Enterprise Integration Patterns - Refresher

EIP.md

#System Architecture patterns

• N-Tier
• Event-Driven - Mediator / Broker
• Microkernel
• MicroServices
• Blackboard
• client - MVC / MVP / MVVM
• server - RPC / Remoting / WS / SOA / REST
• Space-Based

#SOA Patterns

Foundational Structural

• Service Host - infra
• Active Service - worker thread for upstream pre-fetch
• Transactional Service
• Workflow
• Edge Component

QoS Patterns

• Decoupled Invocation - Queues for reli­ability, bursts
• Parallel Pipelines - Steps -> throughput
• Gridable Service
• Service Instance - mutiple stateless copies, NLB
• Virtual Endpoint — location transparency
• Service Watchdog - Monitors and Health Mgmt

Security / Managability patterns

• Secured Message - Encrypts, decrypts, and signs individual messages
• Secured Infrastructure
• Service Firewall
• Identity Provider - Federated Security: Tokens, Claims
• Service Monitor - centralized

Message Exchange patterns

• Fire & Forget
• Request/Response
• Callback
• Inversion of Communications - Peers
• Saga - LRTs

Service Consumer patterns

• Reservation - correlation ticket for submission to a flow
• Composite Front End - client-side microkernel (modules) with Service Workers for model<->DTOs

Service Integration Patterns

• Service Bus - pubsub loosely coupled
• Orchestration — flow flexibility , governance

Anti-Patterns

• Knot - tightly coupled p2p
• Macroservice - not low enough granularity
• Transactional Integration —Transactions cross service boundaries and couple ser­vices together

Messaging Patterns

Messaging Systems

• Message Channel - applications communicate with one another
• Message - applications connected by a message channel exchange a piece of information
• Pipes and Filters - perform pluggable complex processing on a message
• Message Router - decouple individual processing steps - conditionally pass messages
• Message Translator - different data formats
• Message Endpoint - connect to a messaging channel to send and receive messages

Messaging Channels

• Point to Point Channel - caller ensured of exactly one receiver
• Publish Subscribe Channel - sender broadcasts event to all interested receivers
• Dead Letter Channel - messaging system handles undeliverable messages
• Guaranteed Delivery - even if the messaging system fails
• Message Bus - scalable decoupled integration architecture

Message Construction

• Event Message
• Request Reply
• Correlation Identifier - allow sender to correlate request / response
• Return Address

Message Routing

• Content Based Router - distribute a logical workflow across multiple physical systems
• Message Filter - ignore irrelevant messages
• Dynamic Router - avoid dependency of hard-coded destinations
• Recipient List - static / dynamic
• Splitter
• Aggregator - combine results of individual, related messages
• Resequencer - reorder message stream
• Composed Message Processor - logically coordinate message flow
• Scatter-Gather
• Routing Slip - message metadata for controlling its route processing steps
• Throttler - ensure endpoint is overloaded - SLA
• Sampling - algorithmically process a subset of high-load messages
• Delayer - delay the sending of a message
• Load Balancer - across dynamic number of endpoints
• Multicast - simultaneously route a message to multiple endpoints
• Loop - repeat processing a message

Message Transformation

• Content Enricher - add further info to a message
• Content Filter - remove irrelevant info from a message
• Claim Check - replace large message content with a lookup key
• Normalizer - process semantically equivalent messages of different schema
• Sort
• Validate

Messaging Endpoints

• Messaging Mapper - entity <> DTO transform -> decoupling
• Event Driven Consumer - push-oriented recipient - when sender is ready
• Polling Consumer - pull-oriented recipient - when receiver is ready
• Competing Consumers - sender sends to concurrent clients
• Message Dispatcher - sender coordinates sending to concurrent clients
• Selective Consumer - receiver informs sender of filtration logic
• Durable Subscriber - receiver catch up on missed messages
• Idempotent Consumer - receiver handle duplicate messages
• Transactional Client - message delivery guarantee protocols
• Messaging Gateway - system facade
• Service Activator - service can be invoked via messaging or LPC

System Management

• ControlBus - distributed systems coordinator
• Detour - routing pipeline for value added functionality
• Wire Tap - inspect messages
• Message History - analyze message flows in distributed systems
• Log