Using capistrano to deploy from different git branches

Question

I am using capistrano to deploy a RoR application. The codebase is in a git repository, and branching is widely used in development. Capistrano uses deploy.rb f

Answer 1

git rev-parse --abbrev-ref HEAD

will return the current branch you are exactly in.

I always set the gpsh instead of git push -u origin branch_name

$ which gpsh
gpsh: aliased to git push -u origin `git rev-parse --abbrev-ref HEAD`

Answer 2

This works with Capistrano >= 3.1:

add this line to config/deploy.rb:

set :branch, ENV['BRANCH'] if ENV['BRANCH']

and then call capistrano with:

cap production deploy BRANCH=master

This solution works with Capistrano < 3.1:

# call with cap -s env="<env>" branch="<branchname>" deploy

set :branch, fetch(:branch, "master")
set :env, fetch(:env, "production")

Answer 3

I can confirm that the below still works in Cap 3.11.0 13/10/18 as well as Cap 2:

In deploy.rb / stage.rb:

set :branch, ENV['BRANCH'] || 'develop'

On the command line:

cap deploy BRANCH=featurex

This gives you a default branch (which could be different for different environments), and the ability to change branches when you want.

Answer 4

Method 1: Set stage specific branch (e.g. test, production) for deployment

Put branch configuration in stage files instead of 'deploy.rb' and set the target branch for that stage to deploy from.

For a two stage app with associated branch name test and production, the configuration will look like this,

# app_root/config/deploy/test.rb
...
set :branch, "test"
...

# app_root/config/deploy/production.rb
...
set :branch, "production"
...

This method enables to deploy from stage specific branches. So, only additional step that'll be required is to merge or rebase latest code from base branch.

Method 2: Deploy directly from any branch (using tag)

Another approach is to deploy using tag. In order to deploy using tag, set the branch config. in 'deploy.rb' as follows,

set :branch, `git describe --tags $(git rev-list --tags --max-count=1)`.chomp

And, configure the CI to conditionally deploy to different stages if the associated tag pattern matches (e.g. /.*-test$/).

Now, a deploy can be made from any branch,

• First, create a tag from any branch,

  git tag -a v0.1.0-test -m "Version 0.1.0-test"

• And, push

  git push origin v0.1.0-test

Note: The above methods are based on Capistrano 3.

Answer 5

If you're using capistrano-multistage, you only need to run

cap -s branch=$MY_BRANCH deploy

or

cap -s branch=$MY_BRANCH production deploy

without any further edit to your deploy.rb.

Answer 6

This solution should work with all versions of Capistrano.

def branch_name(default_branch)
  branch = ENV.fetch('BRANCH', default_branch)

  if branch == '.'
    # current branch
    `git rev-parse --abbrev-ref HEAD`.chomp
  else
    branch
  end
end

set :branch, branch_name('master')

Usage:

BRANCH=. cap [staging] deploy
# => deploy current branch

BRANCH=master cap [staging] deploy
# => deploy master branch

cap [staging] deploy
# => deploy default branch