Bug/add hf token

[nishika26]

Summary

Target issue is #108

Notes

Summary by CodeRabbit

• Chores
  • Added Hugging Face authentication token configuration
  • Optimized container startup by pre-downloading models during build
  • Enabled pre-installation of Guardrails Hub validators in Docker

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 87599fbd-06fc-4ebf-b6b2-21503f13e9ec

📥 Commits

Reviewing files that changed from the base of the PR and between 3e5be97 and a55d939.

📒 Files selected for processing (3)

• .env.example
• backend/Dockerfile
• docker-compose.yml

📝 Walkthrough

Walkthrough

This PR adds Hugging Face token support and Guardrails Hub API key forwarding to the Docker build pipeline. The .env.example template defines the HF_TOKEN placeholder, the backend/Dockerfile declares these as build arguments, pre-downloads a toxicity-classifier model, and pre-installs Guardrails validators, while docker-compose.yml routes environment variables as build arguments to both services.

Changes

HF Token and Guardrails Pre-configuration

Layer / File(s)	Summary
Environment Configuration .env.example	HF_TOKEN placeholder is added for Hugging Face authentication.
Dockerfile Build Configuration backend/Dockerfile	HuggingFace cache directory HF_HOME=/app/hf_cache is set; build arguments HF_TOKEN and GUARDRAILS_HUB_API_KEY are declared; a RUN step pre-downloads the textdetox/xlmr-large-toxicity-classifier model; a second RUN step pre-installs Guardrails Hub validators via install_guardrails_from_hub.sh with ENABLE_METRICS=false and ENABLE_REMOTE_INFERENCING=true.
Compose Build Arguments docker-compose.yml	build.args forwarding HF_TOKEN and GUARDRAILS_HUB_API_KEY are added to both the prestart and backend service configurations.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 HuggingFace tokens hop along,
Pre-download guards our startup song,
No more delays when containers wake,
Guardrails validators bake, bake, bake! 🎂

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'Bug/add hf token' is vague and uses non-descriptive terms. It lacks clarity about what is being added or fixed, using abbreviations without context.	Provide a more descriptive title that clearly explains the purpose, such as 'Add HuggingFace token support to Docker builds and environment configuration' or 'Configure HuggingFace authentication for model pre-downloads in Docker'.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bug/add_hf_token

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.env.example:
- Line 26: Remove the stray space after the equals sign in the HF_TOKEN
environment variable declaration in .env.example so the token value doesn't
include a leading space; update the HF_TOKEN line (the entry named HF_TOKEN) to
have no space between '=' and the quoted placeholder so dotenv parsers will read
the token correctly.

In `@backend/Dockerfile`:
- Around line 54-65: The Dockerfile currently uses ARG HF_TOKEN and ARG
GUARDRAILS_HUB_API_KEY and interpolates them into RUN commands (the two RUN
blocks that call python to preload transformers and
/app/scripts/install_guardrails_from_hub.sh); replace those ARG-based secrets
with BuildKit secret mounts by changing the RUN lines to use
--mount=type=secret,id=HF_TOKEN (and id=GUARDRAILS_HUB_API_KEY) so the tokens
are read from the secret files during the RUN and not baked into layers, and
update your docker-compose build configuration to declare these secrets at the
top level and reference them under each service’s build:secrets so the secrets
are provided to the build with no args: exposure.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 01c5d084-1465-455c-ac2e-1dfe19266c5d

📥 Commits

Reviewing files that changed from the base of the PR and between b519e43 and 3e5be97.

📒 Files selected for processing (3)

• .env.example
• backend/Dockerfile
• docker-compose.yml