Tenzing is a Clojurescript template offering the following features:
Incremental Clojurescript compilation
Live reloading of your Javascript, CSS, etc.
Browser-REPL
In contrast to some of the options out there it is opinionated in the following ways:
Tenzing uses Boot instead of Leiningen (see below)
Tenzing does not provide a backend layer (see below)
Tenzing allows you to choose between Om, Reagent and others
Rationale
Why Boot?
In contrast to Leiningen Boot offers a clear strategy when it comes to
composing multi-step build processes such as compiling stylesheets and
Javascript whenever a relevant file changes.
Many Leinigen plugins come with an `auto` task that allows similar
behavior. If you want to run multiple of those tasks it's usually done
by starting multiple JVM instances which can lead to
high memory usage. Boot
allows this sort of behaviour to reside in one JVM process while
making sure that build steps don't interfere with each other.
If you figure out that you need a Clojure based backend down the road
it's simple to either add it yourself or create it as a standalone
service that's being used by your clients.
Please, also consider
offline first as an
approach for building early iterations of your application.
If you're wondering how files are served during development: there
is a boot task `serve` that allows you to serve static files.
If you want to add an option,
pull-requests are welcome.
Running it
After you installed Boot
you can run your Clojurescript application in "development mode" by
executing the following:
$ boot dev
After a moment of waiting you can head to
localhost:3000 to see a small sample app. If
you now go and edit one of the Clojurescript source files or a SASS
file (if you've used the +sass option) this change will be picked up
by Boot and the respective source file will get compiled. When a
compiled file changes through that mechanism it will get pushed to the
browser.
If you used the +test option, then you'll be able to run unit
tests via boot test. Use boot auto-test to have tests
automatically rerun on file changes.
Connecting to the browser REPL
After you started your application with boot dev there will be a
line printed like the following:
nREPL server started on port 63518 on host 0.0.0.0
This means there now is an nREPL server that you can connect to. You
can do this with your favorite editor or just by running boot repl --client in the same directory.
Once you are connected you can get into a Clojurescript REPL by
running (start-repl). At this point I usually reload my browser one
last time to make sure the REPL connection is properly setup.
Now you can run things like (.log js/console "test"), which should
print "test" in the console of your browser.
How it works
If you look at the build and run tasks in the build.boot file of
your newly created project you will see something like the following:
Basically this composes all kinds of build steps into a unified run
task that will start our application. From top to bottom:
The build task consists of three other tasks:
speak gives us audible notifications about our build process
cljs will compile Clojurescript source files to Javascript
sass will compile Sass source files to CSS
Now if we just run boot build instead of the aforementioned boot dev we will compile our Clojurescript and Sass exactly once and then
the program will terminate.
This is where the run task comes in:
serve starts a webserver that will serve our compiled JS, CSS
and anything else that is in resources/
watch will watch our filesystem for changes and trigger new
builds when they occur
cljs-repl sets up various things so we can connect to our
application through a browser REPL
reload will watch the compiled files for changes and push them
to the browser
build does the things already described above
Please note that all tasks, except the one we defined ourselves have
extensive documentation that you can view by running boot <taskname> -h (e.g. boot cljs-repl -h).
Writing build artifacts to disk
By default, none of the tasks in projects generated by tenzing output any files.
For example, when running the dev task, your project's source and resources are
compiled to a temporary boot fileset and served from there. When boot quits, the
fileset is no longer available.
This is actually boot's default and, at first, might sound like a strange choice for a build tool!
However, these managed filesets are at the core of boot's philosophy and provide it with
many advantages over declarative, stateful build tools. See the boot homepage or the
[filesets wiki entry] (https://github.com/boot-clj/boot/wiki/Filesets) for more info on these concepts.
So how do you output your built project to disk so that you can deploy it for example?
Simple! Boot has a [built-in target task]
(https://github.com/boot-clj/boot/blob/master/doc/boot.task.built-in.md#target) that you can can compose with other tasks to
output their results to a given directory (by convention the directory is named target).
To build a tenzing project with the production settings and output the
results to disk you would run the following:
$ boot production build target
If you look in your project directory now, you will see a target directory containing the
output of all of the tasks in this chain. By default, this directory is cleaned every time
you run boot, unless you pass the no-clean option to the target task.
Should you need to filter, copy, move or rename the output files, or change the directory
structure, the sift task will help you do this. If you have complex post-processing needs
or want to save typing at the command line, it's a simple matter to define your own tasks.
Deployment
Since Tenzing comes without a backend you can easily deploy your app
to Amazon S3 or even host it in your Dropbox. To do that just copy the
files in target/ to your desired location.
PS. I'm also working on a tool called
Confetti 🎉 that helps
you setting up static sites on AWS infrastructure. It's a bit more
aimed at people that deploy and manage many static sites but you
should probably check it out either way :)
Getting Help
If you run into any problems feel free to open an issue or ping me (martinklepsch) in the ClojureScript room on Riot.im (no signup required).
Credits
The initial release of Tenzing was prompted by the urge to have
something like the awesome
Chestnut template but built on
top of Boot. Many props to Arne Brasseur
for making getting started with ClojureScript a lot easier at the
time!