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The right integration framework is the glue that binds the building blocks of an application architecture. Application components have to continuously exchange critical data that facilitates user operations, service scaling, threat monitoring, back-end operations, event triggering and more. Without a dependable process of integration, application and service failures will inundate a software environment.
To address this, development shops have turned to three top integration frameworks for enterprise applications: Apache Camel, Spring Integration and Mule ESB. Each addresses the quandary of how to simplify integrations between enterprise applications in a way that is scalable. However, they also have their individual strengths, weaknesses and scenarios where they work best.
The top 3 integration frameworks
Apache Camel is an open source framework that has gained broad community support among its users. It works particularly well within software architectures built heavily on open source code. Camel supports over 50 data formats, and features a library of more than 280 add-on components. Architects can extend components for specific scenarios, such as asynchronous messaging, mock testing and event-driven app development.
Next, Spring Integration is part of the broader Spring Framework for Java, which also includes the Spring Boot coding platform. Spring Integration lets developers code using fine-grained components that provide high reusability and simplified app management.
Finally, Mule ESB is the enterprise service bus resident of the MuleSoft data integration platform, which was acquired by Salesforce in 2018. Unlike other frameworks geared toward highly-distributed architectures, Mule ESB lends itself to the more traditional SOA model for enterprise applications. As part of MuleSoft's AnyPoint integration platform, Mule ESB works with the AnyPoint Studio IDE, using the core Mule runtime engine.
Apache Camel vs. Spring Integration vs. Mule ESB
Each of these three integration frameworks can connect a standalone application to others within a broader enterprise ecosystem. Also, they all feature a lightweight, modular approach to application integration that connects endpoints using components and adapters. All three of these frameworks base themselves on the integration model characterized in the book, Enterprise Integration Patterns, by Gregor Hohpe and Bobby Woolf.
However, there are still notable differences from one framework to another, in terms of usability, technology and support:
User interface. Mule ESB has a highly visual UI that is helpful for beginners. However, more experienced developers may prefer the non-visual experience offered by Camel and Spring Integration.
XML vs. DSL. Both Camel and Spring Integration use domain-specific languages (DSLs) to create routes or flows for integrations. Mule ESB, however, relies on more traditional XML configuration files. XML has its purpose, but many Java developers will prefer DSLs, particularly when they build complex routes.
The use of ESBs. As the name suggests, Mule ESB focuses on the enterprise service bus. Though it is still a lightweight option, the ESB has lost significant ground as an implementation model, largely due to the rise of microservices over service-oriented architecture. Camel and Spring, meanwhile, will lend themselves to these newer, more modular forms of architecture design and development.
Documentation. Camel and Spring Integration have excellent documentation that is specific to these platforms, particularly because of their large, active user communities. MuleSoft includes the Mule ESB documentation within the docs for its entire platform. It is reportedly harder to find specific pages and topics for Mule ESB, buried deep within the documentation hierarchy of the overall platform.
Community. Camel has the biggest user community, followed by Spring Integration, and then Mule ESB. Camel has more than 9,000 tagged questions on Stack Overflow, Spring Integration has more than 6,000, while Mule ESB has fewer than 1,000.
Support. MuleSoft offers dedicated support for Mule ESB. Spring is supported by its parent company, VMware. Camel, on the other hand, relies exclusively on the open source community for support. Your decision may come down to how much hand-holding your developers prefer or require.
Cost. Camel is completely open source, which means it has the lowest upfront cost. However, you'll need a skilled internal team to maintain the platform, which may represent an expensive hire. Spring Integration, while open source, charges for its optional training and support services. Mule ESB requires an investment into the broader MuleSoft framework.
Choosing an integration framework
Mule ESB is a great candidate for organizations heavily invested in the Salesforce/MuleSoft ecosystem of enterprise SaaS tools. It offers the simplest experience, and it is relatively quick to implement and start up.
Apache Camel and Spring Integration are closely aligned in terms of architecture and user demographic. Here, Java-centric teams that prefer Spring projects would naturally drift toward Spring Integration. It delivers the best of both open and proprietary worlds: an open framework backed by enterprise-grade support from VMware.
Apache Camel is the most open of the lot, offering the widest support. If your organization makes use of popular open source technologies, like Kubernetes and Apache Kafka, Camel will likely fit in. However, this free technical prowess comes at a cost, as it requires you and your staff to maintain Camel in-house expertise. Luckily, its strong open source community can help provide that expertise, but this still requires putting in the time to explore and learn from that community.