Module: Legion::API::Routes::LexDispatch

Defined in:
lib/legion/api/lex_dispatch.rb

Class Method Summary collapse

Class Method Details

.build_envelope(request) ⇒ Object 



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# File 'lib/legion/api/lex_dispatch.rb', line 174

def self.build_envelope(request)
  task_id         = parse_header_integer(request.env['HTTP_X_LEGION_TASK_ID'])
  conversation_id = request.env['HTTP_X_LEGION_CONVERSATION_ID'] || ::SecureRandom.uuid
  parent_id       = parse_header_integer(request.env['HTTP_X_LEGION_PARENT_ID'])
  master_id       = parse_header_integer(request.env['HTTP_X_LEGION_MASTER_ID'])
  chain_id        = parse_header_integer(request.env['HTTP_X_LEGION_CHAIN_ID'])
  debug           = request.env['HTTP_X_LEGION_DEBUG'] == 'true'

  {
    task_id:         task_id,
    conversation_id: conversation_id,
    parent_id:       parent_id,
    master_id:       master_id || task_id,
    chain_id:        chain_id,
    debug:           debug
  }.compact
end

.definition_blocks_remote?(entry) ⇒ Boolean

Returns true when the definition-level flag explicitly disables remote dispatch. Extension-level gate (entry module) takes precedence over definition flag.

Returns:

  • (Boolean) 


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# File 'lib/legion/api/lex_dispatch.rb', line 209

def self.definition_blocks_remote?(entry)
  defn = entry[:definition]
  return false if defn.nil?

  defn[:remote_invocable] == false
end

.dispatch_async_amqp(exchange_name, routing_key, payload, envelope) ⇒ Object

Publish an async AMQP message for remote dispatch (fire-and-forget).



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# File 'lib/legion/api/lex_dispatch.rb', line 217

def self.dispatch_async_amqp(exchange_name, routing_key, payload, envelope)
  return unless defined?(Legion::Transport) &&
                Legion::Transport.respond_to?(:connected?) &&
                Legion::Transport.connected?

  channel = Legion::Transport.channel
  exchange = channel.exchange(exchange_name, type: :topic, durable: true, passive: true)
  message = Legion::JSON.dump(payload.merge(envelope))
  exchange.publish(message, routing_key: routing_key, content_type: 'application/json', persistent: true)
rescue StandardError => e
  Legion::Logging.warn "[LexDispatch] async AMQP publish failed: #{e.message}" if defined?(Legion::Logging)
  raise
end

.dispatch_hook(context, request, entry, payload, envelope) ⇒ Object 



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# File 'lib/legion/api/lex_dispatch.rb', line 241

def self.dispatch_hook(context, request, entry, payload, envelope)
  hook = entry[:runner_class].new

  # Re-read body for verification (request body was already read for payload parsing)
  request.body.rewind
  body_for_verify = request.body.read
  request.body.rewind

  unless hook.verify(request.env, body_for_verify)
    context.halt 401, Legion::JSON.dump({
                                          task_id: nil, conversation_id: nil, status: 'failed',
                                          error: { code: 401, message: 'hook verification failed' }
                                        })
  end

  function = hook.route(request.env, payload)
  unless function
    context.halt 422, Legion::JSON.dump({
                                          task_id: nil, conversation_id: nil, status: 'failed',
                                          error: { code: 422, message: 'hook could not route this event' }
                                        })
  end

  # If the hook defines the routed function as an instance method, call it to transform
  if hook.class.method_defined?(function) && hook.class.instance_method(function).owner != Legion::Extensions::Hooks::Base
    transformed = hook.send(function, payload)
    payload = transformed if transformed
  end

  runner = hook.runner_class || entry[:runner_class]

  result = Legion::Ingress.run(
    payload:       payload.merge(envelope.slice(:task_id, :conversation_id, :parent_id, :master_id, :chain_id)),
    runner_class:  runner,
    function:      function,
    source:        'hook',
    check_subtask: true,
    generate_task: true
  )

  response_body = envelope.merge(
    status: result[:status],
    result: result[:result]
  ).compact

  Legion::JSON.dump(response_body)
end

.dispatch_request(context, request, params) ⇒ Object

rubocop:disable Metrics/MethodLength,Metrics/AbcSize,Metrics/CyclomaticComplexity



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# File 'lib/legion/api/lex_dispatch.rb', line 67

def self.dispatch_request(context, request, params) # rubocop:disable Metrics/MethodLength,Metrics/AbcSize,Metrics/CyclomaticComplexity
  content_type = 'application/json'
  context.content_type content_type

  entry = Legion::API.router.find_extension_route(
    params[:lex_name], params[:component_type],
    params[:component_name], params[:method_name]
  )

  unless entry
    route_key = "#{params[:lex_name]}/#{params[:component_type]}/#{params[:component_name]}/#{params[:method_name]}"
    context.halt 404, Legion::JSON.dump({
                                          task_id:         nil,
                                          conversation_id: nil,
                                          status:          'failed',
                                          error:           { code: 404, message: "no route registered for '#{route_key}'" }
                                        })
  end

  envelope = build_envelope(request)

  payload = begin
    body = request.body.read
    body.nil? || body.empty? ? {} : Legion::JSON.load(body)
  rescue StandardError => e
    Legion::Logging.warn "[LexDispatch] invalid JSON body: #{e.message}" if defined?(Legion::Logging)
    context.halt 400, Legion::JSON.dump({
                                          task_id:         nil,
                                          conversation_id: nil,
                                          status:          'failed',
                                          error:           { code: 400, message: 'request body is not valid JSON' }
                                        })
  end

  # Remote dispatch: when the runner class is not loaded locally, forward via AMQP
  unless extension_loaded_locally?(entry)
    if definition_blocks_remote?(entry)
      context.halt 403, Legion::JSON.dump({
                                            task_id:         nil,
                                            conversation_id: nil,
                                            status:          'failed',
                                            error:           { code: 403, message: 'Method not remotely invocable' }
                                          })
    end

    exchange_name = entry[:amqp_prefix].to_s.then { |p| p.empty? ? "lex.#{entry[:lex_name]}" : p }
    routing_key   = "#{exchange_name}.#{entry[:component_type]}.#{entry[:component_name]}.#{entry[:method_name]}"

    if request.env['HTTP_X_LEGION_SYNC'] == 'true'
      result = Legion::API::SyncDispatch.dispatch(exchange_name, routing_key, payload, envelope)
      return Legion::JSON.dump(result)
    else
      unless defined?(Legion::Transport) &&
             Legion::Transport.respond_to?(:connected?) &&
             Legion::Transport.connected?
        context.halt 503, Legion::JSON.dump({
                                              task_id:         nil,
                                              conversation_id: nil,
                                              status:          'failed',
                                              error:           { code: 503, message: 'Transport not available' }
                                            })
      end

      dispatch_async_amqp(exchange_name, routing_key, payload, envelope)
      context.status 202
      return Legion::JSON.dump(envelope.merge(status: 'queued'))
    end
  end

  # Hook-aware dispatch: when component_type is 'hooks' and the runner class
  # is a Hooks::Base subclass, apply verify -> route -> transform -> Ingress.
  return dispatch_hook(context, request, entry, payload, envelope) if entry[:component_type] == 'hooks' && hook_base_subclass?(entry[:runner_class])

  result = Legion::Ingress.run(
    payload:       payload.merge(envelope.slice(:task_id, :conversation_id, :parent_id, :master_id, :chain_id)),
    runner_class:  entry[:runner_class],
    function:      entry[:method_name].to_sym,
    source:        'lex_dispatch',
    generate_task: true
  )

  response_body = envelope.merge(
    status: result[:status],
    result: result[:result]
  ).compact

  Legion::JSON.dump(response_body)
rescue StandardError => e
  route_key = "#{params[:lex_name]}/#{params[:component_type]}/#{params[:component_name]}/#{params[:method_name]}"
  Legion::Logging.log_exception(e, payload_summary: "LexDispatch POST #{route_key}", component_type: :api)
  context.status 500
  Legion::JSON.dump({
                      task_id:         nil,
                      conversation_id: nil,
                      status:          'failed',
                      error:           { code: 500, message: e.message }
                    })
end

.extension_loaded_locally?(entry) ⇒ Boolean

Returns true when the runner class referenced by the route entry is available in the current process (i.e. the extension is loaded locally).

Returns:

  • (Boolean) 


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# File 'lib/legion/api/lex_dispatch.rb', line 194

def self.extension_loaded_locally?(entry)
  runner_class = entry[:runner_class]
  return false if runner_class.nil? || runner_class.to_s.empty?

  # Try constant lookup — safe because runner_class is from the route registry,
  # not from user input.
  parts = runner_class.to_s.split('::').reject(&:empty?)
  parts.reduce(Object) { |mod, name| mod.const_get(name, false) }
  true
rescue NameError, TypeError
  false
end

.hook_base_subclass?(runner_class) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/legion/api/lex_dispatch.rb', line 231

def self.hook_base_subclass?(runner_class)
  return false unless defined?(Legion::Extensions::Hooks::Base)
  return false if runner_class.nil?

  klass = runner_class.is_a?(Class) ? runner_class : Kernel.const_get(runner_class.to_s)
  klass < Legion::Extensions::Hooks::Base
rescue NameError, TypeError
  false
end

.parse_header_integer(value) ⇒ Object 



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# File 'lib/legion/api/lex_dispatch.rb', line 166

def self.parse_header_integer(value)
  return nil if value.nil?

  Integer(value)
rescue ArgumentError, TypeError
  nil
end

.register_discovery(app) ⇒ Object

Discovery endpoints (GET)



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# File 'lib/legion/api/lex_dispatch.rb', line 15

def self.register_discovery(app)
  # GET /api/extensions/index — list all extensions
  app.get '/api/extensions/index' do
    content_type :json
    names = Legion::API.router.extension_names
    Legion::JSON.dump({ extensions: names })
  end

  # GET /api/extensions/:lex_name/:component_type/:component_name/:method_name — full contract
  app.get '/api/extensions/:lex_name/:component_type/:component_name/:method_name' do
    content_type :json
    entry = Legion::API.router.find_extension_route(
      params[:lex_name], params[:component_type],
      params[:component_name], params[:method_name]
    )
    unless entry
      halt 404, Legion::JSON.dump({
                                    task_id:         nil,
                                    conversation_id: nil,
                                    status:          'failed',
                                    error:           { code: 404, message: 'route not found' }
                                  })
    end

    amqp_pfx = entry[:amqp_prefix].to_s.then { |p| p.empty? ? "lex.#{params[:lex_name]}" : p }
    response = {
      extension:      params[:lex_name],
      component_type: params[:component_type],
      component:      params[:component_name],
      method:         params[:method_name],
      definition:     entry[:definition],
      amqp:           {
        exchange:    amqp_pfx,
        routing_key: "#{amqp_pfx}.#{params[:component_type]}.#{params[:component_name]}.#{params[:method_name]}"
      }
    }
    if params[:component_type] == 'hooks'
      response[:hook_endpoint] =
        "/api/extensions/#{params[:lex_name]}/hooks/#{params[:component_name]}/#{params[:method_name]}"
    end
    Legion::JSON.dump(response)
  end
end

.register_dispatch(app) ⇒ Object

Dispatch endpoint (POST)



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# File 'lib/legion/api/lex_dispatch.rb', line 60

def self.register_dispatch(app)
  dispatcher = method(:dispatch_request)
  app.post '/api/extensions/:lex_name/:component_type/:component_name/:method_name' do
    dispatcher.call(self, request, params)
  end
end

.registered(app) ⇒ Object 



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# File 'lib/legion/api/lex_dispatch.rb', line 9

def self.registered(app)
  register_discovery(app)
  register_dispatch(app)
end