Design a package installer with dependencies
Company: Amazon
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Design a **package installer system** (like a simplified OS/package manager) that installs packages while respecting dependency resolution.
### Requirements
- Input: a request to install package `P` (optionally with a version constraint).
- Each package may depend on other packages (with version constraints).
- The system must resolve dependencies and install packages in the correct order.
- Detect and report errors clearly:
- missing packages
- version conflicts
- dependency cycles
- Handle partial failure (e.g., installation fails mid-way) safely.
### Follow-up
- What if a package includes a **payload** (configuration/parameters/artifacts) that must be passed into the installation step? How would you model, validate, and deliver that payload securely and reliably?
Quick Answer: This question evaluates understanding of package management and dependency resolution, including version constraints, detection of missing packages, conflicts and cycles, handling partial installation failures, and secure modeling and delivery of installation payloads.
