Star Wars and Software Architecture: Building Galactic-scale Distributed Systems

May the 4th be with you! Today, we celebrate Star Wars Day, a day dedicated to the legendary sci-fi franchise that has captured the imagination of millions. Star Wars Day is celebrated annually on May 4th because of the pun on the famous catchphrase - "May the Force be with you". The phrase was first used on May 4, 1979, the day after Margaret Thatcher was elected as Prime Minister of the United Kingdom. Her political party, the Conservatives, placed a congratulatory advertisement in the London Evening News saying "May the Fourth Be with You, Maggie. Congratulations." However, the first organized celebration of Star Wars Day took place in 2011 at the Toronto Underground Cinema. The day has since evolved into an annual celebration, with fans across the globe hosting parties, wearing costumes, and attending special events.

While Star Wars may be best known for its epic space battles, rich story, and memorable characters, there are also valuable lessons we can learn from its universe. Particularly, when it comes to software architecture and building distributed systems. In this post, I will delve into the fascinating world of Star Wars to uncover insights that can help us design and manage complex distributed systems with a galactic scale in mind.

Insight 1: Decentralization and the Rebel Alliance

The Rebel Alliance, a decentralized network of systems and individuals, managed to topple the mighty Galactic Empire. This serves as a powerful reminder of the benefits of decentralization. It's essential to distribute the workload and decision-making processes across multiple components or nodes, making the systems more resilient, scalable, and adaptable.

Architectural patterns

• Actor model - The actor model is a concurrency model where the basic unit of computation is the actor. Actors are lightweight, independent entities that communicate through message passing. This pattern enables decentralized, concurrent, and fault-tolerant systems as each actor can operate independently, making local decisions based on the messages it receives.
• Data sharding - Sharding is a technique used to distribute data across multiple nodes or databases. By partitioning data based on specific criteria, such as geographical location or user ID, sharding can improve performance, scalability, and fault tolerance in distributed systems.
• Distributed Hash Tables (DHT) - DHT is a decentralized distributed system that allows nodes to store and retrieve data efficiently in a large-scale network. It uses a hashing function to distribute keys across the nodes, ensuring that data can be found quickly and avoiding the need for a central authority or server.
• CQRS - CQRS is a pattern that separates the read and write operations of a system. By splitting these responsibilities, it allows for better horizontal scaling and independent optimization of the read and write sides of an application.
• Saga - The Saga pattern helps manage transactions across multiple independent components in a decentralized distributed architecture, ensuring data consistency and fault tolerance without relying on a centralized coordinator or database.
• Transactional Outbox - The Transactional Outbox pattern enables reliable communication between microservices by using an outbox table to store messages related to a transaction. It supports asynchronous communication, improves performance and scalability, and maintains data consistency even in the case of failures.
• Distributed Ledger Technology (DLT) - DLT, such as blockchain, is a decentralized database system that allows multiple parties to securely share and store data across a distributed network. This technology helps create secure, transparent, and tamper-proof systems for various use cases, including financial transactions, health-care records and more.
• Message Broker - The Message Broker pattern is a messaging pattern that enables communication between applications, services, and components by using a central intermediary called a message broker. This pattern allows for asynchronous, decoupled communication between components, providing flexibility and scalability in a distributed system. The message broker can also provide additional capabilities such as message filtering, routing, and transformation.

Architectural styles?

• Event-driven architecture - In EDA, components communicate through events rather than direct API calls, promoting decoupling and scalability. Events are usually published to a message bus or a broker, and consumers process these events asynchronously.
• Service-oriented architecture (SOA) - SOA is a style that focuses on designing systems as a collection of independent, reusable, and loosely coupled services. These services communicate using standardized protocols and can be implemented using different technologies, promoting interoperability and flexibility in distributed systems.
• Cell-based architecture - Cell-Based Architecture decomposes an application into smaller, autonomous cells that communicate via well-defined interfaces, enabling loose coupling, flexibility in scaling and deployment, and independent team work on different parts of the application.
• Microservices - Microservices is an architectural style that involves breaking a monolithic application into smaller, independent services, each with its responsibility. This style enables better scalability, flexibility, and resilience in distributed systems.
• Peer-to-peer - P2P architecture is a decentralized style where nodes in the network function as both clients and servers, sharing resources and communicating directly with each other. This style eliminates the need for centralized servers, improving scalability and fault tolerance.

Insight 2: Holistic Thinking and the Force

In Star Wars, the Force is an all-encompassing energy field that binds the galaxy together. Just as the Force connects all living things, we need to adopt a holistic approach when designing distributed systems. This means considering how each component fits into the larger ecosystem and its potential impact on other parts of the system.

Questions you may want to ask regarding each component in your systems

1. What is the responsibility of this component?
2. How does this component interact or communicate with other components? Think about data formats, protocols, medium etc.
3. What are the dependencies between components? Can you spot any direct, indirect or circular dependencies?
4. How does this component impact the system's performance, scalability, and reliability? What are the potential bottlenecks, resource consumption, and failure points introduced by the component?
5. What are the security implications of this component? What are the security risks and vulnerabilities associated with the component and its interactions with other components? Is the principle of least privilege implemented in this component (as well as in all inputs and outputs)?
6. How will this component evolve over time? Consider different volatilities such as

• Functional requirements: For example new processes, flows or customer types to support.
• Technology: For example your component uses or runs on a certain framework which might be retired.
• Performance requirements: For example, today when your customers click on the “Add Credit Card” button might take 1 sec, but tomorrow it should happen within 0.2 sec.
• Security: New security requirements, risk appetite, new permissions, encryptions, vulnerabilities.
• Privacy: New privacy requirements, classifications and processes
• Integration: Your component might need to integrate with other components, systems or platforms.
• Infrastructure: your infrastructure might change. For example, your web application now needs to run on mobile devices, or you run on one platform and need to migrate to another, or move from a private data center to the Cloud etc.
• Team, organizations, people: All that can change.
• Regulations: Those can change and you need to support new regulations, sometimes in a short notice.
• Data: Different formats, types, cleansing rules, data handling standards etc. Those can also change over time.How can this component be tested and monitored?

7. How does this component handle failures and unexpected events? Capture some data, for example by looking at previous incidents. Conduct Pre-Mortem or Failure Modes and Effects Analysis (FMEA). Identify risks and implement fault-tolerance and error-handling mechanisms required by the component to maintain system stability as needed by business.?

8. Is there enough knowledge, experience and process rigor within the team to support, maintain and troubleshoot the component? Is there a Root Cause Analysis (RCA) process in place? Look at the past incidents and identify how long it takes to identify outages, engage the on-call engineers, stop the bleeding and recover?

9. What are the potential points of contention or resource constraints within the component (and the system)?

Insight 3: Adaptability and the Droids

From R2-D2 to BB-8, the Star Wars universe is filled with resourceful droids that can adapt to a wide range of situations. Similarly, we should strive to design systems that can easily evolve and adapt to changing requirements, whether it's due to new business needs, technological advancements, or changes in user behavior.

Design patterns

• Dependency Injection: This pattern involves passing dependencies to a component, rather than having the component create them itself. This approach allows for easier substitution of dependencies, making it simpler to modify or replace components.
• Strategy: This pattern enables an object to change its behavior at runtime by encapsulating different algorithms within separate classes, referred to as strategies. By using the strategy pattern, it becomes easier to add, remove, or modify algorithms without modifying the client code.
• Adapter: The adapter pattern is used to convert the interface of a class into another interface that clients expect. This allows for greater flexibility in integrating new or third-party components into a system, making it more adaptable to change.
• Bridge: The bridge pattern separates an abstraction from its implementation, allowing both to evolve independently. This pattern is particularly useful when there's a need to support multiple implementations or when changes in the implementation are expected.
• Observer: The observer pattern defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically. This pattern promotes loose coupling between components, making it easier to modify or extend the system.
• Template Method: This pattern defines the skeleton of an algorithm in a base class while allowing subclasses to override specific steps without changing the overall algorithm structure. This approach promotes code reuse and makes it easier to adapt the algorithm to different situations.
• Command: The command pattern encapsulates a request as an object, allowing you to parameterize clients with different requests, queue or log requests, and support undoable operations. By using the command pattern, you can make a system more evolvable by allowing the addition of new commands without modifying the existing code.
• Facade: The facade pattern provides a unified interface to a set of interfaces in a subsystem, simplifying access to a complex system. By using a facade, you can make it easier to evolve the subsystem without affecting clients.
• Composite: The composite pattern allows you to compose objects into tree structures to represent part-whole hierarchies. This pattern enables clients to treat individual objects and compositions of objects uniformly, making it easier to add or modify components.

Architectural styles?

• Event-driven architecture - In EDA, components communicate through events rather than direct API calls, promoting decoupling and scalability. Events are usually published to a message bus or a broker, and consumers process these events asynchronously. By using events to trigger actions and communicate between components, changes can be made to individual components without affecting the overall system, improving flexibility and adaptability.
• Microservices - Microservices is an architectural style that involves breaking a monolithic application into smaller, independent services, each with its responsibility. Microservices can help software systems evolve and adapt to changing requirements by breaking down monolithic architectures into smaller, independent services that can be developed, deployed, and scaled independently.

Architecture principles and methodologies?

• Evolutionary architecture - Evolutionary architecture is an approach to software architecture that prioritizes incremental, iterative, and adaptive design to accommodate changing requirements over time. This approach promotes flexibility, scalability, and resilience by anticipating and embracing change, allowing the architecture to evolve gradually as the system and its requirements evolve.
• Domain Driven Design (DDD) - Domain-driven design is an approach to software development that focuses on modeling the business domain and its concepts, rather than the technical details of the system. By defining a clear and shared understanding of the domain, we can create software that better reflects the real-world problem it is trying to solve. This approach emphasizes collaboration between domain experts and software engineers, and promotes the use of ubiquitous language and bounded contexts to help manage complexity in large and complex systems.

Insight 4: Interoperability and Galactic Communication

The Star Wars galaxy is a melting pot of diverse cultures, languages, and technologies. Effective communication and interoperability are crucial to the success of the Rebel Alliance and the broader galactic community. When designing distributed systems, it's essential to prioritize interoperability, enabling seamless communication between different services, programming languages, and platforms. This can be achieved using the following architectural principles.

Principles

• Loose Coupling: Designing components to be loosely coupled minimizes dependencies between them, enabling easier integration and smoother communication across different services and platforms.
• Interface Segregation: By separating interfaces and defining clear contracts, you can ensure that services expose only the necessary functionality to their consumers, simplifying integration and promoting interoperability.
• Abstraction and Encapsulation: Abstracting away implementation details and encapsulating functionality within components can make it easier to change underlying technologies or platforms without affecting other parts of the system.

Architectural patterns?

• API Gateway - This pattern provides a single entry point for external consumers to access various services within a distributed system. The API Gateway can handle protocol translation, authentication, request routing, and other cross-cutting concerns, enabling seamless communication between clients and services.
• Adapter - The adapter pattern allows you to convert the interface of a class into another interface that clients expect. This pattern is particularly useful in promoting interoperability when integrating components with different interfaces or third-party libraries.
• Message Broker - The Message Broker pattern is a messaging pattern that enables communication between applications, services, and components by using a central intermediary called a message broker. This pattern allows for asynchronous, decoupled communication between components, providing flexibility and scalability in a distributed system. The message broker can also provide additional capabilities such as message filtering, routing, and transformation
• Service Registry - This pattern allows services to register themselves with a central registry and discover each other at runtime. By using a dynamic registry, services can communicate without hardcoding each other's locations, enhancing the system's flexibility and maintainability.

Architectural styles and methodologies

• Service-oriented architecture (SOA) - SOA is a style that focuses on designing systems as a collection of independent, reusable, and loosely coupled services. These services communicate using standardized protocols and can be implemented using different technologies, promoting interoperability and flexibility in distributed systems.
• Domain Driven Design (DDD) - Domain-driven design is an approach to software development that focuses on modeling the business domain and its concepts, rather than the technical details of the system. By defining a clear and shared understanding of the domain, we can create software that better reflects the real-world problem it is trying to solve. This approach emphasizes collaboration between domain experts and software engineers, and promotes the use of ubiquitous language and bounded contexts to help manage complexity in large and complex systems.
• API-First Design - This methodology involves designing APIs before implementing the underlying services or components. By focusing on API design, you can ensure that services expose consistent, well-defined interfaces that facilitate seamless communication between components.

Insight 5: Balance and the Jedi Code

The Jedi Code emphasizes the importance of balance in the Force. Similarly, striking the right balance is crucial when designing distributed systems. We are required to balance factors such as performance, scalability, security, and maintainability to create robust, resilient systems that meet current and future demands. This can be achieved using the following architectural principles:

• Separation of Concerns: Divide the system into distinct components, each with specific responsibilities, to promote modularity and maintainability.
• Loose Coupling: Designing components to be loosely coupled minimizes dependencies between them, enabling easier integration and smoother communication across different services and platforms.
• High Cohesion: Keep related functionality within a single component, making it easier to understand, maintain, and evolve.
• Fail-Fast and Fail-Safe: Design components to detect and handle failures early, allowing the system to recover or gracefully degrade functionality.
• Defense in Depth: Implement multiple layers of security controls to protect the system from various threats and vulnerabilities.

Methodologies

• Agile Methodologies: Embrace iterative and incremental development, continuous feedback, and adaptation to change, such as Scrum or Extreme Programming (XP).
• DevSecOps: Integrate security practices and policies throughout the development and operations lifecycle, ensuring continuous security and compliance.
• Fraud Prevention Design: Incorporate security measures, monitoring, and data analysis in system design to proactively detect and mitigate fraudulent activities, ensuring a secure and trustworthy environment.
• Continuous Integration and Continuous Deployment (CI/CD): Automate the processes of integrating code changes, testing, and deploying to production, improving the system's overall quality and resilience.
• Test-Driven Development (TDD): Write tests before implementation, promoting more maintainable and modular code.
• Domain Driven Design (DDD) - Domain-driven design is an approach to software development that focuses on modeling the business domain and its concepts, rather than the technical details of the system. By defining a clear and shared understanding of the domain, we can create software that better reflects the real-world problem it is trying to solve. This approach emphasizes collaboration between domain experts and software engineers, and promotes the use of ubiquitous language and bounded contexts to help manage complexity in large and complex systems.
• TRIZ (Theory of Inventive Problem Solving) Methodology: Apply creative problem-solving techniques to identify and resolve contradictions within systems, fostering innovative and adaptable solutions in software architecture. More on this in my talk Systematic Innovation and Problem Solving in Software using TRIZ (DeveloperWeek Global 2020)
• Twelve-Factor App - The Twelve-Factor App is a methodology for building modern, cloud-native applications that are scalable, maintainable, and portable. It defines a set of principles and best practices that emphasize factors such as declarative configuration, stateless processes, and separation of concerns. By adhering to these principles, developers can build applications that are easily deployed, managed, and scaled in modern cloud environments.

Architectural patterns

• Load Balancing: Distribute incoming network traffic across multiple servers to balance the load and ensure high availability, performance, and scalability.
• Caching: Store and reuse previously computed results or frequently requested data to reduce latency and improve performance.
• Circuit Breaker: Prevent cascading failures in a distributed system by detecting failures and allowing the system to recover or gracefully degrade functionality.
• Bulkhead: Isolate critical components and resources to prevent failures in one part of the system from affecting the entire system.
• Event Sourcing: Record all changes to the application state as a sequence of events, enabling better scalability, traceability, and auditability.

Final thoughts

As we celebrate Star Wars Day, let's remember the valuable lessons this epic saga can teach us about software architecture and distributed systems. By embracing decentralization, adopting a holistic approach, prioritizing adaptability, focusing on interoperability, and seeking balance, we can design distributed systems that are truly worthy of a galaxy far, far away. May the Force be with you, and happy Star Wars Day!