feat(llms): add streaming support to textgen (#9295)

- Description: Added streaming support to the textgen component in the
llms module.
  - Dependencies: websocket-client = "^1.6.1"

docs/extras/integrations/llms/textgen.ipynb

@@ -26,7 +26,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": null,
    "metadata": {
     "tags": []
    },
@@ -61,6 +61,71 @@
     "\n",
     "llm_chain.run(question)"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Streaming Version"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "You should install websocket-client to use this feature.\n",
+    "`pip install websocket-client`"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "model_url = \"ws://localhost:5005\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import langchain\n",
+    "from langchain import PromptTemplate, LLMChain\n",
+    "from langchain.llms import TextGen\n",
+    "from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler\n",
+    "\n",
+    "langchain.debug = True\n",
+    "\n",
+    "template = \"\"\"Question: {question}\n",
+    "\n",
+    "Answer: Let's think step by step.\"\"\"\n",
+    "\n",
+    "\n",
+    "prompt = PromptTemplate(template=template, input_variables=[\"question\"])\n",
+    "llm = TextGen(model_url=model_url, streaming=True, callbacks=[StreamingStdOutCallbackHandler()])\n",
+    "llm_chain = LLMChain(prompt=prompt, llm=llm)\n",
+    "question = \"What NFL team won the Super Bowl in the year Justin Bieber was born?\"\n",
+    "\n",
+    "llm_chain.run(question)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "llm = TextGen(\n",
+    "    model_url = model_url,\n",
+    "    streaming=True\n",
+    ")\n",
+    "for chunk in llm.stream(\"Ask 'Hi, how are you?' like a pirate:'\",\n",
+    "        stop=[\"'\",\"\\n\"]):\n",
+    "    print(chunk, end='', flush=True)"
+   ]
   }
  ],
  "metadata": {
@@ -79,7 +144,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.7"
+   "version": "3.10.4"
   }
  },
  "nbformat": 4,