The wait gem executes a block until there's a result. Useful for blocking script execution until:
- an HTTP request was successful
- a port has opened
- an external process has started
- etc.
Add to your Gemfile
:
gem 'wait', :git => '[email protected]:foursquare/wait.git'
wait = Wait.new
# => #<Wait>
wait.until { Time.now.sec.even? }
# Rescued exception while waiting: Wait::NoResultError: result was false
# Attempt 1/5 failed, delaying for 1s
# => true
If you wish to handle an exception by attempting the block again, pass one or an array of exceptions with the :rescue
option.
wait = Wait.new(:rescue => RuntimeError)
# => #<Wait>
wait.until do |attempt|
case attempt
when 1 then nil
when 2 then raise RuntimeError
when 3 then 'foo'
end
end
# Rescued exception while waiting: Wait::NoResultError: result was nil
# Attempt 1/5 failed, delaying for 1s
# Rescued exception while waiting: RuntimeError: RuntimeError
# Attempt 2/5 failed, delaying for 2s
# => "foo"
- :attempts
- Number of times to attempt the block. Default is
5
. - :timeout
- Seconds until the block times out. Default is
15
. - :delay
- Initial (grows exponentially) delay (in seconds) to wait in between attempts. Default is
1
. - :rescue
- One or an array of exceptions to rescue. Default is
nil
. - :debug
- If
true
, logs debugging output. Default isfalse
.
RDoc-generated documentation available here.