TermUI.Widgets.SupervisionTreeViewer (TermUI v0.2.0)

View Source

SupervisionTreeViewer widget for OTP supervision hierarchy visualization.

SupervisionTreeViewer displays the supervision tree with live status indicators, restart counts, and provides controls for process management and inspection.

Usage

SupervisionTreeViewer.new(
  root: MyApp.Supervisor,
  update_interval: 2000,
  on_select: fn node -> handle_select(node) end
)

Features

  • Tree view of supervision hierarchy
  • Live status indicators (running, restarting, terminated)
  • Restart count and history display
  • Supervisor strategy display
  • Process state inspection
  • Restart/terminate controls with confirmation
  • Auto-refresh on supervision tree changes

Keyboard Controls

  • Up/Down: Move selection
  • Left: Collapse node or move to parent
  • Right: Expand node or move to first child
  • Enter: Toggle expand/collapse
  • i: Show process info panel
  • r: Restart selected process (with confirmation)
  • k: Terminate selected process (with confirmation)
  • R: Refresh tree
  • /: Filter by name
  • Escape: Clear filter/close panel

Summary

Types

node_status()
node_type()
sup_node()

Functions

collapse_all(state)

Collapses all nodes.

expand_all(state)

Expands all supervisor nodes.

get_process_state(state)

Gets the process state for the selected node.

get_selected(state)

Gets the currently selected node.

init(props)

Initializes the SupervisionTreeViewer state.

new(opts)

Creates new SupervisionTreeViewer widget props.

refresh(state)

Forces a refresh of the supervision tree.

set_root(state, root)

Sets the root supervisor.

Types

node_status()

@type node_status() :: :running | :restarting | :terminated | :undefined

node_type()

@type node_type() :: :supervisor | :worker

sup_node()

@type sup_node() :: %{
  id: term(),
  pid: pid() | :restarting | :undefined,
  name: atom() | nil,
  type: node_type(),
  status: node_status(),
  child_spec: map() | nil,
  strategy: atom() | nil,
  restart_count: non_neg_integer(),
  max_restarts: non_neg_integer() | nil,
  max_seconds: non_neg_integer() | nil,
  children: [sup_node()] | nil,
  memory: non_neg_integer(),
  reductions: non_neg_integer(),
  message_queue_len: non_neg_integer(),
  depth: non_neg_integer(),
  parent_pid: pid() | nil
}

Functions

collapse_all(state)

@spec collapse_all(map()) :: {:ok, map()}

Collapses all nodes.

expand_all(state)

@spec expand_all(map()) :: {:ok, map()}

Expands all supervisor nodes.

get_process_state(state)

@spec get_process_state(map()) :: {:ok, term()} | {:error, term()}

Gets the process state for the selected node.

get_selected(state)

@spec get_selected(map()) :: sup_node() | nil

Gets the currently selected node.

init(props)

Initializes the SupervisionTreeViewer state.

new(opts)

@spec new(keyword()) :: map()

Creates new SupervisionTreeViewer widget props.

Options

  • :root - Root supervisor (pid, registered name, or module) - required
  • :update_interval - Refresh interval in ms (default: 2000)
  • :on_select - Callback when node is selected: fn node -> ... end

  • :on_action - Callback when action is performed: fn {:restarted | :terminated, pid} -> ... end

  • :show_workers - Show worker processes (default: true)
  • :auto_expand - Expand all nodes initially (default: true)

refresh(state)

@spec refresh(map()) :: {:ok, map()}

Forces a refresh of the supervision tree.

set_root(state, root)

@spec set_root(map(), term()) :: {:ok, map()}

Sets the root supervisor.