Capistrano set_mtimes Task

README.md

This Capistrano task will loop through all of the repository files for the specified branch, and set the atime and mtime to the most recent (relative to each file) commit author date.

I wrote this to get around a limitation in Webpacker 3.5.5 when deploying. Because of how Capistrano works, Webpacker would recompile every deploy even if no Webpack code had changed.

deploy.rb

# ...

# Use the task during deployment.
after 'deploy:set_current_revision', :set_mtimes

# ...

set_mtimes.rake

desc(
  'Set the atime and mtime of all repo files based on the most recent' \
  ' (relative to each file) commit author date.'
)
task :set_mtimes do
  on release_roles :all do
    within repo_path do
      with fetch(:git_environmental_variables) do
        # Everything is done in a single `execute` to avoid numerous SSH
        # connections (one per file plus one to get the list of files).
        #
        # Because Capistrano uses `/usr/bin/env`, we need to "break out" of that
        # by giving it a command name and redirecting output to the null device.
        # `:echo` seems like the simplest and safest choice here.
        #
        # And because of SSHKit's `Symbol` quirk, the first argument must be a
        # `Symbol` to ensure `within` and `with` apply to the loop.
        execute(
          :echo, '> /dev/null ;', <<~CMD
            for path in $(git ls-tree --name-only -r "#{fetch(:branch)}"); do
              touch -t $(git log -1 --format=%ad --date=format:%Y%m%d%H%M.%S "#{fetch(:branch)}" -- "${path}") "#{release_path}/${path}"
            done
          CMD
        )
      end
    end
  end
end