anything-llm/server/utils/AiProviders/native/index.js

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const os = require("os");
const fs = require("fs");
const path = require("path");
const { NativeEmbedder } = require("../../EmbeddingEngines/native");
const { HumanMessage, SystemMessage, AIMessage } = require("langchain/schema");
const { chatPrompt } = require("../../chats");
// Docs: https://api.js.langchain.com/classes/chat_models_llama_cpp.ChatLlamaCpp.html
const ChatLlamaCpp = (...args) =>
import("langchain/chat_models/llama_cpp").then(
({ ChatLlamaCpp }) => new ChatLlamaCpp(...args)
);
class NativeLLM {
constructor(embedder = null) {
if (!process.env.NATIVE_LLM_MODEL_PREF)
throw new Error("No local Llama model was set.");
this.model = process.env.NATIVE_LLM_MODEL_PREF || null;
this.limits = {
history: this.promptWindowLimit() * 0.15,
system: this.promptWindowLimit() * 0.15,
user: this.promptWindowLimit() * 0.7,
};
this.embedder = embedder || new NativeEmbedder();
this.cacheDir = path.resolve(
process.env.STORAGE_DIR
? path.resolve(process.env.STORAGE_DIR, "models", "downloaded")
: path.resolve(__dirname, `../../../storage/models/downloaded`)
);
// Set ENV for if llama.cpp needs to rebuild at runtime and machine is not
// running Apple Silicon.
process.env.NODE_LLAMA_CPP_METAL = os
.cpus()
.some((cpu) => cpu.model.includes("Apple"));
// Make directory when it does not exist in existing installations
if (!fs.existsSync(this.cacheDir)) fs.mkdirSync(this.cacheDir);
}
async #initializeLlamaModel(temperature = 0.7) {
const modelPath = path.join(this.cacheDir, this.model);
if (!fs.existsSync(modelPath))
throw new Error(
`Local Llama model ${this.model} was not found in storage!`
);
global.llamaModelInstance = await ChatLlamaCpp({
modelPath,
temperature,
useMlock: true,
});
}
// If the model has been loaded once, it is in the memory now
// so we can skip re-loading it and instead go straight to inference.
// Note: this will break temperature setting hopping between workspaces with different temps.
async llamaClient({ temperature = 0.7 }) {
if (global.llamaModelInstance) return global.llamaModelInstance;
await this.#initializeLlamaModel(temperature);
return global.llamaModelInstance;
}
streamingEnabled() {
return "streamChat" in this && "streamGetChatCompletion" in this;
}
// Ensure the user set a value for the token limit
// and if undefined - assume 4096 window.
// DEV: Currently this ENV is not configurable.
promptWindowLimit() {
const limit = process.env.NATIVE_LLM_MODEL_TOKEN_LIMIT || 4096;
if (!limit || isNaN(Number(limit)))
throw new Error("No NativeAI token context limit was set.");
return Number(limit);
}
constructPrompt({
systemPrompt = "",
contextTexts = [],
chatHistory = [],
userPrompt = "",
}) {
const prompt = {
role: "system",
content: `${systemPrompt}
Context:
${contextTexts
.map((text, i) => {
return `[CONTEXT ${i}]:\n${text}\n[END CONTEXT ${i}]\n\n`;
})
.join("")}`,
};
return [prompt, ...chatHistory, { role: "user", content: userPrompt }];
}
async isSafe(_input = "") {
// Not implemented so must be stubbed
return { safe: true, reasons: [] };
}
async sendChat(chatHistory = [], prompt, workspace = {}, rawHistory = []) {
try {
const messages = await this.compressMessages(
{
systemPrompt: chatPrompt(workspace),
userPrompt: prompt,
chatHistory,
},
rawHistory
);
const model = await this.llamaClient({
temperature: Number(workspace?.openAiTemp ?? 0.7),
});
const response = await model.call(messages);
return response.content;
} catch (error) {
throw new Error(
`NativeLLM::createChatCompletion failed with: ${error.message}`
);
}
}
async streamChat(chatHistory = [], prompt, workspace = {}, rawHistory = []) {
const model = await this.llamaClient({
temperature: Number(workspace?.openAiTemp ?? 0.7),
});
const messages = await this.compressMessages(
{
systemPrompt: chatPrompt(workspace),
userPrompt: prompt,
chatHistory,
},
rawHistory
);
const responseStream = await model.stream(messages);
return responseStream;
}
async getChatCompletion(messages = null, { temperature = 0.7 }) {
const model = await this.llamaClient({ temperature });
const response = await model.call(messages);
return response.content;
}
async streamGetChatCompletion(messages = null, { temperature = 0.7 }) {
const model = await this.llamaClient({ temperature });
const responseStream = await model.stream(messages);
return responseStream;
}
// Simple wrapper for dynamic embedder & normalize interface for all LLM implementations
async embedTextInput(textInput) {
return await this.embedder.embedTextInput(textInput);
}
async embedChunks(textChunks = []) {
return await this.embedder.embedChunks(textChunks);
}
async compressMessages(promptArgs = {}, rawHistory = []) {
const { messageArrayCompressor } = require("../../helpers/chat");
const messageArray = this.constructPrompt(promptArgs);
const compressedMessages = await messageArrayCompressor(
this,
messageArray,
rawHistory
);
return this.convertToLangchainPrototypes(compressedMessages);
}
convertToLangchainPrototypes(chats = []) {
const langchainChats = [];
for (const chat of chats) {
switch (chat.role) {
case "system":
langchainChats.push(new SystemMessage({ content: chat.content }));
break;
case "user":
langchainChats.push(new HumanMessage({ content: chat.content }));
break;
case "assistant":
langchainChats.push(new AIMessage({ content: chat.content }));
break;
default:
break;
}
}
return langchainChats;
}
}
module.exports = {
NativeLLM,
};