Access variable in email ext template using Jenkins pipeline

I am trying to attach the template file using Jenkins pipeline, emailext. Variable (PROJNAME) is not accessible in the template file and I am receiving exceptions as an email:

Exception raised during template rendering: No such property: env for class: SimpleTemplateScript21 groovy.lang.MissingPropertyException: No such property: env for class: SimpleTemplateScript21 at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:53) at org.codehaus.groovy.runtime.callsite.PogoGetPropertySite.getProperty(PogoGetPropertySite.java:52) at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:307) at SimpleTemplateScript21.run(SimpleTemplateScript21.groovy:1) at groovy.text.SimpleTemplateEngine$SimpleTemplate$1.writeTo(SimpleTemplateEngine.java:168) at groovy.text.SimpleTemplateEngine$SimpleTemplate$1.toString(SimpleTemplateEngine.java:180) at hudson.plugins.emailext.plugins.content.ScriptContent.renderTemplate(ScriptContent.java:151) at hudson.plugins.emailext.plugins.content.ScriptContent.evaluate(ScriptContent.java:82) at org.jenkinsci.plugins.tokenmacro.DataBoundTokenMacro.evaluate(DataBoundTokenMacro.java:208) at org.jenkinsci.plugins.tokenmacro.Parser.processToken(Parser.java:308) at org.jenkinsci.plugins.tokenmacro.Action$KiHW1UeqOdqAwZul.run(Unknown Source) at org.parboiled.matchers.ActionMatcher.match(ActionMatcher.java:96) at org.parboiled.parserunners.BasicParseRunner.match(BasicParseRunner.java:77) at org.parboiled.MatcherContext.runMatcher(MatcherContext.java:351)

Pipeline Script:

stage('Email') {
    def mailRecipients = "myemail@abc.com"
    def jobStatus = currentBuild.currentResult
    env.PROJNAME = 'project_name'
    echo "projname is ${PROJNAME}"
emailext body: '''${SCRIPT, template="test.template"}''',
    mimeType: 'text/html',
    subject: "[Jenkins] ${jobStatus}",
    to: "${mailRecipients}"
}

Template (filename - test.template):

<html>
<head>
<title>Page Title</title>
</head>
<body>
<h1>This is a Heading</h1>
<p>Job is '${env.PROJNAME}'</p>
</body>
</html>

Also tried replacing the variable syntax in template file as "${PROJNAME}" and "${ENV, var="PROJNAME"}" but no luck. Any suggestions?

Didn't help when I replaced with ENV(var="PROJNAME") in template file. I received the email as:

This is a Heading

Job is ENV(var="PROJNAME")

Solution

Try override the env variable in the html template as below

<%
def envOverrides = it.getAction("org.jenkinsci.plugins.workflow.cps.EnvActionImpl").getOverriddenEnvironment()
    project =  envOverrides["PROJNAME"]
%>

you can then use the local variable project in your html like

<p> Job is ${project} </p>

Note: you can use all the required env variables using the envOverrides