Chapter 1. Configuring your Red Hat build of Quarkus applications by using a properties file As an application developer, you can use Red Hat build of Quarkus to create microservices-based applications written in Java that run on OpenShift and serverless environments. Applications compiled to native executables have small memory footprints and fast startup times. You can configure your Quarkus application by using either of the following methods: Setting properties in the application.properties file Applying structured configuration in YAML format by updating the application.yaml file You can also extend and customize the configuration for your application by doing the following: Substituting and composing configuration property values by using property expressions Implementing MicroProfile-compliant classes with custom configuration source converters that read configuration values from different external sources Using configuration profiles to keep separate sets of configuration values for your development, test, and production environments The procedures include configuration examples that are created by using the Quarkus config-quickstart exercise. Prerequisites You have installed OpenJDK 17 or 21 and set the JAVA_HOME environment variable to specify the location of the Java SDK. To download the Red Hat build of OpenJDK, log in to the Red Hat Customer Portal and go to Software Downloads . You have installed Apache Maven 3.8.6 or later. Download Maven from the Apache Maven Project website. You have configured Maven to use artifacts from the Quarkus Maven repository . To learn how to configure Maven settings, see Getting started with Quarkus . 1.1. Red Hat configuration options You can use configuration options to change the settings of your application in a single configuration file. Red Hat build of Quarkus supports configuration profiles that you can use to group related properties and switch between profiles as required. By default, Quarkus reads properties from the application.properties file located in the src/main/resources directory. You can also configure Quarkus to read properties from a YAML file instead. When you add the quarkus-config-yaml dependency to your project pom.xml file, you can configure and manage your application properties in the application.yaml file. For more information, see Adding YAML configuration support . Red Hat build of Quarkus also supports MicroProfile Config, which you can use to load your application's configuration from other sources. You can use the MicroProfile Config specification from the Eclipse MicroProfile project to inject configuration properties into your application and access them by using a method defined in your code. Quarkus can also read application properties from different origins, including the following sources: The file system A database A Kubernetes or OpenShift Container Platform ConfigMap or Secret object Any source that a Java application can load 1.2. Creating the configuration quickstart project With the config-quickstart project, you can get up and running with a simple Quarkus application by using Apache Maven and the Quarkus Maven plugin. The following procedure describes how you can create a Quarkus Maven project. Prerequisites You have installed OpenJDK 17 or 21 and set the JAVA_HOME environment variable to specify the location of the Java SDK. To download Red Hat build of OpenJDK, log in to the Red Hat Customer Portal and go to Software Downloads . You have installed Apache Maven 3.8.6 or later. Download Maven from the Apache Maven Project website. Procedure Verify that Maven uses OpenJDK 17 or 21 and that the Maven version is 3.8.6 or later: mvn --version If the mvn command does not return OpenJDK 17 or 21, ensure that the directory where OpenJDK 17 or 21 is installed on your system is included in the PATH environment variable: export PATH=USDPATH:<path_to_JDK> Enter the following command to generate the project: mvn com.redhat.quarkus.platform:quarkus-maven-plugin:3.8.6.SP3-redhat-00002:create \ -DprojectGroupId=org.acme \ -DprojectArtifactId=config-quickstart \ -DplatformGroupId=com.redhat.quarkus.platform \ -DplatformVersion=3.8.6.SP3-redhat-00002 \ -DclassName="org.acme.config.GreetingResource" \ -Dpath="/greeting" cd config-quickstart Verification The preceding mvn command creates the following items in the config-quickstart directory: The Maven project directory structure An org.acme.config.GreetingResource resource A landing page that you can access at http://localhost:8080 after you start the application Associated unit tests for testing your application in native mode and JVM mode Example Dockerfile.jvm and Dockerfile.native files in the src/main/docker subdirectory The application configuration file Note Alternatively, you can download a Quarkus Maven project to use in this tutorial from the Quarkus Quickstarts archive or clone the Quarkus Quickstarts Git repository. The Quarkus config-quickstart exercise is located in the config-quickstart directory. 1.3. Injecting configuration values into your Red Hat build of Quarkus application Red Hat build of Quarkus uses the MicroProfile Config feature to inject configuration data into the application. You can access the configuration by using context and dependency injection (CDI) or by defining a method in your code. Use the @ConfigProperty annotation to map an object property to a key in the MicroProfile Config Sources file of your application. The following procedure and examples show how you can inject an individual property configuration into a Quarkus config-quickstart project by using the Red Hat build of Quarkus Application configuration file, application.properties . Note You can use a MicroProfile Config configuration file , src/main/resources/META-INF/microprofile-config.properties , in exactly the same way you use the application.properties file. Using the application.properties file is the preferred method. Prerequisites You have created the Quarkus config-quickstart project. Procedure Open the src/main/resources/application.properties file. Add configuration properties to your configuration file where <property_name> is the property name and <value> is the value of the property: <property_name>=<value> The following example shows how to set the values for the greeting.message and the greeting.name properties in the Quarkus config-quickstart project: Example application.properties file greeting.message=hello greeting.name=quarkus Important When you are configuring your applications, do not prefix application-specific properties with the string quarkus . The quarkus prefix is reserved for configuring Quarkus at the framework level. Using quarkus as a prefix for application-specific properties might lead to unexpected results when your application runs. Review the GreetingResource.java Java file in your project. The file contains the GreetingResource class with the hello() method that returns a message when you send an HTTP request on the /greeting endpoint: Example GreetingResource.java file package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { String message; Optional<String> name; String suffix; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } } In the example provided, the values of the message and name strings in the hello() method are not initialized. The application throws a NullPointerException when the endpoint is called and starts successfully in this state. Define the message , name , and suffix fields, and annotate them with @ConfigProperty , matching the values that you defined for the greeting.message and greeting.name properties. Use the @ConfigProperty annotation to inject the configuration value for each string. For example: Example GreetingResource.java file package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") 1 String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") 2 String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; 3 @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } } 1 If you do not configure a value for the greeting.message string, the application fails and throws the following exception: jakarta.enterprise.inject.spi.DeploymentException: io.quarkus.runtime.configuration.ConfigurationException: Failed to load config value of type class java.lang.String for: greeting.message 2 If you do not configure a value for the greeting.suffix , Quarkus resolves it to the default value. 3 If you do not define the greeting.name property, the value of name is not available. Your application still runs even when this value is not available because you set the Optional parameter on name . Note To inject a configured value, you can use @ConfigProperty . You do not need to include the @Inject annotation for members that you annotate with @ConfigProperty . Compile and start your application in development mode: ./mvnw quarkus:dev Enter the following command in a new terminal window to verify that the endpoint returns the message: curl http://localhost:8080/greeting This command returns the following output: hello quarkus! To stop the application, press Ctrl+C. 1.4. Updating the functional test to validate configuration changes Before you test the functionality of your application, you must update the functional test to reflect the changes that you made to the endpoint of your application. The following procedure shows how you can update your testHelloEndpoint method on the Quarkus config-quickstart project. Procedure Open the GreetingResourceTest.java file. Update the content of the testHelloEndpoint method: package org.acme.config; import io.quarkus.test.junit.QuarkusTest; import org.junit.jupiter.api.Test; import static io.restassured.RestAssured.given; import static org.hamcrest.CoreMatchers.is; @QuarkusTest public class GreetingResourceTest { @Test public void testHelloEndpoint() { given() .when().get("/greeting") .then() .statusCode(200) .body(is("hello quarkus!")); // Modified line } } 1.5. Setting configuration properties By default, Quarkus reads properties from the application.properties file that is in the src/main/resources directory. If you change build properties, ensure that you repackage your application. Quarkus configures most properties during build time. Extensions can define properties as overridable at runtime, for example, the database URL, a user name, and a password, which can be specific to your target environment. Prerequisites You have created the Quarkus config-quickstart project. You have defined the greeting.message and greeting.name properties in the application.properties file of your project. Procedure To package your Quarkus project, enter the following command: ./mvnw clean package Use one of the following methods to set the configuration properties: Setting system properties: Enter the following command, where <property_name> is the name of the configuration property that you want to add and <value> is the value of the property: java -D<property_name>=<value> -jar target/quarkus-app/quarkus-run.jar For example, to set the value of the quarkus.datasource.password property, enter the following command: java -Dgreeting.suffix=? -jar target/quarkus-app/quarkus-run.jar Setting environment variables: Enter the following command, where <property_name> is the name of the configuration property that you want to set and <value> is the value of the property: export <property_name>=<value> ; java -jar target/quarkus-app/quarkus-run.jar Note Environment variable names follow the conversion rules of Eclipse MicroProfile . Convert the name to upper case and replace any character that is not alphanumeric with an underscore ( _ ). Using an environment file: Create a .env file in your current working directory and add configuration properties, where <PROPERTY_NAME> is the property name and <value> is the value of the property: <PROPERTY_NAME>=<value> Note In development mode, this file is in the root directory of your project. Do not track the file in version control. If you create a .env file in the root directory of your project, you can define keys and values that the program reads as properties. Using the application.properties file: Place the configuration file in the USDPWD/config/application.properties directory where the application runs so that any runtime properties that are defined in that file override the default configuration. Note You can also use the config/application.properties features in development mode. Place the config/application.properties file inside the target directory. Any cleaning operation from the build tool, for example, mvn clean , also removes the config directory. 1.6. Advanced configuration mapping The following advanced mapping procedures are extensions that are specific to Red Hat build of Quarkus and are outside of the MicroProfile Config specification. 1.6.1. Annotating an interface with @ConfigMapping Instead of individually injecting multiple related configuration values, use the @io.smallrye.config.ConfigMapping annotation to group configuration properties. The following procedure describes how you can use the @ConfigMapping annotation on the Quarkus config-quickstart project. Prerequisites You have created the Quarkus config-quickstart project. You have defined the greeting.message and greeting.name properties in the application.properties file of your project. Procedure Review the GreetingResource.java file in your project and ensure that it contains the contents that are shown in the following example. To use the @ConfigPoperties annotation to inject configuration properties from another configuration source into this class, you must import the java.util.Optional and org.eclipse.microprofile.config.inject.ConfigProperty packages. Example GreetingResource.java file package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } } Create a GreetingConfiguration.java file in the src/main/java/org/acme/config directory. Add the import statements for ConfigMapping and Optional to the file: Example GreetingConfiguration.java file package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.Optional; @ConfigMapping(prefix = "greeting") 1 public interface GreetingConfiguration { String message(); @WithDefault("!") 2 String suffix(); Optional<String> name(); } 1 The prefix property is optional. For example, in this scenario, the prefix is greeting . 2 If greeting.suffix is not set, ! is used as the default value. Inject the GreetingConfiguration instance into the GreetingResource class by using the @Inject annotation, as follows: Note This snippet replaces the three fields that are annotated with @ConfigProperty that are in the initial version of the config-quickstart project. Example GreetingResource.java file package org.acme.config; import jakarta.inject.Inject; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; @Path("/greeting") public class GreetingResource { @Inject GreetingConfiguration config; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return config.message() + " " + config.name().orElse("world") + config.suffix(); } } Compile and start your application in development mode: ./mvnw quarkus:dev Important If you do not give values for the class properties, the application fails to compile, and an io.smallrye.config.ConfigValidationException error is returned to indicate that a value is missing. This does not apply to optional fields or fields with a default value. To verify that the endpoint returns the message, enter the following command in a new terminal window: curl http://localhost:8080/greeting You receive the following message: hello quarkus! To stop the application, press Ctrl+C. 1.6.2. Using nested object configuration You can define an interface that is nested inside another interface. This procedure shows how to create and configure a nested interface in the Quarkus config-quickstart project. Prerequisites You have created the Quarkus config-quickstart project. You have defined the greeting.message and greeting.name properties in the application.properties file of your project. Procedure Review the GreetingResource.java in your project. The file contains the GreetingResource class with the hello() method that returns a message when you send an HTTP request on the /greeting endpoint: Example GreetingResource.java file package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } } Create a GreetingConfiguration.java class file with the GreetingConfiguration instance. This class contains the externalized configuration for the hello() method that is defined in the GreetingResource class: Example GreetingConfiguration.java file package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.Optional; @ConfigMapping(prefix = "greeting") public interface GreetingConfiguration { String message(); @WithDefault("!") String suffix(); Optional<String> name(); } Create the ContentConfig interface that is nested inside the GreetingConfiguration instance, as shown in the following example: Example GreetingConfiguration.java file package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.List; import java.util.Optional; @ConfigMapping(prefix = "greeting") public interface GreetingConfiguration { String message(); @WithDefault("!") String suffix(); Optional<String> name(); ContentConfig content(); interface ContentConfig { Integer prizeAmount(); List<String> recipients(); } } Note The method name of the ContentConfig interface is content . To ensure that you bind the properties to the correct interface, when you define configuration properties for this class, use content in the prefix. In doing so, you can also prevent property name conflicts and unexpected application behavior. Define the greeting.content.prize-amount and greeting.content.recipients configuration properties in your application.properties file. The following example shows the properties defined for the GreetingConfiguration instance and the ContentConfig interface: Example application.properties file greeting.message=hello greeting.name=quarkus greeting.content.prize-amount=10 greeting.content.recipients=Jane,John Instead of the three @ConfigProperty field annotations, inject the GreetingConfiguration instance into the GreetingResource class by using the @Inject annotation, as outlined in the following example. Also, you must update the message string that the /greeting endpoint returns with the values that you set for the new greeting.content.prize-amount and greeting.content.recipients properties that you added. Example GreetingResource.java file package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import jakarta.inject.Inject; @Path("/greeting") public class GreetingResource { @Inject GreetingConfiguration config; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return config.message() + " " + config.name().orElse("world") + config.suffix() + "\n" + config.content().recipients() + " receive total of candies: " + config.content().prizeAmount(); } } Compile and start your application in development mode: ./mvnw quarkus:dev Important If you do not provide values for the class properties, the application fails to compile and you receive a jakarta.enterprise.inject.spi.DeploymentException exception that indicates a missing value. This does not apply to Optional fields and fields with a default value. To verify that the endpoint returns the message, open a new terminal window and enter the following command: curl http://localhost:8080/greeting A message displays, containing two lines of output. The first line displays the greeting, and the second line reports the recipients of the prize together with the prize amount, as follows: hello quarkus! Jane,John receive total of candies: 10 To stop the application, press Ctrl+C. Note You can annotate classes that are annotated with @ConfigMapping with bean validation annotations similar to the following example: @ConfigMapping(prefix = "greeting") public class GreetingConfiguration { @Size(min = 20) public String message; public String suffix = "!"; } Your project must include the quarkus-hibernate-validator dependency. 1.7. Accessing the configuration programmatically You can define a method in your code to retrieve the values of the configuration properties in your application. In doing so, you can dynamically look up configuration property values or retrieve configuration property values from classes that are either CDI beans or Jakarta REST (formerly known as JAX-RS) resources. You can access the configuration by using the org.eclipse.microprofile.config.ConfigProvider.getConfig() method. The getValue() method of the config object returns the values of the configuration properties. Prerequisites You have a Quarkus Maven project. Procedure Use a method to access the value of a configuration property of any class or object in your application code. Depending on whether or not the value that you want to retrieve is set in a configuration source in your project, you can use one of the following methods: To access the value of a property that is set in a configuration source in your project, for example, in the application.properties file, use the getValue() method: String <variable-name> = ConfigProvider.getConfig().getValue(" <property-name> ", <data-type-class-name> .class); For example, to retrieve the value of the greeting.message property that has the data type String , and is assigned to the message variable in your code, use the following syntax: String message = ConfigProvider.getConfig().getValue("greeting.message",String.class); When you want to retrieve a value that is optional or default and might not be defined in your application.properties file or another configuration source in your application, use the getOptionalValue() method: Optional_<String>_ <variable-name> = ConfigProvider.getConfig().getOptionalValue(" <property-name> ", <data-type-class-name> .class); For example, to retrieve the value of the greeting.name property that is optional, has the data type String , and is assigned to the name variable in your code, use the following syntax: Optional_<String>_ name = ConfigProvider.getConfig().getOptionalValue("greeting.name", String.class); The following snippet shows a variant of the aforementioned GreetingResource class by using the programmatic access to the configuration: src/main/java/org/acme/config/GreetingResource.java package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.Config; import org.eclipse.microprofile.config.ConfigProvider; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { Config config = ConfigProvider.getConfig(); String message = config.getValue("greeting.message", String.class); Optional_<String>_ suffix = config.getOptionalValue("greeting.suffix", String.class).orElse("!"); Optional_<String>_ name = config.getOptionalValue("greeting.name", String.class); return message + " " + name.orElse("world") + suffix; } } 1.8. Property expressions You can combine property references and text strings into property expressions and use these expressions as values in your Quarkus configuration. Like variables, property expressions substitute configuration property values dynamically, avoiding hard-coded values. You can expand an expression in one configuration source with a value defined in another. The application resolves a property expression when java.util.Properties reads the property value from a configuration source: at compile time if read then, and at runtime if overridden at that point. If the application cannot resolve the value of a property in an expression, and the property does not have a default value, your application throws a NoSuchElementException error. 1.8.1. Example usage of property expressions To achieve flexibility when you configure your Quarkus application, you can use property expressions as shown in the following examples. Substituting the value of a configuration property: To avoid hardcoding property values in your configuration, you can use a property expression. Use the USD{<property_name>} syntax to write an expression that references a configuration property, as shown in the following example: Example application.properties file remote.host=quarkus.io callable.url=https://USD{remote.host}/ The value of the callable.url property resolves to https://quarkus.io/ . Setting a property value that is specific to a particular configuration profile: In the following example, the %dev configuration profile and the default configuration profile are set to use data source connection URLs with different host addresses. Example application.properties file %dev.quarkus.datasource.jdbc.url=jdbc:mysql://localhost:3306/mydatabase?useSSL=false quarkus.datasource.jdbc.url=jdbc:mysql://remotehost:3306/mydatabase?useSSL=false Depending on the configuration profile used to start your application, your data source driver uses the database URL that you set for the profile. You can achieve the same result in a simplified way by setting a different value for the custom application.server property for each configuration profile. Then, you can reference the property in the database connection URL of your application, as shown in the following example: Example application.properties file %dev.application.server=localhost application.server=remotehost quarkus.datasource.jdbc.url=jdbc:mysql://USD{application.server}:3306/mydatabase?useSSL=false The application.server property resolves to the appropriate value depending on the profile that you choose when you run your application. Setting a default value of a property expression: You can define a default value for a property expression. Quarkus uses the default value if the value of the property that is required to expand the expression is not resolved from any of your configuration sources. You can set a default value for an expression by using the following syntax: In the following example, the property expression in the data source URL uses mysql.db.server as the default value of the application.server property: Example application.properties file quarkus.datasource.jdbc.url=jdbc:mysql://USD{application.server:mysql.db.server}:3306/mydatabase?useSSL=false Nesting property expressions: You can compose property expressions by nesting a property expression inside another property expression. When nested property expressions are expanded, the inner expression is expanded first. You can use the following syntax for nesting property expressions: Combining multiple property expressions: You can join two or more property expressions together by using the following syntax: Combining property expressions with environment variables: You can use property expressions to substitute the values of environment variables. The expression in the following example substitutes the value that is set for the HOST environment variable as the value of the application.host property: Example application.properties file remote.host=quarkus.io application.host=USD{HOST:USD{remote.host}} When the HOST environment variable is not set, the application.host property uses the value of the remote.host property as the default. 1.9. Using configuration profiles You can use different configuration profiles depending on your environment. With configuration profiles, you can have multiple configurations in the same file and to select between them by using a profile name. Red Hat build of Quarkus has the following three default configuration profiles: dev : Activated in development mode test : Activated when running tests prod : The default profile when not running in development or test mode Note In addition, you can create your own custom profiles. Prerequisites You have a Quarkus Maven project. Procedure Open your Java resource file and add the following import statement: import io.quarkus.runtime.configuration.ConfigUtils; To get a List of the current profiles, add a log by invoking the ConfigUtils.getProfiles() method: LOGGER.infof("The application is starting with profiles `%s`", ConfigUtils.getProfiles()); 1.9.1. Setting a custom configuration profile You can create as many configuration profiles as you want. You can have multiple configurations in the same file and you can select a configuration by using a profile name. Procedure To set a custom profile, create a configuration property with the profile name in the application.properties file, where <property_name> is the name of the property, <value> is the property value, and <profile> is the name of a profile: Create a configuration property %<profile>.<property_name>=<value> In the following example configuration, the value of quarkus.http.port is 9090 by default, and becomes 8181 when the dev profile is activated: Example configuration quarkus.http.port=9090 %dev.quarkus.http.port=8181 Use one of the following methods to enable a profile: Set the quarkus.profile system property. To enable a profile by using the quarkus.profile system property, enter the following command: Enable a profile by using quarkus.profile property mvn -Dquarkus.profile=<value> quarkus:dev Set the QUARKUS_PROFILE environment variable. To enable profile by using an environment variable, enter the following command: Enable a profile by using an environment variable export QUARKUS_PROFILE=<profile> Note The system property value takes precedence over the environment variable value. To repackage the application and change the profile, enter the following command: Change a profile ./mvnw package -Dquarkus.profile=<profile> java -jar target/quarkus-app/quarkus-run.jar The following example shows a command that activates the prod-aws profile: Example command to activate a profile ./mvnw package -Dquarkus.profile=prod-aws java -jar target/quarkus-app/quarkus-run.jar Note The default Quarkus application runtime profile is set to the profile that is used to build the application. Red Hat build of Quarkus automatically selects a profile depending on your environment mode. For example, when your application is running as a JAR, Quarkus is in prod mode. 1.10. Setting custom configuration sources By default, a Quarkus application reads properties from the application.properties file in the src/main/resources subdirectory of your project. With Quarkus, you can load application configuration properties from other sources according to the MicroProfile Config specification for externalized configuration. You can enable your application to load configuration properties from other sources by defining classes that implement the org.eclipse.microprofile.config.spi.ConfigSource and the org.eclipse.microprofile.config.spi.ConfigSourceProvider interfaces. This procedure demonstrates how you can implement a custom configuration source in your Quarkus project. Prerequisite You have the Quarkus config-quickstart project. Procedure Create a class file in your project that implements the org.eclipse.microprofile.config.spi.ConfigSourceProvider interface. To return a list of ConfigSource objects, you must override the getConfigSources() method. Example org.acme.config.InMemoryConfigSourceProvider package org.acme.config; import org.eclipse.microprofile.config.spi.ConfigSource; import org.eclipse.microprofile.config.spi.ConfigSourceProvider; import java.util.List; public class InMemoryConfigSourceProvider implements ConfigSourceProvider { @Override public Iterable<ConfigSource> getConfigSources(ClassLoader classLoader) { return List.of(new InMemoryConfigSource()); } } Create the InMemoryConfigSource class that implements the org.eclipse.microprofile.config.spi.ConfigSource interface: Example org.acme.config.InMemoryConfigSource package org.acme.config; import org.eclipse.microprofile.config.spi.ConfigSource; import java.util.HashMap; import java.util.Map; import java.util.Set; public class InMemoryConfigSource implements ConfigSource { private static final Map<String, String> configuration = new HashMap<>(); static { configuration.put("my.prop", "1234"); } @Override public int getOrdinal() { 1 return 275; } @Override public Set<String> getPropertyNames() { return configuration.keySet(); } @Override public String getValue(final String propertyName) { return configuration.get(propertyName); } @Override public String getName() { return InMemoryConfigSource.class.getSimpleName(); } } 1 The getOrdinal() method returns the priority of the ConfigSource class. Therefore, when multiple configuration sources define the same property, Quarkus can select the appropriate value as defined by the ConfigSource class with the highest priority. In the src/main/resources/META-INF/services/ subdirectory of your project, create a file named org.eclipse.microprofile.config.spi.ConfigSourceProvider and enter the fully-qualified name of the class that implements the ConfigSourceProvider in the file that you created: Example org.eclipse.microprofile.config.spi.ConfigSourceProvider file: org.acme.config.InMemoryConfigSourceProvider To ensure that the ConfigSourceProvider that you created is registered and installed when you compile and start your application, you must complete the step. Edit the GreetingResource.java file in your project to add the following update: @ConfigProperty(name="my.prop") int value; In the GreetingResource.java file, extend the hello method to use the new property: @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + " " + value; } To compile and start your application in development mode, enter the following command: ./mvnw quarkus:dev To verify that the /greeting endpoint returns the expected message, open a terminal window and enter the following command: Example request curl http://localhost:8080/greeting When your application successfully reads the custom configuration, the command returns the following response: hello world 1234 1.11. Using custom configuration converters as configuration values You can store custom types as configuration values by implementing org.eclipse.microprofile.config.spi.Converter<T> and adding its fully qualified class name into the META-INF/services/org.eclipse.microprofile.config.spi.Converter file. By using converters, you can transform the string representation of a value into an object. Prerequisites You have created the Quarkus config-quickstart project. Procedure In the org.acme.config package, create the org.acme.config.MyCustomValue class with the following content: Example of custom configuration value package org.acme.config; public class MyCustomValue { private final int value; public MyCustomValue(Integer value) { this.value = value; } public int value() { return value; } } Implement the converter class to override the convert method to produce a MyCustomValue instance. Example implementation of converter class package org.acme.config; import org.eclipse.microprofile.config.spi.Converter; public class MyCustomValueConverter implements Converter<MyCustomValue> { @Override public MyCustomValue convert(String value) { return new MyCustomValue(Integer.valueOf(value)); } } Add the fully-qualified class name of the converter, org.acme.config.MyCustomValueConverter , to your META-INF/services/org.eclipse.microprofile.config.spi.Converter service file. In the GreetingResource.java file, inject the MyCustomValue property: @ConfigProperty(name="custom") MyCustomValue value; Edit the hello method to use this value: @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + " - " + value.value(); } In the application.properties file, add the string representation to be converted: custom=1234 To compile and start your application in development mode, enter the following command: ./mvnw quarkus:dev To verify that the /greeting endpoint returns the expected message, open a terminal window and enter the following command: Example request curl http://localhost:8080/greeting When your application successfully reads the custom configuration, the command returns the following response: hello world - 1234 Note Your custom converter class must be public and must have a public no-argument constructor. Your custom converter class cannot be abstract . Additional resources: List of converters in the microprofile-config GitHub repository 1.11.1. Setting custom converters priority The default priority for all Quarkus core converters is 200. For all other converters, the default priority is 100. You can increase the priority of your custom converters by using the jakarta.annotation.Priority annotation. The following procedure demonstrates an implementation of a custom converter, AnotherCustomValueConverter , which has a priority of 150. This takes precedence over MyCustomValueConverter from the section, which has a default priority of 100. Prerequisites You have created the Quarkus config-quickstart project. You have created a custom configuration converter for your application. Procedure Set a priority for your custom converter by annotating the class with the @Priority annotation and passing it a priority value. In the following example, the priority value is set to 150 . Example AnotherCustomValueConverter.java file package org.acme.config; import jakarta.annotation.Priority; import org.eclipse.microprofile.config.spi.Converter; @Priority(150) public class AnotherCustomValueConverter implements Converter<MyCustomValue> { @Override public MyCustomValue convert(String value) { return new MyCustomValue(Integer.valueOf(value)); } } Create a file named org.eclipse.microprofile.config.spi.Converter in the src/main/resources/META-INF/services/ subdirectory of your project, and enter the fully qualified name of the class that implements the Converter in the file that you created: Example org.eclipse.microprofile.config.spi.Converter file org.acme.config.AnotherCustomValueConverter You must complete the step to ensure that the Converter you created is registered and installed when you compile and start your application. Verification After you complete the required configuration, the step is to compile and package your Quarkus application. For more information and examples, see the compiling and packaging sections of the Getting started with Quarkus guide. 1.12. Additional resources Developing and compiling your Quarkus applications with Apache Maven Deploying your Quarkus applications to OpenShift Container Platform Compiling your Quarkus applications to native executables Revised on 2025-02-28 13:38:38 UTC

Commands:
mvn --version
export PATH=USDPATH:<path_to_JDK>
mvn com.redhat.quarkus.platform:quarkus-maven-plugin:3.8.6.SP3-redhat-00002:create -DprojectGroupId=org.acme -DprojectArtifactId=config-quickstart -DplatformGroupId=com.redhat.quarkus.platform -DplatformVersion=3.8.6.SP3-redhat-00002 -DclassName="org.acme.config.GreetingResource" -Dpath="/greeting" cd config-quickstart
<property_name>=<value>
greeting.message=hello greeting.name=quarkus
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { String message; Optional<String> name; String suffix; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } }
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") 1 String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") 2 String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; 3 @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } }
./mvnw quarkus:dev
curl http://localhost:8080/greeting
hello quarkus!
package org.acme.config; import io.quarkus.test.junit.QuarkusTest; import org.junit.jupiter.api.Test; import static io.restassured.RestAssured.given; import static org.hamcrest.CoreMatchers.is; @QuarkusTest public class GreetingResourceTest { @Test public void testHelloEndpoint() { given() .when().get("/greeting") .then() .statusCode(200) .body(is("hello quarkus!")); // Modified line } }
./mvnw clean package
java -D<property_name>=<value> -jar target/quarkus-app/quarkus-run.jar
java -Dgreeting.suffix=? -jar target/quarkus-app/quarkus-run.jar
export <property_name>=<value> ; java -jar target/quarkus-app/quarkus-run.jar
<PROPERTY_NAME>=<value>
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } }
package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.Optional; @ConfigMapping(prefix = "greeting") 1 public interface GreetingConfiguration { String message(); @WithDefault("!") 2 String suffix(); Optional<String> name(); }
package org.acme.config; import jakarta.inject.Inject; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; @Path("/greeting") public class GreetingResource { @Inject GreetingConfiguration config; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return config.message() + " " + config.name().orElse("world") + config.suffix(); } }
./mvnw quarkus:dev
curl http://localhost:8080/greeting
hello quarkus!
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @ConfigProperty(name = "greeting.message") String message; @ConfigProperty(name = "greeting.suffix", defaultValue="!") String suffix; @ConfigProperty(name = "greeting.name") Optional<String> name; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + suffix; } }
package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.Optional; @ConfigMapping(prefix = "greeting") public interface GreetingConfiguration { String message(); @WithDefault("!") String suffix(); Optional<String> name(); }
package org.acme.config; import io.smallrye.config.ConfigMapping; import io.smallrye.config.WithDefault; import java.util.List; import java.util.Optional; @ConfigMapping(prefix = "greeting") public interface GreetingConfiguration { String message(); @WithDefault("!") String suffix(); Optional<String> name(); ContentConfig content(); interface ContentConfig { Integer prizeAmount(); List<String> recipients(); } }
greeting.message=hello greeting.name=quarkus greeting.content.prize-amount=10 greeting.content.recipients=Jane,John
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import jakarta.inject.Inject; @Path("/greeting") public class GreetingResource { @Inject GreetingConfiguration config; @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return config.message() + " " + config.name().orElse("world") + config.suffix() + "\n" + config.content().recipients() + " receive total of candies: " + config.content().prizeAmount(); } }
./mvnw quarkus:dev
curl http://localhost:8080/greeting
hello quarkus! Jane,John receive total of candies: 10
@ConfigMapping(prefix = "greeting") public class GreetingConfiguration { @Size(min = 20) public String message; public String suffix = "!"; }
String <variable-name> = ConfigProvider.getConfig().getValue(" <property-name> ", <data-type-class-name> .class);
String message = ConfigProvider.getConfig().getValue("greeting.message",String.class);
Optional_<String>_ <variable-name> = ConfigProvider.getConfig().getOptionalValue(" <property-name> ", <data-type-class-name> .class);
Optional_<String>_ name = ConfigProvider.getConfig().getOptionalValue("greeting.name", String.class);
package org.acme.config; import java.util.Optional; import jakarta.ws.rs.GET; import jakarta.ws.rs.Path; import jakarta.ws.rs.Produces; import jakarta.ws.rs.core.MediaType; import org.eclipse.microprofile.config.Config; import org.eclipse.microprofile.config.ConfigProvider; import org.eclipse.microprofile.config.inject.ConfigProperty; @Path("/greeting") public class GreetingResource { @GET @Produces(MediaType.TEXT_PLAIN) public String hello() { Config config = ConfigProvider.getConfig(); String message = config.getValue("greeting.message", String.class); Optional_<String>_ suffix = config.getOptionalValue("greeting.suffix", String.class).orElse("!"); Optional_<String>_ name = config.getOptionalValue("greeting.name", String.class); return message + " " + name.orElse("world") + suffix; } }
remote.host=quarkus.io callable.url=https://USD{remote.host}/
%dev.quarkus.datasource.jdbc.url=jdbc:mysql://localhost:3306/mydatabase?useSSL=false quarkus.datasource.jdbc.url=jdbc:mysql://remotehost:3306/mydatabase?useSSL=false
%dev.application.server=localhost application.server=remotehost quarkus.datasource.jdbc.url=jdbc:mysql://USD{application.server}:3306/mydatabase?useSSL=false
USD{<property_name>:<default_value>}
quarkus.datasource.jdbc.url=jdbc:mysql://USD{application.server:mysql.db.server}:3306/mydatabase?useSSL=false
USD{<outer_property_name>USD{<inner_property_name>}}
USD{<first_property_name>}USD{<second_property_name>}
remote.host=quarkus.io application.host=USD{HOST:USD{remote.host}}
import io.quarkus.runtime.configuration.ConfigUtils;
LOGGER.infof("The application is starting with profiles `%s`", ConfigUtils.getProfiles());
%<profile>.<property_name>=<value>
quarkus.http.port=9090 %dev.quarkus.http.port=8181
mvn -Dquarkus.profile=<value> quarkus:dev
export QUARKUS_PROFILE=<profile>
./mvnw package -Dquarkus.profile=<profile> java -jar target/quarkus-app/quarkus-run.jar
./mvnw package -Dquarkus.profile=prod-aws java -jar target/quarkus-app/quarkus-run.jar
package org.acme.config; import org.eclipse.microprofile.config.spi.ConfigSource; import org.eclipse.microprofile.config.spi.ConfigSourceProvider; import java.util.List; public class InMemoryConfigSourceProvider implements ConfigSourceProvider { @Override public Iterable<ConfigSource> getConfigSources(ClassLoader classLoader) { return List.of(new InMemoryConfigSource()); } }
package org.acme.config; import org.eclipse.microprofile.config.spi.ConfigSource; import java.util.HashMap; import java.util.Map; import java.util.Set; public class InMemoryConfigSource implements ConfigSource { private static final Map<String, String> configuration = new HashMap<>(); static { configuration.put("my.prop", "1234"); } @Override public int getOrdinal() { 1 return 275; } @Override public Set<String> getPropertyNames() { return configuration.keySet(); } @Override public String getValue(final String propertyName) { return configuration.get(propertyName); } @Override public String getName() { return InMemoryConfigSource.class.getSimpleName(); } }
org.acme.config.InMemoryConfigSourceProvider
@ConfigProperty(name="my.prop") int value;
@GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + " " + value; }
./mvnw quarkus:dev
curl http://localhost:8080/greeting
hello world 1234
package org.acme.config; public class MyCustomValue { private final int value; public MyCustomValue(Integer value) { this.value = value; } public int value() { return value; } }
package org.acme.config; import org.eclipse.microprofile.config.spi.Converter; public class MyCustomValueConverter implements Converter<MyCustomValue> { @Override public MyCustomValue convert(String value) { return new MyCustomValue(Integer.valueOf(value)); } }
@ConfigProperty(name="custom") MyCustomValue value;
@GET @Produces(MediaType.TEXT_PLAIN) public String hello() { return message + " " + name.orElse("world") + " - " + value.value(); }
custom=1234
./mvnw quarkus:dev
curl http://localhost:8080/greeting
hello world - 1234
package org.acme.config; import jakarta.annotation.Priority; import org.eclipse.microprofile.config.spi.Converter; @Priority(150) public class AnotherCustomValueConverter implements Converter<MyCustomValue> { @Override public MyCustomValue convert(String value) { return new MyCustomValue(Integer.valueOf(value)); } }
org.acme.config.AnotherCustomValueConverter