[engine] support async and streaming (#1614)

examples/runtime/engine/custom_server.py

@@ -0,0 +1,53 @@
+from sanic import Sanic, text
+from sanic.response import json
+
+import sglang as sgl
+
+engine = None
+
+# Create an instance of the Sanic app
+app = Sanic("sanic-server")
+
+
+# Define an asynchronous route handler
+@app.route("/generate", methods=["POST"])
+async def generate(request):
+    prompt = request.json.get("prompt")
+    if not prompt:
+        return json({"error": "Prompt is required"}, status=400)
+
+    # async_generate returns a dict
+    result = await engine.async_generate(prompt)
+
+    return text(result["text"])
+
+
+@app.route("/generate_stream", methods=["POST"])
+async def generate_stream(request):
+    prompt = request.json.get("prompt")
+
+    if not prompt:
+        return json({"error": "Prompt is required"}, status=400)
+
+    # async_generate returns a dict
+    result = await engine.async_generate(prompt, stream=True)
+
+    # https://sanic.dev/en/guide/advanced/streaming.md#streaming
+    # init the response
+    response = await request.respond()
+
+    # result is an async generator
+    async for chunk in result:
+        await response.send(chunk["text"])
+
+    await response.eof()
+
+
+def run_server():
+    global engine
+    engine = sgl.Engine(model_path="meta-llama/Meta-Llama-3.1-8B-Instruct")
+    app.run(host="0.0.0.0", port=8000, single_process=True)
+
+
+if __name__ == "__main__":
+    run_server()