JarCastingScaleCube Config
ScaleCube Config is a configuration management library for JVM based distributed applications.
It provides the following functionality:
- Dynamic typed properties
- Register callbacks on property changes
- Object binding for grouping properties
- Extensible range of supported property sources (environment variables, program arguments, classpath, property files, mongodb, git repository, zookeeper etc.)
- Support centralized hierarchical property sources
- Control over order of applying different property sources
- Audit log of property changes
- Expose properties and settings via JMX and/or HTTP
Usage
Configure and create configuration registry instance:
Predicate<Path> predicate = path -> path.toString().endsWith(".props"); // match by .props extension
ConfigRegistrySettings settings = ConfigRegistrySettings.builder()
.addLastSource("classpath", new ClassPathConfigSource(predicate))
.addLastSource("configDirectory", new DirectoryConfigSource("conf" /* base path */, predicate))
.addListener(new Slf4JConfigEventListener()) // print all property changes to log
.build();
ConfigRegistry configRegistry = ConfigRegistry.create(settings);
Get dynamic typed configuration property:
LongConfigProperty timeoutProperty = configRegistry.longProperty("http.request-timeout");
long timeout = timeoutProperty.get(30 /* default value */);
Register callbacks on property modifications:
timeoutProperty.addCallback((oldValue, newValue) ->
System.out.println("Timeout value changed to " + newValue));
Register validators on property values (only values which passed all validators will be applied):
timeoutProperty.addValidator(val -> val >= 0); // timeout can't be negative
Utilize object binding:
// Define configuration class
public interface MyConfig {
private boolean meaning;
private int answer;
private double realAnswer;
...
}
// myapp.config.meaning=true
// myapp.config.answer=42
// myapp.config.realAnswer=42.000000000000001
ObjectConfigProperty<MyConfig> config = configRegistry.objectProperty("myapp.config", MyConfig.class);
// Get current config values
MyConfig currentConfig = config.value(MyConfig.defaultValue() /* or default */);
// Register callback (called only once per config reload even when several properties changed)
config.addCallback((oldConfig, newConfig) ->
System.out.println("MyConfig updated from " + oldConfig + " to " + newConfig));
// Register validator
// If meaning is present, an answer should be at least as big as the answer
config.addValidator(val -> val.meaning && val.answer >= 42);
Start embedded HTTP server which exposes configuration endpoints:
ConfigRegistryHttpServer.create(configRegistry, 5050); // starts http server on port 5050
After HTTP server is started explore configuration registry by browsing following endpoints:
- http://localhost:5050/_config/properties
- http://localhost:5050/_config/sources
- http://localhost:5050/_config/events
- http://localhost:5050/_config/settings
See more examples at config-examples module.
Maven
Binaries and dependency information for Maven can be found at http://search.maven.org.
Change history and version numbers can be found at CHANGES.md.
Maven dependency:
<dependency>
<groupId>io.scalecube</groupId>
<artifactId>config</artifactId>
<version>x.y.z</version>
</dependency>
<!-- For exposing config HTTP endpoints -->
<dependency>
<groupId>io.scalecube</groupId>
<artifactId>config-http-server</artifactId>
<version>x.y.z</version>
</dependency>
<!-- For MongoDB integration (beta version) -->
<dependency>
<groupId>io.scalecube</groupId>
<artifactId>config-mongo</artifactId>
<version>x.y.z</version>
</dependency>
Bugs and Feedback
For bugs, questions and discussions please use the GitHub Issues.
