Passing parameters to Capistrano
Solution 1
Update: For Capistrano 3, see scieslak's answer below.
Has jarrad has said, capistrano-ash is a good basic set of helper modules to deploy other project types, though it's not required as at the end of the day. It's just a scripting language and most tasks are done with the system commands and end up becoming almost shell script like.
To pass in parameters, you can set the -s flag when running cap to give you a key value pair. First create a task like this.
desc "Parameter Testing"
task :parameter do
puts "Parameter test #{branch} #{tag}"
end
Then start your task like so.
cap test:parameter -s branch=master -s tag=1.0.0
For the last part. I would recommend setting up passwordless access using ssh keys to your server. But if you want to take it from the current logged in user. You can do something like this.
desc "Parameter Testing"
task :parameter do
system("whoami", user)
puts "Parameter test #{user} #{branch} #{tag}"
end
UPDATE: Edited to work with the latest versions of Capistrano. The configuration array is no longer available.
Global Parameters: See comments Use set :branch, fetch(:branch, 'a-default-value') to use parameters globally. (And pass them with -S instead.)
Solution 2
Update. Regarding passing parameters to Capistrano 3 task only.
I know this question is quite old but still pops up first on Google when searching for passing parameters to Capistrano task. Unfortunately, the fantastic answer provided by Jamie Sutherland is no longer valid with Capistrano 3. Before you waste your time trying it out except the results to be like below:
cap test:parameter -s branch=master
outputs :
cap aborted!
OptionParser::AmbiguousOption: ambiguous option: -s
OptionParser::InvalidOption: invalid option: s
and
cap test:parameter -S branch=master
outputs:
invalid option: -S
The valid answers for Capistrano 3 provided by @senz and Brad Dwyer you can find by clicking this gold link: Capistrano 3 pulling command line arguments
For completeness see the code below to find out about two option you have.
1st option:
You can iterate tasks with the key and value as you do with regular hashes:
desc "This task accepts optional parameters"
task :task_with_params, :first_param, :second_param do |task_name, parameter|
run_locally do
puts "Task name: #{task_name}"
puts "First parameter: #{parameter[:first_param]}"
puts "Second parameter: #{parameter[:second_param]}"
end
end
Make sure there is no space between parameters when you call cap:
cap production task_with_params[one,two]
2nd option:
While you call any task, you can assign environmental variables and then call them from the code:
set :first_param, ENV['first_env'] || 'first default'
set :second_param, ENV['second_env'] || 'second default'
desc "This task accepts optional parameters"
task :task_with_env_params do
run_locally do
puts "First parameter: #{fetch(:first_param)}"
puts "Second parameter: #{fetch(:second_param)}"
end
end
To assign environmental variables, call cap like bellow:
cap production task_with_env_params first_env=one second_env=two
Hope that will save you some time.
Solution 3
I'd suggest to use ENV variables.
Somethings like this (command):
$ GIT_REPO="[email protected]:app" GIT_BRANCH="r2s1" cap testing
Cap config:
#deploy.rb:
task :testing, :roles => :app do
puts ENV['GIT_REPO']
puts ENV['GIT_BRANCH']
end
And take a look at the https://github.com/capistrano/capistrano/wiki/2.x-Multistage-Extension, may be this approach will be useful for you as well.
Solution 4
As Jamie already showed, you can pass parameters to tasks with the -s
flag. I want to show you how you additionally can use a default value.
If you want to work with default values, you have to use fetch
instead of ||=
or checking for nil
:
namespace :logs do
task :tail do
file = fetch(:file, 'production') # sets 'production' as default value
puts "I would use #{file}.log now"
end
end
You can either run this task by (uses the default value production
for file
)
$ cap logs:tail
or (uses the value cron
for file
$ cap logs:tail -s file=cron
Daniel C. Sobral
I have been programming for more than 20 years now, starting with 8 bits computers, assembler and BASIC. My passion for languages meant that, by the time I entered college, I had already programmed for fun or profit in more than 20 languages, including odd ones like Forth, MUMPS and APL, as well as theoretically important ones like Lisp and Prolog. Some of my code ended up in FreeBSD, of which I was a committer for some years, while I got my masters degree in the field of distributed algorithms. I also contributed to Scala, with small amounts of code, some reasonable amount of documentation, and a couple of years of a lot of attention to the Scala questions on Stack Overflow.
Updated on January 08, 2020Comments
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Daniel C. Sobral over 4 years
I'm looking into the possibility of using Capistrano as a generic deploy solution. By "generic", I mean not-rails. I'm not happy with the quality of the documentation I'm finding, though, granted, I'm not looking at the ones that presume you are deploying rails. So I'll just try to hack up something based on a few examples, but there are a couple of problems I'm facing right from the start.
My problem is that
cap deploy
doesn't have enough information to do anything. Importantly, it is missing the tag for the version I want to deploy, and this has to be passed on the command line.The other problem is how I specify my git repository. Our git server is accessed by SSH on the user's account, but I don't know how to change
deploy.rb
to use the user's id as part of the scm URL.So, how do I accomplish these things?
Example
I want to deploy the result of the first sprint of the second release. That's tagged in the git repository as
r2s1
. Also, let's say user "johndoe" gets the task of deploying the system. To access the repository, he has to use the URL[email protected]:app
. So the remote URL for the repository depends on the user id.The command lines to get the desired files would be these:
git clone [email protected]:app cd app git checkout r2s1