         host    : program.host
         port    : program.port
         clients : number_of_clients()
-        ttl     : 2*REGISTER_INTERVAL_S
+        ttl     : 3*REGISTER_INTERVAL_S
         cb      : (err) ->
             if err
                 database_is_working = false

connect_to_database = (opts) ->
    opts = defaults opts,
        error : 120
        cb    : required 
    if database? # already did this
        opts.cb(); return
    dbg = (m) -> winston.debug("connect_to_database: #{m}")


# How frequently to register with the database that this hub is up and running, and also report
# number of connected clients
REGISTER_INTERVAL_S = 45   # every 45 seconds

# node.js -- builtin libraries
net     = require('net')
