Groovy / Grails SimpleTemplateEngine Freezes
I am using Grails to send a lot of HTML emails. I am using SimpleTemplateEngine to create my email bodies this way:
def ccIdToEmailMap = [:]
def emailTemplateFile = Utilities.retrieveFile("email${File.separator}emailTemplate.gtpl")
def engine = new SimpleTemplateEngine()
def clientContacts = ClientContact.list()
for(ClientContact cc in clientContactList) {
def binding = [clientContact : cc]
//STOPS (FREEZES) EITHER HERE OR....
def template = template = engine.createTemplate(emailTemplateFile).make(binding)
//OR STOPS (FREEZES) HERE
def body = template.toString()
def email = [text: body, to: cc.emailAddress]
ccIdToEmailMap.put(cc.id, email)
println "added to map"
}
return ccIdToEmailMap
Here's the template I'm trying to make for each email body:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Happy Holidays from google Partners</title>
</head>
<body>
<table width="492" cellpadding="0" cellspacing="0" style="border:2px solid #acacac;margin:8px auto;" align="center">
<tr>
<td colspan="5" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/cardbg.gif" width="492" height="10" border="0"></td>
</tr>
<tr>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgl.gif" width="6" height="453" border="0"></td>
<td style="background:#fff;border:1px solid #acacac;padding:2px;" width="228">
<div style="width:208px;margin:4px 8px 0px 8px; color:#515151;">
<font face="Times New Roman" size="2">
<span style="font:14px 'Times New Roman',times,serif;">Static text that is the same for each email
<br> <br>
More text
<br> <br>
We wish you health and happiness during the holidays and a year of growth in 2009.
</span>
</font>
</div>
</td>
<td style="background:#c9f4fe;border-top:1px solid #acacac;border-bottom:1px solid #acacac;" width="5"><img src="http://www.google.com/holiday2008/vertbg.gif" border="0" height="453" width="5"></td>
<td width="247" style="background:#fff;border:1px solid #acacac;"><img src="http://www.google.com/holiday2008/snowing.gif" width="247" height="453" border="0"></td>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgr.gif" width="6" height="453" border="0"></td>
</tr>
<tr>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgr.gif" width="6" height="38" border="0"></td>
<td colspan="3" style="border:1px solid #acacac;" align="center"><img src="http://www.google.com/holiday2008/happyholidays.gif" width="480" height="38" alt="Happy Holidays" border="0"></td>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgr.gif" width="6" height="38" border="0"></td>
</tr>
<tr>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgr.gif" width="6" height="120" border="0"></td>
<td colspan="3" style="background-color#fff;border:1px solid #acacac;padding:2px;" valign="top">
<img src="http://www.google.com/holiday2008/gogl_logo_card.gif" width="140" height="40" alt="google partners" border="0" align="right" hspace="4" vspace="4" />
<font face="Times New Roman" size="2">
<div style="padding:4px;font:12pt 'Times New Roman',serif;color:#515151;">
<span style="font-size:10pt"><i>from:</i></span>
<div style="padding:2px 4px;">
<% clientContact.owners.eachWithIndex { it, i -> %>
<% if(i < (clientContact.owners.size() - 1)) { %>
${it.toString()},
<% }else { %>
${it.toString()}
<% } %>
<% } %>
</div>
</div>
</font>
</td>
<td width="6" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/sidebgr.gif" width="6" height="120" border="0"></td>
</tr>
<tr>
<td colspan="5" bgcolor="#c1e0f3"><img src="http://www.google.com/holiday2008/cardbg.gif" width="492" height="10" border="0"></td>
</tr>
</table>
</body>
</html>
Once these methods return the ccIdToEmail card, I send all my emails. For some reason, preparing this clientContactIds and email map causes my application to freeze either of the two lines above. I can successfully prepare / send ~ 140 emails before it hangs. This happens very consistently.
Does anyone know why this will work but stop working after creating 140 email templates from a template? I haven't been able to find anything online about other issues having issues with this.
Andrew
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Looks like there was a problem with lazy loading my customer contact owners in the template. Rather than expecting the owners to be loaded (inefficiently) while the SimpleTemplateEngine creates the email body, I eagerly go to the owners before linking / creating the body.
My above code now looks like this:
def emailTemplateFile = null
def ccIdToEmailMap = [:]
emailTemplateFile = Utilities.retrieveFile("email${File.separator}emailTemplate.gtpl")
def engine = new SimpleTemplateEngine()
def template = engine.createTemplate(emailTemplateFile)
for(ClientContact cc in clientContactList)
{
//there was a locking problem when we tried to create the template for too many client contacts
//i believe it was caused by lazy-fetching of the person/owners. So, I fetch them before we bind
//and make the email body.
def criteria = ClientContact.createCriteria()
cc = criteria.get {
eq("id", cc.id)
fetchMode('relationship', FM.EAGER)
fetchMode('relationship.person', FM.EAGER)
}
def binding = [clientContact : cc]
def body = template.make(binding).toString()
def email = [text: body, to: cc.emailAddress]
ccIdToEmailMap.put(cc.id, email)
}
return ccIdToEmailMap
It's still inefficient to make that many inquiries for each of the customer contacts, but IT WORKS. I can't explain why lazy loading them during template generation caused grails / groovy to freeze, but it did. If anyone can explain this, I would appreciate it.
Thank you for your responses. Siegfried ... you started me in the right direction.
Andrew
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Sounds like a sync problem. As a first step, you need to create a template outside of the loop. Since there is no need to recreate the template every time.
def ccIdToEmailMap = [:]
def emailTemplateFile = Utilities.retrieveFile("email${File.separator}emailTemplate.gtpl")
def engine = new SimpleTemplateEngine()
def template = engine.createTemplate(emailTemplateFile)
def clientContacts = ClientContact.list()
for(ClientContact cc in clientContactList)
{
def binding = [clientContact : cc]
def body = template.make(binding).toString()
def email = [text: body, to: cc.emailAddress]
ccIdToEmailMap.put(cc.id, email)
println "added to map"
}
return ccIdToEmailMap
If that doesn't help, it might help if you post the template content and / or the ClientContact source.
hth, Sigi
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