Don't install locales-all, generate only necessary locales

to reduce image size 654MB -> 462MB.

Dockerfile

@@ -8,9 +8,20 @@ WORKDIR /entrypoint
 RUN ["go", "build", "."]
 
 
+FROM debian:bullseye-slim as etc-locale-gen
+
+RUN ["bash", "-exo", "pipefail", "-c", "export DEBIAN_FRONTEND=noninteractive; apt-get update; apt-get install --no-install-{recommends,suggests} -y locales; apt-get clean; rm -vrf /var/lib/apt/lists/*"]
+
+COPY icingaweb2 /usr/share/icingaweb2
+COPY icinga-L10n /usr/share/icinga-L10n
+COPY uncomment-locales.pl /
+
+RUN ["/uncomment-locales.pl", "/etc/locale.gen"]
+
+
 FROM debian:bullseye-slim
 
-RUN ["bash", "-exo", "pipefail", "-c", "export DEBIAN_FRONTEND=noninteractive; apt-get update; apt-get install --no-install-{recommends,suggests} -y apache2 ca-certificates libapache2-mod-php7.4 libldap-common locales-all php-{imagick,redis} php7.4-{bcmath,bz2,common,curl,dba,enchant,gd,gmp,imap,interbase,intl,json,ldap,mbstring,mysql,odbc,opcache,pgsql,pspell,readline,snmp,soap,sqlite3,sybase,tidy,xml,xmlrpc,xsl,zip}; apt-get clean; rm -vrf /var/lib/apt/lists/*"]
+RUN ["bash", "-exo", "pipefail", "-c", "export DEBIAN_FRONTEND=noninteractive; apt-get update; apt-get install --no-install-{recommends,suggests} -y apache2 ca-certificates libapache2-mod-php7.4 libldap-common locales php-{imagick,redis} php7.4-{bcmath,bz2,common,curl,dba,enchant,gd,gmp,imap,interbase,intl,json,ldap,mbstring,mysql,odbc,opcache,pgsql,pspell,readline,snmp,soap,sqlite3,sybase,tidy,xml,xmlrpc,xsl,zip}; apt-get clean; rm -vrf /var/lib/apt/lists/*"]
 
 COPY --from=entrypoint /entrypoint/entrypoint /entrypoint
 COPY entrypoint/db-init /entrypoint-db-init
@@ -38,6 +49,9 @@ COPY icinga-php /usr/share/icinga-php
 COPY icinga-L10n /usr/share/icinga-L10n
 COPY php.ini /etc/php/7.4/cli/conf.d/99-docker.ini
 
+COPY --from=etc-locale-gen /etc/locale.gen /etc/
+RUN ["locale-gen", "-j", "4"]
+
 RUN ["ln", "-vs", "/usr/share/icingaweb2/packages/files/apache/icingaweb2.conf", "/etc/apache2/conf-enabled/"]
 RUN ["ln", "-vs", "/usr/share/icingaweb2/bin/icingacli", "/usr/local/bin/"]
 

build.bash

@@ -33,6 +33,6 @@ cd /iw2cp
 /bldctx/composer.bash
 patch -d icingaweb2 -p0 < /bldctx/icingaweb2.patch
 
-cp -r /entrypoint /bldctx/php.ini .
+cp -r /entrypoint /bldctx/{php.ini,uncomment-locales.pl} .
 docker build -f /bldctx/Dockerfile -t icinga/icingaweb2 .
 EOF

uncomment-locales.pl

@@ -0,0 +1,26 @@
+#!/usr/bin/perl -i
+
+my %uniqLocs = ();
+
+for my $subDir ('icinga-L10n', 'icingaweb2/modules/*/application') {
+	for my $lcDir (glob "/usr/share/$subDir/locale/*_*") {
+		if ($lcDir =~ /(\w+)$/) {
+			$uniqLocs{$1} = 1
+		}
+	}
+}
+
+my @locs = keys %uniqLocs;
+
+while (<>) {
+	if (/\bUTF-8\b/) {
+		for my $loc (@locs) {
+			if (/\b$loc\b/) {
+				s/^# *//;
+				last
+			}
+		}
+	}
+} continue {
+	print or die $!
+}