https://github.com/ofmooseandmen/halo
An implementation of Multicast DNS Service Discovery in Java.
https://github.com/ofmooseandmen/halo
bonjour java mdns multicast-dns service-discovery
Last synced: 6 months ago
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An implementation of Multicast DNS Service Discovery in Java.
- Host: GitHub
- URL: https://github.com/ofmooseandmen/halo
- Owner: ofmooseandmen
- License: bsd-3-clause
- Created: 2018-01-28T05:46:43.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-05-10T08:07:14.000Z (over 5 years ago)
- Last Synced: 2025-03-24T04:50:53.458Z (7 months ago)
- Topics: bonjour, java, mdns, multicast-dns, service-discovery
- Language: Java
- Homepage:
- Size: 584 KB
- Stars: 4
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Halo
[](https://github.com/ofmooseandmen/halo/actions?query=workflow%3ACI)
[](https://codecov.io/github/ofmooseandmen/halo)
[](http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22com.github.ofmooseandmen%22%20AND%20a%3A%22halo%22)
[](https://www.javadoc.io/doc/com.github.ofmooseandmen/halo)
[](https://opensource.org/licenses/BSD-3-Clause)
> __Halo__ [_Javanese_] is __Bonjour__ [_French_] is __Hello__ [_English_]
An implementation of [Multicast DNS Service Discovery](https://en.wikipedia.org/wiki/Zero-configuration_networking#Service_discovery) in Java.
## Building from Source
You need [JDK-8](http://jdk.java.net/8) or higher to build Halo.
Halo can be built with Gradle using the following command:
```
./gradlew clean build
```
## Tests
Halo is tested with [cucumber](https://cucumber.io) against [JmDNS](https://github.com/jmdns/jmdns). Feature files can be found in the `src/test/resources` folder.
## Usage
### Service Registration
```java
try (final Halo halo = Halo.allNetworkInterfaces(Clock.systemDefaultZone())) {
// allowing service instance name to be changed and with a default TTL of 1 hour:
Registered service = halo.register(RegisterableService.create("Foo Bar", "_http._udp.", 8009).get());
// registered service is returned:
System.err.println(service);
// registering again the service instance and registration type will return a service
// with an instance name of "Foo Bar (2)":
service = halo.register(RegisterableService.create("Foo Bar", "_http._udp.", 8010).get());
System.err.println(service);
// not allowing service instance name to be changed will throw an IOException at this point:
halo.register(RegisterableService.create("Foo Bar", "_http._udp.", 8011).get(), false);
// if blocking until the service has been announced is not acceptable:
ExecutorService es = Executors.newSingleThreadExecutor();
Future future =
es.submit(() -> halo.register(RegisterableService.create("Future", "_http._udp.", 8009).get()));
// changing the attributes of a registered service.
Attributes newAttributes = Attributes.create().with("Changed").get();
service.changeAttributes(newAttributes);
// or
Future future = es.submit(() -> service.changeAttributes(newAttributes));
}
```
### Service Resolution
```java
try (final Halo halo = Halo.allNetworkInterfaces(Clock.systemDefaultZone())) {
// default timeout of 6 seconds:
Optional service = halo.resolve("Foo Bar", "_http._udp.");
// Optional contains the service if it could be resolved, empty otherwise:
System.err.println(service);
// user defined timeout:
service = halo.resolve("Foo Bar", "_http._udp.", Duration.ofSeconds(1));
System.err.println(service);
// if blocking until the service has been resolved is not acceptable:
ExecutorService es = Executors.newSingleThreadExecutor();
Future> future = es.submit(() -> halo.resolved("Foo Bar", "_http._udp."));
}
```
### Services Browsing by Registration Type
```java
try (final Halo halo = Halo.allNetworkInterfaces(Clock.systemDefaultZone())) {
final ServiceBrowserListener l = new ServiceBrowserListener() {
@Override
public final void serviceAdded(final ResolvedService service) {
System.err.println(service + " has been added to the network!!!!!");
}
@Override
public final void serviceRemoved(final ResolvedService service) {
System.err.println(service + " has been removed from the network!!!!!");
}
@Override
public final void serviceUpdated(final ResolvedService service) {
System.err.println(service + " has been updated!!!!!");
}
};
final Browser browser = halo.browse("_http._udp.", l);
// Wait for some services to be registered on the network...
Thread.sleep(5000);
browser.close();
}
```
### Registration Types Browsing
```java
try (final Halo halo = Halo.allNetworkInterfaces(Clock.systemDefaultZone())) {
final Browser browser = halo.browse(System.err::printLn);
// Wait for some services to be registered on the network...
Thread.sleep(5000);
browser.close();
}
```
## Configuration
The following parameters can be configured by system properties:
| Property Key | Description | Default |
| ---------------------------------- | --------------------------------------------------------------------- | ----------- |
| io.omam.halo.mdns.ipv4 | mDNS IPV4 address | 224.0.0.251 |
| io.omam.halo.mdns.ipv6 | mDNS IPV6 address | FF02::FB |
| io.omam.halo.mdns.port | mDNS port | 5353 |
| io.omam.halo.resolution.timeout | resolution timeout in milliseconds | 6000 |
| io.omam.halo.resolution.interval | interval between resolution questions in milliseconds | 200 |
| io.omam.halo.probing.timeout | probing timeout in milliseconds | 6000 |
| io.omam.halo.probing.interval | interval between probe messages in milliseconds | 250 |
| io.omam.halo.probing.number | number of probing messages before announcing a registered service | 3 |
| io.omam.halo.announcement.interval | interval between announcement messages in milliseconds | 1000 |
| io.omam.halo.announcement.number | number of announcement messages to registered service | 2 |
| io.omam.halo.querying.first | delay before transmitting the first browsing query in milliseconds | 50 |
| io.omam.halo.querying.delay | interval between consecutive browsing queries in milliseconds | 1000 |
| io.omam.halo.querying.increase | increase factor between consecutive browsing queries | 2 |
| io.omam.halo.querying.max | maximum interval between consecutive browsing queries in milliseconds | 1200000 |
| io.omam.halo.cancellation.interval | interval between goodbye messages in milliseconds | 250 |
| io.omam.halo.cancellation.number | number of goodbye messages sent when de-registering a service | 3 |
| io.omam.halo.reaper.interval | cache record reaper interval in milliseconds | 10000 |
| io.omam.halo.ttl.default | DNS record default time to live in milliseconds | 3600000 |
| io.omam.halo.ttl.expiry | DNS record time to live after expiry in milliseconds | 1000 |