fireworks.ts

import type { BaseChatModelParams } from "@langchain/core/language_models/chat_models";
import {
  type OpenAIClient,
  type ChatOpenAICallOptions,
  type OpenAIChatInput,
  type OpenAICoreRequestOptions,
  ChatOpenAI,
} from "@langchain/openai";

import { getEnvironmentVariable } from "@langchain/core/utils/env";

type FireworksUnsupportedArgs =
  | "frequencyPenalty"
  | "presencePenalty"
  | "logitBias"
  | "functions";

type FireworksUnsupportedCallOptions = "functions" | "function_call" | "tools";

export type ChatFireworksCallOptions = Partial<
  Omit<ChatOpenAICallOptions, FireworksUnsupportedCallOptions>
>;

/**
 * Wrapper around Fireworks API for large language models fine-tuned for chat
 *
 * Fireworks API is compatible to the OpenAI API with some limitations described in
 * https://readme.fireworks.ai/docs/openai-compatibility.
 *
 * To use, you should have the `openai` package installed and
 * the `FIREWORKS_API_KEY` environment variable set.
 * @example
 * ```typescript
 * const model = new ChatFireworks({
 *   temperature: 0.9,
 *   fireworksApiKey: "YOUR-API-KEY",
 * });
 *
 * const response = await model.invoke("Hello, how are you?");
 * console.log(response);
 * ```
 */
export class ChatFireworks extends ChatOpenAI<ChatFireworksCallOptions> {
  static lc_name() {
    return "ChatFireworks";
  }

  _llmType() {
    return "fireworks";
  }

  get lc_secrets(): { [key: string]: string } | undefined {
    return {
      fireworksApiKey: "FIREWORKS_API_KEY",
    };
  }

  lc_serializable = true;

  fireworksApiKey?: string;

  constructor(
    fields?: Partial<
      Omit<OpenAIChatInput, "openAIApiKey" | FireworksUnsupportedArgs>
    > &
      BaseChatModelParams & { fireworksApiKey?: string }
  ) {
    const fireworksApiKey =
      fields?.fireworksApiKey || getEnvironmentVariable("FIREWORKS_API_KEY");

    if (!fireworksApiKey) {
      throw new Error(
        `Fireworks API key not found. Please set the FIREWORKS_API_KEY environment variable or provide the key into "fireworksApiKey"`
      );
    }

    super({
      ...fields,
      modelName:
        fields?.modelName || "accounts/fireworks/models/llama-v2-13b-chat",
      openAIApiKey: fireworksApiKey,
      configuration: {
        baseURL: "https://api.fireworks.ai/inference/v1",
      },
    });

    this.fireworksApiKey = fireworksApiKey;
  }

  toJSON() {
    const result = super.toJSON();

    if (
      "kwargs" in result &&
      typeof result.kwargs === "object" &&
      result.kwargs != null
    ) {
      delete result.kwargs.openai_api_key;
      delete result.kwargs.configuration;
    }

    return result;
  }

  async completionWithRetry(
    request: OpenAIClient.Chat.ChatCompletionCreateParamsStreaming,
    options?: OpenAICoreRequestOptions
  ): Promise<AsyncIterable<OpenAIClient.Chat.Completions.ChatCompletionChunk>>;

  async completionWithRetry(
    request: OpenAIClient.Chat.ChatCompletionCreateParamsNonStreaming,
    options?: OpenAICoreRequestOptions
  ): Promise<OpenAIClient.Chat.Completions.ChatCompletion>;

  /**
   * Calls the Fireworks API with retry logic in case of failures.
   * @param request The request to send to the Fireworks API.
   * @param options Optional configuration for the API call.
   * @returns The response from the Fireworks API.
   */
  async completionWithRetry(
    request:
      | OpenAIClient.Chat.ChatCompletionCreateParamsStreaming
      | OpenAIClient.Chat.ChatCompletionCreateParamsNonStreaming,
    options?: OpenAICoreRequestOptions
  ): Promise<
    | AsyncIterable<OpenAIClient.Chat.Completions.ChatCompletionChunk>
    | OpenAIClient.Chat.Completions.ChatCompletion
  > {
    delete request.frequency_penalty;
    delete request.presence_penalty;
    delete request.logit_bias;
    delete request.functions;

    if (request.stream === true) {
      return super.completionWithRetry(request, options);
    }

    return super.completionWithRetry(request, options);
  }
}