June 2020 Monthly Update

By Alyssa Parado



June 1-15

Here’s an update broken by project:


June 16-30

Here’s the latest update.



June 1-15

The last two weeks I spent some time documenting the NPM features a bit more. Then I turned my attention to what I call the Jetty conflicts problem. Which eventually lead me to investigate SSL support and how to make connecting to a Figwheel server over HTTPS even easier.

I also spent quite a bit of time looking into some advanced compilation problems that occur when you are switching from Cljsjs based probject to an NPM :bundle based project. This lead me to finally implement a --clean command which makes it easier to clean your compiled artifacts out of your project.

The Jetty conflicts problem

The Jetty conflicts problem has dogged figwheel-main from the beginning.

How did we get here? I switched to Jetty thinking that it would be better to use the most common server used for Clojure development (ring-jetty-adapter) and elimininate some bloat while making things like configuring HTTPS easier. I didn’t realize that switching to Jetty would cause so many headaches for folks.

The main problem is that the way Jetty is packaged, makes version conflicts extremely easy when we use slightly uncommon packages like org.eclipse.jetty.websocket/websocket-servlet and org.eclipse.jetty.websocket/websocket-server.

Jetty is developed across several “independent” packages. Unfortunately these “independent” packages are tightly coupled so you need to ensure that you are running the same version number for each required Jetty package.

This gets easily thrown out of whack when another dependency like datomic-cloud includes a Jetty dependency that is newer than the Jetty dependency in Ring. The main problem is a UX problem because when a conflict occurs the errors are about missing classes or methods deep in Jetty leaving the user with little to go on.

I spent time looking at the server code and considering wether I should get rid of the Jetty websocket packages and just use the HTTP long-polling already in ring for the connection, or perhaps making the websocket connection conditional on having an additional figwheel-websocket package. I also looked at maybe going back to using httpkit. All of these solutions were less than ideal.

Then it came to my attention that then next major release of Ring is going to include websocket support. So I decided to just punt on this until then and see if that improves things.

As it stands right now, I’ve updated to the latest Ring which has a fairly recent version of Jetty and this should reduce colissions for the time being.

HTTPS support

The look at the Jetty conflict problem drew me to consider the neccesity of using websockets, and considering if http long polling could work.

The figwheel-main long polling support works really well, but it becomes a problem if you are serving your development application with SSL. That would require using HTTPS in figwheel as well for long-polling to work.

Even though I decided not to use long-polling, this did lead me to investigate how to make setting up HTTPS in figwheel-main easier. Situations where folks are required to use HTTPS during development are becoming more common and I wanted to see if I could make it easier.

I eventually added a :use-ssl configuration option which is sure that sets up and changes figwheel configuration to support SSL, currently it still requires that you set up a Java Keystore. However I wanted the :use-ssl option to work even if you didn’t have a Java Keystore configured.

Setting up a local dev certificate and getting into the form of a JAva Keystore can be pretty esoteric. Creating a certificate, trusting it in order to eliminate browser warings, and doing this all securely is fairly challenging. This eventually lead to the creation of the certifiable library to ease the creation of a local dev certificate and Java Keystore. Using certifiable should enable figwheel-main to have turn-key HTTPS support.


While lein-figwheel has support for cleaning up your compiled development artifacts figwheel-main has chosen to allow you to implement your own cleaning. Well, I’ve finally added cleaning to figwheel-main. You can either add the --clean to your CLI options or or :clean-ouputs true to your Figwheel options.

This will clean all of your builds compilation output including generated bundles AND all of the compiled output from and extra-mains that you have configured as well.

Clean is a better option in many cases when you just want to target what you are currently woring on.

It’s handy to leave --clean or :clean-outputs in your configuration while you work on debugging something.

June 16-30

Things are really moving along great! For the last two weeks I worked on two main things. I spent most of my time working on getting certifiable up and working well on MacOS, Linux and Windows along with integrating it into figwheel-main to enable zero-config HTTPS support.

Along with that during the last couple of days I’ve been getting React Native support started.

Very Simple HTTPS Configuration

Continued work on Certifiable to make it robust enough that it can dependably create a Java Keystore across common platforms.

This allowed me to finish the implementation of the :use-ssl Figwheel Option which completely automates the configuration of Figwheel’s server to use HTTPS.

Usually setting up your local server as an HTTPS server is tedious combination of searching the web and several rounds of trial and error. Now you can just set :use-ssl true and Figwheel will start using HTTPS including a secure websocket.

Next steps are to allow users to provide the hostnames and ips they want the certificate to be configured for.

This will ultimately be very helpful when you are interacting with applications remote to the computer running the Figwheel, like on a smartphone or touch pad.

Also started on the documentation for :use-ssl here.

React Native Support

I was able to complete an initial pass at React Native support.

The goal is to allow you to simply create a Figwheel project in the root directory of a React Native CLI or React Native Expo project.

One can now set the new :react-native Figwheel option to true and it will take care of the mechanics of hooking up Figwheel to the React Native project.

The initial pass at this for React Native CLI is finished.

One problem is that the npm_deps.js file is regenerated on every compile which causes the metro bundler to reload the whole application on every compile. I solve this by creating a separate source directory and copying npm_deps.js there only when it changes.

I will probably be working on React Native for the next two weeks as there are several things that need to be done to make it all work well.

The most important problems to solve are:

Thanks Again!

As always I want to thank everyone for this opportunity to dedicate time to Figwheel.

I hope everyone is staying safe, and is finding time to care for themselves, their loved ones and their community.


June 1-15

Continued with Practicalli Clojure updates and weekly broadcasts covering Clojure spec and generative testing. Also updates on Practicalli Spacemacs, including a move to doom modeline theme for a clean and modern look to Spacemacs.

I was still feeling the affects of illness for some of this period, but steadily improving.

Practicalli Study Group

Designing specifications for an online bank and basic generative testing video added to the Practicall Clojure Spec playlist

Practicalli Clojure Updates

Adding content and videos to the Introducing Spec section of the book, providing live code examples via klipse enabling the reader to interact with the specs and functions in the Practicalli Clojure book website.

Spec is introduced by showing how it can be used in the REPL and added to project, with the leveraging-spec project containing many different examples.

Divided the Spec section into Spec data, that covers how the use of predicates, literals and custom functions as specifications along with the core functions to verify data agains specs (conform, valid?, explain).

Expanded on Getting Started section, converting to Clojure CLI and tools.deps. Examples on using Clojure CLI tools to evaluate functions, load files and run applications.

Added details on configuring tools.deps and how to define and use multiple aliases. Provided a collection of aliases for community tools, jcenter clojars mirror and how to use a local Artifactory instance.

Added section rebel readline for a feature rich command line REPL, including install, customisation and major features.

Configuring a REPL on starutup for deps.edn projects, examples of using dev/user.clj to require namespaces, call functions and manage component lifecycle services (mount, component, integrant, etc.).

Clojure deps.edn updates

Practicalli Spacemacs Updates

Added page on calling component lifecycle services when refreshing the REPL from CIDER.

Updated practicalli/spacemacs.d to use doom modeline and doom-gruvbox-light theme to give a modern and clean look to Spacemacs.

June 16-30

After the broadcasts on Clojure spec, moving on to more tooling centric topics. Starting with Unit test runners for Clojure CLI tool and preparing a series on continuous integration, packaging and deployment.

Flu symptoms have finally eased, so planning video tutorials in the later part of the sponsorship.

Practicalli Study Group

Wrap up of Clojure spec series of 5 broad, sharing my experiences with spec along with feedback from many others in the community.

Broadcast on unit testing and test runners, focusing on Cognitect Labs test runner and Koacha from Lambda Island.

Practicalli Clojure

Updated and extended the Getting Started section, using rebel readline for the command line REPL UI. Added sections on configuriong Clojure CLI and provided a wide range of community tools and other useful aliases.

Wrote a new section on Clojure Spec and generative testing, covering how to design specifications (composite vs hierachical). Also discussed organising specifications and how they fit into a project and along side Test Driven Development (TDD) and REPL drive development (RDD).

Wrote section on Regular Expressions in Clojure. Added regular expressions for common string patterns, such as passwords, email addresses, etc.

Extended the Unit Testing section to cover useful practices with clojure.test library, refactor is assertions with are to work over data sets.

Added test runner section covering Cognitect Labs test runner and configuring categories of tests. Started a section on kaocha covering the basic use and configuration. This section to be extended as more projects are used with kaocha.

Configured git template to use live branch as the default branch name. The word master has never made any sense as a term in a distributed version control system.

Added :test-runner-cljs alias to practicalli/clojure-deps-edn for the cljs-test-runner from Olical. A test runner inspired by Cognitect Labs test runner for Clojure.

Discussion regarding some defacto approaches and conventions for Clojure tools.deps projects, especially around the idea of naming of aliases. The practicalli/clojure-deps-edn repository is an example of how 30+ aliases could be defined to provide the most common tooling for all tools.deps projects.

Practicalli ClojureScript

Clarified the introduction to the ClojureScript book status and surfaced the work that remains current and functional. This content includes and several reagent based projects, building and deploying a ClojureScript website for ClojureBridge and creating a TicTacToe game with Scalable Vector Graphics.

Depreciated content developed several years ago, as much has changed in the ClojureScript world since then. The older content is still available and will be updated during July 2020 and onward.

Practicalli Spacemacs

Using CIDER test runner in Spacemacs with Clojure CLI projects. Covering the Spacemacs specific key bindings, and how to configure the CIDER test runner in Spacemacs.

Hint on turning off custom themes to get the classic Emacs look. The theme called default looks the same as classic Emacs.

Created a reference sheet for CIDER configuration variables, as there is no overall reference.

Using .dir-locals.el for project specific configuration.

Spacemacs Pull Requests

Refactor applications menu key bindings to create more room for key bindings and improve mnemonic keybinding use. Sub menus added using the layer categories of the packages any existing key bindings originate from.


June 1-30

As we had been working almost full-time on re-frame over the prior period we took a break from re-frame over this period and expect to resume work on re-frame’s meatier enchancement proposals in July.