We've seen a couple of different ways of testing string values already. You can compare strings for equality:
if $role == 'webserver' {
...
}You can also test whether one string is a substring of another:
if 'dunk' in 'doughnuts' {
...
}But what if you want to test for patterns of characters? Say, app followed by any characters, followed by staging. Puppet has a special pattern-matching language you can use for this:
if $::hostname =~ /app.*staging/ {
...
}This expression will be true if $::hostname is any of the following, and many more:
app_stagingapp-1-stagingapplication_stagingappstagingmy_app_staging_server
Note the slash characters surrounding the pattern:
/app.*staging/
This kind of pattern is called a regular expression, or regex for short, and Puppet uses the slash character (/) to mark the start and end of regular expressions.