parseoom - A utility for parsing the output of an oom-kill message

Usage:
    parseoom $LOGFILE

Given a log file containing an oom-killer report, the 'parseoom' program
will extract and format relevant data about memory usage at the time the
oom-killer was invoked. For example, when run with the sample logs from the
messages file included in this repository, 'parseoom' will generate the
following output:

% parseoom messages

Memory total:
    Total RAM: 19.9 GiB

Swap:
    Free swap: 0 KiB

Huge Pages:
    Allocated 2 MiB huge pages:       0.0 GiB  --  (0.1%)
    Allocated 1 GiB huge pages:       2.0 GiB  --  (9.8%)

Slab:
    Unreclaimable slab: 17.4 MiB  --  (0.1%)

Shared Memory:
    Shared memory: 0.6 MiB  --  (0.0%)

Top 10 unique commands using memory:

    clamd                1649.7 MiB
    rspamd                294.9 MiB
    mariadbd               30.0 MiB
    fail2ban-server        17.1 MiB
    redis-server            6.1 MiB
    unattended-upgr         5.8 MiB
    nginx                   3.3 MiB
    config                  1.5 MiB
    freshclam               1.4 MiB
    znc                     1.1 MiB

Processes using most memory:

  pid      uid    tgid    total_vm       rss    pgtables_bytes    swapents    oom_score_adj  name                  MiB
    517    111     517      590364    422324           4395008      107099                0  clamd              1649.7
   1682    108    1682       67131     16509            421888        7811                0  rspamd               64.5
   1680    108    1680       65038     14927            380928        8231                0  rspamd               58.3
    584    108     584       64811     14737            393216        8513                0  rspamd               57.6
   1677    108    1677       64811     14698            376832        8305                0  rspamd               57.4
   1683    108    1683       64811     14614            376832        8614                0  rspamd               57.1
    669    106     669      269508      7688            323584       12110                0  mariadbd             30.0
    590      0     590      177664      4383            208896         343                0  fail2ban-server      17.1
    581    112     581       16276      1567            110592         197                0  redis-server          6.1
    587      0     587       27165      1488            110592         635                0  unattended-upgr       5.8

Total RSS utilized by user processes: 2020.6 MiB

I wrote this program to improve my understanding of Rust by implementing a
non-trivial utility in the language. I make no claims regarding its fitness of
purpose.

This program is capable of cleaning up or ignoring most log noise, but
edge cases may still be lurking out there in the real world. This utility is not
robust enough to handle corrupted logs (which are not unusual in the presence of
memory pressure), unexpected linebreaks, or Murphy's law.

Many variations of an omm-killer parsing utility already exist. Special thanks
to John Siddle for sharing his version!