Puppet how to tell if a variable is set -

in puppet class how should test if variable has been set or not? right checking if variable undefined:

if $http_port != undef {   $run_command = "$run_command --http-port $http_port" } 

is there better way check if variable has been declared or not?

if testing if vaiable undef, way correct. writing

if $http_port {   $run_command = "$run_command --http-port $http_port" } 

would accomplish same. if $http_port undef of false, not run command.

if want test if var has been definded should do:

if defined($http_port) {   $run_command = "$run_command --http-port $http_port" } 

see https://docs.puppet.com/puppet/4.10/function.html#defined.

if var class variable like:

class your_class ( optional[integer[0, 65535]] $http_port = undef, ) {     if $http_port {       notify { "got here http_port=${http_port}": }     } } 

it run notify if class declared http_port set integer between 0 , 65535.