# Limiting how long a method is permiited to run

**URL:** <https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522>\
**Category:** Ruby\
**Created:** [December 5, 2005, 5:57pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522 "2005-12-05T17:57:58Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 5:57pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/1 "2005-12-05T17:57:58Z")

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Hello all,

Is there a means of limiting how long a method is permiited to run? I  
want to be able to mark a method with a number and have the method  
throw, say, a TooMuchTimeException if the running time exceeds this  
number.

I am envisioning declaratively applying such limits, either in the  
class definition or setting the limits on individual objects.

Example: class Foo has instance methods calc1, cal2, etc. Depending  
on the state of the foo object and the parameters passed into the  
methods, these methods might run in a fraction of the second or they  
might take minutes.

class Foo  
def calc1  
#complex work …  
end

def calc2(a, b)  
#more complex work …  
end

#declare maximum time limit like this…  
#TooMuchTimeException exception to be thrown if method takes too long  
time\_limit :calc1=\>5, :calc2=\>20  
end

Is there anything already written that does this type of thing?

Thanks.

–Brian B.

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<div class="post-metadata">

**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 6:02pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/2 "2005-12-05T18:02:04Z")

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Brian B. wrote:

> Hello all,
> 
> Is there a means of limiting how long a method is permiited to run? I  
> want to be able to mark a method with a number and have the method  
> throw, say, a TooMuchTimeException if the running time exceeds this  
> number.

[http://www.ruby-doc.org/stdlib/libdoc/timeout/rdoc/](http://www.ruby-doc.org/stdlib/libdoc/timeout/rdoc/)

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**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 6:06pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/3 "2005-12-05T18:06:11Z")

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> > > > > “B” == Brian B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

B\> Is there a means of limiting how long a method is permiited to run?  
I  
B\> want to be able to mark a method with a number and have the method  
B\> throw, say, a TooMuchTimeException if the running time exceeds this  
B\> number.

Well, you have timeout.rb in the standard distribution

# = timeout.rb

# 

# execution timeout

# 

# = Synopsis

# 

# require ‘timeout’

# status = Timeout::timeout(5) {

# # Something that should be interrupted if it takes too much

time…

# }

# 

# = Description

# 

# A way of performing a potentially long-running operation in a thread,

and terminating

# it’s execution if it hasn’t finished by a fixed amount of time.

# 

# Previous versions of timeout didn’t provide use a module for

namespace. This version

# provides both Timeout.timeout, and a backwards-compatible #timeout.

# 

Guy Decoux

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<div class="post-metadata">

**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 7:07pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/4 "2005-12-05T19:07:59Z")

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On 12/5/05, Brian B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Is there anything already written that does this type of thing?

Try this out Brian:

require ‘timeout’

class TooMuchTimeException \< Exception;end

class Class  
def time\_limit(hash)  
hash.each do |name, limit|  
m = instance\_method(name)  
define\_method(name) do  
timeout(limit, TooMuchTimeException) do  
m.bind(self).call  
end  
end  
end  
end  
end

class Foo  
def calc1  
1  
end

def calc2  
sleep(7)  
2  
end

time\_limit :calc1 =\> 20, :calc2 =\> 5  
end

f = Foo.new  
p f.calc1  
p f.calc2

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<div class="post-metadata">

**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 7:12pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/5 "2005-12-05T19:12:03Z")

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On windows, without having to go to the level of processes or using  
fork, (as it doesn’t work on windows), is there a way to timeout either  
a call to system or a call using the backtic sytax as in the following  
logical code which doesn’t work?

require ‘timeout’

begin  
status = Timeout::timeout(1) do  
`notepad`  
while(true)  
puts “this is to fill up the rest of the time”  
end  
end  
rescue Timeout::Error  
puts “Here is the code from rescue”  
end

puts “And here is code after the begin/end block”

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<div class="post-metadata">

**Author:** ![brian](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/97f17d/32.png) [@brian](https://www.ruby-forum.com/u/brian)\
**Post date:** [December 5, 2005, 7:24pm UTC](https://www.ruby-forum.com/t/limiting-how-long-a-method-is-permiited-to-run/49522/6 "2005-12-05T19:24:19Z")

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> Try this out Brian:

Sweet! I added in \*args and it seems to do exactly what I was looking  
for.

class Class  
def time\_limit(hash)  
hash.each do |name, limit|  
m = instance\_method(name)  
define\_method(name) do |\*args|  
timeout(limit, TooMuchTimeException) do  
m.bind(self).call(\*args)  
end  
end  
end  
end  
end