[BC] Support grouping backups by cluster name (#5)

* Rename instance attribute `cluster` to `db_cluster`
* Support grouping backups by cluster name

manifests/cron_backup.pp

@@ -3,6 +3,7 @@
 # Typically on a catalog (backup) server.
 define pgprobackup::cron_backup(
   String                          $id,
+  String                          $cluster,
   String                          $host_group,
   Pgprobackup::Backup_type        $backup_type,
   String                          $server_address,
@@ -123,7 +124,7 @@
 
     @@cron { "pgprobackup_${backup_type}_${server_address}-${host_group}":
       command  => @("CMD"/L),
-      ${binary} ${backup_cmd} --instance ${id} -b ${backup_type} ${stream}--remote-host=${server_address}\
+      ${binary} ${backup_cmd} --instance ${cluster} -b ${backup_type} ${stream}--remote-host=${server_address}\
        --remote-user=${remote_user} --remote-port=${remote_port} -U ${db_user} -d ${db_name}\
        ${logging}${retention}${_threads}${_temp_slot}${_slot}${_validate}${_compress}${_timeout}
       | -CMD

manifests/instance.pp

@@ -4,10 +4,18 @@
 #
 # @param id
 #   Unique identifier within `host_group`
+# @param cluster
+#   Could be used to group primary with standby servers
 # @param server_address
 #   Address used for connecting to the DB server
 # @param server_port
 #   DB port
+# @param db_name
+#   Database used for backups
+# @param db_user
+#   User connecting to database
+# @param db_cluster
+#   Postgresql cluster e.g. `main`
 # @param db_dir
 #   PostgreSQL home directory
 # @param manage_dbuser
@@ -58,13 +66,14 @@
 #   include pgprobackup::instance
 class pgprobackup::instance(
   String                            $id                   = $::hostname,
+  Optional[String]                  $cluster              = undef,
   String                            $server_address       = $::fqdn,
-  String                            $cluster              = 'main',
   Integer                           $server_port          = 5432,
   Boolean                           $manage_dbuser        = true,
   String                            $db_dir               = '/var/lib/postgresql',
   String                            $db_name              = $pgprobackup::db_name,
   String                            $db_user              = $pgprobackup::db_user,
+  String                            $db_cluster           = 'main',
   Variant[String,Sensitive[String]] $db_password          = '',
   Optional[String]                  $seed                 = undef,
   String                            $remote_user          = 'postgres',
@@ -98,6 +107,11 @@
   Optional[Integer]                 $archive_timeout      = undef,
   ) inherits pgprobackup {
 
+  $_cluster = $cluster ? {
+    undef   => $id,
+    default => $cluster
+  }
+
   class {'pgprobackup::install':
     versions       => [$version],
     package_name   => $package_name,
@@ -204,12 +218,12 @@
 
       @@exec { "pgprobackup_add_instance_${::fqdn}-${host_group}":
         command => @("CMD"/L),
-        pg_probackup-${version} add-instance -B ${backup_dir} --instance ${id} \
+        pg_probackup-${version} add-instance -B ${backup_dir} --instance ${_cluster} \
         --remote-host=${server_address} --remote-user=${remote_user} \
-        --remote-port=${remote_port} -D ${db_dir}/${version}/${cluster}
+        --remote-port=${remote_port} -D ${db_dir}/${version}/${db_cluster}
         | -CMD
         path    => ['/usr/bin'],
-        onlyif  => "test ! -d ${backup_dir}/backups/${id}",
+        onlyif  => "test ! -d ${backup_dir}/backups/${_cluster}",
         tag     => "pgprobackup_add_instance-${host_group}",
         user    => $backup_user, # note: error output might not be captured
         require => Package["${package_name}-${version}"],
@@ -236,6 +250,7 @@
           # declare cron job, use defaults from instance
           create_resources(pgprobackup::cron_backup, {"cron_backup-${host_group}-${server_address}-${backup_type}" => $schedule} , {
             id                   => $id,
+            cluster              => $_cluster,
             db_name              => $db_name,
             db_user              => $db_user,
             version              => $version,

spec/classes/instance_spec.rb

@@ -56,13 +56,14 @@
             }
           },
           version: '12',
+          db_cluster: 'dev',
         }
       end
 
       it {
         expect(exported_resources).to contain_exec('pgprobackup_add_instance_psql.localhost-common').with(
           tag: 'pgprobackup_add_instance-common',
-          command: 'pg_probackup-12 add-instance -B /var/lib/pgbackup --instance foo --remote-host=psql.localhost --remote-user=postgres --remote-port=22 -D /var/lib/postgresql/12/main',
+          command: 'pg_probackup-12 add-instance -B /var/lib/pgbackup --instance foo --remote-host=psql.localhost --remote-user=postgres --remote-port=22 -D /var/lib/postgresql/12/dev',
         )
       }
 
@@ -633,6 +634,40 @@
       end
     end
 
+    context 'with cluster grouping' do
+      let(:params) do
+        {
+          backups: {
+            common: {
+              DELTA: {},
+              FULL: {},
+            }
+          },
+          version: '13',
+          id: 'psql01a',
+          cluster: 'psql01',
+        }
+      end
+
+      ['DELTA', 'FULL'].each do |backup|
+        cmd = '[ -x /usr/bin/pg_probackup-13 ] && /usr/bin/pg_probackup-13 backup'\
+        " -B /var/lib/pgbackup --instance psql01 -b #{backup} --stream"\
+        ' --remote-host=psql.localhost --remote-user=postgres --remote-port=22'\
+        ' -U backup -d backup --log-filename=psql01a.log'\
+        ' --log-level-file=info --log-directory=/var/lib/pgbackup/log'
+
+        it {
+          expect(exported_resources).to contain_cron("pgprobackup_#{backup}_psql.localhost-common")
+            .with(
+              command: cmd,
+              user: 'pgbackup',
+              hour: '4',
+              minute: '0',
+            )
+        }
+      end
+    end
+
     context 'install specific package version' do
       let(:params) do
         {