Updated ServiceInitializer to add ability to load different properties

common/src/main/java/org/apache/hadoop/metadata/service/ServiceInitializer.java

@@ -26,51 +26,109 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * Initializer that uses at startup to bring up all the Metadata startup services.
+ * Initializer that uses at startup to bring up all the Metadata startup
+ * services.
  */
 public class ServiceInitializer {
 
-    private static final Logger LOG = LoggerFactory.getLogger(ServiceInitializer.class);
-    private final Services services = Services.get();
+	private static final Logger LOG = LoggerFactory
+			.getLogger(ServiceInitializer.class);
+	private final Services services = Services.get();
 
-    public void initialize() throws MetadataException {
-        String[] serviceClassNames;
-        try {
-            PropertiesConfiguration configuration =
-                    new PropertiesConfiguration("application.properties");
-            serviceClassNames = configuration.getStringArray("application.services");
-        } catch (ConfigurationException e) {
-            throw new RuntimeException("unable to get server properties");
-        }
+	// default property file name/path
+	private static final String DEFAULT_CONFIG_PATH = "application.properties";
+	// system property referenced by this class to extract user-overriden
+	// properties file
+	public static final String PROPERTIES_SYS_PROP = "metadata.properties";
 
-        for (String serviceClassName : serviceClassNames) {
-            serviceClassName = serviceClassName.trim();
-            if (serviceClassName.isEmpty()) {
-                continue;
-            }
-            Service service = ReflectionUtils.getInstanceByClassName(serviceClassName);
-            services.register(service);
-            LOG.info("Initializing service: {}", serviceClassName);
-            try {
-                service.start();
-            } catch (Throwable t) {
-                LOG.error("Failed to initialize service {}", serviceClassName, t);
-                throw new MetadataException(t);
-            }
-            LOG.info("Service initialized: {}", serviceClassName);
-        }
-    }
+	// Path to the properties file (must be on the classpath for
+	// PropertiesConfiguration to work)
+	private final String propertyPath;
 
-    public void destroy() throws MetadataException {
-        for (Service service : services) {
-            LOG.info("Destroying service: {}", service.getClass().getName());
-            try {
-                service.stop();
-            } catch (Throwable t) {
-                LOG.error("Failed to destroy service {}", service.getClass().getName(), t);
-                throw new MetadataException(t);
-            }
-            LOG.info("Service destroyed: {}", service.getClass().getName());
-        }
-    }
+	/**
+	 * Default constructor. Use the metadata.properties System property to
+	 * determine the property file name.
+	 */
+	public ServiceInitializer() {
+		propertyPath = System.getProperty(PROPERTIES_SYS_PROP,
+				DEFAULT_CONFIG_PATH);
+	}
+
+	/**
+	 * Create a ServiceInitializer, specifying the properties file filename
+	 * explicitly
+	 * 
+	 * @param propPath
+	 *            the filename of the properties file with the service
+	 *            intializer information
+	 */
+	public ServiceInitializer(String propPath) {
+		propertyPath = propPath;
+	}
+
+	/**
+	 * Get the configuration properties for the ServiceInitializer
+	 * 
+	 * @return
+	 * @throws ConfigurationException
+	 */
+	public PropertiesConfiguration getConfiguration()
+			throws ConfigurationException {
+		return new PropertiesConfiguration(propertyPath);
+	}
+
+	/**
+	 * Initialize the services specified by the application.services property
+	 * 
+	 * @throws MetadataException
+	 */
+	public void initialize() throws MetadataException {
+		/*
+		 * TODO - determine whether this service model is the right model;
+		 * Inter-service dependencies can wreak havoc using the current model
+		 */
+
+		String[] serviceClassNames;
+		LOG.info("Loading services using properties file: {}", propertyPath);
+		try {
+			PropertiesConfiguration configuration = getConfiguration();
+			serviceClassNames = configuration
+					.getStringArray("application.services");
+		} catch (ConfigurationException e) {
+			throw new RuntimeException("unable to get server properties");
+		}
+
+		for (String serviceClassName : serviceClassNames) {
+			serviceClassName = serviceClassName.trim();
+			if (serviceClassName.isEmpty()) {
+				continue;
+			}
+			Service service = ReflectionUtils
+					.getInstanceByClassName(serviceClassName);
+			services.register(service);
+			LOG.info("Initializing service: {}", serviceClassName);
+			try {
+				service.start();
+			} catch (Throwable t) {
+				LOG.error("Failed to initialize service {}", serviceClassName,
+						t);
+				throw new MetadataException(t);
+			}
+			LOG.info("Service initialized: {}", serviceClassName);
+		}
+	}
+
+	public void destroy() throws MetadataException {
+		for (Service service : services) {
+			LOG.info("Destroying service: {}", service.getClass().getName());
+			try {
+				service.stop();
+			} catch (Throwable t) {
+				LOG.error("Failed to destroy service {}", service.getClass()
+						.getName(), t);
+				throw new MetadataException(t);
+			}
+			LOG.info("Service destroyed: {}", service.getClass().getName());
+		}
+	}
 }

common/src/main/resources/test.application.properties

+application.services=org.apache.hadoop.metadata.service.TestService
\ No newline at end of file

common/src/test/java/org/apache/hadoop/metadata/service/ServiceInitializerTest.java

+package org.apache.hadoop.metadata.service;
+
+import org.testng.Assert;
+import org.testng.annotations.AfterClass;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.Test;
+
+/**
+ * Unit test for the Service Initializer.
+ * 
+ * Test functionality to allow loading of different property files.
+ */
+public class ServiceInitializerTest {
+
+	private final String propertiesFileName = "test.application.properties";
+	private ServiceInitializer sinit;
+
+	@BeforeClass
+	public void setUp() throws Exception {
+		// setup for the test properties file
+		System.setProperty(ServiceInitializer.PROPERTIES_SYS_PROP,
+				propertiesFileName);
+		sinit = new ServiceInitializer();
+	}
+
+	@AfterClass
+	public void tearDown() throws Exception {
+		// test destruction of the Services - no exceptions is assumed a success
+		sinit.destroy();
+	}
+
+	@Test
+	public void testPropsAreSet() throws Exception {
+		Assert.assertEquals(
+				sinit.getConfiguration().getString(
+						"application.services"),
+				TestService.NAME);
+	}
+
+	@Test
+	public void testInitialize() throws Exception {
+		// test the initialization of the initializer
+		// no exceptions is assumed a success
+		sinit.initialize();
+	}
+}

common/src/test/java/org/apache/hadoop/metadata/service/TestService.java

+package org.apache.hadoop.metadata.service;
+
+import java.io.IOException;
+
+public class TestService implements Service {
+	
+	public static final String NAME = TestService.class.getName();
+
+	@Override
+	public String getName() {
+		return NAME;
+	}
+
+	@Override
+	public void start() throws Exception {
+	}
+
+	@Override
+	public void stop() {
+	}
+
+	@Override
+	public void close() throws IOException {
+	}
+}