Module: Docker::Compose::Future::Session

Included in:
Session
Defined in:
lib/docker/compose/future/session.rb

Constant Summary collapse

SUBSTITUTION =

Pattern that matches an environment substitution in a docker-compose YML file.

See Also:

  • #substitute
/\$\{([A-Z0-9:_-]+)\}/

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(host) ⇒ Object

Hook in env-var substitution by aliasing a method chain for run!



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# File 'lib/docker/compose/future/session.rb', line 11

def self.included(host)
  done = host.instance_methods.include?(:run_without_substitution!)
  host.instance_eval do
    alias_method :run_without_substitution!, :run!
    alias_method :run!, :run_with_substitution!
  end unless done
end

Instance Method Details

#run_with_substitution!(*cmd) ⇒ Object

Read docker-compose YML; perform environment variable substitution; write a temp file; invoke run! with the new file; delete the temp file afterward.

This is a complete reimplementation of run! and we only alias the original to be good citizens.



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# File 'lib/docker/compose/future/session.rb', line 25

def run_with_substitution!(*cmd)
  temp = nil
  project = File.basename(@dir)

  # Find and purge the 'file' flag if it exists; otherwise assume we will
  # substitute our default (session) file.
  fn = nil
  cmd.each do |item|
    fn ||= item.delete(:file) if item.is_a?(Hash)
  end
  fn ||= @file

  # Rewrite YML if the file exists and the file:false "flag" wasn't
  # explicitly passed to us.
  Dir.chdir(@dir) do
    yml = YAML.load(File.read(fn))
    yml = substitute(yml)
    temp = Tempfile.new(fn, @dir)
    temp.write(YAML.dump(yml))
    temp.close

    project_opts = {
      file: temp.path,
      project: File.basename(@dir)
    }

    result, output, error =
      @shell.command('docker-compose', project_opts, *cmd)
    (result == 0) ||
      raise(Docker::Compose::Error.new(cmd.first, result, error))
    output
  end
ensure
  temp.unlink if temp
end