Even-Darker Art of Rails Engines @lazyatom - - PowerPoint PPT Presentation

The

Even-Darker Art

• f

Rails Engines

@lazyatom

github.com/lazyatom/engines

Rails 2.3

history

November 2005

it’s distracting!

reuse is overrated!

Evil!

Evil! Evil! Evil! Evil! Evil! Evil! Evil! Shit!

eek!

appable_plugins

desert

merb slices?

engines

!"#$%&!"#$'#(%&$#)&!"#$%&*$+,#-.!)

!"#$%&'() $$*%&'()$++,$-'%!.%&'()./0#'12%)/'0 "0! 3$405/0"6$%1"$7-(5/06$8/)9$%0$%77:$!/1";)'1<= !"#$"05/0"> $$9%6.%77.!/1";)'1<> "0! 3$?")(106$)1("$/#$)9"$"05/0"$69/76$8/)9$%$1'()/05$#/-" !"#$1'()"!> $$@/-"="A/6)>B1'()/05.#/-"C "0! !"#$D/"8.7%)9 $$@/-"=E'/0B!/1";)'1<F$G%77GF$GD/"86GC "0!

app/controllers/ models/ helpers/ views/ metal/

*$+,#-&"**&23-'!3$$(!&*$+,#-523-'!3$$(!.!)

;-%66$H-(5/0I'0)1'--"1/0/1**$#2"'#3-43-'!3$$(! $$!"#$/0!"A $$$$1"0!"1$J)"A)$,K$LM"--'F$H-(5/0NL $$"0! "0!

9"-7"1$J%--

won’t load from your plugin

Ticket #1905

config/routes.rb

O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$2%7=;'00";)$G:7%)9GF$J;'0)1'--"1$,K$L7-(5/0LF$ $$$$$$$$$$$$$$$$$$$$$$$J%;)/'0$,K$L/0!"AL "0!

*$+,#-&23-6#,&!3+'(%.!)

top precedence

O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$2%7=;'00";)$G:7%)9GF$J;'0)1'--"1$,K$L7-(5/0LF$ $$$$$$$$$$$$$$$$$$$$$$$J%;)/'0$,K$L/0!"AL "0! O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$3$===$')9"1$1'()"6$=== $$2%7=;'00";)$G:7%)9GF$J;'0)1'--"1$,K$L%77LF$ $$$$$$$$$$$$$$$$$$$$$$$J%;)/'0$,K$L/0!"AL $$3$===$')9"1$1'()"6$=== "0!

in your plugin: in your app:

O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$2%7=;'00";)$G:7%)9GF$J;'0)1'--"1$,K$L7-(5/0LF$ $$$$$$$$$$$$$$$$$$$$$$$J%;)/'0$,K$L/0!"AL "0! O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$3$===$')9"1$1'()"6$=== $$2%7=;'00";)$G:7%)9GF$J;'0)1'--"1$,K$L%77LF$ $$$$$$$$$$$$$$$$$$$$$$$J%;)/'0$,K$L/0!"AL $$3$===$')9"1$1'()"6$=== "0!

in your plugin: in your app:

Ticket #2592

(also Ticket #329)

785*$+,#-&$#)&785*$+,#-.!)

2'!(-"$P<H-(5/0 $$!"#$6"-#=%!!.1'()"6B7"*C $$$$2%7=;'00";)$L:6)(##LF$J;'0)1'--"1$,K$L)9/056L $$"0! "0! O;)/'0I'0)1'--"1JJ?'()/05JJ?'()"6=!1%8$!'$+2%7+ $$3$<'(1$%77$1'()"6=== $$P<H-(5/0=%!!.1'()"6B2%7C $$3$");=== "0!

what’s missing?

public assets

copy

file clash

83+!5*$+,#-&#-%'"$$.!)

2<./2%5"6$,$H%)90%2"=0"8B@/-"=!/10%2"B..@QR4..CC$S$ $$$$$$$$$$$$$$L%66")6:/2%5"6L )%15")$,$?%/-6=1'')$S$L7(&-/;:/2%5"6:2<.7-(5/0L @/-"T)/-6=2U!/1.7B)%15")C 2<./2%5"6=;9/-!1"0="%;9$!'$+"+$ $$$$@/-"T)/-6=;7.1B"F$)%15")$S$"=&%6"0%2"C$ "0!

83+!5*$+,#-&#-%'"$$.!)

2<./2%5"6$,$H%)90%2"=0"8B@/-"=!/10%2"B..@QR4..CC$S$ $$$$$$$$$$$$$$L%66")6:/2%5"6L )%15")$,$?%/-6=1'')$S$L7(&-/;:/2%5"6:2<.7-(5/0L )%15")=2%U".6<2-/0UB2<./2%5"6C$(0-"66$)%15")="A/6)>

migrations

simple DSL

rollback

!&:2/51%)": $$VWWXWYWYYVYVZ[.%-79%=1&

version

20090101121234 20090102142345 2008123123456

VWWXWYWVY[VZ[\.&")%=1& 7-(5/0:!&:2/51%)": $$VWW]YVZYZ[\^.5%22%=1&

version

20090101121234 20090102142345 2008123123456

1%U"$!&J1'--&%;U

P/51%)'1=1'--&%;U P/51%)'13;(11"0).D"16/'0 P/51%)'132/51%)"!=-%6) P/51%)'1=5").%--.D"16/'06

BL_4R4I`$D"16/'0$@?aP$ $ $ $$6;9"2%.2/51%)/'06LC =2%7BbJ)'./C=6'1)

it gets worse

!&:2/51%)": $$WWY.%-79%=1&

version

001 002

WWV.&")%=1& 7-(5/0:!&:2/51%)": $$WWY.5%22%=1&

single timeline

app migration 1 app migration 2 plugin migration 1 app migration 3 plugin migration 2 install upgrade You Me

app migration 1 app migration 2 plugin migration 1 app migration 3 plugin migration 2 You

WW[.!"-)%=1& !&:2/51%)": $$WWY.%-79%=1& WWV.&")%=1& 7-(5/0:!&:2/51%)": $$WWY.5%22%=1& WWZ.7-(5/0.)'.WWY=1&

WW[.!"-)%=1& !&:2/51%)": $$WWY.%-79%=1& WWV.&")%=1& 7-(5/0:!&:2/51%)": $$WWY.5%22%=1& WWZ.7-(5/0.)'.WWY=1&

Copy & Retimestamp? Reference? Symlink?

Ticket #2058

interblah.net/plugin-migrations

my recommendation?

(for the moment, at least)

write a generator

c$6;1/7):5"0"1%)"$%;)6.%6.#(.2/51%)/'06 $$$$ $$$"A/6)6$$!&:2/51%)" $$$;1"%)"$$!&:2/51%)":VWWXW\W\YYYZZd.&-%9=1& c$===

(within your plugin)

techniques

• verriding functionality

views just work

controllers

straight override

module

namespaced

playing nice with the class cache

1/23*8/36/1**$#2"'#3-43-'!3$$(!/ 9"%/)((-/!(73:(;/6!37/'9(/73;+$(/ '!((/)+'/#%/%'#$$/"2'#:(< <

<

<

<

<

<<!

O;)/D"_(77'1)JJe"7"0!"0;/"6=-'%!.'0;".7%)96

ApplicationController AppController PluginController

ApplicationController PluginController

23-6#,&(-:#!3-7(-'.!)

?%/-6JJQ0/)/%-/f"1=1(0$!'$+;'0#/5+ $$3$");=== $$;'0#/5=1"-'%!.7-(5/06$,$)1(" $$ "0!

83+!5*$+,#-&"**&23-'!3$$(!%&,33;523-'!3$$(!.!)

;-%66$g''!I'0)1'--"1$h$=== $$(0-'%!%&-" $$ $$3$");$=== "0!

init.rb woes

;'0#/5=)'.71"7%1"$!' $$ "0!

785*$+,#-&#-#'.!)

$$_'2"O77I-%66="A)"0!BP<i"9%D/'(1C

testing

ApplicationController PluginController AppController

ApplicationController PluginController Their Code Your Code

unit test?

test in your own rails environment?

plugin_test_helper

I care about testing my chunk

You care about testing your whole app

empower the developer

avoiding fail

;%6"$;'!"=;'06(2"1 $$89"0$;'!"=%()9'1 $$$$1"(6"=2'6)-<$,j$:"##";)/D": $$89"0$1%0!B!"D"-'7"1C $$$$1"(6"=)1/;U/"1.&().7'66/&-"B)1("C $$"-6" $$$$1"(6"='D"11%)"!N "0!

consume wisely

Serving Size 14 kloc

Nutrition Facts

Amount Per Serving 1 bad engine

Calories 10,666

Long Methods 1578g 34% God Objects 326g 7% Stress 320mg 119% Total Fat 2674g 98% Hairloss 45g 45.8%

% Daily Value*

Technical Debt 13g 87% Untested Code 1578mg 34% Hidden Bugs 326mg 7% Benefit 1mg 0.1%

you will not be able to write some engines.

you will not be able to use some engines.

extract specific functionality

establish some clear integration points

you are customer #1

READ the CODE

james@lazyatom.com lets@gofreerange.com

FIN