Troubleshooting of Streamlit apps: Difference between revisions
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= Troubleshooting of Streamlit Apps: LangChain RAG Integration Issues = | == Troubleshooting of Streamlit Apps: LangChain RAG Integration Issues == | ||
I've built a Streamlit application that implements a RAG (Retrieval Augmented Generation) system using LangChain, Pinecone for vector storage, and LLMs (GPT/Claude). The app is experiencing a critical error when attempting to generate responses. | I've built a Streamlit application that implements a RAG (Retrieval Augmented Generation) system using LangChain, Pinecone for vector storage, and LLMs (GPT/Claude). The app is experiencing a critical error when attempting to generate responses. | ||
I've checked the logs from "Manage App" in Streamlit Cloud and found this error: | I've checked the logs from "Manage App" in Streamlit Cloud and found this error<ref>[https://discuss.streamlit.io/t/streamlit-logging-with-python-logger/51951 Streamlit Logging with Python Logger - Using Streamlit - Streamlit]</ref>: | ||
<pre> | <pre> | ||
KeyError: "Input to ChatPromptTemplate is missing variables {'Source2', 'page', 'Source1'}. Expected: ['Source1', 'Source2', 'chat''history', 'context', 'input', 'page'] Received: ['input', 'chat''history', 'context']" | KeyError: "Input to ChatPromptTemplate is missing variables {'Source2', 'page', 'Source1'}. Expected: ['Source1', 'Source2', 'chat''history', 'context', 'input', 'page'] Received: ['input', 'chat''history', 'context']" | ||
| Line 31: | Line 31: | ||
1. <Source1>, p.<page> | 1. <Source1>, p.<page> | ||
2. <Source2>, p.<page> | 2. <Source2>, p.<page> | ||
Replace <Source1>, <Source2>, etc., with the actual source names, and <page> with the relevant page numbers if available. | |||
</pre> | </pre> | ||
Be cautious when using curly braces {{kbd | key=<nowiki>{xxx}</nowiki>}} in LangChain prompts - they're interpreted as variable placeholders. If you include them in your prompt, you must provide corresponding Python variables to pass these values. | To display curly braces as plain text in your prompt, use double curly braces {{kbd | key=<nowiki>{{</nowiki>}} and {{kbd | key=<nowiki>}}</nowiki>}} for escaping. Alternatively, you can replace them with {{kbd | key=<nowiki><</nowiki>}} and {{kbd | key=<nowiki>></nowiki>}} if that fits your use case. | ||
Be cautious when using curly braces {{kbd | key=<nowiki>{xxx}</nowiki>}} in LangChain prompts - they're interpreted as variable placeholders. If you include them in your prompt, you must provide corresponding Python variables to pass these values. Be cautious when using curly braces {{kbd | key=<nowiki>{{xxx}}</nowiki>}} in LangChain prompts - they're interpreted as variable placeholders. If you include them in your prompt, you must provide corresponding Python variables to pass these values.<ref>[https://github.com/langchain-ai/langchain/issues/10639 When I use a prompt with "{", I get an error · Issue #10639 · langchain-ai/langchain]</ref> | |||
== References == | |||
<references /> | |||
[[Category: Programming]] | [[Category: Programming]] | ||
[[Category: Python]] | [[Category: Python]] | ||
[[Category: LangChain]] | [[Category: LangChain]] | ||
Latest revision as of 10:37, 27 February 2025
Troubleshooting of Streamlit Apps: LangChain RAG Integration Issues[edit]
I've built a Streamlit application that implements a RAG (Retrieval Augmented Generation) system using LangChain, Pinecone for vector storage, and LLMs (GPT/Claude). The app is experiencing a critical error when attempting to generate responses.
I've checked the logs from "Manage App" in Streamlit Cloud and found this error[1]:
KeyError: "Input to ChatPromptTemplate is missing variables {'Source2', 'page', 'Source1'}. Expected: ['Source1', 'Source2', 'chat''history', 'context', 'input', 'page'] Received: ['input', 'chat''history', 'context']"
The error trace shows it's failing in langchain_core/prompts/base.py during the validation of input variables, suggesting a mismatch between what my chain provides and what the prompt template expects.
The issue appears to be in my document formatting pipeline. My current implementation:
- Retrieves documents from Pinecone
- Uses a
format_docs()function that formats documents as strings - Passes this to a LangChain prompt template from a Hub that expects additional variables
I've identified that my prompt template needs modification. Currently it contains:
Current Prompt (causing errors):
Markdown format answer[1][2]
# Data Sources
1. {Source1}, p.{page}
2. {Source2}, p.{page}
Proposed Modified Prompt:
Markdown format answer[1][2] # Data Sources == 1. <Source1>, p.<page> 2. <Source2>, p.<page> Replace <Source1>, <Source2>, etc., with the actual source names, and <page> with the relevant page numbers if available.
To display curly braces as plain text in your prompt, use double curly braces {{ and }} for escaping. Alternatively, you can replace them with < and > if that fits your use case.
Be cautious when using curly braces {xxx} in LangChain prompts - they're interpreted as variable placeholders. If you include them in your prompt, you must provide corresponding Python variables to pass these values. Be cautious when using curly braces {{xxx}} in LangChain prompts - they're interpreted as variable placeholders. If you include them in your prompt, you must provide corresponding Python variables to pass these values.[2]