Automating installation of gems on remote machine with Capis

Ruby
1

Greetings,

I’m wondering if anyone has used Capistrano to automate the installation
of gems on remote machines.

The problem I’m having is that when you install a gem from the command
line, at various stages it will prompt you for a ‘Y’ or ‘N’ answer.

Let’s say I have the following task and I want it to run on a remote
machine:

desc “Install rails”
task :install_rails do
run “gem install rails”
end

The task starts up and begins the installation, but then hangs after I
get the ‘Y’ or ‘N’ prompt.

Is there a way to just skip the prompt and specify ‘Y’ for everything?

Regards,
Steven

2

On 11/27/06, Steven H. [email protected] wrote:

The task starts up and begins the installation, but then hangs after I
get the ‘Y’ or ‘N’ prompt.

Is there a way to just skip the prompt and specify ‘Y’ for everything?

You can use the “–include-dependencies” option. You will have trouble
with
platform specific gems, though, as it will ask you to pick a version.
You
can probably specify the specific version in those cases, though.

Justin

3

Quoting S.n Hansen [email protected]:

Let’s say I have the following task and I want it to run on a remote
Is there a way to just skip the prompt and specify ‘Y’ for everything?
Could you use the Unix ‘yes’ command?

man yes

4

Justin B. wrote:

with
platform specific gems, though, as it will ask you to pick a version. You
can probably specify the specific version in those cases, though.

Justin

Sweet, that’s exactly what I was looking for.

-Steven

5

Instead of:

run “gem install rails”

use:

run “gem install rails -y”

6

Instead of:

run “gem install rails”

use:

run “gem install rails -y”

7

On Nov 27, 2006, at 1:56 PM, Steven H. wrote:

Is there a way to just skip the prompt and specify ‘Y’ for everything?

Regards,
Steven

Hey Steven-

Here is a capistrano plugin for installing gems remotely. This

supports slecting gem versions or letting it pick from the list
itself when it gets presented with a list of choices it will choose
the correct latest version based on architecture.

This is code adapted and extracted from the vmgen gem for generating

Xen instances.

require ‘capistrano’

Installs within Capistrano as the plugin gem.

Prefix all calls to the library with gem.

Manages installing gems and versioned gems.

module Gem

Default install command

* doesn’t install documentation

* installs all required dependencies automatically.

GEM_INSTALL=“gem install -y --no-rdoc”

Upgrade the gem system to the latest version. Runs via sudo

def update_system
sudo “gem update --system”
end

Updates all the installed gems to the latest version. Runs via

sudo.

Don’t use this command if any of the gems require a version

selection.
def upgrade
sudo “gem update --no-rdoc”
end

Removes old versions of gems from installation area.

def cleanup
sudo “gem cleanup”
end

Installs the gems detailed in +packages+, selecting version

+version+ if

specified.

+packages+ can be a single string or an array of strings.

def install(packages, version=nil)
sudo “#{GEM_INSTALL} #{if version then '-v ‘+version.to_s end} #
{packages.to_a.join(’ ')}”
end

Auto selects a gem from a list and installs it.

gem has no mechanism on the command line of disambiguating

builds for

different platforms, and instead asks the user. This method has

the necessary

conversation to select the +version+ relevant to +platform+ (or

the one nearest

the top of the list if you don’t specify +version+).

def select(package, version=nil, platform=‘ruby’)
selections={}
cmd="#{GEM_INSTALL} #{if version then '-v '+version.to_s end} #
{package}"
sudo cmd do |channel, stream, data|
data.each_line do | line |
case line
when /\s(\d+).*(#{platform})/
if selections[channel[:host]].nil?
selections[channel[:host]]=$1.dup+"\n"
logger.info “Selecting #$&”, “#{stream} :: #{channel[:host]}”
end
when /\s\d+./
# Discard other selections from data stream
when /^>/
channel.send_data selections[channel[:host]]
logger.debug line, “#{stream} :: #{channel[:host]}”
else
logger.info line, “#{stream} :: #{channel[:host]}”
end
end
end
end

end

Capistrano.plugin :gem, Gem

Cheers-
– Ezra Z.
– Lead Rails Evangelist
– [email protected]
– Engine Y., Serious Rails Hosting
– (866) 518-YARD (9273)

8

On Nov 28, 2006, at 4:41 PM, Steven H. wrote:

Kind Regards,
Steven

Hey Steven-

It really doesn't matter where you put it as long as it is in the

load path so you can require it in your recipe file. So lib is a fin
place to put it.

Cheers-
– Ezra Z.
– Lead Rails Evangelist
– [email protected]
– Engine Y., Serious Rails Hosting
– (866) 518-YARD (9273)

9

Ezra Z. wrote:

The problem I’m having is that when you install a gem from the

Installs within Capistrano as the plugin gem.

sudo "gem update --no-rdoc"

builds for
data.each_line do | line |
logger.debug line, “#{stream} :: #{channel[:host]}”

Cheers-
– Ezra Z.-- Lead Rails Evangelist
– [email protected]
– Engine Y., Serious Rails Hosting
– (866) 518-YARD (9273)

Ezra,

Thank you! :slight_smile:

One question, is there a standard location to put capistrano plugins?
The capistrano manual didn’t mention anything about this so I suppose I
could just stick it in my app’s lib dir?

Kind Regards,
Steven