fetched mlz version

- before some chamges in the gerrit pipline

Change-Id: I33eb2d75f83345a7039d0fb709e66defefb1c3e0

frappy/config.py

@@ -0,0 +1,189 @@
+#  -*- coding: utf-8 -*-
+# *****************************************************************************
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+# Alexander Zaft <a.zaft@fz-juelich.de>
+#
+# *****************************************************************************
+
+import os
+import re
+
+from frappy.errors import ConfigError
+from frappy.lib import generalConfig
+
+class Undef:
+    pass
+
+
+class Node(dict):
+    def __init__(
+            self,
+            equipment_id,
+            description,
+            interface=None,
+            cls='frappy.protocol.dispatcher.Dispatcher',
+            **kwds
+    ):
+        super().__init__(
+            equipment_id=equipment_id,
+            description=description,
+            interface=interface,
+            cls=cls,
+            **kwds
+        )
+
+
+class Param(dict):
+    def __init__(self, value=Undef, **kwds):
+        if value is not Undef:
+            kwds['value'] = value
+        super().__init__(**kwds)
+
+class Group(tuple):
+    def __new__(cls, *args):
+        return super().__new__(cls, args)
+
+class Mod(dict):
+    def __init__(self, name, cls, description, **kwds):
+        super().__init__(
+            name=name,
+            cls=cls,
+            description=description
+        )
+
+        # matches name from spec
+        if not re.match(r'^[a-zA-Z]\w{0,62}$', name, re.ASCII):
+            raise ConfigError(f'Not a valid SECoP Module name: "{name}". Does it only contain letters, numbers and underscores?')
+        # Make parameters out of all keywords
+        groups = {}
+        for key, val in kwds.items():
+            if isinstance(val, Param):
+                self[key] = val
+            elif isinstance(val, Group):
+                groups[key] = val
+            else:
+                # shortcut to only set value
+                self[key] = Param(val)
+        for group, members in groups.items():
+            for member in members:
+                self[member]['group'] = group
+
+class Collector:
+    def __init__(self, cls):
+        self.list = []
+        self.cls = cls
+
+    def add(self, *args, **kwds):
+        self.list.append(self.cls(*args, **kwds))
+
+    def append(self, mod):
+        self.list.append(mod)
+
+
+class NodeCollector:
+    def __init__(self):
+        self.node = None
+
+    def add(self, *args, **kwds):
+        if self.node is None:
+            self.node = Node(*args, **kwds)
+        else:
+            raise ConfigError('Only one Node is allowed per file!')
+
+
+class Config(dict):
+    def __init__(self, node, modules):
+        super().__init__(
+            node=node.node,
+            **{mod['name']: mod for mod in modules.list}
+        )
+        self.module_names = {mod.pop('name') for mod in modules.list}
+        self.ambiguous = set()
+
+    def merge_modules(self, other):
+        """ merges only the modules from 'other' into 'self'"""
+        self.ambiguous |= self.module_names & other.module_names
+        for name, mod in other.items():
+            if name == 'node':
+                continue
+            if name not in self.module_names:
+                self.module_names.add(name)
+                self.modules.append(mod)
+
+
+def process_file(config_text):
+    node = NodeCollector()
+    mods = Collector(Mod)
+    ns = {'Node': node.add, 'Mod': mods.add, 'Param': Param, 'Command': Param, 'Group': Group}
+
+    # pylint: disable=exec-used
+    exec(config_text, ns)
+    return Config(node, mods)
+
+
+def to_config_path(cfgfile, log):
+    candidates = [cfgfile + e for e in ['_cfg.py', '.py', '']]
+    if os.sep in cfgfile:  # specified as full path
+        filename = cfgfile if os.path.exists(cfgfile) else None
+    else:
+        for filename in [os.path.join(d, candidate)
+                         for d in generalConfig.confdir.split(os.pathsep)
+                         for candidate in candidates]:
+            if os.path.exists(filename):
+                break
+        else:
+            filename = None
+
+    if filename is None:
+        raise ConfigError(f"Couldn't find cfg file {cfgfile!r} in {generalConfig.confdir}")
+    if not filename.endswith('_cfg.py'):
+        log.warning("Config files should end in '_cfg.py': %s", os.path.basename(filename))
+    log.debug('Using config file %s for %s', filename, cfgfile)
+    return filename
+
+
+def load_config(cfgfiles, log):
+    """Load config files.
+
+    Only the node-section of the first config file will be returned.
+    The others will be discarded.
+    Arguments
+    - cfgfiles : str
+        Comma separated list of config-files
+    - log : frappy.logging.Mainlogger
+        Logger aquired from frappy.logging
+    Returns
+    - config: Config
+        merged configuration
+    """
+    config = None
+    for cfgfile in cfgfiles.split(','):
+        filename = to_config_path(cfgfile, log)
+        log.debug('Parsing config file %s...', filename)
+        with open(filename, 'rb') as f:
+            config_text = f.read()
+        cfg = process_file(config_text)
+        if config:
+            config.merge_modules(cfg)
+        else:
+            config = cfg
+
+    if config.ambiguous:
+        log.warning('ambiguous sections in %s: %r',
+                    cfgfiles, list(config.ambiguous))
+    return config