#10 Add preload namespace that calls init-tracing! for use with the :preloads compiler option.

This commit is contained in:
Dexter Gramfors 2017-04-13 00:56:17 +02:00
parent 0a738e27cd
commit 2cecacb6af
2 changed files with 14 additions and 5 deletions

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@ -14,21 +14,23 @@ re-frame has instrumentation to collect traces throughout various important poin
## Getting started
There are three requirements to use re-frame-trace:
There are two requirements to use re-frame-trace:
1. Compile your app with `:closure-defines`: "re_frame.trace.trace_enabled_QMARK_" true, e.g.
1. Compile your app with `:closure-defines: "re_frame.trace.trace_enabled_QMARK_" true` and `:preloads [day8.re-frame.preload]`, e.g.
```cljs
{:builds
[{:id "dev"
:source-paths ["src" "dev"]
:compiler {...
:closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}}}]}
:closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}
:preloads [day8.re-frame.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.
2. In your app's startup method, call `day8.re-frame.trace/init-tracing!` to 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. **N.B.:** because re-frame-trace is a development time only dependency, you may need to create two separate source folders, `dev` and `prod` to get isolation. The `dev` folder would contain an `init!` function in the `myapp.boot` namespace which calls `init-tracing!`, while the prod version of `init!` would be a no-op. It may be possible to use [preloads](https://github.com/clojure/clojurescript/wiki/Compiler-Options#preloads) in the future to remove this step entirely.
3. In your app's view code, add in `day8.re-frame.trace/devtools` as a sibling to the root application view. For example, if your app looks like this:
The [preloads](https://github.com/clojure/clojurescript/wiki/Compiler-Options#preloads) option (`:preloads [day8.re-frame.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.
2. In your app's view code, add in `day8.re-frame.trace/devtools` as a sibling to the root application view. For example, if your app looks like this:
```cljs
(defn main []

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@ -0,0 +1,7 @@
(ns day8.re-frame.preload
(:require [day8.re-frame.trace :as trace]))
;; Use this namespace with the :preloads compiler option to perform the necessary setup for enabling tracing:
;; {:compiler {:preloads [day8.re-frame.preload] ...}}
(trace/init-tracing!)