Don't use Ruby!

My RuPy Brno 2012 conf talk about using the right tool for the right job.

On the examples of building blocks of http://ascii.io/ I show when to consider using other, well established technologies, getting out of the "Ruby tunnel vision".

Transcript

1. Don't use Ruby* * unless otherwise stated ASCII.IO CASE STUDY NERD CONTENT WARNING!
2. MARCIN KULIK
3. I WORK AT
4. I CURRENTLY WORK ON: kanbanery.com
5. I SHARE AT GITHUB & TWITTER AS SICKILL
6. YOU MAY KNOW ME FROM: racksh, ascii.io, git-dude, vim-pasta, bitpocket, coloration, stderred... All of them available at https://github.com/sickill/
7. Don't use Ruby
9. Use the right tool for the right job
10. Quick history lesson
13. VT100 RELEASED IN 1978 FOUNDATION FOR TERMINALS WE USE
14. Developer's workflow
15. rake git vim rails {generate, console, ...}
16. Screencasts
17. "Recording the work in your terminal with screen capture software and serving it as a video is like recording your text reply as an .mp3 file and sending it via email" - Me.
18. typescript
19. /usr/bin/script
20. # man script NAME script — make typescript of terminal session DESCRIPTION script makes a typescript of everything printed on your terminal. It is useful for students who need a hardcopy record of an interactive session as proof of an assignment, as the typescript file can be printed out later with lpr(1).
21. RECORDING: $ script -t session1 2>session1.time
22. /usr/bin/scriptreplay
23. # man scriptreplay NAME scriptreplay - play back typescripts, using timing information DESCRIPTION This program replays a typescript, using timing information to ensure that output happens at the same speed as it originally appeared when the script was recorded.
24. REPLAYING: $ scriptreplay foo.time foo
25. Sharing
26. Requirements for sharing Simplest possible recording in the terminal Simplest possible replay in the browser
27. ascii.io was born
28. "ASCII.IO is the simplest way to record your terminal and share the recordings with your fellow geeks. Simply record and upload your terminal session with single command, and ASCII.IO will play it back in your browser."
29. Quick demo APP SCROLS BY DR NIC
30. 4 building blocks of ascii.io
31. terminal recorder http://ascii.io/ site with an API in-browser player background job for thumbnails
32. terminal recorder http://ascii.io/ site with an API in-browser player background job for thumbnails
33. The recorder
34. Recording is covered /USR/BIN/SCRIPT
35. Well, on Linux yes
36. On OSX /usr/bin/script is crippled
37. A little bit of Yak Shaving
38. script.c 433 LINES OF C CODE CREATES PTY - PSEUDO-TERMINAL
39. How script.c works
40. it has its STDIN and STDOUT connected to the terminal app it forks and execs shell in child process it gets file descriptors for spawned process' STDIN and STDOUT it proxies STDIN and STDOUT and saves STDOUT to a file
41. --XTerm--------------------------- | | | --outer bash---------------- | | | | | | | --script-------------- | | | | | | | | | | | --inner bash---- | | | | | | | | | | | | | | | $ | | | | | | | ---------------- | | | | | | | | | | | ---------------------- | | | | | | | ---------------------------- | | | ----------------------------------
42. Requirements for the recorder
43. works on both Linux and OSX has minimum dependencies has simplest possible installation is targetted not only at Rubyists
44. script.rb?
45. script.rb pros Ruby! Ruby has PTY module in stdlib
46. script.rb cons WELL... RUBY
47. Requires ruby installed
48. PTY module differs between 1.8 / 1.9
49. I don't control user environment DOES USER HAVE 1.8 OR 1.9? NO RUBY AT ALL?
50. script.py?
51. script.py pros Python is preinstalled on Linux/OSX Python has pty module in stdlib
52. pty module haven't changed in years
53. LIKE IN 10+ YEARS
54. script.py then! ~400 LOC no dependencies records STDOUT + timing info saves env info ($TERM, $SHELL...) uploads
55. "It was just safer to use Python here" - Me.
56. Term recording ✔
57. The site
58. Requirements for the site Replaying asciicast Browsing through asciicasts Basic (optional) profile
59. Next slide will be boring...
60. Site is built in Rails * here you can use Ruby
61. The player
62. Ruby?
63. Ruby in the browser NaCl in Chrome JRuby in Applet other hacks..?
64. Java applet?
66. Flash?
67. "That Steve guy famously said it's proprietary and closed, too." http://isflashdeadyet.com/
68. Javascript?
69. Javascript then! TECHNICALLY COFFEESCRIPT :)
70. HTML5 based VT100/102 implementation
71. Multiple renderers: <pre> and <canvas> Fast Tested with Jasmine
72. Renderers 2 AVAILABLE NOW: <pre> , with "copy & paste" <canvas> , faster, no "copy & paste" TODO: WebGL based one
73. Fast & responsive THANKS TO HTML5 requestAnimationFrame WebWorker
74. Soon to be extracted from ascii.io
75. Replaying ✔
76. Thumbnails
78. Requirements for thumbnail generation
79. thumbnail is just a text generation happens in background after uploading takes terminal snapshot at 10 sec mark
80. ffmpeg? WELL, NO. IT'S NOT VIDEO FILE.
81. Xvfb + xterm + scriptreplay? WELL, NO. SCRIPTREPLAY DOESN'T DO SNAPSHOTS.
82. Xvfb + xterm + scriptreplay + screenshot? WELL, NO. I WANT TEXT.
83. scriptreplay won't do then...
84. nodejs maybe?
85. Maybe, via: standalone nodejs bin therubyracer gem
86. Something told me to man tmux
87. tmux?
88. "tmux is a terminal multiplexer: it enables a number of terminals to be created, accessed, and controlled from a single screen. tmux may be detached from a screen and continue running in the background, then later reattached."
89. How tmux fits here???
90. $ man tmux capture-pane [-b buffer-index] [-E end-line] [-S start-line] [-t target-pane] Capture the contents of a pane to the specified buffer, or a new buffer if none is specified.
91. $ man tmux save-buffer [-a] [-b buffer-index] path Save the contents of the specified paste buffer to path. The -a option appends to rather than overwriting the file.
92. scriptreplay will do then!
93. Plan
94. BACKGROUND JOB THAT: creates new, detached tmux session runs `scriptreplay` in it waits for 10 sec runs `tmux capture-pane` runs `tmux save-buffer`
95. // app/jobs/capture_job.rb class CaptureJob def self.perform(...) ... system "tmux new -s $SESS_ID -d -x $X -y $Y 'scriptreplay ....'" sleep 10 system "tmux capture-pane -t $SESS_ID" text = `tmux save-buffer -` system "tmux kill-session -t $SESS_ID &>/dev/null" ... end end
96. Great! Works! BUT LET'S LOOK AT IT AGAIN...
97. Use shell script instead!
98. // script/capture.sh #!/bin/bash ... tmux new -s $SESS_ID -d -x $COLS -y $LINES "scriptreplay ...." sleep 10 tmux capture-pane -t $SESS_ID tmux save-buffer - tmux kill-session -t $SESS_ID &>/dev/null
99. // app/jobs/capture_job.rb class CaptureJob def self.perform(...) ... text = `SESS_ID=#{sess_id} COLS=#{cols} ... script/capture.sh` ... end end
100. Thumbnails ✔
101. Example use cases
102. Tutorials Rails blog app in 15 minutes? ;) Vim git shell tricks
103. Bug reporting app starts leaking memory app starts eating CPU
104. Auto-recording of shell sessions
105. # end of .bashrc if [ -z "$RECORDING" ]; then export RECORDING=1 ASCII_IO_API_URL=http://localhost:3000 exec asciiio -y fi Thx @roy & @_solnic_ !
106. It's open-source Web app: github.com/sickill/ascii.io Recorder: github.com/sickill/ascii.io-cli CONTRIBUTE!
107. Summary
108. Use Ruby where it makes sense
109. Use Python where it makes sense
110. Use X where it makes sense
111. Thanks! QUESTIONS PLEASE! Twitter/Github: @sickill