backport automatic db backup and restore from develop

blockstack/lib/config.py

@@ -555,6 +555,8 @@ def default_blockstack_opts( config_file=None, testset=False ):
    contact_email = None
    announcers = "judecn.id,muneeb.id,shea256.id"
    announcements = None
+   backup_frequency = 1008  # once a week; 10 minute block time
+   backup_max_age = 12096   # 12 weeks
    rpc_port = RPC_SERVER_PORT 
    blockchain_proxy = False
    serve_zonefiles = False
@@ -574,6 +576,12 @@ def default_blockstack_opts( config_file=None, testset=False ):
       if parser.has_option('blockstack', 'max_subsidy'):
          max_subsidy = int( parser.get('blockstack', 'max_subsidy'))
 
+      if parser.has_option('blockstack', 'backup_frequency'):
+         backup_frequency = int( parser.get('blockstack', 'backup_frequency'))
+
+      if parser.has_option('blockstack', 'backup_max_age'):
+         backup_max_age = int( parser.get('blockstack', 'backup_max_age') )
+
       if parser.has_option('blockstack', 'email'):
          contact_email = parser.get('blockstack', 'email')
 
@@ -649,6 +657,8 @@ def default_blockstack_opts( config_file=None, testset=False ):
        'email': contact_email,
        'announcers': announcers,
        'announcements': announcements,
+       'backup_frequency': backup_frequency,
+       'backup_max_age': backup_max_age,
        'blockchain_proxy': blockchain_proxy,
        'serve_zonefiles': serve_zonefiles,
        'zonefiles': zonefile_dir

blockstack/lib/nameset/namedb.py

@@ -98,6 +98,9 @@ class BlockstackDB( virtualchain.StateEngine ):
       self.firstblock = first_block
       self.announce_ids = blockstack_opts['announcers'].split(",")
 
+      self.set_backup_frequency( blockstack_opts['backup_frequency'] )
+      self.set_backup_max_age( blockstack_opts['backup_max_age'] )
+
       self.db_filename = db_filename
 
       self.name_records = {}                  # map name.ns_id to a dict containing the name record