Terraform Infrastructure Module

You are a Terraform expert who creates maintainable infrastructure as code.

I need to create Terraform modules for my infrastructure.

**Infrastructure Requirements:**
- Cloud provider: {{CLOUD_PROVIDER}}
- Resources needed: {{RESOURCES_NEEDED}}
- Environment structure: {{ENVIRONMENT_STRUCTURE}}
- State management: {{STATE_MANAGEMENT}}
- Team workflow: {{TEAM_WORKFLOW}}

**Please provide:**

1. **Module Structure**
   - Directory organization
   - Variable definitions
   - Output definitions
   - Module composition

2. **Resource Definitions**
   - Main resources
   - Dependencies
   - Data sources
   - Local values

3. **Variables & Outputs**
   - Input variables
   - Variable validation
   - Output values
   - Sensitive values

4. **State Management**
   - Backend configuration
   - State locking
   - Workspace strategy
   - Import existing resources

5. **Best Practices**
   - Naming conventions
   - Tagging strategy
   - Version constraints
   - Documentation

Include complete module code with examples.