fix: make LANGFUSE_BASE_URL the preferred URL variable

[mendonk]

Langflow previously used LANGFUSE_HOST as the variable for the Langfuse base URL.
If you copy values from Langfuse, it now uses LANGFUSE_BASE_URL.

This pull request makes LANGFUSE_BASE_URL the preferred environment variable, and includes LANGFUSE_HOST for backward compatibility. LANGFUSE_BASE_URL will be used if both values are set. None host is returned if neither (which is the current behavior).

Docs are updated to use the LANGFUSE_BASE_URL value, and includes a note for users that may still be using LANGFUSE_HOST.

Summary by CodeRabbit

• Documentation

  • Updated Langfuse integration setup instructions with renamed environment variable and API key nomenclature.
  • Added backward compatibility note for existing configurations.
  • Standardized .env file workflow in setup examples.

• Chores

  • Updated environment variable resolution logic to prioritize new naming convention while maintaining backward compatibility.

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Walkthrough

This PR updates the Langfuse integration to rename the host configuration environment variable from LANGFUSE_HOST to LANGFUSE_BASE_URL while maintaining backward compatibility. Both documentation and service code are updated to reflect this change.

Changes

Cohort / File(s)	Summary
Documentation Updates docs/docs/Develop/integrations-langfuse.mdx	Renamed environment variable from LANGFUSE_HOST to LANGFUSE_BASE_URL across all examples, instructions, and docker-compose configurations. Updated terminology from "Host URL" to "Base URL" and adjusted API key labeling. Added backward compatibility note indicating LANGFUSE_HOST remains supported.
Service Implementation src/backend/base/langflow/services/tracing/langfuse.py	Updated environment variable resolution to read LANGFUSE_BASE_URL as primary source with fallback to LANGFUSE_HOST for backward compatibility.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

---

Important

Pre-merge checks failed

Please resolve all errors before merging. Addressing warnings is optional.

❌ Failed checks (1 error, 2 warnings, 1 inconclusive)

Check name	Status	Explanation	Resolution
Test Coverage For New Implementations	❌ Error	PR modifies langfuse.py environment variable resolution logic but includes no test files to verify the changes work correctly.	Add test coverage verifying LANGFUSE_BASE_URL priority over LANGFUSE_HOST, fallback behavior, and backward compatibility.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Test Quality And Coverage	⚠️ Warning	No tests added or modified to verify the new environment variable precedence behavior in langfuse.py configuration function.	Add unit tests covering: (1) LANGFUSE_BASE_URL set scenario, (2) LANGFUSE_HOST backward compatibility, (3) precedence when both variables exist, (4) neither variable case.
Test File Naming And Structure	❓ Inconclusive	No test files are created or modified in this PR. The changes only affect documentation and one backend file for Langfuse environment variable resolution.	Determine if tests should be added to cover the Langfuse configuration changes, or clarify if this check applies to this particular PR.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title clearly and accurately summarizes the main objective: making LANGFUSE_BASE_URL the preferred URL variable for Langfuse integration.
Excessive Mock Usage Warning	✅ Passed	PR modifies only documentation and one config method; no test files added or modified, so custom check for excessive mock usage is not applicable.

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[github-actions]

Frontend Unit Test Coverage Report

Coverage Summary

Lines	Statements	Branches	Functions
	24.14% (8609/35660)	16.89% (4743/28067)	16.87% (1261/7473)

Unit Test Results

Tests	Skipped	Failures	Errors	Time
2776	0 💤	0 ❌	0 🔥	45.012s ⏱️

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 38.40%. Comparing base (aea0796) to head (781f884).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...backend/base/langflow/services/tracing/langfuse.py	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (40.00%). You can increase the patch coverage or adjust the target coverage.
❌ Your project status has failed because the head coverage (44.26%) is below the target coverage (60.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #12154   +/-   ##
=======================================
  Coverage   38.39%   38.40%           
=======================================
  Files        1630     1630           
  Lines       80290    80290           
  Branches    12120    12120           
=======================================
+ Hits        30830    30834    +4     
+ Misses      47724    47719    -5     
- Partials     1736     1737    +1     

Flag	Coverage Δ
backend	57.31% <0.00%> (+0.02%)	⬆️
frontend	21.56% <ø> (ø)
lfx	44.26% <ø> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...backend/base/langflow/services/tracing/langfuse.py	0.00% <0.00%> (ø)

... and 8 files with indirect coverage changes

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@docs/docs/Develop/integrations-langfuse.mdx`:
- Around line 44-54: Add missing title attributes to the code fences shown in
the diff: update the first ```bash fence containing the env vars to ```bash
title=".env", change the ```bash fence with the uv run command to ```bash
title="terminal", change the ```yml fence for the docker-compose snippet to
```yml title="docker-compose.yml", and change the ```sh fence with the docker
compose exec command to ```sh title="terminal" so all code blocks follow the
docs standard; locate these by the existing fences (```bash, ```yml, ```sh) and
the shared snippet contents to apply the titles.
- Around line 133-136: The troubleshooting note is misleading because the sample
command reads LANGFUSE_BASE_URL inside the langflow container; update the text
to instruct users to set LANGFUSE_BASE_URL in the docker compose service's
environment section (not their host shell) and then recreate/restart the
langflow service so the container picks up the change (e.g., recreate the
service via docker compose up -d or equivalent), while keeping the existing
docker compose exec langflow python... check as the validation step.

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📥 Commits

Reviewing files that changed from the base of the PR and between 911bc9d and 913eeb3.

📒 Files selected for processing (2)

• docs/docs/Develop/integrations-langfuse.mdx
• src/backend/base/langflow/services/tracing/langfuse.py

[aimurphy]

approving docs changes with one comment

[github-actions]

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