Suppress Output in Rake Task db:schema:load

问题:

How can you suppress the output of db:load:schema? Running

bundle exec rake db:schema:load

with the -s, -q, or even VERBOSE=false options makes no difference in the output; the same "create_table... add_index..." garbage that I don't want to see appears. I'm invoking this from inside a custom Rake task and I don't want the user to see all of this every time.

UPDATE:

I solved the problem with some guidance from @Deefour by using:

system "bundle exec rake db:schema:load -s RAILS_ENV=#{Rails.env} >NUL"

>NUL is for Windows machines, Unix-based can use > /dev/null.

rather than

Rake::Task['db:schema:load'].invoke

as I had been doing in my custom task. Note that this solution is specific to Windows machines. For Unix-based machines I imagine you should be able to use the accepted solution below.

回答1:

Here is a cleaner solution that works cross-system:

silence_stream(STDOUT) do
  # anything written to STDOUT here will be silenced
  Rake::Task["db:schema:load"].invoke
end

also

quietly do
  # anything written to STDOUT or STDERR here will be silenced
  Rake::Task["db:schema:load"].invoke
end

I prefer silence_stream(STDOUT) toquietly because it will still allow error messages written to STDERR to be shown, which will be helpful when the rake command starts to act up.

References: silence_stream, silence_warnings, & quietly

回答2:

Instead of calling the task with Rake::Task['...'].invoke, you can run the command in a subshell, redirecting output to /dev/null.

system "bundle exec rake db:schema:load > /dev/null 2>&1"