re-frame-trace

A trace window for re-frame

Motivation

re-frame provides a data driven architecture, but we need to be able to inspect it. re-frame-trace takes inspiration from redux-devtools, and provides several ways to visualise the structure and state of your re-frame application.

How does it work?

re-frame has instrumentation to collect traces throughout various important points in the lifecycle of a re-frame app. re-frame-trace is a consumer of these traces, and provides visualisations of the traces. These traces have a well-defined structure, and will eventually be standardised, allowing other developers to create their own tooling to work against the traces. Currently, re-frame's tracing and re-frame-trace are in alpha and are subject to change at any time.

Getting started

Compile your app with :closure-defines: "re_frame.trace.trace_enabled_QMARK_" true and :preloads [day8.re-frame.trace.preload].

So when using leiningen, add the following to project.clj:

• [day8.re-frame/trace "0.1.0"] in :profiles :dev :dependencies

  {:profiles
     {:dev
        {:dependencies [day8.re-frame/trace "0.1.0"] }}
  

• :closure-defines: "re_frame.trace.trace_enabled_QMARK_" true and :preloads [day8.re-frame.trace.preload] in :compiler

      {:builds
         [{:id           "dev"
           :source-paths ["src" "dev"]
           :compiler     {...
                          :closure-defines      {"re_frame.trace.trace_enabled_QMARK_" true}
                          :preloads             [day8.re-frame.trace.preload]}}]}
  

By default, re-frame tracing is compiled out, so it won't impose a performance cost in production. The trade-off here is that you need to explicitly enable it in development.

The preloads option (:preloads [day8.re-frame.trace.preload]) has to be set in order to automatically monkeypatch Reagent to add appropriate lifecycle hooks. Yes this is gross, and yes we will try and make a PR to reagent to add proper hooks, once we know exactly what we need. The preload namespace also injects a div containing the devtools panel into the DOM.

Now you can start up your application. Once it is loaded, press Ctrl+H to slide open the trace panel and enable tracing. When the panel is closed, tracing is disabled.

Development

Setting up re-frame-trace for development

You need both the re-frame-trace project and a test project to develop it against. For example, you can use the todo-mvc project.

• Clone re-frame-trace to your machine:

  git clone git@github.com:Day8/re-frame-trace.git
  

• Go into the root folder of the test project you're using to develop re-frame-trace with.

  cd /your/project/folder
  

• Add re-frame-trace into this test project using the instructions above.

• Still in the test project, create a folder called checkouts, then enter the folder:

  mkdir checkouts
  cd checkouts
  

• Create a relative symlink from your local re-frame-trace project in the checkouts folder. For example:

  ln -s ../relative/path/to/your/local/re-frame-trace re-frame-trace
  

• If you're using figwheel in the test project, you need to add the checkouts folder (checkouts/re-frame-trace/src) to :cljsbuild :source-paths in the project.clj file. If you're having trouble locating the right place to put this, it might help to look to a sample project.clj for inspiration. For example:

  :cljsbuild {:builds {:client {:source-paths ["checkouts/re-frame-trace/src"]}}}
  

• Now run your test project however you usually run it, and re-frame-trace should be in there. \o/