Java Nats Server Runner

Run the NATS messaging system Server from your Java code.

Current Release: 2.0.1   Current Snapshot: 2.0.2-SNAPSHOT

Useful for running unit or integration tests on the localhost.

Executable

By default, the server is found in your path in this order:

• the executablePath set in the builder
• the path found in the nats_server_path environment variable
• the path set via NatsRunnerUtils.setServerPath (deprecated, prefer setting in builder)
• nats-server somewhere in the machine's path.

For simple setup, constructors work well

try (NatsServerRunner server = new NatsServerRunner()) {
    System.out.println("Server running on port: " + server.getPort())
    Connection c = Nats.connect(server.getURI());
    ...
}

Builder

For more complicated setup, use the NatsServerRunnerBuilder

String[] customInserts = new String[] {
    "server_name=srv1",
    "cluster {",
    "  name: testcluster",
    "  listen: 127.0.0.1:4222",
    "  routes: [",
    "    nats-route://127.0.0.2:4222",
    "    nats-route://127.0.0.3:4222",
    "  ]",
    "}",
    ""
};

NatsServerRunner.Builder builder = NatsServerRunner.builder()
    .port(4567)
    .debugLevel(DebugLevel.DEBUG_TRACE)
    .jetstream(true)
    .executablePath("/this/run/only/nats-server")
    .configFilePath("/mypath/custom.conf")
    .configInserts(customInserts);

try (NatsServerRunner server = builder.build()) {
} 
catch (Exception e) {
    throw new RuntimeException(e);
}

Static Settings

If you want to run multiple instances of the server, for instance, in unit tests, you can do some setup statically to reduce the code in the builders. A simple way to do this would be to have a static initializer in a base test class or something that is called before all uses. There are 3 methods available:

static {
    NatsServerRunner.setDefaultOutputSupplier(ConsoleOutput::new);
    NatsServerRunner.setDefaultOutputLevel(Level.WARNING);
    NatsServerRunner.setPreferredServerPath("/path/to/nats-server")
}

License

Unless otherwise noted, the NATS source files are distributed under the Apache Version 2.0 license found in the LICENSE file.