Firestore Database Validator Skill

name: firestore-database-validator description: Validates Firestore database structures, security rules, and configurations for compliance with best practices and internal policies.

Overview

This skill ensures that all Firestore database configurations, security rules, and data model definitions comply with best practices and internal standards for scalability, security, and maintainability.

Policies Enforced

1. Security Rules

• •Authentication Required: No public read/write access without explicit approval
• •Granular Permissions: Rules must specify read/write separately, not combined allow read, write
• •Field-Level Validation: Rules should validate data types and required fields
• •No Wildcards in Production: Avoid allow read, write: if true patterns

2. Collection Naming

• •snake_case Convention: All collection names must use snake_case (e.g., user_profiles, order_items)
• •Plural Nouns: Collections should be named as plural nouns (e.g., users not user)
• •No Special Characters: Only lowercase letters and underscores allowed

3. Document Structure

• •Required Fields: Every document should have created_at and updated_at timestamps
• •ID References: Cross-references should use document ID strings, not nested documents
• •Array Limitations: Arrays should not exceed 20 items for query efficiency
• •Map Depth: Nested maps should not exceed 3 levels deep

4. Index Configuration

• •Composite Indexes: Must be defined for queries with multiple where clauses or orderBy
• •No Redundant Indexes: Single-field indexes are automatic; don't define them manually

5. Data Types

• •Timestamps: Use Firestore Timestamp type, not ISO strings for dates
• •GeoPoints: Use Firestore GeoPoint type for location data
• •References: Use DocumentReference type for relations when appropriate

File Types Validated

Instructions

Step 1: Identify Files to Validate

Check the user's provided files or project structure for Firestore-related configurations:

# Find all Firestore-related files
find . -name "firestore.rules" -o -name "firestore.indexes.json" -o -name "*.schema.json" -o -name "*.rules"

Step 2: Run the Validation Script

Use the validation script against the user's Firestore files:

# Validate security rules
python scripts/validate_firestore.py rules <path_to_rules_file>

# Validate index configuration
python scripts/validate_firestore.py indexes <path_to_indexes_file>

# Validate schema/model definitions
python scripts/validate_firestore.py schema <path_to_schema_file>

# Validate entire project
python scripts/validate_firestore.py project <path_to_firebase_project>

Step 3: Interpret Output

Step 4: Generate Reports

For comprehensive validation, generate a detailed report:

python scripts/validate_firestore.py report <path_to_firebase_project> --output validation_report.md

Common Issues and Fixes

Issue: Overly Permissive Rules

❌ Bad:

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if true;
    }
  }
}

✅ Good:

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read: if request.auth != null;
      allow write: if request.auth.uid == userId;
    }
  }
}

Issue: Incorrect Collection Naming

❌ Bad: UserProfiles, order-items, Products

✅ Good: user_profiles, order_items, products

Issue: Missing Timestamps

❌ Bad:

{
  "name": "John Doe",
  "email": "john@example.com"
}

✅ Good:

{
  "name": "John Doe",
  "email": "john@example.com",
  "created_at": "Timestamp",
  "updated_at": "Timestamp"
}

Issue: Deep Nesting

❌ Bad: Nesting data 5+ levels deep

✅ Good: Use subcollections or flatten structure to max 3 levels

Integration with Firebase CLI

This skill works alongside Firebase CLI commands:

# Deploy rules after validation passes
firebase deploy --only firestore:rules

# Deploy indexes after validation passes
firebase deploy --only firestore:indexes

Schema Definition Format

When documenting Firestore schemas, use this JSON format:

{
  "collection": "users",
  "description": "User account information",
  "fields": {
    "id": { "type": "string", "required": true, "description": "Document ID (auto-generated)" },
    "email": { "type": "string", "required": true, "validation": "email format" },
    "display_name": { "type": "string", "required": true, "maxLength": 100 },
    "profile_image_url": { "type": "string", "required": false },
    "role": { "type": "string", "enum": ["user", "admin", "moderator"], "default": "user" },
    "created_at": { "type": "timestamp", "required": true },
    "updated_at": { "type": "timestamp", "required": true }
  },
  "subcollections": [
    {
      "name": "notifications",
      "description": "User notification history"
    }
  ],
  "indexes": [
    { "fields": ["role", "created_at"], "order": ["asc", "desc"] }
  ]
}

Additional Resources

• •Firestore Security Rules Reference
• •Firestore Data Modeling Guide
• •Firestore Best Practices