A code snippet: Controlled retry

ruby-talk
1

I sometimes find myself retrying operations when in a networked
situation (e.g., maybe server isn’t up, just try again).

I just wrote this little bit of code.

Tell me what you think… I’m sure it can be improved.

Cheers,
Hal

def try(quiet=true,times=5,secs=1,&block)
count = 0
catch :finished do
begin
block.call
rescue => err
puts “Error was: #{err}” if not quiet
count += 1
throw :finished if count > times
sleep secs
retry
end
end
end

2

def try(quiet=true,times=5,secs=1,&block)
return unless block
times.times do
begin
return block.call
rescue => err
puts “Error was: #{err}” unless quiet
sleep secs
end
end
end

Sincerely,
Gennady Bystritsky

···

On Nov 23, 2003, at 22:11, Hal Fulton wrote:

def try(quiet=true,times=5,secs=1,&block)
count = 0
catch :finished do
begin
block.call
rescue => err
puts “Error was: #{err}” if not quiet
count += 1
throw :finished if count > times
sleep secs
retry
end
end
end

3

Oops, times.times should become times.next.times to function like the
original. Also, when all attempts are exhausted, the last exception
must be re-raised or another more appropriate one raised (boolean
return would also do the trick).

···

On Nov 23, 2003, at 23:02, Gennady wrote:

On Nov 23, 2003, at 22:11, Hal Fulton wrote:

def try(quiet=true,times=5,secs=1,&block)
count = 0
catch :finished do
begin
block.call
rescue => err
puts “Error was: #{err}” if not quiet
count += 1
throw :finished if count > times
sleep secs
retry
end
end
end

def try(quiet=true,times=5,secs=1,&block)
return unless block
times.times do
begin
return block.call
rescue => err
puts “Error was: #{err}” unless quiet
sleep secs
end
end
end

4

“Gennady” bystr@mac.com schrieb im Newsbeitrag
news:4BB0276B-1E4F-11D8-A73D-0003939AEA24@mac.com…

def try(quiet=true,times=5,secs=1,&block)
count = 0
catch :finished do
begin
block.call
rescue => err
puts “Error was: #{err}” if not quiet
count += 1
throw :finished if count > times
sleep secs
retry
end
end
end

def try(quiet=true,times=5,secs=1,&block)
return unless block
times.times do
begin
return block.call
rescue => err
puts “Error was: #{err}” unless quiet
sleep secs
end
end
end

Oops, times.times should become times.next.times to function like the
original. Also, when all attempts are exhausted, the last exception
must be re-raised or another more appropriate one raised (boolean
return would also do the trick).

Combining the two of them (i.e. times.next and re-raising) by simply
adding a line,
plus adding a check to allow for non-sleeping retries,
plus output parameter that can be an IO or an Array,
plus changed the first return to an exception in order to let the user
know he forgot something:

def try(times=0, secs=nil, log=nil, &block)
raise LocalJumpError, “no block given” unless block

 times.times do
   begin
     return block.call
   rescue => err
     log << "Error was: #{err}\n" if log
     sleep secs if secs
   end
 end

 block.call

end

Cheers

robert
···

On Nov 23, 2003, at 23:02, Gennady wrote:

On Nov 23, 2003, at 22:11, Hal Fulton wrote: