I have develop a new Connector. This connector requires to be configured with two parameters, lets say:
default_trip_timeout_milis
default_trip_threshold
Challenge is, I want read ${myValue_a} and ${myValue_a} from an API, using an HTTP call, not from a file or inline values.
Since this is a connector, I need to make this API call somewhere before connectors are initialized.
FlowVars aren't an option, since they are initialized with the Flows, and this is happening before in the Mule app life Cycle.
My idea is to create an Spring Bean implementing Initialisable, so it will be called before Connectors are init, and here, using any java based libs (Spring RestTemplate?) , call API, get values, and store them somewhere (context? objectStore?) , so the connector can access them.
Make sense? Any other ideas?
Thanks!
mmm you could make a class that will create the properties in the startup and in this class obtain the API properties via http request. Example below:
public class PropertyInit implements InitializingBean,FactoryBean {
private Properties props = new Properties();
#Override
public Object getObject() throws Exception {
return props;
}
#Override
public Class getObjectType() {
return Properties.class;
}
}
Now you should be able to load this property class with:
<context:property-placeholder properties-ref="propertyInit"/>
Hope you like this idea. I used this approach in a previous project.
I want to give you first a strong warning on doing this. If you go down this path then you risk breaking your application in very strange ways because if any other components depend on this component you are having dynamic components on startup, you will break them, and you should think if there are other ways to achieve this behaviour instead of using properties.
That said the way to do this would be to use a proxy pattern, which is a proxy for the component you recreate whenever its properties are changed. So you will need to create a class which extends Circuit Breaker, which encapsulates and instance of Circuit Breaker which is recreated whenever its properties change. These properties must not be used outside of the proxy class as other components may read these properties at startup and then not refresh, you must keep this in mind that anything which might directly or indirectly access these properties cannot do so in their initialisation phase or your application will break.
It's worth taking a look at SpringCloudConfig which allows for you to have a properties server and then all your applications can hot-reload those properties at runtime when they change. Not sure if you can take that path in Mule if SpringCloud is supported yet but it's a nice thing to know exists.
Related
I have spring boot micro-service with database credentials define in the application properties.
spring.datasource.url=<<url>>
spring.datasource.username=<<username>>
spring.datasource.password=<<password>>
We do not use spring data source to create the connection manually. Only Spring create the database connection with JPA.(org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration)
We only provide the application properties, but spring create the connections automatically to use with the database connection pool.
Our requirement to enhance the security without using db properties in clear text. Two possible methods.
Encrypt the database credentials
Use the AWS secret manager. (then get the credential with the application load)
For the option1, jasypt can be used, since we are just providing the properties only and do not want to create the data source manually, how to do to understand by the spring framework is the problem. If better I can get some working sample or methods.
Regarding the option-2,
first we need to define secretName.
use the secertName and get the database credentials from AWS secret manager.
update the application.properties programatically to understand by spring framework. (I need to know this step)
I need to use either option1 and option2. Mentioned the issues with each option.
What you could do is use environment variables for your properties. You can use them like this:
spring.datasource.url=${SECRET_URL}
You could then retrieve these and start your Spring process using a ProcessBuilder. (Or set the variables any other way)
I have found the solution for my problem.
We need to define org.springframework.context.ApplicationListenerin spring.factories file. It should define the required application context listener like below.
org.springframework.context.ApplicationListener=com.sample.PropsLoader
PropsLoader class is like this.
public class PropsLoader implements ApplicationListener<ApplicationEnvironmentPreparedEvent> {
#Override
public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
ConfigurableEnvironment environment = event.getEnvironment();
String appEnv = environment.getProperty("application.env");
//set new properties based on the application environment.
// calling other methods and depends on the enviornment and get the required value set
Properties props = new Properties();
props.put("new_property", "value");
environment.getPropertySources().addFirst(new PropertiesPropertySource("props", props));
}
}
spring.factories file should define under the resources package and META-INF
folder.
This will set the application context with new properties before loading any other beans.
I am working with Spring and have information in my application.properties that I want to update from an HTML page
Myapplication.properties
...
spring.mail.host=smtp.gmail.com
spring.mail.port=587
...
Let say we need to change the port.
Is it possible to do something like that and what is the result if a user is logged in and we made a change?
I also read this post Update property in spring environment in java code is it the right solution.
I guess if I say that we need to rebuild the appplication.properties after changing some information.
Is it possible to do something like that and what is the result if a
user is logged in and we made a change?
if i understood it right, you want to change mail port in runtime? if so :
of course this is possible, but changing the value in property file alone wouldn't result in a actual change in your system, you should know that it is your responsibility to manage the reconstruction of a new mail sender instance in which you should also consider issues like multi-threading , race-condition , etc
I propose you to use application.properties in system startup to initialize your instance, and in case of change use something like this:
taking advatage of the Changing mail configuration in runtime and singleton pattern you should probabaly reach your aim :
#Component
public class MailSender{
#Value("${spring.mail.host}")
public static String host;
#Value("${spring.mail.port}")
private static Integer port
private static JavaMailSender instance;
public static synchronized JavaMailSender getInstance(Integer port) {
if (instance == null || port!= null) {
MailSender.port = port!=null ? port: MailSender.port;
JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
mailSender.setHost(MailSender.host);
mailSender.setPort(MailSender.port);
return instance;
}
}
The above code is an alteration of singleton pattern in which we check whether the mail instance is null or port has new value recreate the instance otherwise if instance has already a value use that, in this way you can change port run time.
please notice that by the code above I am trying to give you some insight into the problem and you may change it based on your design.
I hope I got your purpose correctly.
First of all, after changing configuration you have to reload beans dependent on changed variables.
I would recommend you to have a look at Spring Cloud Config project.
It has the following features:
Stores configs (and changes) in Git
Can change configuration properties at runtime, and force subscribed applications to reload their context (or even dependent beans only) automatically
Despite it is not direct answer to your question (it doesn't have an UI for configuration), but it is a good reason to search UI for Spring Cloud Config instead.
I d like to make a REST call once on application startup to retrieve some configuration parameters.
For example, we need to retrieve an entity called FleetConfiguration from another server. I d like to do a GET once and save the keep the data in memory for the rest of the runtime.
What s the best way of doing this in Spring? using Bean, Config annotations ..?
I found this for example : https://stackoverflow.com/a/44923402/494659
I might as well use POJOs handle the lifecycle of it myself but I am sure there s a way to do it in Spring without re-inventing the wheel.
Thanks in advance.
The following method will run once the application starts, call the remote server and return a FleetConfiguration object which will be available throughout your app. The FleetConfiguration object will be a singleton and won't change.
#Bean
#EventListener(ApplicationReadyEvent.class)
public FleetConfiguration getFleetConfiguration(){
RestTemplate rest = new RestTemplate();
String url = "http://remoteserver/fleetConfiguration";
return rest.getForObject(url, FleetConfiguration.class);
}
The method should be declared in a #Configuration class or #Service class.
Ideally the call should test for the response code from the remote server and act accordingly.
Better approach is to use Spring Cloud Config to externalize every application's configuration here and it can be updated at runtime for any config change so no downtime either around same.
We're building a Spring-based application which will be delivered to end users as a distribution package. Users are responsible for properly configuring whatever needs to be configured (it's mostly about various filesystem locations, folder access permissions, etc). There's a good idea to make the app help users understand what is not configured or which parts of configuration are invalid.
Our current approach is a custom ApplicationContextInitializer which does all the environment validation "manually" and then registers few "low level" beans in the application context explicitly. If something is wrong, initializer throws, exception is caught somewhere in main(), interpreted (converted into plain English) and then displayed.
While this approach works fine, I'm wondering if there are any best practices to minimize hand-written code and use Spring whenever possible.
Here's an illustrative example. The application requires a folder for file uploads. This means:
There should be a configuration file
This file should be accessible by the app
This file should have no syntax errors
This file should explicitly define some specific property (let it be app.uploads.folder)
This property should describe the existing filesystem entity
This entity should be a folder
The app should have read/write access to this folder
Does Spring provide any tools to implement this sort of validation easily?
Spring Boot has a nice feature for context and external configuration validation. If you define a POJO class and declare it as #ConfigurationProperties then Spring will bind the Environment (external properties and System/OS typically) to its properties using a DataBinder. E.g.
#ConfigurationProperties(name="app.uploads")
public class FileUploadProperties {
private File folder;
// getters and setters ommitted
}
will bind to app.uploads.folder and ensure that it is a File. For extra validation you can do it manually in the setter, or you can implement Validator in your FileUploadProperties or you can use JSR-303 annotations on the fields. By default an external property in app.uploads.* that doesn't bind will throw an exception (e.g. a mis-spelled property name, or a conversion/format error).
If you use Spring Boot Autoconfigure #EnableAutoConfigure you don't have to do anything else, but if it's just vanilla Spring (Boot) you need to say #EnableConfigurationProperties in your #Configuration somewhere as well.
A bonus feature: if you also use the Spring Boot Actuator you will also get JMX and HTTP support (in a webapp) for inspecting the bindable and bound properties of #ConfigurationProperties beans. The HTTP endpoint is "/configprops".
I'm trying to get myself familiar with MVC3 and autofac but I've encountered small problem that I'm having trouble resolving.
I am using autofac integrated with MVC3 and all works well, pages are loading correctly, dependencies are being injected and that's cool. What's bugging me is how to use autofac's Container or MVC's DependencyResover in class library project.
I'm trying to create static class that will help me handle domain events. I simply want to be able to call the method with event parameter and everything should be handeled by this class. Here is code:
public static IContainer Container { get; set; }
public static void Raise<T>(T e) where T : IDomainEvent
{
foreach (var eventHandler in DomainEventManager.Container.Resolve<IEnumerable<EventHandlers.Handles<T>>>())
{
eventHandler.Handle(e);
}
}
As you can see it's pretty straightforward and everything would work great if it wasn't MVC approach. Some of my dependencies are registeres as InstancePerHttpRequest (NHibernate' session), while other are registered as InstancePerDependency or SingleInstance. Thus when I try to use container created in my UI project, I get exception that there is no httpRequest tag available.
How can i reuse the Container created in web project to get access to all of it's features, including InstancePerHttpRequest and httpRequest tag?
Or maybe there is other solution to my problem? I was thinking about using delegate function to obtain event handlers, but I cannot (can I?) create generic delegate that I would not need to initialize with concrete type at time of assignment.
Why I want to do this using static class is basically every entity and aggregate or service needs to be able to raise domain event. Injecting EventManager into every one of these would be troublesome and static class is exactly what would resolve all my problems.
If anyone could help me get my head around it I would be grateful.
Cheers, Pako
You shouldn't be referencing your container directly from your app code. This looks like the Service Locator anti-pattern. The correct action is to pass your objects the services they need to do their jobs, usually done through constructor parameters. BUT... if you are going to insist on depending on a global static, then at least model EventManager as a singleton, such that usage would look like:
EventManager.Current.Raise<SomeEvent>(someObject);
and then you can set EventManager.Current equal to a properly constructed instance when your app is initialized.