Portage log

When using emerge for building a package, it is not uncommon to notice messages coming from Portage itself. Since they may contain important information from Gentoo developers it is a good idea to read them, but often this is not immediately possible because they rapidly scroll out of the screen. This can be easily solved by enabling a Portage feature called elog, whose purpose is to save messages to disk for later review. But other logging capabilities exist as well...

Portage elog subsystem

The Portage elog subsystem keeps track of specific, ebuild-provided log messages that developers have put in the ebuilds to attract attention of the administrator or user. Often, these messages contain important or interesting information related to the build of said package.

Setup

Select which kind of information should be logged through the PORTAGE_ELOG_CLASSES variable. Possible values are info, warn, error, log and qa:

FILE /etc/portage/make.conf

PORTAGE_ELOG_CLASSES="log warn error"

Configuring for file-based storage

Portage can handle the elog events in a number of ways.

In order to save the elog events to disk, enable the save module in the PORTAGE_ELOG_SYSTEM variable:

FILE /etc/portage/make.conf

PORTAGE_ELOG_SYSTEM="save"

The messages will be saved in /var/log/portage/elog or in ${PORT_LOGDIR}/elog if said variable is set.

In order to create per-category elog files, enable the split-elog Portage feature. It will force Portage to create category-based subdirectories of the /var/log/portage/elog location.

Configuring for e-mail

To mail logs to a recipient, enable the mail module. The mail option requires some additional variables to be set. Read /usr/share/portage/config/make.conf.example for more information.

Below, an example setup is shown which is hopefully self-explanatory:

FILE /etc/portage/make.conf

PORTAGE_ELOG_SYSTEM="mail"
# First the mail-to address, then the SMTP server
PORTAGE_ELOG_MAILURI="log-intake@example.com mail.example.com"
PORTAGE_ELOG_MAILFROM="portage@$(hostname).example.com"
PORTAGE_ELOG_MAILSUBJECT="${PACKAGE} is ${ACTION} on ${HOST}"

Another example with nullmailer or sendmail:

FILE /etc/portage/make.conf

PORTAGE_ELOG_SYSTEM="mail"
# First the mail-to address, then the SMTP server
PORTAGE_ELOG_MAILURI="users@host /usr/sbin/sendmail"
PORTAGE_ELOG_MAILFROM="portage@$(hostname).example.com"
PORTAGE_ELOG_MAILSUBJECT="${PACKAGE} is ${ACTION} on ${HOST}"

Related software

The following is a list of elog-related software packages:

• app-portage/elogv - Curses based utility to parse the contents of elogs
• app-portage/elogviewer - Python based elog viewer

Build logs

With the Portage elog subsystem, package build logs are saved on disk or mailed to a remote recipient, regardless of failure or success. This allows for administrators to review builds later or retrieve build logs for support tickets.

Setup

To enable Portage logging, edit /etc/portage/make.conf and set PORT_LOGDIR to a location where the log files should be stored. By default, Portage will use /var/log/portage:

FILE /etc/portage/make.conf

PORT_LOGDIR="/var/log/portage"

Next, you may want to edit and/or set a number of FEATURES= settings in /etc/portage/make.conf which influence how Portage handles build logs.

• With binpkg-logs set, even binary package deployments will have their logs saved
• When clean-logs is set, regular log file clean operations are executed. The command that is executed is defined by PORT_LOGDIR_CLEAN and defaults to a retention of the files of 7 days.
• With split-log set, build logs are stored in category-named subdirectories of ${PORT_LOGDIR}/build

Cleaning up

When clean-logs is set, Portage will execute the command defined by PORT_LOGDIR_CLEAN after every build or unmerge operation. By default, the following command is used:

FILE /usr/share/portage/config/make.globals

PORT_LOGDIR_CLEAN="find \"\${PORT_LOGDIR}\" -type f ! -name \"summary.log*\" -mtime +7 -delete"

When defining a custom command, do not forget to escape the PORT_LOGDIR variable (or immediately hardcode the right location).

External resources

• Underestimated or underused: Portage (e)logging on (Sven Vermeulen's blog)