jnp is a JBoss protocol which exposes jndi. It is, by default, bound to port 1099. I’d been using that port as a heartbeat, but “cheating” — I would open a socket and then close it immediately. However, this caused problems. jnp is chatty. And it got upset at my not letting it say ‘hi’ before I dropped the connection. So, here’s a code snippet (jruby, the Java should be an exercise for the student) which allows you to actually do an intelligent check.
def check_port(server)
@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port})"
begin
env = java.util.Properties.new();
env.set_property("java.naming.factory.initial",
"org.jnp.interfaces.NamingContextFactory");
env.set_property("java.naming.provider.url",
"#{server.host}:#{server.port}");
ctx = javax.naming.InitialContext.new(env);
# if the server is not running, we'll get an error here because
# it will timeout.
ctx.list("")
ctx.close
@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Succeeded"
rescue javax.naming.CommunicationException => comm_error
@logger.debug "check_port: #{server.fqdn}(#{server.host}:#{server.port}): Not Running"
begin
ctx.close
rescue Exception => ignore_me
end
return false
rescue Exception => e2
@logger.info "check_port: #{server.fqdn}(#{server.host}:#{server.port}): FAILED: #{e2.to_s}"
return false
end
return true
end
