synapse/debian/manage_debconf.pl
Richard van der Hoff 0969d688e3
Debian: fix overwriting of config settings on upgrade (#4696)
Make sure that users' changes to the config files are preserved.

Fixes #4440.
2019-02-22 15:02:39 +00:00

131 lines
3.1 KiB
Perl
Executable file

#!/usr/bin/perl
#
# Interface between our config files and the debconf database.
#
# Usage:
#
# manage_debconf.pl <action>
#
# where <action> can be:
#
# read: read the configuration from the yaml into debconf
# update: update the yaml config according to the debconf database
use strict;
use warnings;
use Debconf::Client::ConfModule (qw/get set/);
# map from the name of a setting in our .yaml file to the relevant debconf
# setting.
my %MAPPINGS=(
server_name => 'matrix-synapse/server-name',
report_stats => 'matrix-synapse/report-stats',
);
# enable debug if dpkg --debug
my $DEBUG = $ENV{DPKG_MAINTSCRIPT_DEBUG};
sub read_config {
my @files = @_;
foreach my $file (@files) {
print STDERR "reading $file\n" if $DEBUG;
open my $FH, "<", $file or next;
# rudimentary parsing which (a) avoids having to depend on a yaml library,
# and (b) is tolerant of yaml errors
while($_ = <$FH>) {
while (my ($setting, $debconf) = each %MAPPINGS) {
$setting = quotemeta $setting;
if(/^${setting}\s*:(.*)$/) {
my $val = $1;
# remove leading/trailing whitespace
$val =~ s/^\s*//;
$val =~ s/\s*$//;
# remove surrounding quotes
if ($val =~ /^"(.*)"$/ || $val =~ /^'(.*)'$/) {
$val = $1;
}
print STDERR ">> $debconf = $val\n" if $DEBUG;
set($debconf, $val);
}
}
}
close $FH;
}
}
sub update_config {
my @files = @_;
my %substs = ();
while (my ($setting, $debconf) = each %MAPPINGS) {
my @res = get($debconf);
$substs{$setting} = $res[1] if $res[0] == 0;
}
foreach my $file (@files) {
print STDERR "checking $file\n" if $DEBUG;
open my $FH, "<", $file or next;
my $updated = 0;
# read the whole file into memory
my @lines = <$FH>;
while (my ($setting, $val) = each %substs) {
$setting = quotemeta $setting;
map {
if (/^${setting}\s*:\s*(.*)\s*$/) {
my $current = $1;
if ($val ne $current) {
$_ = "${setting}: $val\n";
$updated = 1;
}
}
} @lines;
}
close $FH;
next unless $updated;
print STDERR "updating $file\n" if $DEBUG;
open $FH, ">", $file or die "unable to update $file";
print $FH @lines;
close $FH;
}
}
my $cmd = $ARGV[0];
my $read = 0;
my $update = 0;
if (not $cmd) {
die "must specify a command to perform\n";
} elsif ($cmd eq 'read') {
$read = 1;
} elsif ($cmd eq 'update') {
$update = 1;
} else {
die "unknown command '$cmd'\n";
}
my @files = (
"/etc/matrix-synapse/homeserver.yaml",
glob("/etc/matrix-synapse/conf.d/*.yaml"),
);
if ($read) {
read_config(@files);
} elsif ($update) {
update_config(@files);
}