[MacRuby-devel] MacRuby with Subprocesses

[Matt Massicotte]

I respectfully disagree :)

NSTask is a huge pain and will result in dramatically more code in the simple cases.  Open3 is much easier to work with, and we can only dream of a solution as simple as backticks in Cocoa.  It becomes less of an issue if you are executing long-running processes and do not want to block on their completion.

All that said, using the Cocoa implementations is definitely generally preferred.  But, if Ruby offers something that Cocoa either doesn't or doesn't do well, you should:

- use the one that best fits your problem
- file a bug so the Cocoa version can be improved

Matt

On Nov 3, 2010, at 9:00 AM, Matt Aimonetti wrote:

> NSTask is the way to go, I used it in many cases, including some examples in my O'Reilly book:
> http://macruby.labs.oreilly.com/ch04.html#_tasks_subprocesses
> 
> You can also look at this more complex example:
> 
> https://github.com/mattetti/couchdbx-app/tree/master/macruby_version/CouchDBX/
> 
> The wrappers might be interesting to look at to see how I'm hiding some of the complexity.
> 
> - Matt
> 
> Sent from my iPhone
> 
> On Nov 3, 2010, at 7:31, Louis-Philippe <default at spiralix.org> wrote:
> 
>> Hi all,
>> 
>> I'm looking  around MacRuby to find a way to run a subprocess and monitor it, here is what I tried:
>> 
>> NSTask:
>> 
>> framework "foundation"
>> task = NSTask.launchedTaskWithLaunchPath("/bin/ls", arguments:"-l")
>> p task.isRunning
>> p task.standardOutput
>> 
>> => Segmentation fault
>> 
>> Open4:
>> 
>> require 'rubygems'
>> require 'popen4'
>> status = POpen4::popen4('irb') { |stdout,stderr,stdin,pid|
>>  stdin.puts "a = 1"
>>  stdin.puts "a == 1"
>>  stdin.close
>>  puts "pid: #{pid}"
>>  puts "stdout: #{stdout.read.strip}"
>>  puts "stderr: #{stderr.read.strip}"
>> }
>> puts "status: #{status.inspect}"
>> puts "exitstatus: #{status.exitstatus}"
>> 
>> => /Library/Frameworks/MacRuby.framework/Versions/0.7/usr/lib/ruby/Gems/1.9.2/gems/open4-1.0.1/lib/open4.rb:15:in `open4:': fork() function is unimplemented on this machine (NotImplementedError)
>> 	from /Library/Frameworks/MacRuby.framework/Versions/0.7/usr/lib/ruby/Gems/1.9.2/gems/POpen4-0.1.4/lib/popen4.rb:75:in `popen4:'
>> 	from /Users/lpperron/Documents/lllaptop/git_repos/Redis/testResque/testOpen4.rb:3:in `<main>'
>> 
>> Open3:
>> 
>> require 'open3'
>> puts "starting..."
>> Open3.popen3('irb') { |stdin,stdout,stderr|
>>  stdin.puts "a = 1"
>>  stdin.puts "a == 1"
>>  stdin.close
>> 
>>  puts "stdout: #{stdout.read.strip}"
>>  puts "stderr: #{stderr.read.strip}"
>> }
>> 
>> => starting...
>> 
>> So...  NSTask segfaults...  Open4 cannot work because of unimplemented 'fork' in MacRuby and Open3 hangs?
>> Anybody has an other solution to launch and monitor a subprocess?
>> 
>> Thanks!
>> 
>> L-P
>> _______________________________________________
>> MacRuby-devel mailing list
>> MacRuby-devel at lists.macosforge.org
>> http://lists.macosforge.org/mailman/listinfo.cgi/macruby-devel
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