort() {
+		new ServerSocket(0).withCloseable { socket ->
+			socket.localPort
+		}
+	}
+
+	static class GemFireServerTask extends DefaultTask {
+		def mainClassName = "sample.ServerConfig"
+		def process
+		def port
+		boolean debug
+
+		@TaskAction
+		def greet() {
+			port = availablePort()
+			println "Starting GemFire Server on port [$port]..."
+	
+			def out = debug ? System.out : new StringBuilder()
+			def err = debug ? System.out : new StringBuilder()
+	
+			String classpath = project.sourceSets.main.runtimeClasspath.collect { it }.join(File.pathSeparator)
+			String gemfireLogLevel = System.getProperty('spring.session.data.gemfire.log-level', 'warning')
+
+			String[] commandLine = [
+				'java', '-server', '-ea', '-classpath', classpath,
+				//"-Dgemfire.log-file=gemfire-server.log",
+				//"-Dgemfire.log-level=config",
+				"-Dspring.session.data.gemfire.log-level=" + gemfireLogLevel,
+				"-Dspring.session.data.gemfire.port=${port}",
+				'sample.ServerConfig'
+			]
+	
+			//println commandLine
+			
+			project.tasks.appRun.ext.process = process = commandLine.execute()
+
+			process.consumeProcessOutput(out, err)
+		}
+	}
+}

buildSrc/src/main/resources/META-INF/gradle-plugins/gemfire-server.properties

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+implementation-class=build.GemFireServerPlugin