Rheo.GroupSupervisor (rheo v1.0.0)

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Dynamic supervisor for local Rheo.Group processes under one Rheo instance.

Started automatically as a child of {Rheo, ...}. Hosts usually supervise a Rheo.Consumer child spec in their own tree; use start_group/2 only when a group must be started dynamically at runtime.

Application Supervisor
      |
      +-- Rheo (named instance)
      |     +-- Backend handle
      |     +-- Rheo.Instance
      |     +-- Task.Supervisor
      |     +-- Rheo.GroupSupervisor   <-- this process
      |              +-- (optional) dynamically started Rheo.Group
      |
      +-- RiskConsumer = Rheo.Group    <-- preferred: host-owned child

Summary

Functions

child_spec(arg)

Returns a specification to start this module under a supervisor.

start_group(rheo, group_opts)

Starts a Rheo.Group under this instance's dynamic supervisor.

start_link(opts)

Starts the instance's group dynamic supervisor.

Functions

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

start_group(rheo, group_opts)

@spec start_group(atom(), keyword()) :: DynamicSupervisor.on_start_child()

Starts a Rheo.Group under this instance's dynamic supervisor.

Prefer supervising use Rheo.Consumer in the host tree. Use this when a group must be created after boot (admin tooling, on-demand workers).

Arguments

  • rheo — instance name (atom())
  • group_opts — same options as Rheo.Group / Rheo.Consumer (:stream, :group, :module, :max_demand, :concurrency, …). :rheo is injected automatically.

Returns

  • {:ok, pid} on success
  • {:error, {:already_started, pid}} if that {rheo, stream, group} already runs on this node
  • other DynamicSupervisor start errors

Examples

# After {Rheo, name: MyRheo, backend: {Rheo.Backend.ETS, []}} is running:
Rheo.GroupSupervisor.start_group(MyRheo,
  stream: "market-events",
  group: "risk",
  module: MyApp.RiskConsumer,
  max_demand: 10,
  concurrency: 4
)

start_link(opts)

@spec start_link(keyword()) :: Supervisor.on_start()

Starts the instance's group dynamic supervisor.

Options

  • :rheo — required instance name (atom()), used to register via Rheo.Names.group_supervisor/1

Returns

{:ok, pid} | {:error, reason} as for DynamicSupervisor.start_link/3.

Examples

Hosts do not call this directly — {Rheo, name: MyRheo, ...} starts it.