Configuration Reference

The followings lists the squbs configuration as defined in reference.conf:

squbs {

  # Name of the actor system for squbs to create.
  actorsystem-name = "squbs"

  # graceful stop timeout
  # default timeout for one actor to process a graceful stop
  # if extends the trait org.squbs.lifecycle.GracefulStopHelper
  default-stop-timeout = 3s

  # An external configuration directory to supply external application.conf. The location of this directory
  # is relative to the working directory of the squbs process.
  external-config-dir = squbsconfig

  # An external configuration file name list. Any file with the name in the list under the external-confi-dir will be
  # loaded during squbs initialization for Actor System settings. Implicit "application.conf" will be loaded
  # besides this file name list
  external-config-files = []

  # Service infra configuration.
  service-infra {
    # Maximum amount of time to wait for all listeners to be started.
    timeout = 60s
    # Maximum amount of time each listener is given to start.
    listener-timeout = 10s

default-listener {

  # All squbs listeners carry the type "squbs.listener"
  type = squbs.listener

  # Add aliases for the listener in case the cube's route declaration binds to a listener with a different name.
  # Just comma separated names are good, like...
  # aliases = [ foo-listener, bar-listener ]
  aliases = []

  # Service bind to particular address/interface. The default is which is any address/interface.
  bind-address = ""

  # Whether or not using full host name for address binding
  full-address = false

  # Service bind to particular port. 8080 is the default.
  bind-port = 8080

  # Listener uses HTTPS?
  secure = false

  # HTTPS needs client authorization? This configuration is not read if secure is false.
  need-client-auth = false

  # Any custom SSLContext provider? Setting to "default" means platform default.
  ssl-context = default

blocking-dispatcher {
  # Dispatcher is the name of the event-based dispatcher
  type = Dispatcher
  # What kind of ExecutionService to use
  executor = "thread-pool-executor"
  thread-pool-executor {
    # Min number of threads to cap factor-based core number to
    core-pool-size-min = 2
    # The core pool size factor is used to determine thread pool core size
    # using the following formula: ceil(available processors * factor).
    # Resulting size is then bounded by the core-pool-size-min and
    # core-pool-size-max values.
    core-pool-size-factor = 3.0
    # Max number of threads to cap factor-based number to
    core-pool-size-max = 24
    # Minimum number of threads to cap factor-based max number to
    # (if using a bounded task queue)
    max-pool-size-min = 2
    # Max no of threads (if using a bounded task queue) is determined by
    # calculating: ceil(available processors * factor)
    max-pool-size-factor  = 3.0
    # Max number of threads to cap factor-based max number to
    # (if using a  bounded task queue)
    max-pool-size-max = 24
  # Throughput defines the maximum number of messages to be
  # processed per actor before the thread jumps to the next actor.
  # Set to 1 for as fair as possible.
  throughput = 2

Blocking Dispatcher

The squbs reference.conf declares a blocking-dispatcher used for blocking I/O calls. This is a standard Akka dispatcher configuration. Please see dispatchers in the Akka documentation for more detail.


A listener defines a port binding and the behavior of this port binding such as security, authentication, etc. A default listener is provided by the squbs reference.conf. This can be overridden by the application providing its application.conf file or the application.conf file in its external config directory. Please see Bootstrapping squbs for details how squbs reads its configuration file.

A listener is declared at the root level of the configuration file. The name generally follows the pattern *-listener but this is not a requirement. What defines the entry as a listener is the type field under the listener entry. It must be set to squbs.listener. Please see the default-listener example above on how to configure new listeners listening to different ports.

A declared listener is not started unless a service route attaches itself to this listener. In other words, just declaring the listener does not automatically cause the listener to start unless there is a real use for the listener.


If defined, a default pipeline is installed for pre-processing every single request and post-processing every response. Services can specify a different pipeline, or none at all as described under Bootstrapping squbs. Applications or infrastructure can implement their own pipelines for pre-processing needs such as logging or tracing. Please see detailed description of pipelines under Request/Response Pipeline.