Microservice Patterns

1. ESCAPING MONOLITHIC HELL
1.1. The slow march towards monolithic hell
1.1.1. The architecture of the FTGO application
1.1.2. The benefits of the monolithic architecture
1.1.3. Living in monolithic hell
1.2. Why this book is relevant to you
1.3. What you’ll learn in this book
1.4. The microservice architecture to the rescue
1.4.1. Scale cube and microservices
1.4.2. Microservices as a form of modularity
1.4.3. Each service has its own database
1.4.4. The FTGO microservice architecture
1.4.5. Isn’t the microservice architecture the same as SOA?
1.5. Benefits and drawbacks of the microservice architecture
1.5.1. Benefits of the microservice architecture
1.5.2. The drawbacks of the microservice architecture
1.6. The microservice architecture pattern language
1.6.1. Microservices are not a silver bullet
1.6.2. What is a pattern and a pattern language?
1.6.3. Overview of the microservice architecture pattern language
1.7. Beyond microservices: process and organization
1.7.1. Software development and delivery organization
1.7.2. Software development and delivery process
1.7.3. The human side of adopting microservices
1.8. Summary

2. DECOMPOSITION STRATEGIES
2.1. What is the microservice architecture exactly?
2.1.1. What is software architecture and why it matters
2.1.2. Overview of architectural styles
2.1.3. The microservice architecture is an architectural style
2.2. Defining an application’s microservice architecture
2.2.1. Identifying the system operations
2.2.2. Defining services by applying the Decompose by business capability pattern
2.2.3. Defining services by applying the Decompose by sub-domain pattern
2.2.4. Decomposition guidelines
2.2.5. Obstacles to decomposing an application into services
2.2.6. Defining service APIs
2.3. Summary

3. INTER-PROCESS COMMUNICATION IN A MICROSERVICE ARCHITECTURE
3.1. Overview of inter-process communication in a microservice architecture
3.1.1. Interaction styles
3.1.2. Defining APIs in a microservice architecture
3.1.3. Evolving APIs
3.1.4. Message formats
3.2. Communicating using the synchronous Remote procedure invocation pattern
3.2.1. Using REST
3.2.2. Using gRPC
3.2.3. Handling partial failure using the Circuit Breaker pattern
3.2.4. Using service discovery
3.3. Communicating using the asynchronous Messaging pattern
3.3.1. Overview of messaging
3.3.2. Implementing the interaction styles using messaging
3.3.3. Creating an API specification for a messaging-based service API
3.3.4. Using a message broker
3.3.5. Competing receivers and message ordering
3.3.6. Handling duplicate messages
3.3.7. Transactional messaging
3.3.8. Libraries and frameworks for messaging
3.4. Using asynchronous messaging to improve availability
3.4.1. Synchronous communication reduces availability
3.4.2. Eliminating synchronous interaction
3.5. Summary

4. MANAGING TRANSACTIONS WITH SAGAS
4.1. Transaction management in a microservice architecture
4.1.1. The need for 'distributed transactions' in a microservice architecture
4.1.2. The trouble with distributed transactions
4.1.3. Using the Saga pattern to maintain data consistency
4.2. Coordinating sagas
4.2.1. Choreography-based sagas
4.2.2. Orchestration-based sagas
4.3. Handling the lack of isolation
4.3.1. Overview of anomalies.
4.3.2. Countermeasures for handling the lack of isolation
4.4. The design of the Order Service and the Create Order Saga
4.4.1. The OrderService class
4.4.2. The implementation of the Create Order Saga
4.4.3. The OrderCommandHandlers class
4.4.4. The OrderServiceConfiguration class
4.5. Summary

5. DESIGNING BUSINESS LOGIC IN A MICROSERVICE ARCHITECTURE
5.1. Business logic organization patterns
5.1.1. Designing business logic using the Transaction script pattern
5.1.2. Designing business logic using the Domain Model pattern
5.1.3. About Domain Driven Design
5.2. Designing a domain model using the DDD aggregate pattern
5.2.1. The problem with fuzzy boundaries
5.2.2. Aggregates have explicit boundaries
5.2.3. Aggregate rules
5.2.4. Aggregate granularity
5.2.5. Designing business logic with aggregates
5.3. Publishing domain events
5.3.1. Why publish change events?
5.3.2. What is a domain event
5.3.3. Event enrichment
5.3.4. Identifying domain events
5.3.5. Generating and publishing domain events
5.3.6. Consuming domain events
5.4. Kitchen Service business logic
5.4.1. The Ticket aggregate
5.5. The Order Service business logic
5.5.1. The Order Aggregate
5.5.2. The OrderService class
5.6. Summary

6. DEVELOPING BUSINESS LOGIC WITH EVENT SOURCING
6.1. Developing business logic using event sourcing
6.1.1. The trouble with traditional persistence
6.1.2. Overview of event sourcing
6.1.3. Handling concurrent updates using optimistic locking
6.1.4. Event sourcing and publishing events
6.1.5. Using snapshots to improve performance
6.1.6. Idempotent message processing
6.1.7. Evolving domain events
6.1.8. Benefits of event sourcing
6.1.9. Drawbacks of event sourcing
6.2. Implementing an event store
6.2.1. How the Eventuate Local event store works
6.2.2. The Eventuate client framework for Java
6.3. Using sagas and event sourcing together
6.3.1. Implementing choreography-based sagas using event sourcing
6.3.2. Creating an orchestration-based saga
6.3.3. Implementing an event sourcing-based saga participant
6.3.4. Implementing saga orchestrators using event sourcing
6.4. Summary

7. IMPLEMENTING QUERIES IN A MICROSERVICE ARCHITECTURE
7.1. Querying using the API Composition pattern
7.1.1. The findOrder() query operation
7.1.2. An overview of the API composition pattern
7.1.3. Implementing the findOrder() query operation using the API Composition pattern
7.1.4. API Composition design issues
7.1.5. The benefits and drawbacks of the API composition pattern
7.2. Using the Command Query Responsibility Segregation (CQRS) pattern
7.2.1. Motivations for using CQRS
7.2.2. Overview of CQRS
7.2.3. The benefits of CQRS
7.2.4. The drawbacks of CQRS
7.3. Designing CQRS Views
7.3.1. Choosing a view datastore
7.3.2. Data access module design
7.3.3. Adding and updating CQRS views
7.4. Implementing a CQRS view with AWS DynamoDB
7.4.1. OrderHistoryEventHandlers module
7.4.2. Data modeling and query design with DynamoDB
7.4.3. The OrderHistoryDaoDynamoDb class
7.5. Summary

8. EXTERNAL API PATTERNS
8.1. External API design issues
8.1.1. API design issues for the FTGO mobile client
8.1.2. API design issues for other kinds of clients
8.2. The API gateway pattern
8.2.1. Overview of the API gateway pattern
8.2.2. Benefits and drawbacks of an API gateway
8.2.3. Netflix as an example of an API gateway
8.2.4. API gateway design issues
8.3. Implementing an API gateway
8.3.1. Using an off-the-shelf API gateway product/service
8.3.2. Developing your own API gateway
8.3.3. Implementing an API gateway using GraphQL
8.4. Summary

9. TESTING MICROSERVICES - PART 1
9.1. Testing strategies for microservice architectures
9.1.1. Overview of testing
9.1.2. The challenge of testing microservices
9.1.3. The deployment pipeline
9.2. Writing unit tests for a service
9.2.1. Developing unit tests for entities
9.2.2. Writing unit tests for value objects
9.2.3. Developing unit tests for sagas
9.2.4. Writing unit tests for domain services
9.2.5. Developing unit tests for controllers
9.2.6. Writing unit tests for event and message handlers
9.3. Summary

10. TESTING MICROSERVICES - PART 2
10.1. Writing integration tests
10.1.1. Persistence integration tests
10.1.2. Integration testing REST-based request/reply style interactions
10.1.3. Integration testing publish/subscribe-style interactions
10.1.4. Integration contract tests for Request/async reply interactions
10.2. Developing component tests
10.2.1. Defining acceptance tests
10.2.2. Writing acceptance tests using Gherkin
10.2.3. Designing component tests
10.2.4. Writing component tests for the FTGO Order Service
10.3. Writing end-to-end tests
10.3.1. Designing end-to-end tests
10.3.2. Writing end-to-end tests
10.3.3. Running the end-to-end tests
10.4. Summary

11. DEVELOPING PRODUCTION READY SERVICES
11.1. Developing secure services
11.1.1. Overview of security in a traditional monolithic application
11.1.2. Implementing security in a microservice architecture
11.2. Designing configurable services
11.2.1. Using push-based externalized configuration
11.2.2. Using pull-based externalized configuration
11.3. Designing observable services
11.3.1. Using the Health check API pattern
11.3.2. Apply the Log aggregation pattern
11.3.3. Using the Distributed tracing pattern
11.3.4. Applying the Application metrics patterns
11.3.5. Using the Exception tracking pattern
11.3.6. Applying the Audit logging pattern
11.4. Developing services using the Microservice chassis pattern
11.4.1. Using a microservice chassis
11.4.2. From microservice chassis to service mesh
11.5. Summary

12. DEPLOYING MICROSERVICES
12.1. Deploying services using the Language-specific packaging format pattern
12.1.1. Benefits of the Service as a language-specific package pattern
12.1.2. Drawbacks of the Service as a language-specific package pattern
12.2. Deploying services using the Service per Virtual machine pattern
12.2.1. The benefits of deploying services as VMs
12.2.2. The drawbacks of deploying services as VMs
12.3. Deploying services using the Service per container pattern
12.3.1. Deploying services using Docker
12.3.2. Benefits of deploying services as containers
12.3.3. Drawbacks of deploying services as containers
12.4. Deploying the FTGO application with Kubernetes
12.4.1. Overview of Kubernetes
12.4.2. Deploying the Restaurant service on Kubernetes
12.4.3. Deploying the API gateway
12.4.4. Zero-downtime deployments
12.4.5. Using a service mesh so separate deployment from release
12.5. Deploying services using the Serverless deployment pattern
12.5.1. Overview of serverless deployment with AWS Lambda
12.5.2. Developing a lambda function
12.5.3. Invoking lambda functions
12.5.4. Benefits of using lambda functions
12.5.5. Drawbacks of using lambda functions
12.6. Deploying a RESTful service using AWS Lambda and AWS Gateway
12.6.1. The design of the AWS Lambda version of the Restaurant Service
12.6.2. Packaging the service as ZIP file
12.6.3. Deploying lambda functions using the Serverless framework
12.7. Summary

13. REFACTORING TO MICROSERVICES
13.1. Overview of refactoring to microservices
13.1.1. Why refactor a monolith?
13.1.2. Strangling the monolith
13.2. Strategies for refactoring a monolith to microservices
13.2.1. Implement new features as services
13.2.2. Separate presentation tier from the back end
13.2.3. Extract business capabilities into services
13.3. Designing how the service and the monolith collaborate
13.3.1. Designing the integration glue
13.3.2. Maintaining data consistency across a service and a monolith
13.3.3. Handling authentication and authorization
13.4. Implementing a new feature as a service: handling mis-delivered orders
13.4.1. The design of the Delayed Delivery Service
13.4.2. Designing the integration glue for the Delayed Delivery Service
13.5. Breaking apart the monolith: extracting delivery management
13.5.1. Overview the existing delivery management functionality
13.5.2. Overview of the Delivery Service
13.5.3. Designing the Delivery Service domain model
13.5.4. The design of the Delivery Service integration glue
13.5.5. Changing the FTGO monolith to interact with the Delivery Service
13.6. Summary