Langchain output parser python example github

Langchain output parser python example github. GREEN = "green". It can often be useful to have an agent return something with more structure. The case I'm interested in is precisely the one that's described in your link under the Option 2 section / Pydantic. A good example of this is an agent tasked with doing question-answering over some sources. This output parser wraps another output parser, and in the event that the first one fails it calls out to another LLM to fix any errors. Hello @lilong669,. Jun 17, 2023 · Traceback (most recent call last): File "C:\Users\catsk\SourceCode \a zure_openai_poc \v env\lib\site-packages\langchain \a gents\chat\output_parser. Question: what is 2. Mar 11, 2024 · This will output a JSON representation of your comparison table. This output parser can be used when you want to return multiple fields. 04. This method safely parses a string containing a Python literal or container display. parse ( output) Aug 18, 2023 · From what I understand, the issue you reported is related to the ConvoOutputParser in the langchain package failing to parse LLM output randomly when certain keywords are missing. 5*3. Expected key `{key}` " f"to be present, but got {json_obj}" ) return json_obj. This notebook shows how to use an Enum output parser. content: str prompt: str output_format_sample_json_str: str = None model = ChatOpenAI () async def run_extraction ( request: OneContentToOneRequest ): Thank you for bringing this to our attention. from_chain_type' response in LangChain, you can use Python's ast. 320 OS: Ubuntu 18. fix import OutputFixingParser. To see how this works, let's create a chain that takes a topic and generates a joke: %pip install --upgrade --quiet langchain-core langchain-community langchain-openai. Apr 15, 2023 · Langchain with fastapi stream example. Parse a single string model output into some structure. schema. Sometimes (about 1 in 15 runs) it's this: % python3 app. When using this tool, sometimes output is abbreviated - make sure it does not look abbreviated before using it in your answer. let routerTemplate = 'Given a raw text input to a language model select the model ' +. Final Answer: 2. predict ( query="Generate the filmography for a random actor. Example Code. LangChain document loaders to load content from files. You can see there is no "```json" string in the output of LLM, so it will step into the "if" in the first row of this function and raise the bug. """. , lists, datetime, enum, etc). With this tutorial and code in this repo you will learn to: set up the data model in a way that Langchain’s output parser can be used to generate structured data. """. The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package). 1. When used in streaming mode, it will yield partial JSON objects containing all the keys that have been returned so far. The aiter() method is typically used to iterate over asynchronous iterators. See here for setup instructions for these LLMs. The latest version of Langchain has improved its compatibility with asynchronous FastAPI, making it easier to implement streaming functionality in your applications. mrkl = initialize_agent (. In the case of load_qa_with_sources_chain and lang_qa_chain, the very simple solution is to use a custom RegExParser that does handle formatting errors. split ("```")[1] IndexError: list index out of range During handling of the above exception, another exception occurred: Traceback (most recent call last Jun 8, 2023 · System Info python 3. API Reference: EnumOutputParser. Example Code Feb 22, 2024 · I searched the LangChain documentation with the integrated search. Oct 24, 2023 · Python Version: Python 3. llamafiles bundle model weights and a specially-compiled version of llama. Apr 7, 2023 · Based on my understanding, the issue you reported was related to the gpt-4 model in the langchain library. This makes it more efficient and bulletproof than existing approaches. Sep 16, 2023 · System Info langchain ==0. prompts import PromptTemplate from langchain. llm = AzureChatOpenAI(deployment_name="gpt-4", temperature=0. Feel free to adapt it to your own use cases. Jul 14, 2023 · import boto3 import json import os import sys from langchain. Use the most basic and common components of LangChain: prompt templates, models, and output parsers. The exact process of integrating these into a langgraph would depend on the specifics of your application and how you've structured your langgraph. Mar 11, 2024 · I searched the LangChain documentation with the integrated search. Specify the schema of what should be extracted and provide some examples. I coded the same logic both in Langchain python and in Langchain JS, but I am getting the problem that in the latter, I can't use ChatPrompt without breaking the StructuredOutputParser parser, getting errors like: 3 days ago · The default implementation allows usage of async code even if the runnable did not implement a native async version of invoke. Mar 9, 2017 · To address this issue, you could modify the parse method in your StructuredOutputParser class to handle the case where the output ends with two triple-backticks. agent_types import AgentType from langchain. Here's a general idea of how you can modify it: Mar 20, 2024 · from langchain_core. May 3, 2023 · masta-g3. literal_eval method. Aug 23, 2023 · However, in the current design of LangChain, the parse() method is not automatically invoked. main. 0. agents. To seek assistance and better understand the usage of the output parser, I attempted to access the documentation for the Python implementation. After importing, you can use it in your code as per your requirements. Mar 23, 2024 · self. 325 Python version: Python 3. Input should be a valid python command. Currently, I was doing it in two steps, getting the answer from this chain and then chat chai with the answer and custom prompt + memory to provide the final reply. Keep in mind that large language models are leaky abstractions! You'll have to use an LLM with sufficient capacity to generate well-formed JSON. Jul 6, 2023 · I am currently taking the "Langchain/lesson/2/models, prompts, and parsers" course from deeplearning. In this quickstart we'll show you how to: Get setup with LangChain, LangSmith and LangServe. py "Who won the superbowl the year j Oct 23, 2023 · 🤖. `defusedxml` is a wrapper around the standard library parser that sets To add the OutputFixingParser to LCEL in LangChain, you would first need to import it in the file where you are using LCEL. from langchain_core. class Task(BaseModel): task_description: str = Field(description="Description of the task") role_list: List It is built using FastAPI, LangChain and Postgresql. output_parsers import StructuredOutputParser, ResponseSchema from langchain. Quickstart. utilities import PythonREPL ImportError: cannot import name 'PythonREPL' from 'langchain_experimental. llms import OpenAI from langchain_core. 'prompt best suited for the input. class Colors(Enum): RED = "red". When using an StruturedAgent with a pythonRepl tool, the agent tends to stop producing text before taking an action or providing an answer. Also, same question like @blazickjp is there a way to add chat memory to this ?. Use LangChain Expression Language, the protocol that LangChain is built on and which facilitates component chaining. Dec 18, 2023 · As we conclude our exploration into the world of output parsers, the PydanticOutputParser emerges as a valuable asset in the LangChain arsenal. OpenAI. Jan 26, 2024 · I'm using GPT-4 without any initialization parameter. LLMs/Chat Models; Embedding Models; Prompts / Prompt Templates / Prompt Selectors; Output Parsers; Document Loaders; Vector Stores docs: Syntax correction according to langchain version update in 'Retry Parser' tutorial example #16699 Merged hwchase17 added a commit that referenced this issue Jan 29, 2024 . The official example notebooks/scripts; My own modified scripts; Related Components. 0, openai Jan 11, 2024 · The problem is that it passes the constructed object (the output of PydanticOutputParser. It seems like the issue you're encountering is similar to a couple of previously solved issues in the LangChain repository. In agents, a language model is used as a reasoning engine to determine which actions to take and in which order. schema = Mar 15, 2024 · The problem is that this seems hackish, and I don't know if this will be portable in new versions of the parser (at least, in the example in the docs, I see no reference to the params that should be passed to parse_with_prompt, although I can see in the source code that they are completion: str and prompt_value: PromptValue, but I'm not sure if this should be considered an implementation Oct 27, 2023 · System Info Langchain version: 0. Structured Output Parser with Zod Schema. callbacks. document_loaders import TextLoader llm = AzureChatOpenAI (temperature = 0. 】 18 LangChain Chainsとは？【Simple・Sequential・Custom】 19 LangChain Memoryとは？【Chat Message History・Conversation Buffer Memory】 20 LangChain Agents 4 days ago · Parse the output of an LLM call to a JSON object. output_parsers. i was struggling to get the desired output for a while until i tried this approach: I had the same issue and fixed it by adding 'please output your response in the demanded json format' to the end of my prompt template. ai. The name of the dataframe is `df`. Specifically, we can pass the misformatted output, along with the formatted instructions, to the model and ask it to fix it. ) In this code, output_parser=agent_output_parser is used to pass your custom output parser to the agent. The suggested solution is to modify the parse method in the OutputFixingParser class to support asynchronous operations by adding the async keyword and using the await keyword to call other asynchronous functions. The problem you're experiencing is due to the regular expression pattern used in the StructuredChatOutputParser class. XML output parser. Can't post the full code due to restrictions. enum import EnumOutputParser. The suggested solution in both cases was to Testing: Write tests for your output parser. utilities' Idea or request for content: I assume the fix is below Apr 26, 2023 · EDIT: My original tool definition doesn't work anymore as of 0. For example, here we show how to run GPT4All or LLaMA2 locally (e. Now, you can use these in your langgraph. Pass this instance as the output_parser argument to create_react_agent. Return type. By seamlessly bridging the gap between raw text and DOTALL) parser: Literal ["defusedxml", "xml"] = "defusedxml" """Parser to use for XML parsing. g. astream() method in the test_agent_stream function: output = [ a async for a in agent. 4 Langchain Version: 0. BLUE = "blue". agents import AgentOutputParser # Step 1: Define your custom output parser class MyCustomOutputParser ( AgentOutputParser ): def parse ( self, input, output ): To create a new LangChain project and install this as the only package, you can do: langchain app new my-app --package guardrails-output-parser. agents import create_pandas_dataframe_agent from langchain. 5. This output parser allows users to obtain results from LLM in the popular XML format. Here's how you can do it: from langchain. Structured output parser. Output-fixing parser. Document Loading First, install packages needed for local embeddings and vector storage. * 'defusedxml' is the default parser and is used to prevent XML vulnerabilities present in some distributions of Python's standard library xml. Keep in mind that large language models are leaky abstractions! You'll have to use an LLM with sufficient capacity to generate well-formed XML. What is it used for? It is used when you want to parse an LLM’s response into a structured format like a dict, or JSON. Who can help? @hwchase17 @agola11. ) llm=llm, tools=tools, agent=agent_obj, tools=tools, verbose=True, return_intermediate_steps=True. 2 LTS langchain 0. Ollama allows you to run open-source large language models, such as Llama 2, locally. The parser leverages Pydantic’s BaseModel for data validation and type checking. , on your laptop) using local embeddings and a local LLM. import { z } from "zod"; ChatOllama. Here's how you can do it: output = chain. Well, I don't want a function to be called, but I need to fill a structured object. It optimizes setup and configuration details, including GPU usage. In this tutorial I used OpenAI's ChatGPT API to support LLM. System Info langchain 0. I used the GitHub search to find a similar question and didn't find it. 11. While the Pydantic/JSON parser is more powerful, this is useful for less powerful models. This Code is just an example. output_parsers import PydanticOutputParser from langchain. It will then cover how to use Prompt Templates to format the inputs to these models, and how to use Output Parsers to work with the outputs. If False, then the model can elect whether to use the output schema. Please see list of integrations. Ollama bundles model weights, configuration, and data into a single package, defined by a Modelfile. Thought: I don't know this one, I'll use the calculator. Please note that this is a simplified example and might not cover all your needs. langchain. 16 LangChain Model I/Oとは？【Prompts・Language Models・Output Parsers】 17 LangChain Retrievalとは？【Document Loaders・Vector Stores・Indexing etc. In the OpenAI family, DaVinci can do reliably but Curie from langchain. Mar 26, 2024 · This class is used to parse the output of tool invocations and final answers that are in JSON format. T. In chains, a sequence of actions is hardcoded (in code). It will introduce the two different types of models - LLMs and Chat Models. py. Action: Calculator. llms import OpenAI llm = OpenAI (model_name = "text-davinci-003") # 告诉他我们生成的内容需要哪些字段，每个字段类型式啥 response_schemas = [ ResponseSchema (name = "bad_string Feb 2, 2024 · Another option is to try to use JSONParser and then follow up with a custom parser that uses the pydantic model to parse the json once its complete. Pydantic parser. from langchain_experimental. LangChain simplifies every stage of the LLM application lifecycle: Development: Build your applications using LangChain's open-source building blocks and components. Jun 2, 2023 · This is because the parser is returning an AgentFinish object immediately if FINAL_ANSWER_ACTION is in the text, rather than checking if the text also includes a valid action. The simplest kind of output parser extends the BaseOutputParser<T> class and must implement the following methods: parse, which takes extracted string output from the model and returns an instance of T. parse) instead of the output message as a plain string. 194 Who can help? @eyurtsev Information The official example notebooks/scripts My own modified scripts Related Components LLMs/Chat Models Embedding Models Prompts / Prompt May 24, 2023 · raise OutputParserException (. You might need to adjust it according to your specific requirements. For these applications, LangChain simplifies the entire application lifecycle: Open-source libraries: Build your applications using LangChain's modular building blocks and components. The output parser also supports streaming outputs. Nov 9, 2023 · In the LangChain framework, tools are defined as Python functions that return an instance of a class derived from BaseTool. Use this to execute python commands. I had this appear when using the Python agent, where the LLM returned a code block as the action, but simultaneously hallucinated the output and a final answer in one Mar 3, 2023 · Unfortunately, out of the box, langchain does not automatically handle these "failed to parse errors when the output isn't formatted right" errors. From what I understand, the issue is related to the prompt for the structured output parser having invalid JSON examples due to double brackets, which causes parsing errors. Returning Structured Output. LangChain is a framework for developing applications powered by large language models (LLMs). If there is a custom format you want to transform a model’s output into, you can subclass and create your own output parser. Dosubot has suggested potential solutions, such as modifying the regular expression or handling exceptions in the script. I hope this helps! Jan 4, 2024 · from langchain. Usage Jsonformer is a wrapper around Hugging Face models that fills in the fixed tokens during the generation process, and only delegates the generation of content tokens to the language model. The Zod schema passed in needs be parseable from a JSON string, so eg. You need to explicitly call it to parse the output into the appropriate object. If True and model does not return any structured outputs then chain output is None. It provides a comprehensive overview of the library's features and how to use them. Integrate with hundreds of third-party providers. 10. 6 Who can help? @hwchase17 chain_type="map_rerank" is not working when the search cannot be found on the DB Information The official example notebooks/scripts My own modi Jun 6, 2023 · The developers of LangChain keep adding new features at a very rapid pace. If you want to add this to an existing project, you can just run: langchain app add guardrails-output-parser. Apr 3, 2024 · The output parser I used (JsonOutputParser) can be encapsulated into a RetryOutputParser (or similar) to ensure that the output will be well formatted JSON; I can use a Python function that parses the output as the final step of my chain to ensure that this output is a valid JSON. Agents. This can help you catch errors and inconsistencies early, and it can also serve as documentation for how your output parser is supposed to work. llms import LlamaCpp from langchain. return_single: Only applies when mode is 'openai-tools'. fromTemplate('{input}'); let defaultChain = new LLMChain({llm: llm2, prompt: defaultPrompt}); // Now set up the router and it's template. The core idea of agents is to use a language model to choose a sequence of actions to take. Currently, the XML parser does not contain support for self closing tags, or attributes on tags. tools, llm , output_parser=agent_output_parser. During the discussion, it was suggested to add examples in the prompt of the zero-shot-react-agent to reduce the frequency of such issues. Action Input: 2. " parsed_output = parser. f"Got invalid return object. 162, code updated. This is a half-baked prototype that "helps" you extract structured data from text using LLMs 🧩. text ( str) – String output of a language model. manager import CallbackManager from langchain. LangChain has integrations with many open-source LLMs that can be run locally. It changes the way we interact with LLMs. Mar 25, 2024 · To parse the 'result' from 'RetrievalQA. The agent_executor_kwargs argument is not used since it's not needed for the output parser. 0 XML parser. documents import Document from langchain_experimental. By default, most of the agents return a single string. Here's an example: from langchain. output_parsers. Interestingly, the following code snippet does not cause mypy to report a type error: def make_parser() -> PydanticOutputParser: return PydanticOutputParser(pydantic_object=InputSourceResponse) However, the following, which should be semantically identical, gives the same error: def make_parser This repository is part of a tutorial for LangChain 🦜️🔗. astream ( "when was langchain made" )] The below quickstart will cover the basics of using LangChain's Model I/O components. py file: LangChain is a framework for developing applications powered by large language models (LLMs). This currently supports a subset of JSON Schema. While working on the course material, I encountered difficulties with the output parser in Python. Sep 18, 2023 · Solution for me on Colab at least (but maybe relevant to anyone with this issue) is that after noticing that pip install openapi_schema_pydantic simply didn't work (pip can't find the package, no doubt because there's no PyPi package for the Colab OS) I installed the package from github and that worked fine: Mar 27, 2024 · I searched the LangChain documentation with the integrated search. streaming_stdout import StreamingStdOutCallbackHandler callback_manager XML output parser. Apr 28, 2023 · Hey there, thanks for langchain! It's super awesome! 👍 I am currently trying to write a simple REST API but i am getting somewhat random errors. The LLM output was not in the expected format for the zero-shot-react-description agent. Illustrative example: Dec 14, 2023 · The output_parser cannot extract the JSON content correctly when LLM services like GPT4 wrap the JSON code with a JSON code block or prepend an explanation about what it wants to do. In this context, it is used to iterate over the output of the agent. And add the following code to your server. Aug 31, 2023 · specifically, i wanted the output to be 2 lists containing 5 strings each, the strings from the 2 lists are logically connected. You offered to open a PR to fix this, and it was confirmed that the issue is still present despite attempts to address it. Nov 2, 2023 · The StructuredOutputParser is an output parser that allows parsing raw text from an LLM into a Python dictionary or other object based on a provided schema. To resolve this, you would need to update the "regex" in the "output_parser" section to match the output format of the new model. In streaming, if diff is set to True, yields JSONPatch operations describing the difference between the previous and the current object. This notebook covers how to have an agent return a structured output. cpp into a single file that can run on most computers any additional dependencies. Whether to a list of structured outputs or a single one. Contribute to gkamradt/langchain-tutorials development by creating an account on GitHub. The most basic and common use case is chaining a prompt template and a model together. Jun 13, 2023 · let defaultPrompt = PromptTemplate. You should use the tools below to answer the question posed of you: python_repl_ast: A Python shell. So yes – it’s just another wrapper on top of LLMs All you need to do is: 1) Download a llamafile from HuggingFace 2) Make the file executable 3) Run the file. Introduction. Jul 26, 2023 · raise OutputParserException(. from langchain. Hit the ground running using third-party integrations and Templates. You can then use this JSON to generate a table-like output in your desired format. output_parsers import ResponseSchema, StructuredOutputParser. py file: 2 days ago · Structured output. To create a new LangChain project and install this as the only package, you can do: langchain app new my-app --package guardrails-output-parser. Can be either 'defusedxml' or 'xml'. I wanted to let you know that we are marking this issue as stale. output_parser. Hello, Thank you for bringing this issue to our attention. I am sure that this is a bug in LangChain rather than my code. But we can do other things besides throw errors. The prompt is largely provided in the event the OutputParser wants to retry or fix the output in some way, and needs information from the prompt to do so. I'm a bot designed to assist with issues in the LangChain repository. It demonstrates how to use LangChain with OpenAI models and provides various examples to show how LangChain can be used to build AI-powered applications. This output parser can be also be used when you want to define the output schema using Zod, a TypeScript validation library. Specifically, these two issues: too many doc url invalid and DOC: Broken Python Information Link in Langchain Documentation. Here's an example of how you can do this: def parse ( self, text: str) -> Any : """Returns the input text with no changes. py", line 18, in parse action = text. prompts import PromptTemplate from langchain_community. The XMLOutputParser takes language model output which contains XML and parses it into a JSON object. I'm here to help you troubleshoot bugs, answer questions, and guide you on how to be a contributor. 10 ubuntu Ubuntu 22. For example: C Apr 19, 2024 · rpgoldman commented 52 minutes ago. I searched the LangChain documentation with the integrated search. Subclasses should override this method if they can run asynchronously. In this article, we will go through an example use case to demonstrate how using output parsers with prompt templates helps getting more structured output from LLMs. OutputParserException: Parsing LLM output produced both a final answer and a parse-able action: that was easy. Nov 22, 2023 · 🤖. Hi, @hjr3!I'm Dosu, and I'm helping the langchainjs team manage their backlog. parse_with_prompt (completion: str, prompt: PromptValue) → Any ¶ Parse the output of an LLM call with the input prompt for context. Overview and tutorial of the LangChain Library. From what I understand, you reported an issue with the prompt for the structured output parser containing double brackets, causing problems with the JSON output. pydantic_v1 import BaseModel, Field, validator from typing import List model = llm # Define your desired data structure. prompts import PromptTemplate. Other Resources The output parser documentation includes various parser examples for specific types (e. Parameters 2 days ago · If True, then the model will be forced to use the given output schema. These tools provide access to various resources and services like APIs, databases, file systems, etc. Information. As for resources, the Pydantic documentation is a great place to start. Basic example: prompt + model + output parser. z. jacoblee93 has been asked to help you with the issue. Checked other resources I added a very descriptive title to this issue. 287 python fastapi Who can help? No response Information The official example notebooks/scripts My own modified scripts Related Components LLMs/Chat Models Embedding Models Prompts / Prompt Templates / Prompt Jul 20, 2023 · From what I understand, the issue is that the OutputFixingParser in the LangChain Python library does not support async flows. import { z } from "zod"; Mar 23, 2024 · Create an instance of your custom parser. date() is not allowed. Language models in LangChain come in two Aug 9, 2023 · Hey there, I am trying to generate a simple list of quotes, using langchain with GPT-4. """This is an example of how to use async langchain with fastapi and return a streaming response. Kor will generate a prompt, send it to the specified LLM and parse out the output. You might even get results back. from enum import Enum. For a complete list of supported models and model variants, see the Ollama model Nov 26, 2023 · This is likely due to a mismatch between the output format of the new model and the regex pattern specified in the "output_parser" section of your configuration. Raw. This output parser allows users to specify an arbitrary Pydantic Model and query LLMs for outputs that conform to that schema. graph_transformers import LLMGraphTransformer from langchain_openai import AzureChatOpenAI, ChatOpenAI from langchain_text_splitters import TokenTextSplitter from langchain_community. dq qi bl um oi tb wz go ex io