import json import multiprocessing from threading import Lock from functools import partial from typing import Iterator, List, Optional, Union, Dict from typing_extensions import TypedDict, Literal import llama_cpp import anyio from anyio.streams.memory import MemoryObjectSendStream from starlette.concurrency import run_in_threadpool, iterate_in_threadpool from fastapi import Depends, FastAPI, APIRouter, Request from fastapi.middleware.cors import CORSMiddleware from pydantic import BaseModel, Field from pydantic_settings import BaseSettings from sse_starlette.sse import EventSourceResponse class Settings(BaseSettings): model: str = Field( description="The path to the model to use for generating completions." ) model_alias: Optional[str] = Field( default=None, description="The alias of the model to use for generating completions.", ) n_ctx: int = Field(default=2048, ge=1, description="The context size.") n_gpu_layers: int = Field( default=0, ge=0, description="The number of layers to put on the GPU. The rest will be on the CPU.", ) tensor_split: List[float] = Field( default=None, description="Split layers across multiple GPUs in proportion.", ) seed: int = Field( default=1337, description="Random seed. -1 for random." ) n_batch: int = Field( default=512, ge=1, description="The batch size to use per eval." ) n_threads: int = Field( default=max(multiprocessing.cpu_count() // 2, 1), ge=1, description="The number of threads to use.", ) f16_kv: bool = Field(default=True, description="Whether to use f16 key/value.") use_mlock: bool = Field( default=llama_cpp.llama_mlock_supported(), description="Use mlock.", ) use_mmap: bool = Field( default=llama_cpp.llama_mmap_supported(), description="Use mmap.", ) embedding: bool = Field(default=True, description="Whether to use embeddings.") low_vram: bool = Field( default=False, description="Whether to use less VRAM. This will reduce performance.", ) last_n_tokens_size: int = Field( default=64, ge=0, description="Last n tokens to keep for repeat penalty calculation.", ) logits_all: bool = Field(default=True, description="Whether to return logits.") cache: bool = Field( default=False, description="Use a cache to reduce processing times for evaluated prompts.", ) cache_type: Literal["ram", "disk"] = Field( default="ram", description="The type of cache to use. Only used if cache is True.", ) cache_size: int = Field( default=2 << 30, description="The size of the cache in bytes. Only used if cache is True.", ) vocab_only: bool = Field( default=False, description="Whether to only return the vocabulary." ) verbose: bool = Field( default=True, description="Whether to print debug information." ) host: str = Field(default="localhost", description="Listen address") port: int = Field(default=8000, description="Listen port") interrupt_requests: bool = Field( default=True, description="Whether to interrupt requests when a new request is received.", ) router = APIRouter() settings: Optional[Settings] = None llama: Optional[llama_cpp.Llama] = None def create_app(settings: Optional[Settings] = None): if settings is None: settings = Settings() app = FastAPI( title="🦙 llama.cpp Python API", version="0.0.1", ) app.add_middleware( CORSMiddleware, allow_origins=["*"], allow_credentials=True, allow_methods=["*"], allow_headers=["*"], ) app.include_router(router) global llama llama = llama_cpp.Llama( model_path=settings.model, n_gpu_layers=settings.n_gpu_layers, tensor_split=settings.tensor_split, seed=settings.seed, f16_kv=settings.f16_kv, use_mlock=settings.use_mlock, use_mmap=settings.use_mmap, embedding=settings.embedding, logits_all=settings.logits_all, n_threads=settings.n_threads, n_batch=settings.n_batch, n_ctx=settings.n_ctx, last_n_tokens_size=settings.last_n_tokens_size, vocab_only=settings.vocab_only, verbose=settings.verbose, ) if settings.cache: if settings.cache_type == "disk": if settings.verbose: print(f"Using disk cache with size {settings.cache_size}") cache = llama_cpp.LlamaDiskCache(capacity_bytes=settings.cache_size) else: if settings.verbose: print(f"Using ram cache with size {settings.cache_size}") cache = llama_cpp.LlamaRAMCache(capacity_bytes=settings.cache_size) cache = llama_cpp.LlamaCache(capacity_bytes=settings.cache_size) llama.set_cache(cache) def set_settings(_settings: Settings): global settings settings = _settings set_settings(settings) return app llama_outer_lock = Lock() llama_inner_lock = Lock() def get_llama(): # NOTE: This double lock allows the currently streaming llama model to # check if any other requests are pending in the same thread and cancel # the stream if so. llama_outer_lock.acquire() release_outer_lock = True try: llama_inner_lock.acquire() try: llama_outer_lock.release() release_outer_lock = False yield llama finally: llama_inner_lock.release() finally: if release_outer_lock: llama_outer_lock.release() def get_settings(): yield settings model_field = Field(description="The model to use for generating completions.", default=None) max_tokens_field = Field( default=16, ge=1, le=2048, description="The maximum number of tokens to generate." ) temperature_field = Field( default=0.8, ge=0.0, le=2.0, description="Adjust the randomness of the generated text.\n\n" + "Temperature is a hyperparameter that controls the randomness of the generated text. It affects the probability distribution of the model's output tokens. A higher temperature (e.g., 1.5) makes the output more random and creative, while a lower temperature (e.g., 0.5) makes the output more focused, deterministic, and conservative. The default value is 0.8, which provides a balance between randomness and determinism. At the extreme, a temperature of 0 will always pick the most likely next token, leading to identical outputs in each run.", ) top_p_field = Field( default=0.95, ge=0.0, le=1.0, description="Limit the next token selection to a subset of tokens with a cumulative probability above a threshold P.\n\n" + "Top-p sampling, also known as nucleus sampling, is another text generation method that selects the next token from a subset of tokens that together have a cumulative probability of at least p. This method provides a balance between diversity and quality by considering both the probabilities of tokens and the number of tokens to sample from. A higher value for top_p (e.g., 0.95) will lead to more diverse text, while a lower value (e.g., 0.5) will generate more focused and conservative text.", ) stop_field = Field( default=None, description="A list of tokens at which to stop generation. If None, no stop tokens are used.", ) stream_field = Field( default=False, description="Whether to stream the results as they are generated. Useful for chatbots.", ) top_k_field = Field( default=40, ge=0, description="Limit the next token selection to the K most probable tokens.\n\n" + "Top-k sampling is a text generation method that selects the next token only from the top k most likely tokens predicted by the model. It helps reduce the risk of generating low-probability or nonsensical tokens, but it may also limit the diversity of the output. A higher value for top_k (e.g., 100) will consider more tokens and lead to more diverse text, while a lower value (e.g., 10) will focus on the most probable tokens and generate more conservative text.", ) repeat_penalty_field = Field( default=1.1, ge=0.0, description="A penalty applied to each token that is already generated. This helps prevent the model from repeating itself.\n\n" + "Repeat penalty is a hyperparameter used to penalize the repetition of token sequences during text generation. It helps prevent the model from generating repetitive or monotonous text. A higher value (e.g., 1.5) will penalize repetitions more strongly, while a lower value (e.g., 0.9) will be more lenient.", ) presence_penalty_field = Field( default=0.0, ge=-2.0, le=2.0, description="Positive values penalize new tokens based on whether they appear in the text so far, increasing the model's likelihood to talk about new topics.", ) frequency_penalty_field = Field( default=0.0, ge=-2.0, le=2.0, description="Positive values penalize new tokens based on their existing frequency in the text so far, decreasing the model's likelihood to repeat the same line verbatim.", ) mirostat_mode_field = Field( default=0, ge=0, le=2, description="Enable Mirostat constant-perplexity algorithm of the specified version (1 or 2; 0 = disabled)", ) mirostat_tau_field = Field( default=5.0, ge=0.0, le=10.0, description="Mirostat target entropy, i.e. the target perplexity - lower values produce focused and coherent text, larger values produce more diverse and less coherent text", ) mirostat_eta_field = Field( default=0.1, ge=0.001, le=1.0, description="Mirostat learning rate" ) class CreateCompletionRequest(BaseModel): prompt: Union[str, List[str]] = Field( default="", description="The prompt to generate completions for." ) suffix: Optional[str] = Field( default=None, description="A suffix to append to the generated text. If None, no suffix is appended. Useful for chatbots.", ) max_tokens: int = max_tokens_field temperature: float = temperature_field top_p: float = top_p_field mirostat_mode: int = mirostat_mode_field mirostat_tau: float = mirostat_tau_field mirostat_eta: float = mirostat_eta_field echo: bool = Field( default=False, description="Whether to echo the prompt in the generated text. Useful for chatbots.", ) stop: Optional[Union[str, List[str]]] = stop_field stream: bool = stream_field logprobs: Optional[int] = Field( default=None, ge=0, description="The number of logprobs to generate. If None, no logprobs are generated.", ) presence_penalty: Optional[float] = presence_penalty_field frequency_penalty: Optional[float] = frequency_penalty_field logit_bias: Optional[Dict[str, float]] = Field(None) logprobs: Optional[int] = Field(None) # ignored or currently unsupported model: Optional[str] = model_field n: Optional[int] = 1 best_of: Optional[int] = 1 user: Optional[str] = Field(default=None) # llama.cpp specific parameters top_k: int = top_k_field repeat_penalty: float = repeat_penalty_field logit_bias_type: Optional[Literal["input_ids", "tokens"]] = Field(None) model_config = { "json_schema_extra": { "examples": [ { "prompt": "\n\n### Instructions:\nWhat is the capital of France?\n\n### Response:\n", "stop": ["\n", "###"], } ] } } def make_logit_bias_processor( llama: llama_cpp.Llama, logit_bias: Dict[str, float], logit_bias_type: Optional[Literal["input_ids", "tokens"]], ): if logit_bias_type is None: logit_bias_type = "input_ids" to_bias: Dict[int, float] = {} if logit_bias_type == "input_ids": for input_id, score in logit_bias.items(): input_id = int(input_id) to_bias[input_id] = score elif logit_bias_type == "tokens": for token, score in logit_bias.items(): token = token.encode("utf-8") for input_id in llama.tokenize(token, add_bos=False): to_bias[input_id] = score def logit_bias_processor( input_ids: List[int], scores: List[float], ) -> List[float]: new_scores = [None] * len(scores) for input_id, score in enumerate(scores): new_scores[input_id] = score + to_bias.get(input_id, 0.0) return new_scores return logit_bias_processor @router.post( "/v1/completions", ) async def create_completion( request: Request, body: CreateCompletionRequest, llama: llama_cpp.Llama = Depends(get_llama), ) -> llama_cpp.Completion: if isinstance(body.prompt, list): assert len(body.prompt) <= 1 body.prompt = body.prompt[0] if len(body.prompt) > 0 else "" exclude = { "n", "best_of", "logit_bias", "logit_bias_type", "user", } kwargs = body.model_dump(exclude=exclude) if body.logit_bias is not None: kwargs['logits_processor'] = llama_cpp.LogitsProcessorList([ make_logit_bias_processor(llama, body.logit_bias, body.logit_bias_type), ]) if body.stream: send_chan, recv_chan = anyio.create_memory_object_stream(10) async def event_publisher(inner_send_chan: MemoryObjectSendStream): async with inner_send_chan: try: iterator: Iterator[llama_cpp.CompletionChunk] = await run_in_threadpool(llama, **kwargs) # type: ignore async for chunk in iterate_in_threadpool(iterator): await inner_send_chan.send(dict(data=json.dumps(chunk))) if await request.is_disconnected(): raise anyio.get_cancelled_exc_class()() if settings.interrupt_requests and llama_outer_lock.locked(): await inner_send_chan.send(dict(data="[DONE]")) raise anyio.get_cancelled_exc_class()() await inner_send_chan.send(dict(data="[DONE]")) except anyio.get_cancelled_exc_class() as e: print("disconnected") with anyio.move_on_after(1, shield=True): print( f"Disconnected from client (via refresh/close) {request.client}" ) raise e return EventSourceResponse( recv_chan, data_sender_callable=partial(event_publisher, send_chan) ) # type: ignore else: completion: llama_cpp.Completion = await run_in_threadpool(llama, **kwargs) # type: ignore return completion class CreateEmbeddingRequest(BaseModel): model: Optional[str] = model_field input: Union[str, List[str]] = Field(description="The input to embed.") user: Optional[str] = Field(default=None) model_config = { "json_schema_extra": { "examples": [ { "input": "The food was delicious and the waiter...", } ] } } @router.post( "/v1/embeddings", ) async def create_embedding( request: CreateEmbeddingRequest, llama: llama_cpp.Llama = Depends(get_llama) ): return await run_in_threadpool( llama.create_embedding, **request.model_dump(exclude={"user"}) ) class ChatCompletionRequestMessage(BaseModel): role: Literal["system", "user", "assistant"] = Field( default="user", description="The role of the message." ) content: str = Field(default="", description="The content of the message.") class CreateChatCompletionRequest(BaseModel): messages: List[ChatCompletionRequestMessage] = Field( default=[], description="A list of messages to generate completions for." ) max_tokens: int = max_tokens_field temperature: float = temperature_field top_p: float = top_p_field mirostat_mode: int = mirostat_mode_field mirostat_tau: float = mirostat_tau_field mirostat_eta: float = mirostat_eta_field stop: Optional[List[str]] = stop_field stream: bool = stream_field presence_penalty: Optional[float] = presence_penalty_field frequency_penalty: Optional[float] = frequency_penalty_field logit_bias: Optional[Dict[str, float]] = Field(None) # ignored or currently unsupported model: Optional[str] = model_field n: Optional[int] = 1 user: Optional[str] = Field(None) # llama.cpp specific parameters top_k: int = top_k_field repeat_penalty: float = repeat_penalty_field logit_bias_type: Optional[Literal["input_ids", "tokens"]] = Field(None) model_config = { "json_schema_extra": { "examples": [ { "messages": [ ChatCompletionRequestMessage( role="system", content="You are a helpful assistant." ).model_dump(), ChatCompletionRequestMessage( role="user", content="What is the capital of France?" ).model_dump(), ] } ] } } @router.post( "/v1/chat/completions", ) async def create_chat_completion( request: Request, body: CreateChatCompletionRequest, llama: llama_cpp.Llama = Depends(get_llama), settings: Settings = Depends(get_settings), ) -> llama_cpp.ChatCompletion: exclude = { "n", "logit_bias", "logit_bias_type", "user", } kwargs = body.model_dump(exclude=exclude) if body.logit_bias is not None: kwargs['logits_processor'] = llama_cpp.LogitsProcessorList([ make_logit_bias_processor(llama, body.logit_bias, body.logit_bias_type), ]) if body.stream: send_chan, recv_chan = anyio.create_memory_object_stream(10) async def event_publisher(inner_send_chan: MemoryObjectSendStream): async with inner_send_chan: try: iterator: Iterator[llama_cpp.ChatCompletionChunk] = await run_in_threadpool(llama.create_chat_completion, **kwargs) # type: ignore async for chat_chunk in iterate_in_threadpool(iterator): await inner_send_chan.send(dict(data=json.dumps(chat_chunk))) if await request.is_disconnected(): raise anyio.get_cancelled_exc_class()() if settings.interrupt_requests and llama_outer_lock.locked(): await inner_send_chan.send(dict(data="[DONE]")) raise anyio.get_cancelled_exc_class()() await inner_send_chan.send(dict(data="[DONE]")) except anyio.get_cancelled_exc_class() as e: print("disconnected") with anyio.move_on_after(1, shield=True): print( f"Disconnected from client (via refresh/close) {request.client}" ) raise e return EventSourceResponse( recv_chan, data_sender_callable=partial(event_publisher, send_chan), ) # type: ignore else: completion: llama_cpp.ChatCompletion = await run_in_threadpool( llama.create_chat_completion, **kwargs # type: ignore ) return completion class ModelData(TypedDict): id: str object: Literal["model"] owned_by: str permissions: List[str] class ModelList(TypedDict): object: Literal["list"] data: List[ModelData] @router.get("/v1/models") async def get_models( settings: Settings = Depends(get_settings), ) -> ModelList: assert llama is not None return { "object": "list", "data": [ { "id": settings.model_alias if settings.model_alias is not None else llama.model_path, "object": "model", "owned_by": "me", "permissions": [], } ], }