Notify Approvers of Pending Approvals via Email

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.mail.Email
import groovy.json.JsonSlurper
import groovy.xml.MarkupBuilder

def key = issue.key

def applicationProperties = ComponentAccessor.applicationProperties
def mailServerManager = ComponentAccessor.mailServerManager
def mailServer = mailServerManager.defaultSMTPMailServer

final def host = applicationProperties.getString('jira.baseurl')
final def restEndpointName = 'getApprovers'

def baseUrl = "${host}/rest/scriptrunner/latest/custom/${restEndpointName}?issueKey=${key}"
def response = baseUrl.toURL().text

def json = new JsonSlurper().parseText(response)
def artifacts = json.collect()

def emailBody = new StringWriter()
def html = new MarkupBuilder(emailBody)
def mkp = html.mkp
html.html {
    body {
        p {
            mkp.yield 'Awaiting your Approval for this Issue'
            a(href: "${host}/browse/${key}", key.toString())
        }
    }
}

artifacts.findAll {
    def emailAddress = it.toString()
    def subject = 'Approval Reminder'
    def body = emailBody.toString()
    def email = new Email(emailAddress)
    email.setSubject(subject)
    email.setBody(body)
    email.setMimeType('text/html')
    def threadClassLoader = Thread.currentThread().contextClassLoader
    Thread.currentThread().contextClassLoader = mailServer.class.classLoader
    mailServer.send(email)
    Thread.currentThread().contextClassLoader = threadClassLoader
}