TT#108502 Refactor Debian release information gathering

Change get_debian_release into set_debian_info, and make the former call
the latter.

This new library will populate debian.version and debian.codename from
the current system.

Change-Id: If0d5ed6da359b35e9ef4a6135944c3a7a58848c1

lib/get_debian_release

@@ -4,25 +4,10 @@
 # Returns the Debian release codename of the node calling this function.
 #
 # @return out   The Debian release codename of the node calling this function.
+
+# XXX: This is a deprecated alias for set_debian_info.
+
+PROCESS '/usr/lib/ngcp-ngcpcfg/set_debian_info';
+out = debian.codename;
+
 -%]
-[% PERL -%]
-  open my $hh, '<', '/etc/debian_version' or die "Error opening /etc/debian_version";
-  my $debian_version = <$hh>;
-  my $debian_codename;
-  close $hh;
-  chomp $debian_version;
-  if ($debian_version =~ /^8\.*/) {
-    $debian_codename = 'jessie';
-  } elsif ($debian_version =~ /^9\.*/) {
-    $debian_codename = 'stretch';
-  } elsif ($debian_version =~ /^10\.*/) {
-    $debian_codename = 'buster';
-  } elsif ($debian_version =~ /^11\.*/) {
-    $debian_codename = 'bullseye';
-  } elsif ($debian_version =~ /^[[:alnum:]]+\.*\/sid/) {
-    $debian_codename = (split /\//, $debian_version, 2)[0];
-  }
-  die "Fatal error retrieving Debian release codename [$debian_codename]" unless length $debian_codename;
-  die "Fatal error retrieving Debian release version [$debian_version]" unless length $debian_version;
-  $stash->set(out => $debian_codename);
-[% END -%]

lib/set_debian_info

@@ -0,0 +1,51 @@
+[%
+# vi: ft=tt2
+
+# Sets the Debian release information for the node calling this function.
+#
+# This sets the global variables:
+#   debian.codename
+#   debian.version
+-%]
+[% PERL -%]
+  my $version_file = '/etc/debian_version';
+  my $debian_codename;
+  my $debian_version;
+  my $debian_version_major;
+
+  open my $hh, '<', $version_file or die "Error opening $version_file";
+  $debian_version = <$hh>;
+  close $hh;
+  chomp $debian_version;
+  die "Fatal error retrieving Debian release version from $version_file"
+    unless length $debian_version;
+
+  my %versions = (
+    8 => 'jessie',
+    9 => 'stretch',
+    10 => 'buster',
+    11 => 'bullseye',
+  );
+  my %codenames = map { $versions{$_} => $_ } keys %versions;
+
+  if ($debian_version =~ m/^([0-9]+)\.[0-9]+/) {
+    $debian_version_major = $1;
+    $debian_codename = $versions{$debian_version_major};
+    die "Error: unsupported Debian release $debian_version"
+      unless defined $debian_codename;
+  } elsif ($debian_version =~ m{^([[:alnum:]]+)/sid}) {
+    $debian_codename = $1;
+    $debian_version_major = $codenames{$debian_codename};
+    die "Error: unsupported Debian codename $debian_codename"
+      unless defined $debian_version_major;
+  } else {
+    die "Fatal error retrieving Debian release codename [$debian_version]";
+  }
+
+  $stash->update({
+    debian => {
+      version => $debian_version_major,
+      codename => $debian_codename,
+    }
+  });
+[% END -%]