configuration

Orbit Server offers extensive configuration and an extension model to support many situations outside the defaults. The OrbitServerConfig class supplied to the OrbitServer constructor has overrides for lease timing, process management, addressable and node storage, and metrics.

The OrbitServerConfig class is well documented and will be the authoritative source for the latest options. Some settings, like the pipelineBufferCount is a simple Int type. Others, like the addressableLeaseDuration are more complex objects.

ExternallyConfigured<T> settings allow replacement of implementations of some classes, such as the Node Directory. They are settable from serialized JSON data in a configuration file. The configuration class must derive from ExternallyConfigured, where T is the interface this implementation will replace.

A truncated example of the EtcdNodeDirectory implementation of Node Directory:

class EtcdNodeDirectory(config: EtcdNodeDirectoryConfig, private val clock: Clock) : NodeDirectory {
    data class EtcdNodeDirectoryConfig(
        val url: String
    ) : ExternallyConfigured<NodeDirectory> {
        override val instanceType: Class<out NodeDirectory> = EtcdNodeDirectory::class.java
    }
    ... EtcdNodeDirectory implementation
}

Configuration File

Orbit Server is set up with sensible default values for a simple, single node service. The easiest way to customize an Orbit Server is to use a configuration file. Orbit Server by default uses a SettingsLoader class which loads from a JSON-formatted configuration file. This file is searched for in 3 ways:

ORBIT_SETTINGS_RAW environment variable

Orbit will first attempt to read a raw JSON data from an environment variable ORBIT_SETTINGS_RAW.

ORBIT_SETTINGS environment variable

Orbit will then attempt to load a configuration file found at the path specified in the ORBIT_SETTINGS environment variable, such as /etc/orbit/orbit.json.

orbit.settings system property

Orbit will finally attempt to load a configuration file found at the path speciied in the 'orbit.settings` system property.

For ExternallyConfigured classes, configuration takes the form of a serialized class to be loaded from Jackson ObjectMapper:

    "nodeDirectory": [
        "orbit.server.etcd.EtcdNodeDirectory$EtcdNodeDirectoryConfig",
        {
            "url": "http://orbit-node-directory:2379"
        }
    ],