[fix] Use context variables in Vpn.auto_client for OpenVPN backend

[pandafy]

Checklist

• I have read the OpenWISP Contributing Guidelines.
• I have manually tested the changes proposed in this pull request.
• N/A I have written new test cases for new code and/or updated existing tests for changes to existing code.
• N/A I have updated the documentation.

Description of Changes

Bug:

The Vpn.auto_client method was incorrectly using the Vpn.host field when generating the client configuration for the OpenVPN backend.

This resulted in the remote directive being hardcoded in the Template.config, instead of being rendered from the provided context variables.

Fix:

The Vpn.auto_client method has been updated to use the correct context-based values.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

📜 Recent review details

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Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 012a094 and 8ee0c8e.

📒 Files selected for processing (2)

• openwisp_controller/config/base/vpn.py
• openwisp_controller/config/tests/test_vpn.py

🧰 Additional context used

🧠 Learnings (2)

📚 Learning: 2026-01-15T15:05:49.557Z

Learnt from: DragnEmperor
Repo: openwisp/openwisp-controller PR: 1175
File: openwisp_controller/config/management/commands/clear_last_ip.py:38-42
Timestamp: 2026-01-15T15:05:49.557Z
Learning: In Django projects, when using select_related() to traverse relations (for example, select_related("organization__config_settings")), the traversed relation must not be deferred. If you also use .only() in the same query, include the relation name or FK field (e.g., "organization" or "organization_id") in the .only() list to avoid the error "Field X cannot be both deferred and traversed using select_related at the same time." Apply this guideline to Django code in openwisp_controller/config/management/commands/clear_last_ip.py and similar modules by ensuring any select_related with an accompanying only() includes the related field names to prevent deferred/traversed conflicts.

Applied to files:

• openwisp_controller/config/tests/test_vpn.py
• openwisp_controller/config/base/vpn.py

📚 Learning: 2026-01-15T15:07:17.354Z

Learnt from: DragnEmperor
Repo: openwisp/openwisp-controller PR: 1175
File: openwisp_controller/geo/estimated_location/tests/tests.py:172-175
Timestamp: 2026-01-15T15:07:17.354Z
Learning: In this repository, flake8 enforces E501 (line too long) via setup.cfg (max-line-length = 88) while ruff ignores E501 via ruff.toml. Therefore, use '# noqa: E501' on lines that intentionally exceed 88 characters to satisfy flake8 without affecting ruff checks. This applies to Python files across the project (any .py) and is relevant for tests as well. Use sparingly and only where breaking lines is not feasible without hurting readability or functionality.

Applied to files:

• openwisp_controller/config/tests/test_vpn.py
• openwisp_controller/config/base/vpn.py

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (10)

• GitHub Check: Python==3.11 | django~=4.2.0
• GitHub Check: Python==3.12 | django~=5.2.0
• GitHub Check: Python==3.11 | django~=5.1.0
• GitHub Check: Python==3.13 | django~=5.2.0
• GitHub Check: Python==3.13 | django~=5.1.0
• GitHub Check: Python==3.10 | django~=5.1.0
• GitHub Check: Python==3.10 | django~=4.2.0
• GitHub Check: Python==3.12 | django~=5.1.0
• GitHub Check: Python==3.11 | django~=5.2.0
• GitHub Check: Python==3.12 | django~=4.2.0

🔇 Additional comments (3)

openwisp_controller/config/base/vpn.py (1)

621-654: LGTM! Correct fix for using context variables in OpenVPN auto_client.

The pop("vpn_host", self.host) correctly extracts the wrapped context variable (e.g., {{vpn_host_<hex>}}) and passes it as host to backend.auto_client, ensuring the remote directive is rendered from context rather than hardcoded. The pop also properly removes vpn_host from context_keys to avoid passing an unsupported kwarg.

openwisp_controller/config/tests/test_vpn.py (2)

193-222: LGTM! Tests correctly updated to mirror the production code change.

The test now constructs the control value using context_keys.pop("vpn_host") as the host argument, matching the new behavior in auto_client where host is derived from context variables rather than vpn.host directly.

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224-245: LGTM!

Consistent with the test_auto_client update above.

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Walkthrough

The change modifies the AbstractVpn.auto_client method to derive the host argument from context_keys (specifically the vpn_host key, defaulting to self.host) instead of directly using self.host when invoking the backend's auto_client. The corresponding tests are updated to reflect this new host extraction pattern.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: using context variables in Vpn.auto_client method for OpenVPN backend, which aligns with the changeset.
Description check	✅ Passed	The description includes key sections (checklist completion, description of bug and fix) but lacks reference to an existing issue and test case details.

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• Post copyable unit tests in a comment
• Commit unit tests in branch fix-vpn-auto-client

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[pandafy]

@nemesifier IMO, this needs to be backported as well.

[coveralls]

coverage: 98.636% (+0.03%) from 98.607%
when pulling 8ee0c8e on fix-vpn-auto-client
into 012a094 on master.