Elixir Playbook
Setup
Mix.install([
{:jason, "~> 1.4"},
{:kino, "~> 0.11.0"},
{:explorer, "~> 0.7.0"},
{:mox, "~> 1.0"},
{:telemetry, "~> 1.0"}
])
defmodule Playbook do
def strategies do
%{
"state_management" => %{
name: "State Management Strategies",
scenarios: [
%{
name: "Simple State",
when_to_use: "Single process, basic state needs",
implementation: :genserver,
code: """
defmodule SimpleState do
use GenServer
def start_link(initial_state) do
GenServer.start_link(__MODULE__, initial_state)
end
def get(pid), do: GenServer.call(pid, :get)
def update(pid, new_state), do: GenServer.cast(pid, {:update, new_state})
@impl true
def init(state), do: {:ok, state}
@impl true
def handle_call(:get, _from, state), do: {:reply, state, state}
@impl true
def handle_cast({:update, new_state}, _state), do: {:noreply, new_state}
end
""",
test: """
defmodule SimpleStateTest do
use ExUnit.Case
test "maintains state" do
{:ok, pid} = SimpleState.start_link(%{count: 0})
assert %{count: 0} = SimpleState.get(pid)
SimpleState.update(pid, %{count: 1})
assert %{count: 1} = SimpleState.get(pid)
end
end
"""
},
%{
name: "Distributed State",
when_to_use: "Multiple nodes, replicated state",
implementation: :horde,
code: """
defmodule DistributedState do
use Horde.DynamicSupervisor
def start_link(_) do
Horde.DynamicSupervisor.start_link(__MODULE__, :ok, name: __MODULE__)
end
def init(:ok) do
Horde.DynamicSupervisor.init(
strategy: :one_for_one,
members: :auto
)
end
end
"""
}
]
},
"event_handling" => %{
name: "Event Handling Patterns",
scenarios: [
%{
name: "Event Broadcasting",
when_to_use: "System-wide notifications",
implementation: :pubsub,
code: """
defmodule EventBroadcaster do
def broadcast(topic, event) do
Phoenix.PubSub.broadcast(MyApp.PubSub, topic, event)
end
def subscribe(topic) do
Phoenix.PubSub.subscribe(MyApp.PubSub, topic)
end
end
"""
}
]
},
"fault_tolerance" => %{
name: "Fault Tolerance Patterns",
scenarios: [
%{
name: "Circuit Breaker",
when_to_use: "Protect against cascading failures",
implementation: :circuit_breaker,
code: """
defmodule CircuitBreaker do
use GenServer
defstruct [:name, :threshold, :timeout, failures: 0, state: :closed]
def handle_call({:execute, action}, _from, %{state: :open} = state) do
{:reply, {:error, :circuit_open}, state}
end
def handle_call({:execute, action}, _from, state) do
case action.() do
{:ok, result} ->
{:reply, {:ok, result}, %{state | failures: 0}}
{:error, _reason} ->
new_failures = state.failures + 1
new_state = if new_failures >= state.threshold,
do: %{state | state: :open},
else: %{state | failures: new_failures}
{:reply, {:error, :operation_failed}, new_state}
end
end
end
"""
}
]
}
}
end
endStrategy Explorer
inputs = [
category: Kino.Input.select("Strategy Category", [
"State Management": "state_management",
"Event Handling": "event_handling",
"Fault Tolerance": "fault_tolerance"
]),
implementation: Kino.Input.select("Implementation", [
"All": "all",
"GenServer": "genserver",
"PubSub": "pubsub",
"Circuit Breaker": "circuit_breaker",
"Horde": "horde"
])
]
form = Kino.Control.form(inputs, submit: "Show Strategy")
frame = Kino.Frame.new()
Kino.listen(form, fn %{data: %{category: category, implementation: impl}} ->
strategy = Playbook.strategies()[category]
scenarios = if impl == "all" do
strategy.scenarios
else
Enum.filter(strategy.scenarios, & &1.implementation == String.to_atom(impl))
end
content = Kino.Layout.grid([
Kino.Markdown.new("""
## #{strategy.name}
#{Enum.map_join(scenarios, "\n\n", fn scenario -> """
### #{scenario.name}
**When to use:** #{scenario.when_to_use}
#### Implementation:
```elixir
#{scenario.code}
```
#{if Map.has_key?(scenario, :test), do: """
#### Tests:
```elixir
#{scenario.test}
```
""", else: ""}
""" end)}
""")
])
Kino.Frame.render(frame, content)
end)
frame## Pattern Composer
composer_inputs = [
patterns: Kino.Input.select(
"Select Patterns",
[
"State Management": "state",
"Event Broadcasting": "events",
"Circuit Breaker": "circuit_breaker",
"Telemetry": "telemetry"
],
multiple: true
),
module_name: Kino.Input.text("Module Name"),
options: Kino.Input.text("Additional Options (comma-separated)")
]
composer_form = Kino.Control.form(composer_inputs, submit: "Compose Module")
composer_frame = Kino.Frame.new()
defmodule PatternComposer do
def compose(patterns, module_name, options) do
opts = String.split(options, ",", trim: true)
"""
defmodule #{module_name} do
#{generate_uses(patterns)}
#{generate_struct(patterns)}
#{generate_client_api(patterns)}
#{generate_callbacks(patterns)}
#{generate_private_functions(patterns, opts)}
end
"""
end
defp generate_uses(patterns) do
uses = []
uses = if "state" in patterns, do: ["use GenServer" | uses], else: uses
uses = if "telemetry" in patterns, do: ["require Logger" | uses], else: uses
Enum.join(uses, "\n ")
end
defp generate_struct(patterns) do
if "state" in patterns do
"""
defstruct [
:name,
:status,
metadata: %{},
#{if "circuit_breaker" in patterns, do: "failures: 0,\n state: :closed,", else: ""}
#{if "events" in patterns, do: "subscribers: [],", else: ""}
]
"""
else
""
end
end
# Add more generation functions...
end
Kino.listen(composer_form, fn %{data: %{patterns: patterns, module_name: name, options: opts}} ->
code = PatternComposer.compose(patterns, name, opts)
content = Kino.Layout.grid([
Kino.Markdown.new("""
### Composed Module
```elixir
#{code}
```
""")
])
Kino.Frame.render(composer_frame, content)
end)
composer_frame## Implementation Guides
guide_inputs = [
pattern: Kino.Input.select("Select Pattern", [
"GenServer Basics": "genserver_basic",
"Advanced State Management": "state_advanced",
"Event Systems": "events",
"Fault Tolerance": "fault_tolerance"
])
]
guide_form = Kino.Control.form(guide_inputs, submit: "Show Guide")
guide_frame = Kino.Frame.new()
defmodule ImplementationGuides do
def get_guide(pattern) do
guides()[pattern]
end
def guides do
%{
"genserver_basic" => %{
title: "GenServer Basics",
steps: [
%{
title: "1. Define the Module",
code: "defmodule MyServer do\n use GenServer\nend",
explanation: "Start by defining your module and using GenServer"
},
%{
title: "2. Implement start_link",
code: """
def start_link(opts \\\\ []) do
GenServer.start_link(__MODULE__, :ok, opts)
end
""",
explanation: "This is how you'll start your GenServer"
},
# Add more steps...
]
}
# Add more guides...
}
end
end
Kino.listen(guide_form, fn %{data: %{pattern: pattern}} ->
guide = ImplementationGuides.get_guide(pattern)
content = Kino.Layout.grid([
Kino.Markdown.new("""
## #{guide.title}
#{Enum.map_join(guide.steps, "\n\n", fn step -> """
### #{step.title}
#{step.explanation}
```elixir
#{step.code}
```
""" end)}
""")
])
Kino.Frame.render(guide_frame, content)
end)
guide_frameThis playbook provides:
1. Strategy Explorer: - Browse different implementation strategies - See when to use each approach - View example code and tests
2. Pattern Composer: - Combine multiple patterns - Generate complete modules - Customize implementations
3. Implementation Guides: - Step-by-step instructions - Best practices - Common pitfalls to avoid
Would you like me to expand any particular section or add more patterns?