feat: remove llm client use (#1316)

api/core/chain/llm_chain.py

@@ -0,0 +1,36 @@
+from typing import List, Dict, Any, Optional
+
+from langchain import LLMChain as LCLLMChain
+from langchain.callbacks.manager import CallbackManagerForChainRun
+from langchain.schema import LLMResult, Generation
+from langchain.schema.language_model import BaseLanguageModel
+
+from core.model_providers.models.entity.message import to_prompt_messages
+from core.model_providers.models.llm.base import BaseLLM
+from core.third_party.langchain.llms.fake import FakeLLM
+
+
+class LLMChain(LCLLMChain):
+    model_instance: BaseLLM
+    """The language model instance to use."""
+    llm: BaseLanguageModel = FakeLLM(response="")
+
+    def generate(
+        self,
+        input_list: List[Dict[str, Any]],
+        run_manager: Optional[CallbackManagerForChainRun] = None,
+    ) -> LLMResult:
+        """Generate LLM result from inputs."""
+        prompts, stop = self.prep_prompts(input_list, run_manager=run_manager)
+        messages = prompts[0].to_messages()
+        prompt_messages = to_prompt_messages(messages)
+        result = self.model_instance.run(
+            messages=prompt_messages,
+            stop=stop
+        )
+
+        generations = [
+            [Generation(text=result.content)]
+        ]
+
+        return LLMResult(generations=generations)