Integration with Other Systems

Most Clojure systems do not live alone. They talk to databases, HTTP APIs, Java libraries, native components, message brokers, and cloud services with their own assumptions about types, errors, lifecycle, and concurrency.

This chapter is about those seams. Some integration problems are basically serialization problems. Others are ownership problems, retry problems, trust-boundary problems, or resource-lifecycle problems. The useful pattern is often not in the client call itself but in the contract around it.

Read this section as a guide to designing honest boundaries. Good integration code makes failure visible, keeps data conversion explicit, and avoids letting foreign runtime models leak everywhere into the rest of the Clojure codebase.

In this section

• Interoperability with Java Libraries
  How to use Java libraries from Clojure with modern dependency setup, careful boundary design, and reduced reflection overhead.
• Writing Clojure Libraries for Other JVM Languages
  How to design Clojure libraries that Java, Kotlin, or Scala consumers can use without fighting Clojure-specific conventions.
• Communicating with External Services in Clojure: A Comprehensive Guide
  Explore strategies for integrating Clojure applications with external services and APIs, including HTTP clients, authentication, data parsing, and error handling.
• Database Integration with JDBC and Datahike
  Choose between relational SQL access and immutable Datalog modeling, and learn the transaction, query, and schema trade-offs each approach brings in Clojure.
• Message Brokers and Queues: Integrating RabbitMQ and Kafka with Clojure
  Explore how to integrate Clojure with message brokers like RabbitMQ and Kafka for asynchronous, decoupled communication. Learn about Pub/Sub patterns, message queuing, serialization, and scaling considerations.
• HTTP Clients and REST Integration in Clojure
  Consume external APIs safely with blocking and asynchronous HTTP clients, deliberate timeout policy, and explicit handling of JSON, retries, and failure modes.
• gRPC and Protobuf Integration: Efficient Data Serialization in Clojure
  Explore the integration of gRPC services and Protocol Buffers in Clojure for efficient, language-neutral data serialization, leveraging libraries like Protojure.
• Mastering JSON and Data Serialization with Cheshire in Clojure
  Explore JSON serialization and deserialization in Clojure using Cheshire, a fast and efficient JSON library. Learn encoding, decoding, customization, and performance optimization techniques.
• Using Clojure in Existing Systems
  How to introduce Clojure into existing JVM systems with modern Clojure CLI workflows, clear boundaries, and safe incremental adoption.
• Integrating with Cloud Services (AWS, GCP, Azure)
  Learn how to integrate Clojure applications with major cloud services like AWS, GCP, and Azure for storage, computing, and infrastructure needs. Explore SDKs, libraries, authentication, configuration management, and best practices for security and cost optimization.
• Handling Network Errors and Retries
  How to handle unreliable networks in Clojure with timeout discipline, idempotent retries, backoff with jitter, and circuit-aware client design.
• Distributed Systems and Service Discovery
  How Clojure services participate in modern distributed systems with platform DNS, registries such as Consul, and selective coordination services.
• Java Interop Patterns: Mastering Clojure's Integration with Java
  Explore Java Interop Patterns in Clojure to leverage Java's vast ecosystem, enhance code reuse, and achieve seamless integration. Learn idiomatic ways to interact with Java classes, handle overloaded methods, manage exceptions, and optimize performance with type hinting.
• Cross-Language Interoperability Patterns: Integrating Clojure with Python and JavaScript
  Explore patterns for integrating Clojure with languages beyond Java, such as Python or JavaScript. Learn about tools, libraries, and best practices for seamless cross-language interoperability.
• Implementing Foreign Function Interfaces (FFI) in Clojure
  Explore how to interface with native code using Foreign Function Interfaces (FFI) in Clojure, enabling seamless integration with C or C++ libraries.
• Advanced Java Interop Techniques
  Explore advanced techniques for Java interoperability in Clojure, including implementing interfaces and extending classes using gen-class, proxy, and reify.
• Interacting with Native Libraries Using JNI and JNA
  Explore the intricacies of using JNI and JNA for native library interaction in Clojure, focusing on advanced use cases, performance, and resource management.