17 mins
Jun 25, 2024
Clojure isn’t the mainstream programming language.
However, being a product engineering company, we regularly deliver projects with this powerful and convenient solution.
We know you might have a question like what’s so unique about Clojure?
Well, the decision to use Clojure is not based on a single reason alone. And that’s precisely why we have dedicated this entire blog to it.
In this blog, we’ll explore its real-world applications and how it is addressing the modern challenges of software product engineering.
But before that, let us share a success story that revolves around our client’s experience with Clojure development.
Our expertise in software product engineering and our decision to leverage Clojure for the client’s online policy system resulted in a remarkable transformation.
Here is a quick overview of the client’s success with Clojure.
We’re sharing a few samples of the code base so you can see how Clojure helped us overcome the client’s challenges.
(ns my-insurance-system.policy (:require [clojure.core.async :as async :refer [go <! chan buffer]])) ;; Simulate fetching policy data from a remote API (defn fetch-policies [] [{:id 1 :premium 500} {:id 2 :premium 750} {:id 3 :premium 1000} {:id 4 :premium 900} {:id 5 :premium 600}]) ;; Fetch and process policy data concurrently (defn update-policy-in-some-way [policy] (assoc policy :discounted true)) (defn get-policy-data [] (let [policies (fetch-policies) policy-chan (chan 5 (buffer 10))] (async/pipeline-async 5 policy-chan (fn [policy] (update-policy-in-some-way policy)) (map :id policies)) (async/<!! (async/into [] policy-chan))))
In this example, the insurance company employs Clojure for its implementation, which utilizes core.async to concurrently fetch and process policy data.
The fetch-policies function simulates fetching policy data from a remote API. Meanwhile, get-policy-data performs the concurrent retrieval and processing of policies.
Now, they are currently enjoying the benefits of efficient concurrent data processing.
(ns my-insurance-system.calculations) ;; Calculate total premiums for policies using reduce and pure functions (defn calculate-total-premium [policies] (reduce (fn [sum policy] (+ sum (:premium policy))) 0 policies))
In this example, the insurance company utilizes Clojure’s functional programming paradigm to calculate the total premiums for policies.
The calculate-total-premium function uses reduce and pure functions to aggregate the premium amounts, ensuring efficient and maintainable code.
Our journey took an exciting turn when we encountered the concept of Polylithic Architecture – a groundbreaking approach to structuring our system.
Note: The code examples for Polylithic Architecture are more conceptual and less implementation-focused.
The following snippets illustrate the principles of component-based development.
(ns my-insurance-system.components.policy (:require [my-insurance-system.db :as db])) (defn create-policy [data] (db/save-policy data)) (defn get-policy [id] (db/get-policy id)) (defn update-policy [id data] (db/update-policy id data)) (defn delete-policy [id] (db/delete-policy id))
This example showcases how the Policy component contains functions associated with managing policies.
It delegates the actual database operations to the my-insurance-system.db namespace, following the component-based development approach.
In which, each component focuses on a specific domain and offers a well-defined interface for interacting with the system.
(ns my-insurance-system.components.claim (:require [my-insurance-system.db :as db])) (defn create-claim [data] (db/save-claim data)) (defn get-claim [id] (db/get-claim id)) (defn update-claim [id data] (db/update-claim id data)) (defn delete-claim [id] (db/delete-claim id))
Much like the Policy component, the Claim component encompasses operations related to claim management.
It adheres to the same component-based development principles, providing clear and isolated functionality for interacting with claim data.
Embracing the CQRS pattern further optimized our system’s performance and overall user experience.
(ns my-insurance-system.commands.policy (:require [my-insurance-system.components.policy :as policy])) (defn create-policy [data] (policy/create-policy data)) (defn update-policy [id data] (policy/update-policy id data)) (defn delete-policy [id] (policy/delete-policy id))
In a system following the CQRS principles, command handlers are responsible for accepting user commands and triggering corresponding actions within the domain.
In this example, the Command Handlers for policies delegate the command operations to the Policy component, ensuring proper command execution.
(ns my-insurance-system.queries.policy (:require [my-insurance-system.components.policy :as policy])) (defn get-policy [id] (policy/get-policy id)) (defn get-all-policies [] (policy/get-all-policies))
On the read side, the Query Handlers are responsible for processing read requests and returning data to users.
In this example, the Query Handlers for policies retrieve policy data from the Policy component and return it to the users, ensuring separation between read and write operations.
Clojure offers a wide range of use cases due to its unique features and flexibility.
Here are some common use cases of Clojure.
In the world of software product engineering, Node.js and Clojure stand out as ideal solutions for back-end development.
Node.js, a JavaScript runtime, is known for its event-driven approach and vast ecosystem.
Meanwhile, Clojure, a functional language on the JVM, offers immutable data structures and powerful concurrency support.
So, let’s compare Node.js and Clojure, highlighting their strengths and weaknesses.
Runtime environment for JavaScript | Functional programming language for the JVM |
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Extensive npm package ecosystem | Limited library availability compared to Node.js |
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Single-threaded event loop (non-blocking I/O) |
Built-in support for immutable data and parallelism |
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Asynchronous, event-driven, imperative |
Functional programming with immutable data |
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Generally faster due to the V8 engine |
Performance can be slower due to JVM overhead |
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Easier for developers familiar with JavaScript |
The steeper learning curve for functional programming |
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Large and active community |
Smaller but dedicated community |
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Callbacks, Promises, and async/await |
Software Transactional Memory (STM) and Try/Catch |
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Abundant tools and libraries for various tasks |
Fewer specialized libraries compared to Node.js |
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Popular for building web applications |
Can be used for web development but is less common |
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Scalable with cluster modules or microservices |
Can scale with multi-threading and STM |
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- Large ecosystem & community support - Easy for JavaScript developers to adapt - Asynchronous I/O for high concurrency |
- Powerful concurrency with immutable data - Functional programming paradigm - JVM's stability and performance |
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- Callback hell & potential callback issues - May have performance issues with heavy computation - JavaScript's dynamic typing can lead to errors |
- Smaller library ecosystem - The learning curve for imperative developers - Overhead of JVM and garbage collection |