[GH-ISSUE #8772] how to catch exception from a pipe to render the toast.error like in router/openai #118559

New Issue

GiteaMirror · 2026-05-20T19:54:44-05:00

GiteaMirror commented

2026-05-20 19:54:44 -05:00

Originally created by @sir3mat on GitHub (Jan 22, 2025).
Original GitHub issue: https://github.com/open-webui/open-webui/issues/8772

Bug Report

Issue Description

When streaming data from a pipe to OpenWebUI, exceptions raised by the pipe are not properly captured or propagated to trigger a toast.error in the OpenWebUI chat UI. This behavior is inconsistent with the router/openai endpoint, where exceptions are properly surfaced to the UI.

Steps to Reproduce

Set up a pipe to stream data to OpenWebUI.
Raise an exception from the pipe during the streaming process.
Observe that the exception is not propagated to the UI as a toast.error notification.

Expected Behavior

The exception raised from the pipe should trigger the same toast.error behavior in the OpenWebUI chat UI as when an exception is raised from the router/openai endpoint.

Code Reference

The issue seems to occur in the following code snippet: 568dbc545c/backend/open_webui/functions.py (L278)

Observations

In router/openai, exceptions raised by the OpenAI endpoint result in a toast.error notification in the UI. However, this behavior is not observed when exceptions are raised from a pipe during streaming.

Questions

How can exceptions raised from a pipe during streaming be captured and propagated to the UI to achieve consistent behavior with the router/openai endpoint?
Are there specific mechanisms or error-handling structures that need to be implemented to ensure this behavior?

Originally created by @sir3mat on GitHub (Jan 22, 2025). Original GitHub issue: https://github.com/open-webui/open-webui/issues/8772 Bug Report Issue Description When streaming data from a pipe to OpenWebUI, exceptions raised by the pipe are not properly captured or propagated to trigger a toast.error in the OpenWebUI chat UI. This behavior is inconsistent with the router/openai endpoint, where exceptions are properly surfaced to the UI. Steps to Reproduce 1. Set up a pipe to stream data to OpenWebUI. 2. Raise an exception from the pipe during the streaming process. 3. Observe that the exception is not propagated to the UI as a toast.error notification. Expected Behavior The exception raised from the pipe should trigger the same toast.error behavior in the OpenWebUI chat UI as when an exception is raised from the router/openai endpoint. Code Reference The issue seems to occur in the following code snippet: https://github.com/open-webui/open-webui/blob/568dbc545cdd7e1d08e0db7851bace82db04a418/backend/open_webui/functions.py#L278 Observations In router/openai, exceptions raised by the OpenAI endpoint result in a toast.error notification in the UI. However, this behavior is not observed when exceptions are raised from a pipe during streaming. Questions 1. How can exceptions raised from a pipe during streaming be captured and propagated to the UI to achieve consistent behavior with the router/openai endpoint? 2. Are there specific mechanisms or error-handling structures that need to be implemented to ensure this behavior?

GiteaMirror closed this issue

2026-05-20 19:54:44 -05:00

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Reference: github-starred/open-webui#118559