We are developing a system to manage and schedule audits for various suppliers, ensuring efficient use of our auditors and adherence to different client subscription levels. This solution aims to address typical scenarios where companies require timely and fair distribution of audit resources.
The system will handle the scheduling of audits for a supplier company, "Supplier 4 Live," with the following requirements and constraints:
- An auditor can audit only one site per day.
- We aim to distribute the audits proportionally among auditors to ensure fairness.
Clients pay for different subscription levels, each with distinct commitments for audit report delivery:
- Essentials: Report available no earlier than 4 weeks after the request, with a maximum wait time of 4 months.
- Advanced: Report available no earlier than 3 weeks after the request, with a maximum wait time of 2 months.
- Premium: Report published as soon as it is ready, with a maximum wait time of 4 weeks.
Ensure the system can handle concurrent audit requests efficiently. The audit assignment logic should balance the load among auditors while adhering to subscription-level constraints.
You have been provided with the problem statement a few days in advance to familiarize yourself with the requirements and constraints. During the live coding session, which will last 90 minutes, your task is to design and implement a part of this system, focusing on:
Design an architecture that supports the requirements above, using principles of hexagonal architecture and Domain-Driven Design (DDD). Ensure the system can manage auditor availability, client subscriptions, and audit scheduling.
Implement a feature to assign auditors to sites, ensuring that:
- Each auditor audits only one site per day.
- Audits are distributed proportionally among auditors.
- Adherence to subscription-level constraints for report delivery.
Implement a basic event management system to handle notifications for audit assignments and report deliveries. Consider concurrency issues that might arise from multiple audit requests and provide solutions to handle them efficiently.
- Client: "Farma World Champion SLU"
- Supplier: "Supplier 4 Live"
- Subscription Levels: Essentials, Advanced, Premium
The system should schedule audits as per the subscription level constraints and assign auditors proportionally while ensuring that no auditor is double-booked on any given day.
- Architecture Design: Explain how you would organize the system using hexagonal architecture and DDD. Identify key aggregates, entities, and value objects.
- Event Management: Describe how you would implement event handling for notifications.
- Concurrency and Performance: Discuss how you would manage concurrency in audit assignments. Outline strategies to optimize system performance.
- You will be provided with the problem statement a few days ahead of the live coding meeting. Read the problem statement carefully, especially to address possible questions related to the problem itself. We will answer all questions as long as they're not related to how to implement the solution to the problem.
- You will be doing the live coding call along with one or two potential teammates in a pair-programming or mob-programming fashion (depending on whether we are one or two people along with you). You will be the main driver, and we will support you in whatever way we can. This means that we will be doing our best to make you feel as comfortable as we can, providing help, advice, or whatever you need. Our goal is to evaluate your fit into the team, so we will do our best to help you shine your best version, simulating a common team situation with potential teammates.
- We value simple solutions with simple code above all. Try to avoid rabbit holes as much as you can, and if you feel that you are falling into one, it's perfectly fine to stop going that way and try to go simpler. We really value this kind of pragmatic attitude. Having said that, we know that this kind of interview can be stressful, so if we feel that you can go a simpler way because you're stuck or for any other reason, we will try to advise you.
- We do not seek a complete solution. We aim to focus on the system design and the implementation rather than a complete solution. So do not rush and focus on finding the best implementation possible.
- Some implementation details:
- The code will be in TypeScript. If you're not familiar with it, we suggest you take a quick look at the basics. We do not demand guru-level skills, but a basic level to get going. We can cover gaps if you need help.
- The framework will be NestJS as provided in this repository. Same thing here, if you're not familiar with it, we suggest you take a quick look at the basics (the Overview topics in the NestJS documentation). We can cover gaps if you need help here.
- The tools that we use to collaborate in the team are:
- To host calls: Google Meet
- To sketch diagrams: Miro
- To do pair programming: Code With Me from IntelliJ.
- If you do not have any of those or you're not familiar with them, no worries. We will adapt to what you feel most comfortable with.
- Some other tips. For obvious reasons, they're not mandatory, just a few suggestions to have your mind and body as fresh as possible (all of the suggestions are proven to improve the freshness of body and mind).
- Sleep well the day before. This will help you make better decisions.
- If you are used to doing sports/workout, we suggest you do your workout before or the day before. This is proven to lower stress levels and improve focus.
- Eat well before or the day before, as healthy as you can with no alcohol, no soft drinks, and with minimal ultra-processed food. This is proven to enhance concentration, energy levels, mood, and sleep quality, thereby boosting mental performance.
- Supplier: A company that requires audits for its sites (fabrication plants, warehouses, etc.).
- Site: A location to be audited by an auditor.
- Auditor: A professional responsible for auditing a site and delivering a report.
- Audit: The process of examining a site to ensure compliance with regulations and standards.
- Client: A company that request audits for its suppliers.
- Subscription Level: A client subscription level that determines the audit report delivery time.