wildfly: reading properties from configuration directory

Question

I'm trying to read deployment specific information from a properties file in my wildfly configuration folder. I tried this:

@Singleton
@Startup
public class DeploymentConfiguration {

  protected Properties props;

  @PostConstruct
  public void readConfig() {

    props = new Properties();
    try {
      props.load(getClass().getClassLoader().getResourceAsStream("my.properties"));
    } catch (IOException e) {
      // ... whatever
    }
  }

But apparently this is not working since the configuration folder is not in the classpath anymore. Now I can't find an easy way to do it. My favorite would be something like this:

@InjectProperties("my.properties")
protected Properties props;

The only solution I found on the web so far involves making my own OSGi module, but I believe there must be an easier way to do it (one without OSGi!). Can anyone show me how?

Answer 1

If you want to explicitly read a file from the configuration directory (e.g. $WILDFLY_HOME/standalone/configuration or domain/configuration) there's a system property with the path in it. Simply do System.getProperty("jboss.server.config.dir"); and append your file name to that to get the file.

You wouldn't read it as a resource though, so...

String fileName = System.getProperty("jboss.server.config.dir") + "/my.properties";
try(FileInputStream fis = new FileInputStream(fileName)) {
  properties.load(fis);
}

Then the file would be loaded for you.

Also, since WildFly doesn't ship with OSGi support anymore, I don't know how creating an OSGi module would help you here.

Answer 2

Here is a full example using just CDI, taken from this site.

1. Create and populate a properties file inside the WildFly configuration folder

   $ echo 'docs.dir=/var/documents' >> .standalone/configuration/application.properties
   

2. Add a system property to the WildFly configuration file.

   $ ./bin/jboss-cli.sh --connect
   [standalone@localhost:9990 /] /system-property=application.properties:add(value=${jboss.server.config.dir}/application.properties)
   

This will add the following to your server configuration file (standalone.xml or domain.xml):

<system-properties>
    <property name="application.properties" value="${jboss.server.config.dir}/application.properties"/>
</system-properties>

3. Create the singleton session bean that loads and stores the application wide properties

   import java.io.File;
   import java.io.FileInputStream;
   import java.io.IOException;
   import java.util.HashMap;
   import java.util.Map;
   import java.util.Properties;
   
   import javax.annotation.PostConstruct;
   import javax.ejb.Singleton;
   
   @Singleton
   public class PropertyFileResolver {
   
       private Logger logger = Logger.getLogger(PropertyFileResolver.class);
       private String properties = new HashMap<>();
   
       @PostConstruct
       private void init() throws IOException {
   
           //matches the property name as defined in the system-properties element in WildFly
           String propertyFile = System.getProperty("application.properties");
           File file = new File(propertyFile);
           Properties properties = new Properties();
   
           try {
               properties.load(new FileInputStream(file));
           } catch (IOException e) {
               logger.error("Unable to load properties file", e);
           }
   
           HashMap hashMap = new HashMap<>(properties);
           this.properties.putAll(hashMap);
       }
   
       public String getProperty(String key) {
           return properties.get(key);
       }
   }
   

4. Create the CDI Qualifier. We will use this annotation on the Java variables we wish to inject into.

   import java.lang.annotation.ElementType;
   import java.lang.annotation.Retention;
   import java.lang.annotation.RetentionPolicy;
   import java.lang.annotation.Target;
   
   import javax.inject.Qualifier;
   
   @Qualifier
   @Retention(RetentionPolicy.RUNTIME)
   @Target({ ElementType.METHOD, ElementType.FIELD, ElementType.CONSTRUCTOR })
   public @interface ApplicationProperty {
   
       // no default meaning a value is mandatory
       @Nonbinding
       String name();
   }
   

5. Create the producer method; this generates the object to be injected

   import javax.enterprise.inject.Produces;
   import javax.enterprise.inject.spi.InjectionPoint;
   import javax.inject.Inject;
   
   public class ApplicaitonPropertyProducer {
   
       @Inject
       private PropertyFileResolver fileResolver;
   
       @Produces
       @ApplicationProperty(name = "")
       public String getPropertyAsString(InjectionPoint injectionPoint) {
   
           String propertyName = injectionPoint.getAnnotated().getAnnotation(ApplicationProperty.class).name();
           String value = fileResolver.getProperty(propertyName);
   
           if (value == null || propertyName.trim().length() == 0) {
               throw new IllegalArgumentException("No property found with name " + value);
           }
           return value;
       }
   
       @Produces
       @ApplicationProperty(name="")
       public Integer getPropertyAsInteger(InjectionPoint injectionPoint) {
   
           String value = getPropertyAsString(injectionPoint);
           return value == null ? null : Integer.valueOf(value);
       }
   }
   

6. Lastly inject the property into one of your CDI beans

   import javax.ejb.Stateless;
   import javax.inject.Inject;
   
   @Stateless
   public class MySimpleEJB {
   
       @Inject
       @ApplicationProperty(name = "docs.dir")
       private String myProperty;
   
       public String getProperty() {
           return myProperty;
       }
   }