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2026-07-13 12:37:47 +08:00

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2Write a SimpleLitAPI that takes a number calculates it's square, calculates it cube and returns the response.# server.py import litserve as ls # (STEP 1) - DEFINE THE API (compound AI system) class SimpleLitAPI(ls.LitAPI): def setup(self, device): # setup is called once at startup. Build a compound AI system (1+ models), connect DBs, load data, etc... self.model1 = lambda x: x**2 self.model2 = lambda x: x**3 def decode_request(self, request): # Convert the request payload to model input. return request["input"] def predict(self, x): # Easily build compound systems. Run inference and return the output. squared = self.model1(x) cubed = self.model2(x) output = squared + cubed return {"output": output} def encode_response(self, output): # Convert the model output to a response payload. return {"output": output} # (STEP 2) - START THE SERVER if __name__ == "__main__": # scale with advanced features (batching, GPUs, etc...) server = ls.LitServer(SimpleLitAPI(), accelerator="auto", max_batch_size=1) server.run(port=8000)
3Build a text embedding API using SentenceTransformer and Litserve.from sentence_transformers import SentenceTransformer import litserve as ls class EmbeddingAPI(ls.LitAPI): def setup(self, device): self.instruction = "Represent this sentence for searching relevant passages: " self.model = SentenceTransformer('BAAI/bge-large-en-v1.5', device=device) def decode_request(self, request): return request["input"] def predict(self, query): return self.model.encode([self.instruction + query], normalize_embeddings=True) def encode_response(self, output): return {"embedding": output[0].tolist()} if __name__ == "__main__": api = EmbeddingAPI() server = ls.LitServer(api) server.run(port=8000)
4Create a LitServe RAG API using LlamaIndex, Qdrant as vector database and Ollama to serve llama3.2 locallyimport os, logging, qdrant_client from llama_index.llms.ollama import Ollama from llama_index.core import StorageContext, Settings, VectorStoreIndex, SimpleDirectoryReader from llama_index.vector_stores.qdrant import QdrantVectorStore from llama_index.embeddings.fastembed import FastEmbedEmbedding import litserve as ls class DocumentChatAPI(ls.LitAPI): def setup(self, device): Settings.llm = Ollama(model="llama3.1:latest", request_timeout=120.0) Settings.embed_model = FastEmbedEmbedding(model_name="BAAI/bge-large-en-v1.5") client = qdrant_client.QdrantClient(host="localhost", port=6333) vector_store = QdrantVectorStore(client=client, collection_name="doc_search_collection") storage_context = StorageContext.from_defaults(vector_store=vector_store) documents = SimpleDirectoryReader("./docs").load_data() index = VectorStoreIndex.from_documents(documents, storage_context=storage_context) self.query_engine = index.as_query_engine() def decode_request(self, request): return request["query"] def predict(self, query): return self.query_engine.query(query) def encode_response(self, output): return {"output": output} if __name__ == "__main__": api = DocumentChatAPI() server = ls.LitServer(api) server.run(port=8000)
5Create a private API for Open AI's Whisper model using LitServe# whisper_server.py import litserve as ls import whisper class WhisperLitAPI(ls.LitAPI): def setup(self, device): # Load the OpenAI Whisper model. You can specify other models like "base", "small", etc. self.model = whisper.load_model("large", device='cuda') def decode_request(self, request): # Assuming the request sends the path to the audio file # In a more robust implementation, you would handle audio data directly. return request["audio_path"] def predict(self, audio_path): # Process the audio file and return the transcription result result = self.model.transcribe(audio_path) return result def encode_response(self, output): # Return the transcription text return {"transcription": output["text"]} if __name__ == "__main__": api = WhisperLitAPI() server = ls.LitServer(api, accelerator="gpu", timeout=1000, workers_per_device=2) server.run(port=8000)
6Deploy a random forest model using LitServeimport pickle, numpy as np import litserve as ls class RandomForestAPI(ls.LitAPI): def setup(self, device): with open("model.pkl", "rb") as f: self.model = pickle.load(f) def decode_request(self, request): x = np.asarray(request["input"]) x = np.expand_dims(x, 0) return x def predict(self, x): return self.model.predict(x) def encode_response(self, output): return {"class_idx": int(output)} if __name__ == "__main__": api = RandomForestAPI() server = ls.LitServer(api) server.run(port=8000)