The validating string parameter plugin contributes a new parameter type to Jenkins that supports regular expression validation of the user's entered parameter.

This plugin is used wherever build parameter selection is available, most commonly in the job configuration page by enabling parameterized builds (this parameter type will also be available as release parameters using the release plugin).

Configure the parameter by entering a name, regular expression to validate the entered value and optionally a default value, an error message shown when the user entered value fails the regular expression check and a parameter description.

When a build is requested, the user will be prompted with the parameters to enter. Users enter the parameter as normal, but will now be prompted with an error message if the entered value does not meet the regular expression.

Once the entered value meets the configured regular expression, the error message is no longer displayed.

pipeline {
    agent any

    parameters {
        validatingString(
            name: 'param1', 
            defaultValue: '', 
            regex: /^[0-9]+$/, 
            failedValidationMessage: '', 
            description: 'Numbers only parameter example'
        )
    }

    stages {
        stage("Check") {
            steps {
                echo "${params.param1}"
            }
        }
    }
}