[PostgresAdmin] Use pg-logical_replication

Use PG::LogicalReplication::Client to remove subscriptions or
publications on a db prior to doing a database reload.

Doesn't drop the `MiqRegion`, as was previously done as part of
PglogicalSubscription in core:

  https://github.com/ManageIQ/manageiq/blob/8ca93da126aada556685db5d05aaf5e9a0666900/app/models/pglogical_subscription.rb#L70

But since this is a database reload, and the Region will be removed from
the DB anyway, this should not matter, and the necessary code required
to perform that delete will be pointless to include in this gem.

lib/manageiq/appliance_console/postgres_admin.rb

@@ -339,6 +339,8 @@ class << self
         raise message
       end
 
+      disable_replication(dbname)
+
       if connection_count(backup_type) > 1
         message = "Database restore failed. #{connection_count - 1} connections remain to the database."
         ManageIQ::ApplianceConsole.logger.error(message)
@@ -356,6 +358,33 @@ class << self
       result[0]["count"] > 0
     end
 
+    ALWAYS_EXCLUDED_TABLES = %w(ar_internal_metadata schema_migrations repl_events repl_monitor repl_nodes).freeze
+    private_class_method def self.disable_replication(dbname)
+      require 'pg/logical_replication'
+
+      with_pg_connection do |conn|
+        pglogical = PG::LogicalReplication::Client.new(conn)
+
+        if pglogical.subscriber?
+          pglogical.subcriptions(dbname).each do |subscriber|
+            sub_id = subscriber["subscription_name"]
+            begin
+              pglogical.drop_subscription(sub_id, true)
+            rescue PG::InternalError => e
+              raise unless e.message =~ /could not connect to publisher/
+              raise unless e.message =~ /replication slot .* does not exist/
+
+              pglogical.disable_subscription(sub_id).check
+              pglogical.alter_subscription_options(sub_id, "slot_name" => "NONE")
+              pglogical.drop_subscription(sub_id, true)
+            end
+          end
+        elsif pglogical.publishes?('miq')
+          pglogical.drop_publication(PUBLICATION_NAME)
+        end
+      end
+    end
+
     private_class_method def self.connection_count(backup_type, dbname)
       result = nil
 

manageiq-appliance_console.gemspec

@@ -32,6 +32,7 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency "net-scp",                 "~> 1.2.1"
   spec.add_runtime_dependency "optimist",                "~> 3.0"
   spec.add_runtime_dependency "pg"
+  spec.add_runtime_dependency "pg-logical_replication"
   spec.add_runtime_dependency "rbnacl",                  ">= 3.2", "< 5.0"
 
   spec.add_development_dependency "bundler"