Enterprise Integration Patterns with Apache Camel

A comprehensive guide to the 65 Enterprise Integration Patterns (Hohpe & Woolf) — implemented with Apache Camel on three runtimes (Quarkus, Spring Boot, and YAML DSL), backed by Kafka, Pulsar, and Redis, with runnable examples on Podman.

Read the tutorial

What's inside

• 44 tutorial chapters — 10 parts covering all 65 EIP patterns, from integration styles through system management, plus 25 deep-dive appendices.
• 67 Excalidraw diagrams — visual architecture and pattern flow diagrams with EIP stencil icons embedded throughout.
• 37 runnable examples — Camel projects (Quarkus and Spring Boot variants) you can build and run against a local Podman stack, plus operational scripts for the Kafka appendices, including Loan Broker and Bond Trading case studies.
• Shipping domain — A consistent e-commerce scenario (orders, inventory, payments, shipping, notifications) that drives every pattern example.
• Local infrastructure — One-command Podman stack with Kafka (KRaft), Pulsar, Redis, PostgreSQL, Apicurio Registry, and an optional LGTM observability overlay (Grafana, Loki, Tempo, Mimir).

Quick start

# Clone
gh repo clone patterncatalyst/enterprise-integration-patterns-with-camel
cd enterprise-integration-patterns-with-camel

# Start the local stack
./scripts/setup-stack.sh

# Run a Quarkus example
cd examples/09-routing-fundamentals/quarkus
mvn quarkus:dev

# Or the Spring Boot variant
cd examples/09-routing-fundamentals/spring-boot
mvn spring-boot:run

# Start with observability (Grafana, Loki, Tempo, Mimir)
./scripts/setup-stack.sh --lgtm

Running the integration tests? Point Testcontainers at Podman first — it looks for a Docker socket by default, and Docker is not a dependency of this project:

systemctl --user enable --now podman.socket
export DOCKER_HOST="unix://${XDG_RUNTIME_DIR}/podman/podman.sock"

# Tests bind the same ports as the dev stack, so stop it first
podman-compose -p eip -f examples/_infra/compose.yaml down
./scripts/build-all-examples.sh --with-tests

See Prerequisites & Setup for full environment setup.

Runnable examples

Example	Patterns	Chapter
examples/04-channel-types	Point-to-Point, Publish-Subscribe, Datatype Channel (Kafka + Pulsar + Redis Pub/Sub)	Ch 4
examples/05-reliability	Dead Letter Channel, Guaranteed Delivery	Ch 5
examples/06-channel-infra	Channel Adapter (REST→PostgreSQL→Kafka), Kafka↔Pulsar Bridge, Message Bus	Ch 6
examples/07-message-types	Command, Document, Event Message	Ch 7
examples/08-message-metadata	Correlation ID, Message Sequence, Expiration, Format Indicator	Ch 8
examples/09-routing-fundamentals	Content-Based Router, Filter, Splitter, Recipient List	Ch 9
examples/10-composed-routing	Scatter-Gather, Routing Slip	Ch 10
examples/11-advanced-routing	Dynamic Router, Wire Tap, Resequencer, Composed Message Processor, Load Balancer	Ch 11
examples/12-transformation	Message Translator, Content Enricher (Redis), Content Filter	Ch 12
examples/13-aggregator	Aggregator (in-memory + PostgreSQL JDBC), Normalizer	Ch 13
examples/14-consumer-patterns	Polling Consumer (Kafka + PostgreSQL), Event-Driven Consumer (Kafka + Pulsar), Competing Consumers, Message Dispatcher	Ch 14
examples/15-endpoints	Idempotent Receiver (JDBC), Outbox Pattern (PostgreSQL), Durable Subscriber (Pulsar), Service Activator	Ch 15
examples/16-endpoint-management	Messaging Gateway, Selective Consumer, Channel Purger, Messaging Mapper	Ch 16
examples/17-observability	Control Bus, Wire Tap, Message History, Message Store (PostgreSQL)	Ch 17
examples/18-testing-management	Test Message, Detour, Smart Proxy, Circuit Breaker	Ch 18
examples/loan-broker	Scatter-Gather case study (13 patterns)	Appendix J
examples/19-dsl-comparison	The same route on Quarkus, Spring Boot and the YAML DSL	Appendix A
examples/20-kafka-deep-dive	Key-based partitioning, transactional pipeline, consumer lag monitoring	Appendix B
examples/21-pulsar-deep-dive	Shared/Key_Shared subscriptions, dead letter topics	Appendix C
examples/22-redis-integration	Caching enrichment, idempotent receiver, distributed locking	Appendix D
examples/23-quarkus-dev	Dev Services, live reload, continuous testing (Quarkus-only by design)	Appendix E
examples/24-drools-rules	Rule-based content routing with Drools 10 rule units	Appendix F
examples/27-observability-stack	OpenTelemetry tracing, Micrometer metrics, health probes	Appendix I
examples/25-quarkus-flow	Order fulfillment saga with CDI state machine and Camel routes	Appendix G
examples/26-feature-flags	Flag-controlled Detour, fractional A/B routing, targeted rollout (OpenFeature + flagd)	Appendix H
examples/34-kafka-share-groups	KIP-932 share groups: fan-out beyond partition count, ACCEPT/RELEASE/REJECT	Appendix P
examples/35-kafka-diagnostics	The diagnostic workflow as a script: lag, group state, broker health, JVM dumps	Appendix Q
examples/36-kafka-connect-offsets	Listing, altering and resetting connector offsets over the Connect REST API	Appendix R
examples/32-kafka-consumer-tuning	Throughput-tuned, safety-first, and static-membership consumers	Appendix N
examples/33-kafka-producer-tuning	Batched, compressed, idempotent, and synchronous producers	Appendix O
examples/37-testing-strategies	Three-tier testing: unit (MockEndpoint), integration (REST Assured), Newman	Appendix S
examples/38-kubernetes-deploy	Standard Maven-based container builds and Kubernetes deployment on Minikube	Appendix T
examples/39-camel-cli	CLI prototype-to-production workflow with content-based routing and Redis enrichment	Appendix U
examples/40-camel-tui	TUI dashboard demo with order validation, data generation, and multi-step processing	Appendix V
examples/41-citrus-testing	End-to-end integration testing with Citrus, Kafka, and HTTP validation	Appendix W
examples/42-ai-mcp	AI-powered order classification and assistant using Camel LangChain4j	Appendix X
examples/bond-trading	Market data normalization, desk filtering, trade validation (16 patterns)	Appendix K

Examples with quarkus/ and spring-boot/ subdirectories support both runtimes. Ten examples also include a yaml-dsl/ directory with standalone YAML routes for the Camel CLI. Run with mvn quarkus:dev (Quarkus), mvn spring-boot:run (Spring Boot), or camel run * (YAML DSL) against the infrastructure stack.

Tutorial structure

Part	Topic	Patterns
0	Getting Started	Prerequisites, the shipping domain
1	Integration Styles	File Transfer, Shared Database, RPI, Messaging
2	Messaging Systems	Channel, Message, Pipes & Filters, Router, Translator, Endpoint
3	Messaging Channels	Point-to-Point, Pub/Sub, Dead Letter, Guaranteed Delivery, and more
4	Message Construction	Command, Document, Event messages, Request-Reply, Correlation
5	Message Routing	Content-Based Router, Splitter, Aggregator, Scatter-Gather, and more
6	Message Transformation	Translator, Enricher, Content Filter, Normalizer, Canonical Model
7	Messaging Endpoints	Gateway, Consumers, Dispatcher, Idempotent Receiver, Service Activator
8	System Management	Control Bus, Wire Tap, Message History, Message Store
9	Appendices	Spring Boot vs Quarkus, Kafka, Pulsar, Redis, Quarkus Dev Mode, Drools, Quarkus Flow, Feature Flags, Observability, Kubernetes Deployment, Camel CLI, Camel TUI, Citrus Testing, AI and MCP, Secure by Default, Loan Broker & Bond Trading case studies, Glossary, Virtual Threads, Consumer/Producer Tuning, Share Groups, Diagnostics, Kafka Connect Offsets, Testing Strategies

Stack

Component	Role
Apache Camel 4.x	Integration framework (Java DSL)
Quarkus 3.x	Runtime (fast startup, Dev Services, native builds)
Spring Boot 4.x	Runtime (Spring ecosystem, wide adoption)
Apache Kafka (KRaft)	Primary messaging backbone
Apache Pulsar	Multi-tenant messaging, geo-replication
Redis	Caching, idempotent repositories, Pub/Sub
PostgreSQL	Persistent storage, outbox pattern
Apicurio Registry	Avro/Protobuf schema registry
Grafana + Loki + Tempo + Mimir	Observability (optional LGTM overlay)

Presentations

Two slide decks in presentations/:

Deck	Slides	Focus
EIP 101	98	Conceptual guide — all 65 patterns with diagrams
EIP 201	126	Implementation deep-dive — Java DSL, code, case studies

Getting started

See GETTING-STARTED.md for a quick-start guide, or the tutorial site for the full walkthrough.

Contributing

See CONTRIBUTING.md.

License

Apache 2.0