set blockstack atlas hostname (BLOCKSTACK_ATLAS_HOSTNAME) as an environ

blockstack/lib/config.py

@@ -37,6 +37,8 @@ DEBUG = True
 VERSION = __version__
 
 ATLAS_SEEDS_ENV_VAR = 'BLOCKSTACK_ATLAS_SEEDS'
+ATLAS_HOSTNAME_ENV_VAR = 'BLOCKSTACK_ATLAS_HOSTNAME'
+
 # namespace version bits
 NAMESPACE_VERSION_PAY_TO_BURN = 0x1
 NAMESPACE_VERSION_PAY_TO_CREATOR = 0x2
@@ -1141,6 +1143,9 @@ def default_blockstack_opts( working_dir, config_file=None ):
        atlas_seed_peers = os.environ[ATLAS_SEEDS_ENV_VAR]
        check_hostport_list(atlas_seed_peers)
 
+   if os.environ.get(ATLAS_HOSTNAME_ENV_VAR, False):
+       atlas_hostname = os.environ[ATLAS_HOSTNAME_ENV_VAR]
+
    if os.path.exists( announce_path ):
        # load announcement list
        with open( announce_path, "r" ) as f: