Subversion Repositories zfs_utils

#!/usr/bin/env perl

# cleanSnaps - detect and remove old ZFS snapshots named like YYYY-MM-DD-<N><d|w|m>
# Usage: cleanSnaps [-n] [-f] [-v]
#   -n  dry-run (default)
#   -f  actually destroy snapshots
#   -v  verbose

use strict;
use warnings;
use Getopt::Std;
use Time::Piece;

my %opts;
getopts('nfv', \%opts);

my $DRY_RUN = $opts{f} ? 0 : 1;    # default dry-run, -f disables dry-run
my $FORCE = $opts{f} ? 1 : 0;
my $VERBOSE = $opts{v} ? 1 : 0;

my $ZFS_CMD = $ENV{ZFS_CMD} // 'zfs';

sub logmsg { print @_, "\n" if $VERBOSE }

# gather snapshots
my $now = time();
my @candidates;

open my $fh, '-|', "$ZFS_CMD list -H -o name -t snapshot" or die "Failed to run $ZFS_CMD: $!";
while (my $snap = <$fh>) {
    chomp $snap;
    next unless defined $snap && $snap =~ /\S/;

    unless ($snap =~ /@/) {
        logmsg("skipping invalid snapshot name: $snap");
        next;
    }
    my ($dataset, $snapname) = split /@/, $snap, 2;

    # match date + retention tag
    unless ($snapname =~ m/^(\d{4}-\d{2}-\d{2}).*(\d+)([dwm])$/) {
        logmsg("snapshot does not match YYYY-MM-DD-<N><d|w|m>: $snap");
        next;
    }
    my ($snap_date, $num, $unit) = ($1, $2, $3);

    # parse snapshot date using Time::Piece
    my $snap_epoch;
    eval {
        my $tp = Time::Piece->strptime($snap_date, '%Y-%m-%d');
        $snap_epoch = $tp->epoch;
        1;
    } or do {
        logmsg("failed to parse date $snap_date for $snap");
        next;
    };

    my $days;
    if ($unit eq 'd') { $days = $num }
    elsif ($unit eq 'w') { $days = $num * 7 }
    elsif ($unit eq 'm') { $days = $num * 30 }
    elsif ($unit eq 'y') { $days = $num * 365}
    else { logmsg("unknown unit $unit for $snap"); next }

    my $retention_seconds = $days * 86400;
    my $age = $now - $snap_epoch;
    if ($age > $retention_seconds) {
        push @candidates, $snap;
    } else {
        logmsg("keep: $snap (age " . int($age/86400) . "d <= ${days}d)");
    }
}
close $fh;

if (!@candidates) {
    print "No snapshots to remove.\n";
    exit 0;
}

printf "Snapshots to remove (%d):\n", scalar @candidates;
for my $s (@candidates) { printf "  %s\n", $s }

if ($DRY_RUN) {
    print "\nDry-run: no snapshots were destroyed. Use -f to actually remove them.\n";
    exit 0;
}

# actual removal
my $failed = 0;
for my $s (@candidates) {
    printf "Destroying: %s\n", $s;
    my $rc = system($ZFS_CMD, 'destroy', $s);
    if ($rc != 0) {
        printf STDERR "Failed to destroy %s\n", $s;
        $failed = 1;
    }
}

if ($failed) {
    print STDERR "One or more destroys failed.\n";
    exit 1;
}

print "Done.\n";