Display HTML page inside mail body with Email-ext plugin in Jenkins

Look deeper into the plugin documentations. No need for groovy here.

Just make sure Content Type is set to HTML and add the following to the body:

${FILE,path="my.html"}

This will place the my.html content in your email body (location of file is relative to job's workspace. I use it and it works well.

I hope this helps.

EDIT: Note that you must have the Jenkins version 1.532.1 (or higher) to support this feature with the email-ext plugin.

It worked for me with Jenkins 1.558

${FILE,path="target/failsafe-reports/emailable-report.html"}

Besides reading the file with body: ${FILE,path="index.html"}, you need to set the proper content type, either globally or explicitly for one execution, with mimeType: 'text/html.

emailext subject: '$DEFAULT_SUBJECT',
                    body: '${FILE,path="index.html"}',
                    recipientProviders: [
                        [$class: 'CulpritsRecipientProvider'],
                        [$class: 'DevelopersRecipientProvider'],
                        [$class: 'RequesterRecipientProvider']
                    ], 
                    replyTo: '$DEFAULT_REPLYTO',
                    to: '$DEFAULT_RECIPIENTS',
                    mimeType: 'text/html'

It should be something like this:

Navigation:

Configure -> Editable Email Notification

Default Content:

${FILE,path="path/result.html"}

You just need to assign the link to the environment variable and then you can use that variable to print in the email using ${ENV, var=ENV_VARIABLE}.