Definition:
The Sidecar Pattern is a software architecture design where additional functionality is attached to an application by deploying it in a separate but closely connected container or process, similar to how a motorcycle sidecar attaches to provide extra capability without modifying the main vehicle.
In simple terms: Enhanced functionality Add features to your app without changing the main code by running helper services alongside it.
How It Works
- Main container: Your actual application
- Sidecar container: Helper services (logging, monitoring, etc.)
- Shared resources: Network, storage volumes
- Separate concerns: Each container has one responsibility
Example:
E-commerce Website with Security Sidecar
┌─────────────────┐ ┌──────────────────┐
│ Shopping App │ │ Security Sidecar │
│ ┌─────────────┐ │ │ ┌──────────────┐ │
│ │• Orders │ │◄──►│ │• SSL/TLS │ │
│ │• Inventory │ │ │ │• Auth tokens │ │
│ │• Products │ │ │ │• Rate limits │ │
│ └─────────────┘ │ │ │• Logging │ │
└─────────────────┘ │ └──────────────┘ │
└──────────────────┘