Add lightweight healtcheck script

To be used for e.g. loadbalancer control, just pings the server

core/server/MANIFEST

@@ -579,6 +579,7 @@ cgi-bin/soap.fcgi
 cgi-bin/download.fcgi
 cgi-bin/rpc.fcgi
 cgi-bin/est.fcgi
+cgi-bin/healthcheck.fcgi
 
 # Client UI
 htdocs/img/logo.png

core/server/cgi-bin/healthcheck.fcgi

@@ -0,0 +1,43 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+
+use CGI;
+use CGI::Fast;
+use CGI::Carp qw (fatalsToBrowser);
+
+use English;
+use JSON;
+use OpenXPKI::Client;
+use Log::Log4perl qw(:easy);
+
+Log::Log4perl->easy_init($ERROR);
+
+my $client;
+my $json = new JSON();
+
+my $socketfile = $ENV{OPENXPKI_CLIENT_SOCKETFILE} || '/var/openxpki/openxpki.socket';
+
+while (my $cgi = CGI::Fast->new()) {
+
+    if (!$client) {
+        eval{
+            $client = OpenXPKI::Client->new({
+                SOCKETFILE => $socketfile,
+            });
+            $client->init_session();
+        };
+    }
+
+    if (!$client || !$client->is_connected()) {
+        print $cgi->header( -type => 'text/plain', charset => 'utf8', -status => 500 );
+        print $json->encode({ ping => 0 });
+        $client = undef;
+    } else {
+        print $cgi->header( -type => 'text/plain', charset => 'utf8', -status => 200 );
+        print $json->encode({ ping => 1 });
+    }
+}
+
+$client->close_connection() if ($client);

package/debian/core/libopenxpki-perl.install

@@ -4,4 +4,5 @@ cgi-bin/soap.fcgi    usr/lib/cgi-bin
 cgi-bin/rpc.fcgi    usr/lib/cgi-bin
 cgi-bin/est.fcgi    usr/lib/cgi-bin
 cgi-bin/download.fcgi usr/lib/cgi-bin
+cgi-bin/healthcheck.fcgi usr/lib/cgi-bin
 htdocs/* var/www/openxpki/