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.
Related
I'm working on a Spring Boot project, where some static contents are served from the src/main/resources/static directory.
My goal is that whenever a user tries to access static contents that end with a certain suffix (e.g. ".xlsx"), the request is intercepted and I check to see if the user has the right permission using Spring AOP, and reject the request if necessary. I've got the AOP part working in other scenarios, but not in this scenario yet.
Currently I've tried something like the following, but the method isn't being invoked upon accessing a file of ".xlsx" suffix:
#RequestMapping("/*.xlsx")
public void checkPermission() {
}
Can this be done without using Spring Security? Thanks in advance.
Have you tried Filter interface? much more available.
LINK: https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/filter/OncePerRequestFilter.html
Using this you can easily parse the request before even it reaches the controller and add you business logic/validation to it.
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 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.
We use Spring to implement REST controller, for example:
#Controller
#RequestMapping("/myservice")
public class MyController {
#RequestMapping(value = "foo", method = RequestMethod.GET)
public #ResponseBody string foo() {...}
}
I can call this service using spring RestTemplate, and it works fine, but I would prefer to invoke it using a proxy, instead of typeless invocation using string url:
// client code:
MyController proxy = getProxy("baseUrl", MyController.class);
String results = proxy.foo();
So the input to proxy generation is java interface with annotations describing REST details.
I read this article and it looks like all types of remote calls do have proxies, and all I need for REST is something like RestProxyFactoryBean, that would take my REST java interface and return type-safe proxy that uses RestTemplate as implementation.
The closest solution I found is JBoss RESTEasy.
But it seems to use different set of annotations, so I am not sure it will work with annotations I already have: #Controller, #RequestMapping.
Are there other options, or RESTEasy is the only one?
Note, I am spring newbie so some obvious spring things are pretty new to me.
Thank you.
Dima
You can try Feign by Netflix, a lightweight proxy-based REST client. It works declaratively through annotations, and it's used by Spring Cloud projects to interact with Netflix Eureka.
One of the reasons the REST paradigm was invented was because expirience with other remoting technologies (RMI, CORBA, SOAP) shows us that often, the proxy-based approach creates more problems than it solves.
Theoretically, a proxy makes the fact that a function call is remote transparent to its users, so they can use the function exactly the same way as if it were a local function call.
In practice however this promise cannot be fulfilled, because remote function calls simply have other properties than local calls. Network outages, congestion, timeouts, load problems to name just a few. If you choose to ignore all these things that can go wrong with remote calls, your code probably won't be very stable.
TL;DR: You probably shouldn't work with a proxy, it's not state of the art any more. Just use RestTemplate.
Here is a project trying to generate runtime proxies from the controller annotations (using RestTemplate in the background to handle proxy calls): spring-rest-proxy-client Very early in implementation though.
This seems to do it: https://swagger.io/swagger-codegen/, and swagger has many other nice things for REST API.
Have a look at https://github.com/ggeorgovassilis/spring-rest-invoker.
All you need is to register FactoryBean:
#Configuration
public class MyConfiguration {
#Bean
SpringRestInvokerProxyFactoryBean BankService() {
SpringRestInvokerProxyFactoryBean proxyFactory = new SpringRestInvokerProxyFactoryBean();
proxyFactory.setBaseUrl("http://localhost/bankservice");
proxyFactory.setRemoteServiceInterfaceClass(BankService.class);
return proxyFactory;
}
and after that you can autowire the interface class:
#Autowired
BookService bookService;
I also ended up making my own library for this. I wanted something that is as small as possible, adds only itself to classpath and no transitive dependencies.
A client is created like:
final StoreApi storeApi = SpringRestTemplateClientBuilder
.create(StoreApi.class)
.setRestTemplate(restTemplate)
.setUrl(this.getMockUrl())
.build();
And rest-requests will be performed when invoking the methods:
storeApi.deleteOrder(1234L);
The is supports both method signatures:
ResponseEntity<X> deleteOrder(Long)
X deleteOrder(Long)
I have a JIRA plugin that I'm developing that has a REST service. That service should be able to accept POSTed requests, unmarshall some data and store it. The seemingly suggested way to do this in JIRA is to make use of the Bandana persistence framework. According to this page, I should be able to simply define a setter that Spring should call to give me my Bandana manager.
#Path("/path")
public class SCMService {
private BandanaManager bandanaManager;
// setter called by Spring
public void setBandanaManager(BandanaManager bandanaManager) {
this.bandanaManager = bandanaManager;
}
//...More methods...
}
However, when I test this, the setter is never being called and my manager is null. I'm guessing this should be as simple as registering this service with Spring for injection somehow but I can't seem to find anything like that.
How would I get my setter called? Is there a better way to do this?
Er, I'm not sure that JIRA uses Bandana in that way, though Confluence does. You can certainly post data to a JIRA rest resource and then store it using properties tables
Something like this:
#POST
#Consumes (MediaType.APPLICATION_XML)
public Response createComponentAndIssues(#Context HttpServletRequest request, ...