View Source Kino.Process (Kino v0.8.1)

This module contains kinos for generating visualizations to help introspect your running processes.

Link to this section Summary

Functions

Generates a visualization of an application tree.

Renders a visual of the provided application tree.

Renders a sequence diagram of process messages and returns the function result.

Renders a visual of the provided supervision tree.

Generate a sequence diagram of process messages starting from self().

Generates a visualization of a supervision tree.

Link to this section Types

@type supervisor() :: pid() | atom()
@type trace_target() :: :all | pid() | [pid()]

Link to this section Functions

Link to this function

app_tree(application, opts \\ [])

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@spec app_tree(
  atom(),
  keyword()
) :: Kino.Mermaid.t()

Generates a visualization of an application tree.

Given the name of an application as an atom, this function will render the application tree. It is displayed with solid lines denoting supervisor-worker relationships and dotted lines denoting links between processes. The graph rendering supports the following options:

options

Options

  • :direction - defines the direction of the graph visual. The value can either be :top_down or :left_right. Defaults to :top_down.

examples

Examples

To view the applications running in your instance run:

:application_controller.which_applications()

You can then call Kino.Process.app_tree/1 to render the application tree using using the atom of the application.

Kino.Process.app_tree(:logger)

You can also change the direction of the rendering by calling Kino.Process.app_tree/2 with the :direction option.

Kino.Process.app_tree(:logger, direction: :left_right)
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render_app_tree(application, opts \\ [])

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@spec render_app_tree(
  atom(),
  keyword()
) :: Kino.nothing()

Renders a visual of the provided application tree.

This function renders an application tree much like app_tree/2 with the difference being that this function can be called anywhere within the Livebook code block whereas app_tree/2 must have its result be the last thing returned from the code block in order to render the visual. It supports the same options as app_tree/2 as it delegates to that function to generate the visual.

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render_seq_trace(trace_target \\ :all, trace_function)

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@spec render_seq_trace(trace_target(), (() -> any())) :: any()

Renders a sequence diagram of process messages and returns the function result.

This function renders a sequence diagram much like seq_trace/2 with the difference being that this function can be called anywhere within the Livebook code block whereas seq_trace/2 must have its result be the last thing returned from the code block in order to render the visual. In addition, this function returns the result from the provided trace function.

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render_sup_tree(supervisor, opts \\ [])

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@spec render_sup_tree(
  supervisor(),
  keyword()
) :: Kino.nothing()

Renders a visual of the provided supervision tree.

This function renders a supervision tree much like sup_tree/2 with the difference being that this function can be called anywhere within the Livebook code block whereas sup_tree/2 must have its result be the last thing returned from the code block in order to render the visual. It supports the same options as sup_tree/2 as it delegates to that function to generate the visual.

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seq_trace(trace_target \\ :all, trace_function)

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@spec seq_trace(trace_target(), (() -> any())) :: {any(), Kino.Mermaid.t()}

Generate a sequence diagram of process messages starting from self().

The provided function is executed and traced, with all the events sent to and received by the trace target processes rendered in a sequence diagram. The trace target argument can either be a single PID, a list of PIDs, or the atom :all depending on what messages you would like to retain in your trace.

examples

Examples

To generate a trace of all the messages occurring during the execution of the provided function, you can do the following:

Kino.Process.seq_trace(fn ->
  {:ok, agent_pid} = Agent.start_link(fn -> [] end)
  Process.monitor(agent_pid)

  1..2
  |> Task.async_stream(
    fn value ->
      Agent.get(agent_pid, fn value -> value end)
      100 * value
    end,
    max_concurrency: 3
  )
  |> Stream.run()

  Agent.stop(agent_pid)
end)

If you are only interested in messages being sent to or received by certain PIDs, you can filter the sequence diagram by specifying the PIDs that you are interested in:

{:ok, agent_pid} = Agent.start_link(fn -> [] end)
Process.monitor(agent_pid)

Kino.Process.seq_trace(agent_pid, fn ->
  1..2
  |> Task.async_stream(
    fn value ->
      Agent.get(agent_pid, fn value -> value end)
      100 * value
    end,
    max_concurrency: 3
  )
  |> Stream.run()

  Agent.stop(agent_pid)
end)
Link to this function

sup_tree(supervisor, opts \\ [])

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@spec sup_tree(
  supervisor(),
  keyword()
) :: Kino.Mermaid.t()

Generates a visualization of a supervision tree.

The provided supervisor can be either a named process or a PID. The supervision tree is displayed with solid lines denoting supervisor-worker relationships and dotted lines denoting links between processes. The graph rendering supports the following options:

options

Options

  • :direction - defines the direction of the graph visual. The value can either be :top_down or :left_right. Defaults to :top_down.

examples

Examples

With a supervisor definition like so:

{:ok, supervisor_pid} =
  Supervisor.start_link(
    [
      {DynamicSupervisor, strategy: :one_for_one, name: MyApp.DynamicSupervisor},
      {Agent, fn -> [] end}
    ],
    strategy: :one_for_one,
    name: MyApp.Supervisor
  )

Enum.each(1..3, fn _ ->
  DynamicSupervisor.start_child(MyApp.DynamicSupervisor, {Agent, fn -> %{} end})
end)

You can then call Kino.Process.sup_tree/1 to render the supervision tree using using the PID of the supervisor.

Kino.Process.sup_tree(supervisor_pid)

You can also render the supervisor by passing the name of the supervisor if the supervisor was started with a name.

Kino.Process.sup_tree(MyApp.Supervisor)

You can also change the direction of the rendering by calling Kino.Process.sup_tree/2 with the :direction option.

Kino.Process.sup_tree(MyApp.Supervisor, direction: :left_right)