No need to recompile a fixed regular expression each time the function executes. Abstracting it to the `init()` method. Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo) Upstream-commit: a4d57d8a851bf288804215b39c9d56a51550a228 Component: engine