Handle a configuration file specified on the command line.

 * pyrseas/cmdargs.py (cmd_parser): Initialize global _cfg here.
   (parse_args): If config file specified, load it and merge it.
 * pyrseas/config.py (Config.__init__): Use new merge method.
   (Config.merge): New method to merge configuration dicts.
 * tests/test_config.py: New test.

pyrseas/cmdargs.py

@@ -4,9 +4,11 @@
 from argparse import ArgumentParser, FileType
 import getpass
 
+import yaml
+
 from pyrseas.config import Config
 
-_cfg = Config()
+_cfg = None
 
 HELP_TEXT = {
     'host': "database server host or socket directory",
@@ -30,9 +32,13 @@ def cmd_parser(description, version):
     :param version: version of the caller
     :return: the created parser
     """
+    global _cfg
+
     parent = ArgumentParser(add_help=False)
     parent.add_argument('dbname', help='database name')
     group = parent.add_argument_group('Connection options')
+    if _cfg is None:
+        _cfg = Config()
     cfg = _cfg['database'] if 'database' in _cfg else {}
     group.add_argument('-H', '--host', **_help_dflt('host', cfg))
     group.add_argument('-p', '--port', type=int, **_help_dflt('port', cfg))
@@ -70,5 +76,7 @@ def parse_args(parser):
     for key in ['output', 'config']:
         _cfg['files'][key] = args[key]
         del args[key]
+    if 'config' in _cfg['files'] and _cfg['files']['config']:
+        _cfg.merge(yaml.safe_load(_cfg['files']['config']))
     _cfg['options'] = arg_opts
     return _cfg

pyrseas/config.py

@@ -41,14 +41,15 @@ def __init__(self, sys_only=False):
                     os.path.join(os.path.dirname(__file__), '..', 'config'))))
         if sys_only:
             return
-        cfg = _load_cfg("PYRSEAS_USER_CONFIG",
-                        os.path.join(_home_dir(), 'pyrseas'))
-        for key, val in list(cfg.items()):
-            if key in self:
-                self[key].update(val)
-            else:
-                self[key] = val
-        cfg = _load_cfg("PYRSEAS_REPO_DIR", None)
+        self.merge(_load_cfg("PYRSEAS_USER_CONFIG",
+                             os.path.join(_home_dir(), 'pyrseas')))
+        self.merge(_load_cfg("PYRSEAS_REPO_DIR", None))
+
+    def merge(self, cfg):
+        """Merge extra configuration
+
+        :param cfg: extra configuration (dict)
+        """
         for key, val in list(cfg.items()):
             if key in self:
                 self[key].update(val)

tests/test_config.py

@@ -40,3 +40,15 @@ def test_repo_config(tmpdir):
     os.environ["PYRSEAS_REPO_DIR"] = tmpdir.strpath
     cfg = Config()
     assert cfg['schema public'] == CFG_TABLE_DATA
+
+
+def test_cmd_parser(tmpdir):
+    "Test parsing a configuration file specified on the command line"
+    f = tmpdir.join(CFG_FILE)
+    f.write(yamldump(CFG_DATA))
+    sys.argv = ['testprog', 'testdb', '--config', f.strpath]
+    os.environ["PYRSEAS_USER_CONFIG"] = ''
+    os.environ["PYRSEAS_REPO_DIR"] = ''
+    parser = cmd_parser("Test description", '0.0.1')
+    cfg = parse_args(parser)
+    assert cfg['schema public'] == CFG_TABLE_DATA