Let me introduce DPKG::Log and dpkg-report

We have customers, which require a report about what we’ve done during maintenance windows. Usually this includes a report about upgrades, newly installed packages etc. and obviously everything we’ve done apart from that.
Till now we’ve prepared them manually. For a greater bunch of systems this is a big PITA, because to be somehow useful you have to collect the data for all systems and after that, prepare a report where you have:

  • The upgrades done on all systems (e.g. a libc or kernel update)

    seperated from

  • the updates specific to a certain system or system class

Its also error-prone because humans make mistakes.

Perl to the rescue!
At least the part about generating a report about installed/upgraded/removed packages could be automated, because dpkg writes a well-formed logfile in /var/log/dpkg.log. But I noticed that there appearently is no library specialised at parsing that file. Its not a big deal, because the format of that file is really simple, but a proper library would be nice anyway.
And so I wrote such a library.
It basically takes a logfile, reads it line by line and stores each line parameterized into a generic object.

Its features include:

  • Parsing the logfile (obviously)
  • Storing each line in a logfile as a DPKG::Log::Entry object that holds informations about the entry type (e.g. action or status update), the package associated (if any), timestamp, verbatim line, line number etc.
  • Limiting the number of lines parsed to a time range specified by DateTime objects

Based on that, I wrote another library DPKG::Log::Analyse, which takes a log, parses it with DPKG::Log and then extracts the more relevant information such as installed packages, upgraded packages, removed packages etc.

This, in turn, features:
– Info about newly installed packages
– Info about removed packages
– Info about upgraded packages
– Info about packages which got installed and removed again
– Info about packages which stayed halfinstalled or halfconfigured at the end of the logfile (or defined reporting period)

These libraries are already uploaded to CPAN and packaged for Debian.
They passed the NEW queue very quickly and are therefore available for Sid:

http://packages.debian.org/sid/libdpkg-log-perl

As an example use (and for my own use case, as stated above), I wrote dpkg-report, which uses the module and a Template::Toolkit based template to generate a report about what happened in the given logfile.
It currently misses some documentation, but it works somehow like this:

Report for a single host over the full log:

dpkg-report

Report for a single host for the last two days:

dpkg-report –last-two-days

Report for multiple hosts (and logfiles):
The script expects that each log file has the name .dpkg.log so that it can guess the hostname from the system and can grab all such log files from a directory if a directory is specified as log-file arguments:

dpkg-report –log-file /path/to/logs

This will generate a report about all systems without any merging.

Report for multiple hosts with merging:

dpkg-report –log-file /path/to/logs –merge

This will do the following:

  • Report packages which where installed/removed/etc. on all systems seperate from the upgrades only done on the specific systems
  • If systems start with a common name and end on a number (e.g. mail1, mail2, mail3 etc.), report packages which where installed on all systems with that common name seperate from the upgrades only done on the specific systems
  • For a specific system list only the changes on that particular system and nothing else.

A (fictive) report could look some what like this:

dpkg-Report for all:
————————
Newly Installed:
abc
Removed:
foo
Upgraded:
bar (0.99-12 – 1.00-1)
dpkg-Report for test*:
————————
Newly Installed:
blub
dpkg-Report for test1:
————————
Upgraded:
baz (1.0.0-1 -> 1.0.0-2)
dpkg-Report for test2:
————————
Upgraded:
zab (0.9.7 -> 0.9.8)

Currently this report generator is only included in the source package or in the git(hub) repository of the library. I wonder if it makes sense to let the source package build another binary package for it.
But its only a 238 lines perl script with a dependency on the perl library so I’m unsure if it warrants a new binary package. What do others think?

2 Gedanken zu „Let me introduce DPKG::Log and dpkg-report“

  1. I've seen several packages include useful/utility scripts which rely upon a particular library as an example.

    If the script is "large" then it will be compressed, but it does avoid the overhead of the separate binary package.

  2. I would suggest you to submit Dpkg::Log to dpkg itself… to be included in libdpkg-perl.

    I wonder why you did not ask in the first place. That way we can keep the code in sync in case dpkg starts outputting different stuff in the log file.

    See http://bugs.debian.org/608930 for instance…

    Raphael, dpkg co-maintainer.

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