Provides before/after execution hooks for FunConfig.

Hooks allow users to run custom code before and/or after a function is executed through the API. They are configured per-function via the before_execute and after_execute fields in FunConfig.

Hook Signature

Hooks are specified as MFA tuples:

• {module, function} — Calls module.function(request, fun_config) for before, or module.function(request, fun_config, result) for after.
• {module, function, extra_args} — Appends extra arguments after the standard ones.

Before execute

Must return one of:

• {:ok, request, fun_config} — Proceed with (possibly modified) request/config.
• {:error, reason} — Abort execution and return an error response.

After execute

Must return the (possibly modified) result. Any other return value is ignored and the original result is preserved.

Telemetry

Hooks emit telemetry events at:

• [:phoenix_gen_api, :hook, :before, :start]
• [:phoenix_gen_api, :hook, :before, :stop]
• [:phoenix_gen_api, :hook, :before, :exception]
• [:phoenix_gen_api, :hook, :after, :start]
• [:phoenix_gen_api, :hook, :after, :stop]
• [:phoenix_gen_api, :hook, :after, :exception]

Examples

# In your FunConfig:
%FunConfig{
  before_execute: {MyApp.Hooks, :validate_quota},
  after_execute: {MyApp.Hooks, :log_response}
}

# Hook module:
defmodule MyApp.Hooks do
  alias PhoenixGenApi.Structs.{Request, FunConfig}

  def validate_quota(request, fun_config) do
    # Check rate quota, enrich request, etc.
    {:ok, request, fun_config}
  end

  def log_response(request, fun_config, result) do
    # Log metrics, audit trail, etc.
    result
  end
end