[LOG4J2-1192] Dynamic Subject for SMTP Appender

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.1, 2.15.0
• Fix Version/s: 2.6, 2.15.0
• Component/s: Appenders
• Labels: features

Environment

ALL

• External issue URL: http://stackoverflow.com/questions/29435825/log4j2-custom-email-subject-from-map
• Assignee: Gary D. Gregory
• Reporter: Jörg Bretschneider
• Created: 03/Nov/15 16:06
• Updated: 14/Jan/22 00:28
• Resolved: 14/Jan/22 00:28

Description

It is annoying to have log messages sent to users via SMTP Appender with a static subject, requiring recipients to open each of possibly a vast amount of log emails in order to find out what went wrong.

Users should be able to insert runtime diagnostic context information to the message text AND to the message subject as well.

While the first seems to be working with Patternlayout using the mechanism with the %X

{<key>}

pattern based on a NDC or MDC <key> in the "ConversionPattern" parameter, it does NOT work with the "Subject" parameter with log4j (neither 1.2 nor 2.x), though some bloggers suggest it, e.g. http://stackoverflow.com/a/7015453.

See http://stackoverflow.com/questions/29435825/log4j2-custom-email-subject-from-map as an example where others found this also.

This issue should have been fixed long ago.

I suggest to extend SMTP appender in order to be able to use %X and other Pattern conversion in the "Subject" parameter properly.

http://openutils.sourceforge.net/openutils-log4j/smtpappender.html
has already done the part for applying PatternLayout to the SMTP Appender "Subject". I didn't test if this works properly.
Maybe this work can be included into log4j with minimal effort?

This feature has originally been realized in LOGBACK using an MDC in Patternlayouts: http://logback.qos.ch/manual/mdc.html

Issue Links

• is fixed by: LOG4J2-3174 Wrong subject on mail when it depends on the LogEvent
• links to: GitHub Pull Request #308