BB.Server.ParamResolution (bb v0.15.2)

Shared parameter resolution logic for wrapper servers.

This module provides functions for resolving ParamRef values in options and subscribing to parameter change notifications. Used by:

Usage

In your server's init/1:

{param_subscriptions, resolved_opts} =
  ParamResolution.resolve_and_subscribe(raw_opts, robot_module)

In handle_info/2 for parameter changes:

def handle_info({:bb, [:param | param_path], %{payload: %ParameterChanged{}}}, state) do
  ParamResolution.handle_param_change(
    param_path,
    state.param_subscriptions,
    state.raw_opts,
    robot_module,
    fn new_resolved ->
      # Call user's handle_options callback
    end
  )
end

Summary

Types

subscriptions()

Functions

handle_change(param_path, subscriptions, raw_opts, robot_module_or_state)

Handle a parameter change message.

resolve(opts, robot_module_or_state)

Resolve ParamRefs in options without subscribing.

resolve_and_subscribe(opts, robot_module_or_state)

Resolve ParamRefs in options and subscribe to parameter change topics.

subscribe(robot_module, subscriptions)

Subscribe to parameter change topics for tracked parameters.

Types

subscriptions()

@type subscriptions() :: %{required([atom()]) => atom()}

Functions

handle_change(param_path, subscriptions, raw_opts, robot_module_or_state)

@spec handle_change(
  [atom()],
  subscriptions(),
  keyword(),
  module() | BB.Robot.State.t()
) ::
  {:changed, keyword()} | :ignored

Handle a parameter change message.

Checks if the changed parameter is one we're subscribed to, re-resolves all options, and calls the provided callback with the new options.

Returns {:changed, new_resolved} if the parameter was tracked, or :ignored if not.

resolve(opts, robot_module_or_state)

@spec resolve(
  keyword(),
  module() | BB.Robot.State.t()
) :: {subscriptions(), keyword()}

Resolve ParamRefs in options without subscribing.

Takes either a robot module or a BB.Robot.State struct directly. Passing the state directly avoids a lookup and potential deadlock during init when the Runtime is still starting.

resolve_and_subscribe(opts, robot_module_or_state)

@spec resolve_and_subscribe(
  keyword(),
  module() | BB.Robot.State.t()
) :: {subscriptions(), keyword()}

Resolve ParamRefs in options and subscribe to parameter change topics.

Returns {subscriptions_map, resolved_opts} where:

subscriptions_map maps parameter paths to option keys
resolved_opts has ParamRefs replaced with their current values

This is a convenience function that calls resolve/2 and subscribe/2.