thrilltrack-explorer/docs/PHASE_2_RESILIENCE_IMPROVEMENTS_COMPLETE.md

Phase 2: Resilience Improvements - COMPLETE ✅

Deployment Date: 2025-11-06
Status: All resilience improvements deployed and active

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Overview

Phase 2 focused on hardening the submission pipeline against data integrity issues, providing better error messages, and protecting against abuse. All improvements are non-breaking and additive.

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1. Slug Uniqueness Constraints ✅

Migration: 20251106220000_add_slug_uniqueness_constraints.sql

Changes Made:

• Added UNIQUE constraint on companies.slug
• Added UNIQUE constraint on ride_models.slug
• Added indexes for query performance
• Prevents duplicate slugs at database level

Impact:

• Data Integrity: Impossible to create duplicate slugs (was previously possible)
• Error Detection: Immediate feedback on slug conflicts during submission
• URL Safety: Guarantees unique URLs for all entities

Error Handling:

// Before: Silent failure or 500 error
// After: Clear error message
{
  "error": "duplicate key value violates unique constraint \"companies_slug_unique\"",
  "code": "23505",
  "hint": "Key (slug)=(disneyland) already exists."
}

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2. Foreign Key Validation ✅

Migration: 20251106220100_add_fk_validation_to_entity_creation.sql

Changes Made:

Updated create_entity_from_submission() function to validate foreign keys before INSERT:

Parks:

• ✅ Validates location_id exists in locations table
• ✅ Validates operator_id exists and is type operator
• ✅ Validates property_owner_id exists and is type property_owner

Rides:

• ✅ Validates park_id exists (REQUIRED)
• ✅ Validates manufacturer_id exists and is type manufacturer
• ✅ Validates ride_model_id exists

Ride Models:

• ✅ Validates manufacturer_id exists and is type manufacturer (REQUIRED)

Impact:

• User Experience: Clear, actionable error messages instead of cryptic FK violations
• Debugging: Error hints include the problematic field name
• Performance: Early validation prevents wasted INSERT attempts

Error Messages:

-- Before:
ERROR: insert or update on table "rides" violates foreign key constraint "rides_park_id_fkey"

-- After:
ERROR: Invalid park_id: Park does not exist
HINT: park_id

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3. Rate Limiting ✅

File: supabase/functions/process-selective-approval/index.ts

Changes Made:

• Integrated rateLimiters.standard (10 req/min per IP)
• Applied via withRateLimit() middleware wrapper
• CORS-compliant rate limit headers added to all responses

Protection Against:

• ❌ Spam submissions
• ❌ Accidental automation loops
• ❌ DoS attacks on approval endpoint
• ❌ Resource exhaustion

Rate Limit Headers:

HTTP/1.1 200 OK
X-RateLimit-Limit: 10
X-RateLimit-Remaining: 7

HTTP/1.1 429 Too Many Requests
Retry-After: 42
X-RateLimit-Limit: 10
X-RateLimit-Remaining: 0

Client Handling:

if (response.status === 429) {
  const retryAfter = response.headers.get('Retry-After');
  console.log(`Rate limited. Retry in ${retryAfter} seconds`);
}

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Combined Impact

Metric	Before Phase 2	After Phase 2
Duplicate Slug Risk	🔴 HIGH	🟢 NONE
FK Violation User Experience	🔴 POOR	🟢 EXCELLENT
Abuse Protection	🟡 BASIC	🟢 ROBUST
Error Message Clarity	🟡 CRYPTIC	🟢 ACTIONABLE
Database Constraint Coverage	🟡 PARTIAL	🟢 COMPREHENSIVE

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Testing Checklist

Slug Uniqueness:

• Attempt to create company with duplicate slug → blocked with clear error
• Attempt to create ride_model with duplicate slug → blocked with clear error
• Verify existing slugs remain unchanged
• Performance test: slug lookups remain fast (<10ms)

Foreign Key Validation:

• Create ride with invalid park_id → clear error message
• Create ride_model with invalid manufacturer_id → clear error message
• Create park with invalid operator_id → clear error message
• Valid references still work correctly
• Error hints match the problematic field

Rate Limiting:

• 11th request within 1 minute → 429 response
• Rate limit headers present on all responses
• CORS headers present on rate limit responses
• Different IPs have independent rate limits
• Rate limit resets after 1 minute

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Deployment Notes

Zero Downtime:

• All migrations are additive (no DROP or ALTER of existing data)
• UNIQUE constraints applied to tables that should already have unique slugs
• FK validation adds checks but doesn't change success cases
• Rate limiting is transparent to compliant clients

Rollback Plan:

If critical issues arise:

-- Remove UNIQUE constraints
ALTER TABLE companies DROP CONSTRAINT IF EXISTS companies_slug_unique;
ALTER TABLE ride_models DROP CONSTRAINT IF EXISTS ride_models_slug_unique;

-- Revert function (restore original from migration 20251106201129)
-- (Function changes are non-breaking, so rollback not required)

For rate limiting, simply remove the withRateLimit() wrapper and redeploy edge function.

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Monitoring & Alerts

Key Metrics to Watch:

1. Slug Constraint Violations:

   SELECT COUNT(*) FROM approval_transaction_metrics
   WHERE success = false
   AND error_message LIKE '%slug_unique%'
   AND created_at > NOW() - INTERVAL '24 hours';
   

2. FK Validation Errors:

   SELECT COUNT(*) FROM approval_transaction_metrics
   WHERE success = false
   AND error_code = '23503'
   AND created_at > NOW() - INTERVAL '24 hours';
   

3. Rate Limit Hits:

   • Monitor 429 response rate in edge function logs
   • Alert if >5% of requests are rate limited

Success Thresholds:

• Slug violations: <1% of submissions
• FK validation errors: <2% of submissions
• Rate limit hits: <3% of requests

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Next Steps: Phase 3

With Phase 2 complete, the pipeline now has:

• ✅ CORS protection (Phase 1)
• ✅ Transaction atomicity (Phase 1)
• ✅ Idempotency protection (Phase 1)
• ✅ Deadlock retry logic (Phase 1)
• ✅ Timeout protection (Phase 1)
• ✅ Slug uniqueness enforcement (Phase 2)
• ✅ FK validation with clear errors (Phase 2)
• ✅ Rate limiting protection (Phase 2)

Ready for Phase 3: Monitoring & observability improvements