A few months ago I was playing with Scala\/Spray on Bluemix (Cloud Foundry). Deploying it wasn\u2019t as straight forward as I thought, here is what I learnt. \n<\/p>\n\n
Creating a straight jar artefact with Maven shade plugin run perfectly on local machine. However, this artefact doesn\u2019t seem to work on Bluemix when deployed.<\/p>\n\n
This is strange because Cloud Foundry\/Bluemix should support all standard JVM executable. A quick look at the buildpack<\/a> seem to suggest it does support a variety of artefact formats, so let\u2019s go to plan B\u2026<\/p>\n\n One of the other artefact formats it support is the distzip<\/a> format. Once the build script was switched to generate artefact in that format, it worked!<\/p>\n\n Using the distzip format should be straight forward if you are using Gradle build system. If you prefer Maven, then check out this build file<\/a> in my demo project.<\/p>\n\n Once built, all that is left is to push the zip:<\/p>\n I haven\u2019t looked back at why the basic Jar didn\u2019t work, it\u2019s something still on my ToDo list. Hope this helps if someone else ran into this problem.<\/p>\n","pubDate":"Tue, 13 Sep 2016 08:21:49 +0000","link":"http:\/\/www.clianz.com\/2016\/09\/13\/deploying-scala-app-on-cloud-foundry\/","guid":"http:\/\/www.clianz.com\/2016\/09\/13\/deploying-scala-app-on-cloud-foundry\/","category":["Bluemix","Cloud","Scala"]},{"title":"Reagent - ClojureScript and React made easy","description":" Recently I\u2019ve started reading into Clojure and came across something really interesting.<\/p>\n\n Clojure is a JVM based functional programming language, based on Lisp. React is a recent web frontend framework from Facebook that has been everywhere lately. React a reactive Javascript framework, similar to AngularJS, but takes a different approach in component management to make it much faster and more scalable.<\/p>\n\n Now this is where it gets interesting - Clojure can be compiled to Javascript via the ClojureScript plugin. Combine the two and you get Reagent, a framework that integrated them together nicely.\n<\/p>\n\n There are two ways to run ClojureScript + React, the first to build multi page app and build both server and client side in Clojure, the other way is to just build the frontend with it as a single page app. We\u2019re much more interested in the latter.<\/p>\n\n You should see the \u2018Welcome to Reagent\u2019<\/strong> demo page. Simple!<\/p>\n\n The Clojure script in<\/p>\n\n got compiled into a Javascript file at<\/p>\n\n The index.html page does nothing more than including that Javascript file, and voila!<\/p>\n\n Now let\u2019s have a look at the reactive part by demoing the obligatory live counter button. Update your core.cljs file to the following:<\/p>\n\n Refresh the index.html<\/em> page and you will see the button, with a counter below that increments count on click.<\/p>\n\n Notice the component is \u2018mounted\u2019 to a HTML tag, and the content of the tag are eventually rendered via Javascript, this is React\u2019s framework in action. ClojureScript works nicely here with it\u2019s tag almost always matching the HTML ones, while not being as clutered as HTML itself - it reminds me of the lovely Jade template in NodeJS.<\/p>\n\n Demo code available on Github<\/a><\/p>\n\n That\u2019s all for now, I got to go hone up my Clojure skills!<\/p>\n","pubDate":"Sun, 29 May 2016 10:55:48 +0000","link":"http:\/\/www.clianz.com\/2016\/05\/29\/clojurescript-react-reagent\/","guid":"http:\/\/www.clianz.com\/2016\/05\/29\/clojurescript-react-reagent\/","category":["Clojure","ClojureScript","React","Reagent","Clojure","ClojureScript","React","Reagent"]},{"title":"Generating Java Spring-MVC code from Swagger Spec","description":" (Edit, July 2017: This Async Spring template in Swagger codegen is deprecated and no longer maintained. Please use the normal Spring template or use a custom template instead. You\u2019ll probably want the newer streaming API oriented convention in Spring 5.x anyway. The plugin and configuration example should still work with other available templates. Keeping this post for reference purposes)<\/strong><\/p>\n\n REST services skeleton code generation is a quick way to get started in implementing the service from popular Swagger spec describing the interface.<\/p>\n\n In this post we\u2019ll look at generating Java Spring MVC code from Swagger spec. There are a few frameworks out there, but at the time I couldn\u2019t find the one that I want - and so I\u2019ve created a new template for my needs. Here is a quick walkthrough on setting up code-gen for Java Spring MVC project.\n<\/p>\n\n There are plenty of projects and templates out there there to generate skeleton server code from Swagger spec, but at the time I haven\u2019t came across one that suit my needs. Ideally it should:<\/p>\n\n Take advantage of Java servlet 3.0+ async<\/strong> feature.<\/p>\n <\/li>\n Generate code for Spring MVC<\/strong> (my preferred framework)<\/p>\n <\/li>\n Integrate with the rest of my stack and build tools (Spring Boot + Maven<\/strong>)<\/p>\n <\/li>\n Generate code directly in target\/gen<\/strong>, instead of a new standalone stub that need us to manually copy\/paste the bits we want.\n This will be useful for updating Swagger spec on existing project, otherwise it\u2019s messy trying to manually figure out what is fresh generated code and merge it with existing implementations.<\/p>\n <\/li>\n<\/ul>\n\n The default Spring MVC template from Swagger codegen was a good start. The j8-async<\/strong> template is a modified version of it with the following changes:<\/p>\n\n Added Generate code with Java 8\u2019s inteface default instead of a plain class.<\/p>\n <\/li>\n<\/ul>\n\nWhat worked<\/h2>\n
cf push awesomeServiceName -p awesome-projet-1.0-SNAPSHOT-bin.zip\n<\/code><\/pre><\/div><\/div>\n\nStarting a Reagent Project - in 3 steps<\/h2>\n\n
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lein new reagent-frontend myproject\n<\/code><\/pre><\/div><\/div>\n\n
cd myproject\nlein cljsbuild auto\n<\/code><\/pre><\/div><\/div>\n\n
myproject\/public\/index.html\n<\/code><\/pre><\/div><\/div>\n\nHow did it work?<\/h2>\n\n
myproject\/src\/myproject\/core.cljs\n<\/code><\/pre><\/div><\/div>\nmyproject\/public\/js\/app.js\n<\/code><\/pre><\/div><\/div>\n\nMaking things happen reactively<\/h2>\n
(<\/span>ns<\/span> <\/span>myproject.core<\/span>\n <\/span>(<\/span>:require<\/span> <\/span>[<\/span>reagent.core<\/span> <\/span>:as<\/span> <\/span>r<\/span> <\/span>:refer<\/span> <\/span>[<\/span>atom<\/span>]]<\/span>\n <\/span>[<\/span>reagent.session<\/span> <\/span>:as<\/span> <\/span>session<\/span>]<\/span>\n <\/span>[<\/span>secretary.core<\/span> <\/span>:as<\/span> <\/span>secretary<\/span> <\/span>:include-macros<\/span> <\/span>true<\/span>]))<\/span>\n\n<\/span>;; -------------------------<\/span>\n<\/span>;; Views<\/span>\n\n<\/span>(<\/span>defonce<\/span> <\/span>click-count<\/span> <\/span>(<\/span>r\/atom<\/span> <\/span>0<\/span>))<\/span>\n\n<\/span>(<\/span>defn<\/span> <\/span>home-page<\/span> <\/span>[]<\/span>\n <\/span>[<\/span>:div<\/span>\n <\/span>[<\/span>:h2<\/span> <\/span>\"Welcome to Reagent\"<\/span>]<\/span>\n <\/span>[<\/span>:p<\/span> <\/span>\"Just playin around...\"<\/span>]<\/span>\n <\/span>[<\/span>:input<\/span> <\/span>{<\/span>:type<\/span> <\/span>\"button\"<\/span> <\/span>:value<\/span> <\/span>\"click this\"<\/span> <\/span>:on-click<\/span> <\/span>#<\/span>(<\/span>swap!<\/span> <\/span>click-count<\/span> <\/span>inc<\/span>)}]<\/span>\n <\/span>[<\/span>:p<\/span> <\/span>\"i've been clicked for: \"<\/span> <\/span>@<\/span>click-count<\/span>]<\/span>\n <\/span>]<\/span>\n<\/span>)<\/span>\n\n<\/span>;; -------------------------<\/span>\n<\/span>;; Initialize app<\/span>\n\n<\/span>(<\/span>defn<\/span> <\/span>mount-root<\/span> <\/span>[]<\/span>\n <\/span>(<\/span>r\/render<\/span> <\/span>[<\/span>home-page<\/span>]<\/span> <\/span>(<\/span>.getElementById<\/span> <\/span>js\/document<\/span> <\/span>\"app\"<\/span>)))<\/span>\n\n<\/span>(<\/span>defn<\/span> <\/span>init!<\/span> <\/span>[]<\/span>\n <\/span>(<\/span>mount-root<\/span>))<\/span>\n<\/span><\/code><\/pre><\/div><\/div>\n\nMore Reading<\/h2>\n
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Spring MVC Java Templates<\/h2>\n
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The Solution<\/h2>\n\n
Introducing the j8-async template in Swagger-codegen<\/h3>\n\n
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<Callable><\/code> tag to response to use Spring\u2019s async servlet feature.<\/p>\n <\/li>\n