Jython example which uses JNDI to query DNS for MX hosts

send_mail_using_jndi.py

sender = "Chris Adams <chris@improbable.org>"
recipients = [ "Chris Adams <chris@improbable.org>", ]
msg = "test message"
smtp = smtplib.SMTP()

# To avoid hard-coding our SMTP server list we'll query the
# MX records for yale.edu using the Java JNDI API:
from javax.naming.directory import InitialDirContext
jndi_ctx = InitialDirContext()
mx_hosts = jndi_ctx.getAttributes("dns:///example.edu", ["MX"]).get("MX")

for rec in mx_hosts.getAll():
	mx_host = rec.split(' ', 2)[1]

	try:
		smtp.connect(mx_host)
		smtp.sendmail(sender, recipients, msg)
		smtp.close()
		log("Alert email was sent to %s using %s" % (recipients, mx_host))
		return
	except smtplib.SMTPException, e:
		log("ERROR: Unable to send message using SMTP server %s: %s" % (mx_host, e))
		continue

log("ERROR: Unable to send alert email using any server in %s!" % mx_hosts)