[EPIC-5-1] FastAPI Service with Health Check and Scheduler#28
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- What: Created FastAPI application entry point with modern lifespan events, APScheduler integration, health check endpoints, and placeholder items router - Why: Establishes core API service infrastructure for Noosphere (Issue #16) - How: Modern FastAPI patterns with @asynccontextmanager lifespan, AsyncIOScheduler for background jobs, and fail-fast startup strategy Acceptance criteria addressed: - [x] FastAPI application with modern lifespan events (startup/shutdown) - [x] Three health check endpoints (/health, /health/ready, /health/live) - [x] APScheduler integration for background jobs (surfacing, cleanup) - [x] Placeholder items router (GET/POST/PUT/DELETE with 501/404 responses) - [x] CORS middleware configuration - [x] Startup script (run.sh) for development - [x] Comprehensive test suite with 100% coverage Implementation details: - app/main.py: FastAPI app with @asynccontextmanager lifespan pattern - Startup: load config → connect database → start scheduler - Shutdown: gracefully stop scheduler - CORS middleware with configurable origins - Router registration for health and items endpoints - app/services/scheduler.py: APScheduler service (AsyncIOScheduler) - Surfacing job (interval trigger, configurable seconds) - Cleanup job (cron trigger, daily at 2 AM) - Graceful startup/shutdown with error handling - app/api/endpoints/health.py: Three health check endpoints - GET /health: Detailed status (database + scheduler + version) - GET /health/ready: Kubernetes readiness probe (database check) - GET /health/live: Kubernetes liveness probe (always 200) - app/api/endpoints/items.py: Placeholder CRUD endpoints - GET /items: Returns empty list [] - GET /items/{id}: Returns 404 Not Found - POST/PUT/DELETE: Returns 501 Not Implemented - run.sh: Startup script with .env loading, config validation, migrations, uvicorn server Testing: - Unit tests: 30 tests for scheduler, health endpoints, and items endpoints - Integration tests: 9 tests for app creation, lifespan, and router registration - Total: 39 tests, all passing - Coverage: 100% on new code (exceeds 90% target) Database changes: - None (infrastructure only) Dependencies added: - apscheduler>=3.10.4,<3.11.0 for background job scheduling - httpx>=0.25.0,<0.28.0 pinned to avoid breaking changes in 0.28+ Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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Summary of ChangesHello @deserat, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request lays the groundwork for the Noosphere API service by establishing its core FastAPI application. It focuses on creating a resilient and observable service foundation, integrating essential components like a configurable background job scheduler and a comprehensive health monitoring system. The inclusion of placeholder API routes ensures that the infrastructure can be tested and validated independently of future business logic development. Highlights
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Code Review
This pull request lays a solid foundation for the FastAPI service, with a well-structured application, modern practices like lifespan management, and comprehensive tests. My review focuses on improving the correctness of the health check endpoints to align with standard practices, enhancing the security and robustness of the startup script, and a few maintainability improvements to reduce hardcoded values and dead code.
| async def health(): | ||
| """Detailed health check endpoint. | ||
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| Returns comprehensive health status of all components. | ||
| Returns 503 if any component is unhealthy. | ||
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| Returns: | ||
| HealthResponse: Detailed status of database, scheduler, and service | ||
| """ | ||
| db_healthy = check_database_health() | ||
| scheduler_status = get_scheduler_status() | ||
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| # Determine overall status | ||
| overall_status = "healthy" if db_healthy and scheduler_status == "running" else "degraded" | ||
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| response = HealthResponse( | ||
| status=overall_status, | ||
| database=db_healthy, | ||
| scheduler=scheduler_status, | ||
| version="0.1.0", | ||
| ) | ||
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| # Return 503 if any component is unhealthy | ||
| if not db_healthy or scheduler_status != "running": | ||
| return response | ||
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| return response |
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The docstring for the /health endpoint states it "Returns 503 if any component is unhealthy," but the current implementation always returns a 200 OK status code, which can be misleading for monitoring systems. Additionally, the final if/return block is redundant. You can use JSONResponse to conditionally set the correct status code while returning the same response body.
You will need to add from fastapi.responses import JSONResponse to the imports at the top of the file.
async def health():
"""Detailed health check endpoint.
Returns comprehensive health status of all components.
Returns 503 if any component is unhealthy.
Returns:
HealthResponse: Detailed status of database, scheduler, and service
"""
db_healthy = check_database_health()
scheduler_status = get_scheduler_status()
# Determine overall status
is_healthy = db_healthy and scheduler_status == "running"
overall_status = "healthy" if is_healthy else "degraded"
response_data = HealthResponse(
status=overall_status,
database=db_healthy,
scheduler=scheduler_status,
version="0.1.0",
)
if not is_healthy:
return JSONResponse(status_code=503, content=response_data.model_dump())
return response_data| async def ready(): | ||
| """Readiness probe endpoint for Kubernetes. | ||
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| Checks if the service is ready to handle requests. | ||
| Load balancers use this to decide if instance should receive traffic. | ||
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| Returns: | ||
| ReadyResponse: Readiness status | ||
| """ | ||
| # Check database connection - critical for readiness | ||
| db_healthy = check_database_health() | ||
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| if not db_healthy: | ||
| return ReadyResponse(ready=False) | ||
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| return ReadyResponse(ready=True) |
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The /health/ready probe should return a 503 status code when the service is not ready to handle traffic. Currently, it returns a 200 OK with {"ready": false}, which may be misinterpreted by systems like Kubernetes that expect a non-2xx status code to mark a pod as unready.
To fix this, you can use JSONResponse to return the correct status code. You'll need to add from fastapi.responses import JSONResponse if you haven't already.
| async def ready(): | |
| """Readiness probe endpoint for Kubernetes. | |
| Checks if the service is ready to handle requests. | |
| Load balancers use this to decide if instance should receive traffic. | |
| Returns: | |
| ReadyResponse: Readiness status | |
| """ | |
| # Check database connection - critical for readiness | |
| db_healthy = check_database_health() | |
| if not db_healthy: | |
| return ReadyResponse(ready=False) | |
| return ReadyResponse(ready=True) | |
| async def ready(): | |
| """Readiness probe endpoint for Kubernetes. | |
| Checks if the service is ready to handle requests. | |
| Load balancers use this to decide if instance should receive traffic. | |
| Returns: | |
| ReadyResponse: Readiness status | |
| """ | |
| # Check database connection - critical for readiness | |
| db_healthy = check_database_health() | |
| if not db_healthy: | |
| return JSONResponse(status_code=503, content={"ready": False}) | |
| return ReadyResponse(ready=True) |
| # Load environment variables | ||
| if [ -f .env ]; then | ||
| echo "✓ Loading environment variables from .env..." | ||
| export $(grep -v '^#' .env | xargs) |
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The command export $(grep -v '^#' .env | xargs) is not a safe way to parse .env files. It is vulnerable to command injection if the .env file is compromised and will fail for variable values containing spaces. A more robust and secure method should be used.
| export $(grep -v '^#' .env | xargs) | |
| # Use `set -a` to automatically export all variables defined from now on. | |
| set -a | |
| # shellcheck source=.env | |
| source .env | |
| # Disable auto-exporting. | |
| set +a |
| app = FastAPI( | ||
| title="Noosphere API", | ||
| description="Knowledge management system with spaced repetition and AI classification", | ||
| version="0.1.0", | ||
| lifespan=lifespan, | ||
| ) |
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The application version '0.1.0' is hardcoded here and in other places (the root endpoint and health.py). To avoid inconsistencies and make version bumps easier, it's best practice to define the version in a single place. Consider adding __version__ = "0.1.0" at the top of this module and referencing it everywhere, or loading it from a configuration file.
| try: | ||
| config = get_config() | ||
| cors_origins = config.api.get("cors_origins", ["http://localhost:3000"]) | ||
| api_prefix = config.api.get("api_prefix", "/api") | ||
| api_version = config.api.get("api_version", "v1") | ||
| except RuntimeError: | ||
| # Config not loaded yet (e.g., during test imports) - use defaults | ||
| cors_origins = ["http://localhost:3000"] | ||
| api_prefix = "/api" | ||
| api_version = "v1" |
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This try...except block duplicates the default values for cors_origins, api_prefix, and api_version. This could lead to inconsistencies if one is updated and the other is forgotten. Consider defining these defaults as constants at the module level to ensure a single source of truth for both the .get() calls and the except block.
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| # Get configuration values | ||
| surfacing_interval = scheduler_config.get("surfacing_interval_seconds", 86400) | ||
| batch_size = scheduler_config.get("batch_size", 50) |
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The batch_size variable is retrieved from the configuration and logged, but it's never actually used. The scheduled jobs (surfacing_job, cleanup_job) don't accept it as an argument. This is unused code and can be confusing. If it's intended for future use, consider adding a TODO or passing it to the jobs. Otherwise, it should be removed for now.
| """ | ||
| if scheduler.running: | ||
| return "running" | ||
| elif scheduler.state == 0: # STATE_STOPPED |
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Using the magic number 0 for STATE_STOPPED is brittle and harms readability. The scheduler instance itself exposes state constants like STATE_STOPPED, which should be used to avoid issues if the underlying values change in future library versions.
| elif scheduler.state == 0: # STATE_STOPPED | |
| elif scheduler.state == scheduler.STATE_STOPPED: # STATE_STOPPED |
- What: Fixed 2 critical health endpoint bugs, 1 high-priority security vulnerability, and 4 code quality issues - Why: Gemini Code Assist review identified critical status code bugs, command injection risk, and code quality improvements - How: Implemented 6-phase fix addressing all identified issues Critical Fixes: - [CRITICAL] Health endpoint now returns HTTP 503 when unhealthy (was 200) - [CRITICAL] Ready endpoint returns HTTP 503 when not ready (was 200) - [HIGH] Fixed command injection vulnerability in run.sh .env loading Code Quality Improvements: - [MEDIUM] Centralized version management in app/__init__.py - [MEDIUM] Extracted configuration defaults to module-level constants - [MEDIUM] Removed unused batch_size variable from scheduler - [MEDIUM] Replaced magic number 0 with STATE_STOPPED constant Review comments addressed: - [x] Issue #1: /health endpoint returns 503 when degraded (health.py:66) - [x] Issue #2: /health/ready returns 503 when not ready (health.py:92) - [x] Issue #3: Fixed unsafe .env parsing in run.sh (run.sh:19) - [x] Issue #4: Version hardcoded in 3 locations (centralized to app/__init__.py) - [x] Issue #5: Duplicate default values in main.py (extracted to constants) - [x] Issue #6: Unused batch_size variable (scheduler.py:66) - [x] Issue #7: Magic number 0 instead of STATE_STOPPED (scheduler.py:131) Testing: - Updated 4 health endpoint tests to expect 503 status codes - All 143 tests passing - Coverage: 97% (target: 90%+) Files modified: - Created: app/__init__.py (version constant) - Modified: app/main.py (version import, config constants) - Modified: app/api/endpoints/health.py (JSONResponse, 503 status codes) - Modified: app/services/scheduler.py (STATE_STOPPED constant, removed batch_size) - Modified: run.sh (secure .env loading) - Modified: tests/unit/api/test_health.py (503 status code assertions) Security Impact: - Fixed command injection vulnerability in .env file parsing - Now uses secure 'set -a; source .env; set +a' pattern - Properly handles values with spaces and special characters Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Review Comments Addressed ✓Thank you for the thorough review! I've addressed all 7 comments from Gemini Code Assist. Here's a summary of the fixes: Critical Issues Fixed (2)1. ✅ Health endpoint status codes (CRITICAL)Issue: 2. ✅ Ready endpoint status codes (CRITICAL)Issue: High Priority Security Fix (1)3. ✅ Command injection vulnerability in run.sh (HIGH)Issue: Unsafe set -a # Automatically export all variables
source .env
set +a # Disable auto-exportBenefits:
Code Quality Improvements (4)4. ✅ Version hardcoded in 3 locations (MEDIUM)Issue: Version "0.1.0" duplicated in 5. ✅ Duplicate default values (MEDIUM)Issue: Configuration defaults duplicated in try/except block in DEFAULT_CORS_ORIGINS = ["http://localhost:3000"]
DEFAULT_API_PREFIX = "/api"
DEFAULT_API_VERSION = "v1"6. ✅ Unused batch_size variable (MEDIUM)Issue: 7. ✅ Magic number instead of constant (MEDIUM)Issue: Using from apscheduler.schedulers.base import STATE_STOPPED
# ...
elif scheduler.state == STATE_STOPPED:Verification Results ✓All quality checks passing: ✅ ruff format app/ # 1 file reformatted, 21 unchanged
✅ ruff check app/ # 0 errors in modified files
✅ pyright app/ # 0 errors, 0 warnings
✅ pytest --cov=app # 143 tests passed, 97% coverage (target: 90%+)Test UpdatesUpdated 4 health endpoint tests to expect 503 status codes:
Files Changed
Breaking ChangesMigration: Update monitoring systems to treat 503 as unhealthy (this is standard). Commit: 7c06291 |
1 participant
Summary
Created the FastAPI application entry point with modern lifespan events, comprehensive health check system, APScheduler integration for background jobs, and placeholder items router for infrastructure testing.
Related Issue
Closes #16 (EPIC-5-1)
Changes
FastAPI Application (
app/main.py):@asynccontextmanagerlifespan pattern for startup/shutdownAPScheduler Service (
app/services/scheduler.py):Health Check Endpoints (
app/api/endpoints/health.py):GET /health: Detailed status (database + scheduler + version)GET /health/ready: Kubernetes readiness probe (database check only)GET /health/live: Kubernetes liveness probe (always 200)Placeholder Items Router (
app/api/endpoints/items.py):GET /items: Returns empty list[]GET /items/{id}: Returns 404 Not FoundPOST /items: Returns 501 Not ImplementedPUT /items/{id}: Returns 501 Not ImplementedDELETE /items/{id}: Returns 501 Not ImplementedStartup Script (
run.sh):.envconfig.yamlexistsalembic upgrade head)Testing
Test Summary:
Database Changes
Dependencies Added
apscheduler>=3.10.4,<3.11.0- Background job schedulinghttpx>=0.25.0,<0.28.0- Pinned to avoid breaking changes in 0.28+Verification Steps
Checklist
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