Gemini Backend (#9)

Co-authored-by: Ying Sheng <sqy1415@gmail.com>

examples/quick_start/gemini_example_complete.py

+from sglang import function, gen, set_default_backend, Gemini
+
+
+@function
+def few_shot_qa(s, question):
+    s += (
+"""The following are questions with answers.
+Q: What is the capital of France?
+A: Paris
+Q: What is the capital of Germany?
+A: Berlin
+Q: What is the capital of Italy?
+A: Rome
+""")
+    s += "Q: " + question + "\n"
+    s += "A:" + gen("answer", stop="\n", temperature=0)
+
+
+set_default_backend(Gemini("gemini-pro"))
+
+state = few_shot_qa.run(question="What is the capital of the United States?")
+answer = state["answer"].strip().lower()
+
+assert "washington" in answer, f"answer: {state['answer']}"
+
+print(state.text())

examples/quick_start/gemini_example_multimodal_chat.py

+from sglang import function, user, assistant, gen, image, set_default_backend, Gemini
+
+
+@function
+def image_qa(s, image_file1, image_file2, question):
+    s += user(image(image_file1) + image(image_file2) + question)
+    s += assistant(gen("answer_1", max_tokens=256))
+
+set_default_backend(Gemini("gemini-pro-vision"))
+
+state = image_qa.run(
+    image_file1="./images/cat.jpeg",
+    image_file2="./images/dog.jpeg",
+    question="Describe difference of the 2 images in one sentence.",
+    stream=True
+)
+
+for out in state.text_iter():
+    print(out, end="", flush=True)
\ No newline at end of file

examples/quick_start/gemini_example_stream.py

+from sglang import function, user, assistant, gen, set_default_backend, Gemini
+
+
+@function
+def multi_turn_question(s, question_1, question_2):
+    s += user(question_1)
+    s += assistant(gen("answer_1", max_tokens=256))
+    s += user(question_2)
+    s += assistant(gen("answer_2", max_tokens=256))
+
+set_default_backend(Gemini("gemini-pro"))
+
+state = multi_turn_question.run(
+    question_1="What is the capital of the United States?",
+    question_2="List two local attractions.",
+    stream=True
+)
+
+for out in state.text_iter():
+    print(out, end="", flush=True)

python/sglang/api.py

@@ -4,6 +4,7 @@ from typing import Callable, List, Optional, Union
 
 from sglang.backend.anthropic import Anthropic
 from sglang.backend.base_backend import BaseBackend
+from sglang.backend.gemini import Gemini
 from sglang.backend.openai import OpenAI
 from sglang.backend.runtime_endpoint import RuntimeEndpoint
 from sglang.global_config import global_config

python/sglang/backend/gemini.py

+import os
+import warnings
+from typing import List, Optional, Union
+
+import numpy as np
+from sglang.backend.base_backend import BaseBackend
+from sglang.lang.chat_template import get_chat_template
+from sglang.lang.interpreter import StreamExecutor
+from sglang.lang.ir import SglSamplingParams
+
+try:
+    import vertexai
+    from vertexai.preview.generative_models import (
+        GenerationConfig,
+        GenerativeModel,
+        Image,
+    )
+except ImportError as e:
+    GenerativeModel = e
+
+GEMINI_MODEL_NAMES = [
+    "gemini-pro",
+    "gemini-pro-vision",
+]
+
+
+class Gemini(BaseBackend):
+    def __init__(self, model_name):
+        super().__init__()
+
+        if isinstance(GenerativeModel, Exception):
+            raise GenerativeModel
+
+        project_id = os.environ["GCP_PROJECT_ID"]
+        location = os.environ["GCP_LOCATION"]
+        vertexai.init(project=project_id, location=location)
+
+        self.model_name = model_name
+        self.chat_template = get_chat_template("default")
+
+    def get_chat_template(self):
+        return self.chat_template
+
+    def generate(
+        self,
+        s: StreamExecutor,
+        sampling_params: SglSamplingParams,
+    ):
+        if s.messages_:
+            prompt = self.messages_to_gemini_input(s.messages_)
+        else:
+            # single-turn
+            prompt = (
+                self.text_to_gemini_input(s.text_, s.cur_images)
+                if s.cur_images
+                else s.text_
+            )
+        ret = GenerativeModel(self.model_name).generate_content(
+            prompt,
+            generation_config=GenerationConfig(**sampling_params.to_gemini_kwargs()),
+        )
+
+        comp = ret.text
+
+        return comp, {}
+
+    def generate_stream(
+        self,
+        s: StreamExecutor,
+        sampling_params: SglSamplingParams,
+    ):
+        if s.messages_:
+            prompt = self.messages_to_gemini_input(s.messages_)
+        else:
+            # single-turn
+            prompt = (
+                self.text_to_gemini_input(s.text_, s.cur_images)
+                if s.cur_images
+                else s.text_
+            )
+        generator = GenerativeModel(self.model_name).generate_content(
+            prompt,
+            stream=True,
+            generation_config=GenerationConfig(**sampling_params.to_gemini_kwargs()),
+        )
+        for ret in generator:
+            yield ret.text, {}
+
+    def text_to_gemini_input(self, text, images):
+        input = []
+        # split with image token
+        text_segs = text.split(self.chat_template.image_token)
+        for image_path, image_base64_data in images:
+            text_seg = text_segs.pop(0)
+            if text_seg != "":
+                input.append(text_seg)
+            input.append(Image.from_bytes(image_base64_data))
+        text_seg = text_segs.pop(0)
+        if text_seg != "":
+            input.append(text_seg)
+        return input
+
+    def messages_to_gemini_input(self, messages):
+        gemini_message = []
+        # from openai message format to gemini message format
+        for msg in messages:
+            if isinstance(msg["content"], str):
+                text = msg["content"]
+            else:
+                text = msg["content"][0]["text"]
+
+            if msg["role"] == "system":
+                warnings.warn("Warning: system prompt is not supported in Gemini.")
+                gemini_message.append(
+                    {
+                        "role": "user",
+                        "parts": [{"text": "System prompt: " + text}],
+                    }
+                )
+                gemini_message.append(
+                    {
+                        "role": "model",
+                        "parts": [{"text": "Understood."}],
+                    }
+                )
+                continue
+            if msg["role"] == "user":
+                gemini_msg = {
+                    "role": "user",
+                    "parts": [{"text": text}],
+                }
+            elif msg["role"] == "assistant":
+                gemini_msg = {
+                    "role": "model",
+                    "parts": [{"text": text}],
+                }
+
+            # images
+            if isinstance(msg["content"], list) and len(msg["content"]) > 1:
+                for image in msg["content"][1:]:
+                    assert image["type"] == "image_url"
+                    gemini_msg["parts"].append(
+                        {
+                            "inline_data": {
+                                "data": image["image_url"]["url"].split(",")[1],
+                                "mime_type": "image/jpeg",
+                            }
+                        }
+                    )
+
+            gemini_message.append(gemini_msg)
+        return gemini_message

python/sglang/lang/interpreter.py

@@ -428,6 +428,7 @@ class StreamExecutor:
             self.messages_.append(last_msg)
             self.cur_images = []
         else:
+            # OpenAI chat API format
             self.messages_.append({"role": expr.role, "content": new_text})
 
         self.cur_role = None

python/sglang/lang/ir.py

@@ -49,6 +49,16 @@ class SglSamplingParams:
             "presence_penalty": self.presence_penalty,
         }
 
+    def to_gemini_kwargs(self):
+        return {
+            "candidate_count": 1,
+            "max_output_tokens": self.max_new_tokens,
+            "stop_sequences": self.stop,
+            "temperature": self.temperature,
+            "top_p": self.top_p,
+            "top_k": self.top_k if self.top_k > 0 else None,
+        }
+
     def to_anthropic_kwargs(self):
         # Anthropic does not support frequency_penalty or presence_penalty, so we drop it here
         return {

python/sglang/srt/models/mixtral.py

@@ -355,7 +355,7 @@ class MixtralForCausalLM(nn.Module):
         ):
             if "rotary_emb.inv_freq" in name:
                 continue
-            for (param_name, weight_name, shard_id) in stacked_params_mapping:
+            for param_name, weight_name, shard_id in stacked_params_mapping:
                 if weight_name not in name:
                     continue
                 name = name.replace(weight_name, param_name)

python/sglang/test/test_programs.py

@@ -304,7 +304,10 @@ def test_image_qa():
         temperature=0,
         max_new_tokens=64,
     )
-    assert "taxi" in state.messages()[-1]["content"]
+    assert (
+        "taxi" in state.messages()[-1]["content"]
+        or "car" in state.messages()[-1]["content"]
+    )
 
 
 def test_stream():

test/lang/test_gemini_backend.py

+import unittest
+
+from sglang.test.test_programs import (
+    test_expert_answer,
+    test_few_shot_qa,
+    test_image_qa,
+    test_mt_bench,
+    test_parallel_decoding,
+    test_parallel_encoding,
+    test_stream,
+)
+
+from sglang import Gemini, set_default_backend
+
+
+class TestGeminiBackend(unittest.TestCase):
+    backend = None
+    chat_backend = None
+    chat_vision_backend = None
+
+    def setUp(self):
+        cls = type(self)
+
+        if cls.backend is None:
+            cls.backend = Gemini("gemini-pro")
+            cls.chat_backend = Gemini("gemini-pro")
+            cls.chat_vision_backend = Gemini("gemini-pro-vision")
+
+    def test_few_shot_qa(self):
+        set_default_backend(self.backend)
+        test_few_shot_qa()
+
+    def test_mt_bench(self):
+        set_default_backend(self.chat_backend)
+        test_mt_bench()
+
+    def test_expert_answer(self):
+        set_default_backend(self.backend)
+        test_expert_answer()
+
+    def test_parallel_decoding(self):
+        set_default_backend(self.backend)
+        test_parallel_decoding()
+
+    def test_parallel_encoding(self):
+        set_default_backend(self.backend)
+        test_parallel_encoding()
+
+    def test_image_qa(self):
+        set_default_backend(self.chat_vision_backend)
+        test_image_qa()
+
+    def test_stream(self):
+        set_default_backend(self.backend)
+        test_stream()
+
+
+if __name__ == "__main__":
+    unittest.main(warnings="ignore")
+
+    # from sglang.global_config import global_config
+
+    # global_config.verbosity = 2
+    # t = TestGeminiBackend()
+    # t.setUp()
+    # t.test_stream()

test/lang/test_openai_backend.py

@@ -88,4 +88,15 @@ if __name__ == "__main__":
     # global_config.verbosity = 2
     # t = TestOpenAIBackend()
     # t.setUp()
+    # t.test_few_shot_qa()
+    # t.test_mt_bench()
+    # t.test_select()
+    # t.test_decode_int()
     # t.test_decode_json()
+    # t.test_expert_answer()
+    # t.test_tool_use()
+    # t.test_react()
+    # t.test_parallel_decoding()
+    # t.test_parallel_encoding()
+    # t.test_image_qa()
+    # t.test_stream()