Looks like we don't need sprintf for how it's used. Replacing sprintf makes it
more performant (~2.4x as fast), and less memory, allocations:
BenchmarkGetRandomName-8 8203230 142.4 ns/op 37 B/op 2 allocs/op
BenchmarkGetRandomNameOld-8 3499509 342.9 ns/op 85 B/op 5 allocs/op
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Fixes#2586
This fixes a few races where the name generator asks if a name is free
but another container takes the name before it can be reserved. This
solves this by generating the name and setting it. If the set fails
with a non unique error then we try again.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)