Feature request: keyword to specify a default stage

[Fjan]

I would like the option to specify a default stage for a task. I have a number of tasks that only make sense to run on a particular stage, so I find myself typing:
cap backup_server backup_task or cap logging_server logging_task

To save myself from typing out the stage name for these I optimised my workflow a little by adding:

invoke :backup_server if ARGV.first&.start_with?('backup_task')

But this is a bit brittle as it depends on argument order (and depending on plugins it complains about load:default getting loaded twice). It would be really nice if the DSL allowed me to specify default_stage <task> => <stage> or something like that.

Looking at the code it seems it should be fairly straightforward to add this. If we take a shortcut by using the existing DSL and do set :default_stage, {task: stage} then it would just require a few additional lines in the task ensure_stage in task_enhancements.rb. But it would be nicer to add a proper default_stage keyword so that it can be called multiple times so you can call it in the same place where the task is defined.

What do people think?

[leehambley]

Hi @Fjan thanks for the report.

Have you considered defining your task like:

task :backup_task => :backup_server do
  # ...
end

I'm shooting a bit here from the hip, but logically this says "backup_task depends on backup_server", if memory serves the "env" task (backup_server) is a simple task and can be declared as a prerequisite this way.

If this works, I'd prefer it over the introduction of a new configuration option, could you try it out and let me know please?

[Fjan]

Interesting suggestion, and I agree that might be better than introducing a new configuration option. It doesn't currently work however. It looks like ensure_stage verifies the task at hand before running the dependencies (which makes sense). Perhaps we can make it clever enough to see if there is a stage as one of the dependencies?

[leehambley]

Thanks for checking that so fast.

I think we could refine/patch {Capistrano|Rake}::Task to have some accessor like defines_a_stage? and ensure_stage could check if one of the prerequisites of the current task already `defines_a_stage?

How would you feel about that?

[Fjan]

Yes, it looks like there already is a @top_level_tasks that contains what you need, so the check would need to see if one of the prerequisites is in there.

[Fjan]

It turns out that this can be done by adding a single line to the ensure_stages method. I love how succinct ruby makes this monkey patch:

module Capistrano
  module TaskEnhancements
    def ensure_stage
      Rake::Task.define_task(:ensure_stage) do
        next if @top_level_tasks.any?{|task| !(Rake::Task[task.split('[').first].prerequisites & stages).empty?}
        unless stage_set?
          puts t(:stage_not_set)
          exit 1
        end
      end
    end
  end
end