Getting Gem Version from Within a Gem

ruby-talk
1

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Thanks!
-fREW

···

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2

Using 'gem' , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i'm not sure, is it what you expect.

Best Regards, Kuba.

···

On 7/10/07, Frew Schmidt <frioux@gmail.com> wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

3

Gem.loaded_specs.map do |n,s| s.full_name end

Better to just have a VERSION constant somewhere, though.

···

On Jul 9, 2007, at 23:40, Frew Schmidt wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

--
Poor workers blame their tools. Good workers build better tools. The
best workers get their tools to do the work for them. -- Syndicate Wars

4

invert!

Have your program know what its version is and have your gemspec ask it:

=== lib/blah.rb

class Blah
   VERSION = "1.2.3"
   # ...
end

=== Rakefile

require 'rubygems'
require 'hoe'

require './lib/blah.rb'

Hoe.new("Blah", Blah::VERSION) do |p| # this builds the gemspec and defines a lot of commands
   # ...
end

···

On Jul 9, 2007, at 23:40 , Frew Schmidt wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

5

Kuba wrote:

···

On 7/10/07, Frew Schmidt <frioux@gmail.com> wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Using 'gem' , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i'm not sure, is it what you expect.

Best Regards, Kuba.

So there's not a variable inside the program that I can access that
contains the Gem info?

--
Posted via http://www.ruby-forum.com/\.

6

Frew,

If you don't mind requiring Hoe then this is an excellent approach to use.

···

On Jul 10, 2007, at 21:01 , Ryan Davis wrote:

<snip>
=== lib/blah.rb

class Blah
  VERSION = "1.2.3"
  # ...
end

=== Rakefile

require 'rubygems'
require 'hoe'

require './lib/blah.rb'

Hoe.new("Blah", Blah::VERSION) do |p| # this builds the gemspec and defines a lot of commands
  # ...
end

--
Wayne E. Seguin
Sr. Systems Architect & Systems Admin
wayneseguin@gmail.com

7

Frew,

The usual method of accessing the version of a gem from within a running Ruby app is:

GemConstName::Version::STRING

This works if the author followed convention.

···

On Jul 10, 2007, at 09:37 , Frew Schmidt wrote:

So there's not a variable inside the program that I can access that
contains the Gem info?

--
Wayne E. Seguin
Sr. Systems Architect & Systems Admin
wayneseguin@gmail.com

8

Frew Schmidt wrote:

Kuba wrote:

Does anyone know if there is a way that I can have my program output
what version it is and get the version from the Gem that it is installed
from?

Using 'gem' , you can execute sth. like:

gem list --local | grep <your_prog_name>

but i'm not sure, is it what you expect.

Best Regards, Kuba.

So there's not a variable inside the program that I can access that
contains the Gem info?

I think, it depends on your gems' library/program.
There is no general variable (fix me if i'm wrong).

E.g.: In module 'Inline' is defined const. VERSION, so you can print
Inline::VERSION, but 'rake' defined const. RAKEVERSION

···

On 7/10/07, Frew Schmidt <frioux@gmail.com> wrote:

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9

Huh? Even without hoe the point and the example still stand.

···

On Jul 11, 2007, at 14:11 , Wayne E. Seguin wrote:

class Blah
  VERSION = "1.2.3"
  # ...
end

=== Rakefile

require 'rubygems'
require 'hoe'

require './lib/blah.rb'

Hoe.new("Blah", Blah::VERSION) do |p| # this builds the gemspec and defines a lot of commands
  # ...
end

If you don't mind requiring Hoe then this is an excellent approach to use.

10

Wayne E. Seguin wrote:

So there's not a variable inside the program that I can access that
contains the Gem info?

Frew,

The usual method of accessing the version of a gem from within a
running Ruby app is:

GemConstName::Version::STRING

This works if the author followed convention.

I am the author of the application in question. I tested your
suggestion by doing a

puts GemConstName::Version::STRING

to see if it would have the variable defined by the gem system as
defined in my gemspec, but it didn't work. Is there something I need to
do to make this work?

Thanks for your help!

-fREW

···

On Jul 10, 2007, at 09:37 , Frew Schmidt wrote:

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11

E.g.: In module 'Inline' is defined const. VERSION, so you can print
Inline::VERSION, but 'rake' defined const. RAKEVERSION

So what I really need to do here is define a constant in a separate file
as a module and include it in the gemspec and my other code. Is that
correct?

···

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12

Frew, why yes there is!!! Thank you for clarifying the question. Tis simple!

In lib/gem_name/version.rb place code like:

···

On Jul 10, 2007, at 11:05 , Frew Schmidt wrote:

I am the author of the application in question. I tested your
suggestion by doing a

puts GemConstName::Version::STRING

to see if it would have the variable defined by the gem system as
defined in my gemspec, but it didn't work. Is there something I need to
do to make this work?

Thanks for your help!

=================================
module GemName
   module Version
     # A method for comparing versions of required modules. It expects two
     # arrays as parameters, and returns true if the first is no more than the
     # second.
     def self.check(expected, actual) #:nodoc:
       good = false
       if actual[0] > expected[0]
         good = true
       elsif actual[0] == expected[0]
         if actual[1] > expected[1]
           good = true
         elsif actual[1] == expected[1] && actual[2] >= expected[2]
           good = true
         end
       end

       good
     end

     MAJOR = 0
     MINOR = 1
     TINY = 2

     STRING = [MAJOR, MINOR, TINY].join(".")

     SSH_REQUIRED = [1,0,10]
     SFTP_REQUIRED = [1,1,0]
   end
end

Then require the version file in one of the main entry point files:

require "lib/gem_name/version"

Hope this helps! Gems are so much fun to develop.

--
Wayne E. Seguin
Sr. Systems Architect & Systems Admin
wayneseguin@gmail.com

13

Sorry, these aren't required, they were specific to my gem.

···

On Jul 10, 2007, at 11:13 , Wayne E. Seguin wrote:

<snip>
    SSH_REQUIRED = [1,0,10]
    SFTP_REQUIRED = [1,1,0]
<snip>

--
Wayne E. Seguin
Sr. Systems Architect & Systems Admin
wayneseguin@gmail.com

14

Wayne E. Seguin wrote:

···

On Jul 10, 2007, at 11:05 , Frew Schmidt wrote:

Thanks for your help!

Frew, why yes there is!!! Thank you for clarifying the question. Tis
simple!

In lib/gem_name/version.rb place code like:

module GemName
   module Version
     # A method for comparing versions of required modules. It
expects two
     # arrays as parameters, and returns true if the first is no more
than the
     # second.
     def self.check(expected, actual) #:nodoc:
       good = false
       if actual[0] > expected[0]
         good = true
       elsif actual[0] == expected[0]
         if actual[1] > expected[1]
           good = true
         elsif actual[1] == expected[1] && actual[2] >= expected[2]
           good = true
         end
       end

       good
     end

     MAJOR = 0
     MINOR = 1
     TINY = 2

     STRING = [MAJOR, MINOR, TINY].join(".")

     SSH_REQUIRED = [1,0,10]
     SFTP_REQUIRED = [1,1,0]
   end
end

Then require the version file in one of the main entry point files:

require "lib/gem_name/version"

Hope this helps! Gems are so much fun to develop.

Ok, I want to ensure that I am doing this the correct way, so is this
right?

lib/delish/version.rb

module Delish

  module Version
    MAJOR = 0
    MINOR = 7
    TINY = 9

    STRING = [MAJOR, MINOR, TINY].join(".")
  end

end

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15

Looks correct to me. You still might want to provide the check method as it provides an interface for versioning checks.

So now you should be able to report the version from within your app via:
Delish::Version::STRING

···

On Jul 10, 2007, at 11:24 , Frew Schmidt wrote:

Wayne E. Seguin wrote:
Ok, I want to ensure that I am doing this the correct way, so is this
right?

lib/delish/version.rb

module Delish

  module Version
    MAJOR = 0
    MINOR = 7
    TINY = 9

    STRING = [MAJOR, MINOR, TINY].join(".")
  end

end

--
Wayne E. Seguin
Sr. Systems Architect & Systems Admin
wayneseguin@gmail.com

16

UGH!

KISS, or employ YAGNI.

module Delish

   VERSION = '0.7.9'

end

You don't need major/minor/tiny.

···

On Jul 10, 2007, at 08:24, Frew Schmidt wrote:

Ok, I want to ensure that I am doing this the correct way, so is this
right?

lib/delish/version.rb

module Delish

  module Version
    MAJOR = 0
    MINOR = 7
    TINY = 9

    STRING = [MAJOR, MINOR, TINY].join(".")
  end

end

--
Poor workers blame their tools. Good workers build better tools. The
best workers get their tools to do the work for them. -- Syndicate Wars

17

Looks correct to me. You still might want to provide the check method
as it provides an interface for versioning checks.

So now you should be able to report the version from within your app
via:
Delish::Version::STRING

So if I did end up using the check method would I do something like this

Delish::Version::check(GTK::Version, Delish::Version::GTK_VERSION)
# Some gtk code here

Or something like that?

What's the use of this if the gemspec already has dependencies like
this?

Thanks again for your help!

-fREW

···

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