bundles/postgresql: improvements

- support other postgresql versions
- manage configs using bw

bundles/postgresql/metadata.py

@@ -13,6 +13,15 @@ defaults = {
             },
         },
     },
+    'postgresql': {
+        'max_connections': 100,
+        'autovacuum_max_workers': 3,
+        'maintenance_work_mem': 64,
+        'work_mem': 4,
+        'shared_buffers': 128,
+        'temp_buffers': 8,
+        'slow_query_log_sec': 0,
+    },
 }
 
 if node.has_bundle('zfs'):
@@ -23,3 +32,39 @@ if node.has_bundle('zfs'):
             },
         },
     }
+
+
+@metadata_reactor.provides(
+    'apt/repos/postgresql',
+    'postgresql/version',
+)
+def default_postgresql_version_for_debian(metadata):
+    # <https://packages.debian.org/search?keywords=postgresql>
+    versions_in_debian = {
+        '10': '11', # buster
+        '11': '13', # bullseye
+    }
+    os = str(node.os_version[0])
+    version_to_be_installed = metadata.get('postgresql/version', versions_in_debian[os])
+
+    if version_to_be_installed != versions_in_debian[os]:
+        return {
+            'apt': {
+                'repos': {
+                    'postgresql': {
+                        'items': {
+                            'deb https://apt.postgresql.org/pub/repos/apt/ {os_release}-pgdg main',
+                        },
+                    },
+                },
+            },
+            'postgresql': {
+                'version': version_to_be_installed,
+            },
+        }
+    else:
+        return {
+            'postgresql': {
+                'version': version_to_be_installed,
+            },
+        }