Module: Legion::LLM::API::OpenAI::ChatCompletions

Extended by:
Legion::Logging::Helper
Defined in:
lib/legion/llm/api/openai/chat_completions.rb

Class Method Summary collapse

Class Method Details

.build_handler ⇒ Object

rubocop:disable Metrics/MethodLength,Metrics/AbcSize



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# File 'lib/legion/llm/api/openai/chat_completions.rb', line 25

def self.build_handler # rubocop:disable Metrics/MethodLength,Metrics/AbcSize
  proc do # rubocop:disable Metrics/BlockLength
    require_llm!
    body = parse_request_body

    unless body[:messages].is_a?(Array) && !body[:messages].empty?
      halt 400, { 'Content-Type' => 'application/json' },
           Legion::JSON.dump({ error: { message: 'messages is required and must be a non-empty array',
                                        type: 'invalid_request_error', param: 'messages', code: nil } })
    end

    request_id = SecureRandom.uuid
    normalized = Legion::LLM::API::Translators::OpenAIRequest.normalize(body)
    model = normalized[:model] || Legion::LLM::Settings.value(:default_model) || 'default'
    streaming = normalized[:stream] == true

    log.info("[llm][api][openai][chat_completions] action=accepted request_id=#{request_id} model=#{model} stream=#{streaming}")

    tool_declarations = Legion::LLM::API::OpenAI::ChatCompletions.build_openai_tool_classes(normalized[:tools])

    effective_caller = build_server_caller(source: 'openai_compat', path: request.path, env: env)

    inference_request = Legion::LLM::Inference::Request.build(
      id:       request_id,
      messages: normalized[:messages],
      system:   normalized[:system],
      routing:  { model: model },
      tools:    tool_declarations,
      caller:   effective_caller,
      stream:   streaming,
      cache:    { strategy: :default, cacheable: true }
    )

    executor = Legion::LLM::Inference::Executor.new(inference_request)

    if streaming
      content_type 'text/event-stream'
      headers 'Cache-Control'     => 'no-cache',
              'Connection'        => 'keep-alive',
              'X-Accel-Buffering' => 'no'

      stream do |out|
        pipeline_response = executor.call_stream do |chunk|
          text = chunk.respond_to?(:content) ? chunk.content.to_s : chunk.to_s
          next if text.empty?

          chunk_obj = Legion::LLM::API::Translators::OpenAIResponse.format_stream_chunk(
            text, model: model, request_id: request_id
          )
          out << "data: #{Legion::JSON.dump(chunk_obj)}\n\n"
        end

        routing = pipeline_response.routing || {}
        final_model = (routing[:model] || routing['model'] || model).to_s
        tool_calls = Legion::LLM::API::Translators::OpenAIResponse.build_tool_calls(pipeline_response)

        tool_calls.each_with_index do |tool_call, index|
          out << "data: #{Legion::JSON.dump(Legion::LLM::API::Translators::OpenAIResponse.format_stream_tool_call_chunk(
                                              tool_call,
                                              model:      final_model,
                                              request_id: request_id,
                                              index:      index
                                            ))}\n\n"
        end

        done_chunk = Legion::LLM::API::Translators::OpenAIResponse.format_stream_chunk(
          nil,
          model:         final_model,
          request_id:    request_id,
          finish_reason: tool_calls.empty? ? 'stop' : 'tool_calls',
          usage:         {
            prompt_tokens:     Legion::LLM::API::Translators::OpenAIResponse.extract_token_count(pipeline_response.tokens, :input),
            completion_tokens: Legion::LLM::API::Translators::OpenAIResponse.extract_token_count(pipeline_response.tokens, :output),
            total_tokens:      Legion::LLM::API::Translators::OpenAIResponse.extract_token_count(pipeline_response.tokens, :input).to_i +
                               Legion::LLM::API::Translators::OpenAIResponse.extract_token_count(pipeline_response.tokens, :output).to_i
          }
        )
        out << "data: #{Legion::JSON.dump(done_chunk)}\n\n"
        out << "data: [DONE]\n\n"

        log.info("[llm][api][openai][chat_completions] action=stream_complete request_id=#{request_id} model=#{final_model}")
      rescue StandardError => e
        handle_exception(e, level: :error, handled: false, operation: 'llm.api.openai.chat_completions.stream', request_id: request_id)
        out << "data: #{Legion::JSON.dump({ error: { message: e.message, type: 'server_error' } })}\n\n"
        out << "data: [DONE]\n\n"
      end
    else
      pipeline_response = executor.call
      response_body = Legion::LLM::API::Translators::OpenAIResponse.format_chat_completion(
        pipeline_response, model: model, request_id: request_id
      )

      log.info("[llm][api][openai][chat_completions] action=complete request_id=#{request_id} model=#{response_body[:model]}")
      content_type :json
      status 200
      Legion::JSON.dump(response_body)
    end
  rescue Legion::LLM::AuthError => e
    handle_exception(e, level: :error, handled: true, operation: 'llm.api.openai.chat_completions.auth')
    halt 401, { 'Content-Type' => 'application/json' },
         Legion::JSON.dump({ error: { message: e.message, type: 'authentication_error' } })
  rescue Legion::LLM::RateLimitError => e
    handle_exception(e, level: :warn, handled: true, operation: 'llm.api.openai.chat_completions.rate_limit')
    halt 429, { 'Content-Type' => 'application/json' },
         Legion::JSON.dump({ error: { message: e.message, type: 'requests', code: 'rate_limit_exceeded' } })
  rescue Legion::LLM::ProviderDown, Legion::LLM::ProviderError => e
    handle_exception(e, level: :error, handled: true, operation: 'llm.api.openai.chat_completions.provider')
    halt 502, { 'Content-Type' => 'application/json' },
         Legion::JSON.dump({ error: { message: e.message, type: 'server_error' } })
  rescue StandardError => e
    handle_exception(e, level: :error, handled: false, operation: 'llm.api.openai.chat_completions')
    halt 500, { 'Content-Type' => 'application/json' },
         Legion::JSON.dump({ error: { message: e.message, type: 'server_error' } })
  end
end

.build_openai_tool_classes(tools) ⇒ Object 



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# File 'lib/legion/llm/api/openai/chat_completions.rb', line 141

def self.build_openai_tool_classes(tools)
  return [] if tools.nil? || !tools.is_a?(Array) || tools.empty?

  tools.filter_map do |tool|
    t = nil
    t = tool.respond_to?(:transform_keys) ? tool.transform_keys(&:to_sym) : tool
    next unless t[:name].to_s.length.positive?

    Legion::LLM::Types::ToolDefinition.build(
      name:        t[:name].to_s,
      description: t[:description].to_s,
      parameters:  t[:parameters] || {},
      source:      { type: :client, executable: true }
    )
  rescue StandardError => e
    tool_name = t.is_a?(Hash) ? t[:name] : nil
    handle_exception(e, level: :warn, handled: true, operation: "llm.api.openai.build_tool.#{tool_name || 'unknown'}")
    nil
  end
end

.registered(app) ⇒ Object 



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# File 'lib/legion/llm/api/openai/chat_completions.rb', line 14

def self.registered(app)
  log.debug('[llm][api][openai][chat_completions] registering POST /v1/chat/completions + /api/llm/inference/v1/chat/completions')

  handler = build_handler

  app.post('/v1/chat/completions') { instance_exec(&handler) }
  app.post('/api/llm/inference/v1/chat/completions') { instance_exec(&handler) }

  log.debug('[llm][api][openai][chat_completions] routes registered')
end