feat(health): ping database and Redis, return 503 on failure

[Janeeshareddy]

Closes #78

Changes

• backend/app/cache.py — new Redis client manager (singleton, optional if redis_url not set)
• backend/app/main.py — updated /health to async-ping PostgreSQL and Redis with 2s timeout
• backend/tests/unit/test_health.py — 5 tests covering all scenarios

Behavior

Scenario	Status Code	Response
Both healthy	200	"status": "healthy"
DB down	503	"status": "degraded"
Redis down	503	"status": "degraded"
Both down	503	"status": "degraded"
Redis not configured	200	"redis": "not_configured"

Summary by CodeRabbit

• New Features

  • Enhanced health status monitoring: The health check now validates database and Redis availability, reporting service health as either healthy or degraded.
  • Added optional Redis support for caching, with graceful fallback if not configured.

• Tests

  • Improved health check test coverage to verify correct status reporting when database or Redis services are unavailable.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 91532f61-663a-4d8e-bee3-17647b4c3643

📥 Commits

Reviewing files that changed from the base of the PR and between 6db4575 and d5b6323.

📒 Files selected for processing (3)

• backend/app/cache.py
• backend/app/main.py
• backend/tests/unit/test_health.py

📝 Walkthrough

Walkthrough

This PR adds a Redis client singleton module and replaces the static /health endpoint with a service-dependent health check that verifies database and Redis connectivity, returning 200 when healthy and 503 when any critical service is unavailable, along with comprehensive test coverage for all health scenarios.

Changes

Health Endpoint Enhancement

Layer / File(s)	Summary
Redis client singleton management backend/app/cache.py	New module provides async Redis client singleton via get_redis_client() that lazily initializes on first call and returns None if redis_url is not configured, making Redis an optional dependency.
Enhanced health endpoint implementation backend/app/main.py	Adds imports for asyncio, JSONResponse, and sqlalchemy.text; includes the compatibility router under /api/v1; replaces /health handler with a dependency-checking implementation that verifies database and Redis connectivity using short timeouts, returning JSONResponse with 200 and status "healthy" when all services are reachable, or 503 and status "degraded" when any dependency fails, plus per-service status entries and app version.
Health endpoint test coverage backend/tests/unit/test_health.py	Replaces old tests with comprehensive mock-based suite using TestClient that validates all health scenarios: all services healthy (200, status "healthy"), database unavailable (503, status "degraded", database "unavailable"), Redis unavailable (503, status "degraded", redis "unavailable"), both unavailable (503, both "unavailable"), and Redis not configured (200, redis "not_configured").

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• rishabh0510rishabh/EnvForage#66: Both PRs modify the /health endpoint response shape and update health endpoint tests.

Suggested labels

type:feature

Suggested reviewers

• rishabh0510rishabh

Poem

🐰 A health check that's truly alive,
Pings the database and Redis alike,
When services thrive, we reply "OK",
But when they stumble, we signal dismay—
Now load balancers can trust what we say! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 36.36% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly summarizes the main objective: enhancing the health endpoint to ping database and Redis dependencies and return 503 on failure.
Linked Issues check	✅ Passed	The pull request implements all core objectives from issue #78: active dependency verification via async pings to PostgreSQL and Redis, dependency status in JSON response, and HTTP 503 return on failure.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to issue #78. New cache.py module supports optional Redis dependency management; main.py and test_health.py changes focus exclusively on health endpoint enhancement.

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

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Janeeshareddy]

Hey @rishabh0510rishabh, fixed the main.py content issue. PR is ready for review!

[coderabbitai]

Actionable comments posted: 3

🤖 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 `@backend/app/cache.py`:
- Line 1: Remove the shell heredoc wrapper lines from backend/app/cache.py:
delete the leading "cat > backend/app/cache.py << 'EOF'" line and the trailing
"EOF" line so the file contains only valid Python code; then verify the module
(cache.py) imports cleanly and contains the intended Python definitions
(functions/classes) without the heredoc tokens.

In `@backend/tests/unit/test_health.py`:
- Line 35: The tests are patching the wrong symbol: AsyncSessionLocal is
imported inside the /health route handler, so patching
app.main.AsyncSessionLocal has no effect; update the tests to patch the symbol
where the handler imports it (patch "app.routes.health.AsyncSessionLocal" or the
module that defines the health endpoint) so the mock returned by
AsyncSessionLocal is used during the request, and adjust the existing patch(...)
calls in the test_health tests to reference AsyncSessionLocal in the health
route module.
- Line 1: Remove the accidental heredoc wrapper lines from the test file so it
contains only valid Python test code (delete the leading "cat > ... << 'EOF'"
and trailing "EOF"), and update the patch target used in the test from
patch("app.main.AsyncSessionLocal", ...) to
patch("app.database.AsyncSessionLocal", ...) while leaving
patch("app.cache.get_redis_client", ...) unchanged; ensure imports and any
patched fixtures reference AsyncSessionLocal and get_redis_client accordingly.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 99c95adb-8d3f-473f-87a0-70616f308240

📥 Commits

Reviewing files that changed from the base of the PR and between b7ddb2b and 6db4575.

📒 Files selected for processing (3)

• backend/app/cache.py
• backend/app/main.py
• backend/tests/unit/test_health.py

[rishabh0510rishabh]

hey @Janeeshareddy address all coderabbit review and fix test fails
if you need any help feel free to reach out

[rishabh0510rishabh]

some checks still failed, please review them and make updates accordingly