This establishes a timeout controlled via ClusterController::request_timeout,
triggering a ClusterController::Request::request_expired event whenever a
timeout rolls around before request state has been finalized by a request's
normal processing.
Request records for configuration updates now store the full configuration. The
ClusterController::Request module now provies a to_string() function for
rendering requests to a string.
This is a preliminary implementation of a subset of the functionality set out in
our cluster controller architecture. The controller is the central management
node, existing once in any Zeek cluster. The agent is a node that runs once per
instance, where an instance will commonly be a physical machine. The agent in
turn manages the "data cluster", i.e. the traditional notion of a Zeek cluster
with manager, worker nodes, etc.
Agent and controller live in the policy folder, and are activated when loading
policy/frameworks/cluster/agent and policy/frameworks/cluster/controller,
respectively. Both run in nodes forked by the supervisor. When Zeek doesn't use
the supervisor, they do nothing. Otherwise, boot.zeek instructs the supervisor
to create the respective node, running main.zeek.
Both controller and agent have their own config.zeek with relevant knobs. For
both, controller/types.zeek provides common data types, and controller/log.zeek
provides basic logging (without logger communication -- no such node might
exist).
A primitive request-tracking abstraction can be found in controller/request.zeek
to track outstanding request events and their subsequent responses.
