Develop Reference

Configuring flapdoodle embedded mongo with Mongodb version 4 and replica

I am currently working on a spring boot application 2.0.3.RELEASE. I want to configure Flapdoodle MongoDb with MongoDb version 4.0 and I also want to set a single mongo instance and create replicas for it.
So far i haven't figured out the process of creating cluster and replicas using flapdoodle.
I am using
MongodConfigBuilder().version(Version.Main.DEVELOPMENT)
.replication(new Storage(null, null, 0))
.build();
i have read many questions here related to this configuration but none of them is related to my problem. eg
How to configure two instance mongodb use spring boot and spring data
The flapdoodle configuration has an implemetation for this but i am not sure how to access it.
https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo/blob/master/src/main/java/de/flapdoodle/embed/mongo/tests/MongosSystemForTestFactory.java
Is there any way to configure it in my test class before application starts.
thanks

I had to start the Embedded mongo with replicaset in web Integration tests, used below code
#Configuration
public class MongoConfig {
public static int mongodPort;
public static String defaultHost = "localhost";
static {
try {
mongodPort = Network.getFreeServerPort();
} catch (IOException e) {
e.printStackTrace();
}
}
#Bean
public IMongodConfig prepareMongodConfig() throws IOException {
IMongoCmdOptions cmdOptions = new MongoCmdOptionsBuilder()
.useNoPrealloc(false)
.useSmallFiles(false)
.master(false)
.verbose(false)
.useNoJournal(false)
.syncDelay(0)
.build();
IMongodConfig mongoConfigConfig = new MongodConfigBuilder()
.version(Version.Main.PRODUCTION)
.net(new Net(mongodPort, Network.localhostIsIPv6()))
.replication(new Storage(null, "testRepSet", 5000))
.configServer(false)
.cmdOptions(cmdOptions)
.build();
return mongoConfigConfig;
}
}
and before calling my controller I enabled the DB with replica set using below code
Public class ITtest {
public void setSystemProperty() {
System.setProperty("spring.data.mongodb.port", String.valueOf(MongoConfig.mongodPort));
System.setProperty("spring.data.mongodb.host", MongoConfig.defaultHost);
}
public static boolean isReplicaSetRun = false;
public static void setupMongoReplica() {
if (! isReplicaSetRun) {
System.out.println("Starting db on port: " +MongoConfig.mongodPort);
MongoClient client = new MongoClient(MongoConfig.defaultHost, MongoConfig.mongodPort);
client.getDatabase("admin").runCommand(new Document("replSetInitiate", new Document()));
client.close();
isReplicaSetRun = true;
}
}
#Test
#Order(1)
public void testParallel() {
setSystemProperty();
setupMongoReplica();
// call web controller
}
}
If want to run application, then enabling of replicaset can be done in implementation of ApplicationListener

How to set unpackwars=true in embedded tomcat server in Spring Boot?

I have an application that uses Spring to create an executable war file. The startup is pretty slow (3-6 minutes). I have read other posts that this appears to be a setting with Apache Tomcat 8 where if unpackWars=false then performance is slow (https://bz.apache.org/bugzilla/show_bug.cgi?id=57251, https://github.com/spring-projects/spring-boot/issues/5200). But changing the unpackWars=true can help speed that up. However, these posts are referring to a server.xml file which I don't have access to since this project is using an embedded tomcat server.
I first tried looking to see if there was some setting I can set in the application.properties file, but I don't seen anything off of server or server.tomcat that I might be able to use.
I have a TomcatConfig class that is consumed during startup and I am wondering if there is a way to set this unpackWars property to true to help speed up the start time. I noticed what was happening in this class is similar to a post found here: (https://www.mkyong.com/spring-boot/spring-boot-how-to-change-context-path/)
#Slf4j
public class TomcatConfig {
#Value("${httpPort}")
private int port;
#Bean
public TomcatEmbeddedServletContainerFactory tomcatFactory(){
return new TomcatEmbeddedServletContainerFactory(port);
}
#Bean
public EmbeddedServletContainerCustomizer tomcatCustomizer() throws URISyntaxException, UnknownHostException {
return new EmbeddedServletContainerCustomizer() {
#Override
public void customize(ConfigurableEmbeddedServletContainer container) {
if(container instanceof TomcatEmbeddedServletContainerFactory){
TomcatEmbeddedServletContainerFactory containerFactory = (TomcatEmbeddedServletContainerFactory) container;
configureTomcat(containerFactory);
}
}
};
}
private void configureTomcat(TomcatEmbeddedServletContainerFactory cf) {
// configure unpackWars here somehow?
}
}

How to stop and start jms listener

I'm using Spring and I have a JMS queue to send messages from client to server. I'd like to stop the messages from being sent when the server is down, and resend them when it's back up.
I know it was asked before but I can't make it work. I created a JmsListener and gave it an ID, but I cannot get it's container in order to stop\start it.
#Resource(name="testId")
private AbstractJmsListeningContainer _probeUpdatesListenerContainer;
public void testSendJms() {
_jmsTemplate.convertAndSend("queue", "working");
}
#JmsListener(destination="queue", id="testId")
public void testJms(String s) {
System.out.println("Received JMS: " + s);
}
The container bean is never created. I also tried getting it from the context or using #Autowired and #Qualifier("testId") with no luck.
How can I get the container?

You need #EnableJms on one of your configuration classes.
You need a jmsListenerContainerFactory bean.
You can stop and start the containers using the JmsListenerEndpointRegistry bean.
See the Spring documentation.

If you use CachingConnectionFactory in your project, you need to call the resetConnection() method between stop and restart, otherwise the old physical connection will remain open, and it will be reused when you restart.

I used JmsListenerEndpointRegistry. Here's my example. I hope this will help.
Bean configuration in JmsConfiguration.java. I changed default autostart option.
#Bean(name="someQueueScheduled")
public DefaultJmsListenerContainerFactory odsContractScheduledQueueContainerFactory() {
DefaultJmsListenerContainerFactory factory = new DefaultJmsListenerContainerFactory();
ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory(someActiveMQ);
Map<String, Class<?>> typeIds = new HashMap<>();
typeIds.put(SomeDTO);
factory.setMessageConverter(messageConverter(Collections.unmodifiableMap(typeIds)));
factory.setPubSubDomain(false);
factory.setConnectionFactory(cf);
factory.setAutoStartup(false);
return factory;
}
Invoke in SomeFacade.java
public class SomeFacade {
#Autowired
JmsListenerEndpointRegistry someUpdateListener;
public void stopSomeUpdateListener() {
MessageListenerContainer container = someUpdateListener.getListenerContainer("someUpdateListener");
container.stop();
}
public void startSomeUpdateListener() {
MessageListenerContainer container = someUpdateListener.getListenerContainer("someUpdateListener");
container.start();
}
}
JmsListener implementation in SomeService.java
public class SomeService {
#JmsListener(id = "someUpdateListener",
destination = "${some.someQueueName}",
containerFactory ="someQueueScheduled")
public void pullUpdateSomething(SomeDTO someDTO) {
}
}

How to start H2 TCP server on Spring Boot application startup?

I'm able to start the H2 TCP server (database in a file) when running app as Spring Boot app by adding following line into the SpringBootServletInitializer main method:
#SpringBootApplication
public class NatiaApplication extends SpringBootServletInitializer {
public static void main(String[] args) {
Server.createTcpServer().start();
SpringApplication.run(NatiaApplication.class, args);
}
}
But if I run the WAR file on Tomcat it doesn't work because the main method is not called. Is there a better universal way how to start the H2 TCP server on the application startup before beans get initialized? I use Flyway (autoconfig) and it fails on "Connection refused: connect" probably because the server is not running. Thank you.

This solution works for me. It starts the H2 server if the app runs as Spring Boot app and also if it runs on Tomcat. Creating H2 server as a bean did not work because the Flyway bean was created earlier and failed on "Connection refused".
#SpringBootApplication
#Log
public class NatiaApplication extends SpringBootServletInitializer {
public static void main(String[] args) {
startH2Server();
SpringApplication.run(NatiaApplication.class, args);
}
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
startH2Server();
return application.sources(NatiaApplication.class);
}
private static void startH2Server() {
try {
Server h2Server = Server.createTcpServer().start();
if (h2Server.isRunning(true)) {
log.info("H2 server was started and is running.");
} else {
throw new RuntimeException("Could not start H2 server.");
}
} catch (SQLException e) {
throw new RuntimeException("Failed to start H2 server: ", e);
}
}
}

Yup, straight from the documentation, you can use a bean reference:
<bean id = "org.h2.tools.Server"
class="org.h2.tools.Server"
factory-method="createTcpServer"
init-method="start"
destroy-method="stop">
<constructor-arg value="-tcp,-tcpAllowOthers,-tcpPort,8043" />
There's also a servlet listener option that auto-starts/stops it.
That answers your question, but I think you should probably be using the embedded mode instead if it's deploying along with your Spring Boot application. This is MUCH faster and lighter on resources. You simply specify the correct URL and the database will start:
jdbc:h2:/usr/share/myDbFolder
(straight out of the cheat sheet).

There's a caveat that hasn't been considered in the other answers. What you need to be aware of is that starting a server is a transient dependency on your DataSource bean. This is due to the DataSource only needing a network connection, not a bean relationship.
The problem this causes is that spring-boot will not know about the h2 database needing to be fired up before creating the DataSource, so you could end up with a connection exception on application startup.
With the spring-framework this isn't a problem as you put the DB server startup in the root config with the database as a child. With spring boot AFAIK there's only a single context.
To get around this what you can do is create an Optional<Server> dependency on the data-source. The reason for Optional is you may not always start the server (configuration parameter) for which you may have a production DB.
#Bean(destroyMethod = "close")
public DataSource dataSource(Optional<Server> h2Server) throws PropertyVetoException {
HikariDataSource ds = new HikariDataSource();
ds.setDriverClassName(env.getProperty("db.driver"));
ds.setJdbcUrl(env.getProperty("db.url"));
ds.setUsername(env.getProperty("db.user"));
ds.setPassword(env.getProperty("db.pass"));
return ds;
}

For WAR packaging you can do this:
public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
#Override
protected Class<?>[] getRootConfigClasses() {
return null;
}
#Override
protected Class<?>[] getServletConfigClasses() {
Server.createTcpServer().start();
return new Class[] { NatiaApplication.class };
}
#Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
}

You can do like this:
#Configuration
public class H2ServerConfiguration {
#Value("${db.port}")
private String h2TcpPort;
/**
* TCP connection to connect with SQL clients to the embedded h2 database.
*
* #see Server
* #throws SQLException if something went wrong during startup the server.
* #return h2 db Server
*/
#Bean
public Server server() throws SQLException {
return Server.createTcpServer("-tcp", "-tcpAllowOthers", "-tcpPort", h2TcpPort).start();
}
/**
* #return FlywayMigrationStrategy the strategy for migration.
*/
#Bean
#DependsOn("server")
public FlywayMigrationStrategy flywayMigrationStrategy() {
return Flyway::migrate;
}
}

Updating Dropwizard config at runtime

Is it possible to have my app update the config settings at runtime? I can easily expose the settings I want in my UI but is there a way to allow the user to update settings and make them permanent ie save them to the config.yaml file? The only way I can see it to update the file by hand then restart the server which seems a bit limiting.

Yes. It is possible to reload the service classes at runtime.
Dropwizard by itself does not have the way to reload the app, but jersey has.
Jersey uses a container object internally to maintain the running application. Dropwizard uses the ServletContainer class of Jersey to run the application.
How to reload the app without restarting it -
Get a handle to the container used internally by jersey
You can do this by registering a AbstractContainerLifeCycleListener in Dropwizard Environment before starting the app. and implement its onStartup method as below -
In your main method where you start the app -
//getting the container instance
environment.jersey().register(new AbstractContainerLifecycleListener() {
#Override
public void onStartup(Container container) {
//initializing container - which will be used to reload the app
_container = container;
}
});
Add a method to your app to reload the app. It will take in the list of string which are the names of the service classes you want to reload. This method will call the reload method of the container with the new custom DropWizardConfiguration instance.
In your Application class
public static synchronized void reloadApp(List<String> reloadClasses) {
DropwizardResourceConfig dropwizardResourceConfig = new DropwizardResourceConfig();
for (String className : reloadClasses) {
try {
Class<?> serviceClass = Class.forName(className);
dropwizardResourceConfig.registerClasses(serviceClass);
System.out.printf(" + loaded class %s.\n", className);
} catch (ClassNotFoundException ex) {
System.out.printf(" ! class %s not found.\n", className);
}
}
_container.reload(dropwizardResourceConfig);
}
For more details see the example documentation of jersey - jersey example for reload
Consider going through the code and documentation of following files in Dropwizard/Jersey for a better understanding -
Container.java
ContainerLifeCycleListener.java
ServletContainer.java
AbstractContainerLifeCycleListener.java
DropWizardResourceConfig.java
ResourceConfig.java

No.
Yaml file is parsed at startup and given to the application as Configuration object once and for all. I believe you can change the file after that but it wouldn't affect your application until you restart it.
Possible follow up question: Can one restart the service programmatically?
AFAIK, no. I've researched and read the code somewhat for that but couldn't find a way to do that yet. If there is, I'd love to hear that :).

I made a task that reloads the main yaml file (it would be useful if something in the file changes). However, it is not reloading the environment. After researching this, Dropwizard uses a lot of final variables and it's quite hard to reload these on the go, without restarting the app.
class ReloadYAMLTask extends Task {
private String yamlFileName;
ReloadYAMLTask(String yamlFileName) {
super("reloadYaml");
this.yamlFileName = yamlFileName;
}
#Override
public void execute(ImmutableMultimap<String, String> parameters, PrintWriter output) throws Exception {
if (yamlFileName != null) {
ConfigurationFactoryFactory configurationFactoryFactory = new DefaultConfigurationFactoryFactory<ReportingServiceConfiguration>();
ValidatorFactory validatorFactory = Validation.buildDefaultValidatorFactory();
Validator validator = validatorFactory.getValidator();
ObjectMapper objectMapper = Jackson.newObjectMapper();
final ConfigurationFactory<ServiceConfiguration> configurationFactory = configurationFactoryFactory.create(ServiceConfiguration.class, validator, objectMapper, "dw");
File confFile = new File(yamlFileName);
configurationFactory.build(new File(confFile.toURI()));
}
}
}

You can change the configuration in the YAML and read it while your application is running. This will not however restart the server or change any server configurations. You will be able to read any changed custom configurations and use them. For example, you can change the logging level at runtime or reload other custom settings.
My solution -
Define a custom server command. You should use this command to start your application instead of the "server" command.
ArgsServerCommand.java
public class ArgsServerCommand<WC extends WebConfiguration> extends EnvironmentCommand<WC> {
private static final Logger LOGGER = LoggerFactory.getLogger(ArgsServerCommand.class);
private final Class<WC> configurationClass;
private Namespace _namespace;
public static String COMMAND_NAME = "args-server";
public ArgsServerCommand(Application<WC> application) {
super(application, "args-server", "Runs the Dropwizard application as an HTTP server specific to my settings");
this.configurationClass = application.getConfigurationClass();
}
/*
* Since we don't subclass ServerCommand, we need a concrete reference to the configuration
* class.
*/
#Override
protected Class<WC> getConfigurationClass() {
return configurationClass;
}
public Namespace getNamespace() {
return _namespace;
}
#Override
protected void run(Environment environment, Namespace namespace, WC configuration) throws Exception {
_namespace = namespace;
final Server server = configuration.getServerFactory().build(environment);
try {
server.addLifeCycleListener(new LifeCycleListener());
cleanupAsynchronously();
server.start();
} catch (Exception e) {
LOGGER.error("Unable to start server, shutting down", e);
server.stop();
cleanup();
throw e;
}
}
private class LifeCycleListener extends AbstractLifeCycle.AbstractLifeCycleListener {
#Override
public void lifeCycleStopped(LifeCycle event) {
cleanup();
}
}
}
Method to reload in your Application -
_ymlFilePath = null; //class variable
public static boolean reloadConfiguration() throws IOException, ConfigurationException {
boolean reloaded = false;
if (_ymlFilePath == null) {
List<Command> commands = _configurationBootstrap.getCommands();
for (Command command : commands) {
String commandName = command.getName();
if (commandName.equals(ArgsServerCommand.COMMAND_NAME)) {
Namespace namespace = ((ArgsServerCommand) command).getNamespace();
if (namespace != null) {
_ymlFilePath = namespace.getString("file");
}
}
}
}
ConfigurationFactoryFactory configurationFactoryFactory = _configurationBootstrap.getConfigurationFactoryFactory();
ValidatorFactory validatorFactory = _configurationBootstrap.getValidatorFactory();
Validator validator = validatorFactory.getValidator();
ObjectMapper objectMapper = _configurationBootstrap.getObjectMapper();
ConfigurationSourceProvider provider = _configurationBootstrap.getConfigurationSourceProvider();
final ConfigurationFactory<CustomWebConfiguration> configurationFactory = configurationFactoryFactory.create(CustomWebConfiguration.class, validator, objectMapper, "dw");
if (_ymlFilePath != null) {
// Refresh logging level.
CustomWebConfiguration webConfiguration = configurationFactory.build(provider, _ymlFilePath);
LoggingFactory loggingFactory = webConfiguration.getLoggingFactory();
loggingFactory.configure(_configurationBootstrap.getMetricRegistry(), _configurationBootstrap.getApplication().getName());
// Get my defined custom settings
CustomSettings customSettings = webConfiguration.getCustomSettings();
reloaded = true;
}
return reloaded;
}

Although this feature isn't supported out of the box by dropwizard, you're able to accomplish this fairly easy with the tools they give you.
Before I get started, note that this isn't a complete solution for the question asked as it doesn't persist the updated config values to the config.yml. However, this would be easy enough to implement yourself simply by writing to the config file from the application. If anyone would like to write this implementation feel free to open a PR on the example project I've linked below.
Code
Start off with a minimal config:
config.yml
myConfigValue: "hello"
And it's corresponding configuration file:
ExampleConfiguration.java
public class ExampleConfiguration extends Configuration {
private String myConfigValue;
public String getMyConfigValue() {
return myConfigValue;
}
public void setMyConfigValue(String value) {
myConfigValue = value;
}
}
Then create a task which updates the config:
UpdateConfigTask.java
public class UpdateConfigTask extends Task {
ExampleConfiguration config;
public UpdateConfigTask(ExampleConfiguration config) {
super("updateconfig");
this.config = config;
}
#Override
public void execute(Map<String, List<String>> parameters, PrintWriter output) {
config.setMyConfigValue("goodbye");
}
}
Also for demonstration purposes, create a resource which allows you to get the config value:
ConfigResource.java
#Path("/config")
public class ConfigResource {
private final ExampleConfiguration config;
public ConfigResource(ExampleConfiguration config) {
this.config = config;
}
#GET
public Response handleGet() {
return Response.ok().entity(config.getMyConfigValue()).build();
}
}
Finally wire everything up in your application:
ExampleApplication.java (exerpt)
environment.jersey().register(new ConfigResource(configuration));
environment.admin().addTask(new UpdateConfigTask(configuration));
Usage
Start up the application then run:
$ curl 'http://localhost:8080/config'
hello
$ curl -X POST 'http://localhost:8081/tasks/updateconfig'
$ curl 'http://localhost:8080/config'
goodbye
How it works
This works simply by passing the same reference to the constructor of ConfigResource.java and UpdateConfigTask.java. If you aren't familiar with the concept see here:
Is Java "pass-by-reference" or "pass-by-value"?
The linked classes above are to a project I've created which demonstrates this as a complete solution. Here's a link to the project:
scottg489/dropwizard-runtime-config-example
Footnote: I haven't verified this works with the built in configuration. However, the dropwizard Configuration class which you need to extend for your own configuration does have various "setters" for internal configuration, but it may not be safe to update those outside of run().
Disclaimer: The project I've linked here was created by me.