[gentoo-commits] proj/R_overlay:master commit in: roverlay/config/

[André Erdmann]

commit:     d72284c4978f84bbdcdc54ce0c4b4d66b6d91ad3
Author:     André Erdmann <dywi <AT> mailerd <DOT> de>
AuthorDate: Sun Jan 26 16:37:44 2014 +0000
Commit:     André Erdmann <dywi <AT> mailerd <DOT> de>
CommitDate: Sun Jan 26 16:37:44 2014 +0000
URL:        http://git.overlays.gentoo.org/gitweb/?p=proj/R_overlay.git;a=commit;h=d72284c4

roverlay/config/, ConfigTree: get options by name

Added get_by_name() to the ConfigTree, which is similar to get(), but takes an
option name (used in config files, e.g. OVERLAY_DIR) instead of a config path
(used in the code, e.g. ['OVERLAY','dir']) as key.
query_by_name() can be used to get multiple options and return them as dict.

Might be useful for scripting.

---
 roverlay/config/entryutil.py  | 43 +++++++++++++++-----
 roverlay/config/exceptions.py | 40 +++++++++++++++++++
 roverlay/config/tree.py       | 92 ++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 159 insertions(+), 16 deletions(-)

diff --git a/roverlay/config/entryutil.py b/roverlay/config/entryutil.py
index cd5f230..716c166 100644
--- a/roverlay/config/entryutil.py
+++ b/roverlay/config/entryutil.py
@@ -1,6 +1,6 @@
 # R overlay -- config package, entryutil
 # -*- coding: utf-8 -*-
-# Copyright (C) 2012 André Erdmann <dywi@×××××××.de>
+# Copyright (C) 2012-2014 André Erdmann <dywi@×××××××.de>
 # Distributed under the terms of the GNU General Public License;
 # either version 2 of the License, or (at your option) any later version.
 
@@ -11,9 +11,11 @@ __all__ = [ 'list_entries', ]
 import re
 import textwrap
 
+import roverlay.config.exceptions
 from roverlay.config.entrymap import CONFIG_ENTRY_MAP
 
 def deref_entry ( name ):
+   # COULDFIX: raise ConfigOptionNotFound
    entry_name = name.lower()
    entry_next = CONFIG_ENTRY_MAP [entry_name]
    while isinstance ( entry_next, str ):
@@ -25,29 +27,50 @@ def deref_entry ( name ):
 def deref_entry_safe ( name ):
    visited    = set()
    entry_name = name.lower()
-   entry_next = CONFIG_ENTRY_MAP [entry_name]
+   try:
+      entry_next = CONFIG_ENTRY_MAP [entry_name]
+   except KeyError:
+      # entry does not exist
+      raise roverlay.config.exceptions.ConfigOptionNotFound ( name )
 
    while isinstance ( entry_next, str ):
       visited.add ( entry_name )
       entry_name = entry_next
-      entry_next = CONFIG_ENTRY_MAP [entry_name]
+      try:
+         entry_next = CONFIG_ENTRY_MAP [entry_name]
+      except KeyError:
+         raise roverlay.config.exceptions.ConfigEntryMapException (
+            "dangling config map entry {!r} (<- {!r})".format (
+               entry_name, name
+            )
+         )
 
       if entry_name in visited:
-         raise Exception (
-         "cyclic config entry detected for {!r}!".format ( name )
-      )
+         raise roverlay.config.exceptions.ConfigEntryMapException (
+            "cyclic config entry detected for {!r}!".format ( name )
+         )
 
    return ( entry_name, entry_next )
 # --- end of deref_entry_safe (...) ---
 
 def find_config_path ( name ):
    entry_name, entry =  deref_entry_safe ( name )
-   try:
-      return entry ['path']
-   except KeyError:
-      return entry_name.split ( '_' )
+   if entry:
+      try:
+         return entry ['path']
+      except KeyError:
+         return entry_name.split ( '_' )
+   else:
+      # hidden entry
+      raise roverlay.config.exceptions.ConfigOptionNotFound ( name )
 # --- end of find_config_path (...) ---
 
+def iter_config_keys():
+   for key, entry in CONFIG_ENTRY_MAP.items():
+      if isinstance ( entry, dict ):
+         yield key
+# --- end of iter_config_keys (...) ---
+
 def _iter_entries():
    """Iterates through all entries in CONFIG_ENTRY_MAP and yields config
    entry information (entry name, description).

diff --git a/roverlay/config/exceptions.py b/roverlay/config/exceptions.py
new file mode 100644
index 0000000..715d9eb
--- /dev/null
+++ b/roverlay/config/exceptions.py
@@ -0,0 +1,40 @@
+# R overlay -- config package, exceptions
+# -*- coding: utf-8 -*-
+# Copyright (C) 2014 André Erdmann <dywi@×××××××.de>
+# Distributed under the terms of the GNU General Public License;
+# either version 2 of the License, or (at your option) any later version.
+
+__all__ = [
+   'ConfigException', 'ConfigEntryMapException',
+   'ConfigKeyError', 'ConfigOptionNotFound',
+   'ConfigTreeUsageError',
+]
+
+
+class ConfigException ( Exception ):
+   pass
+# --- end of ConfigException ---
+
+class ConfigEntryMapException ( ConfigException ):
+   pass
+# --- end of ConfigEntryMapException ---
+
+
+class ConfigKeyError ( ConfigException ):
+   # or inherit KeyError
+   def __init__ ( self, config_key ):
+      super ( ConfigKeyError, self ).__init__ (
+         "config key {!r} not found but required.".format ( config_key )
+      )
+# --- end of ConfigKeyError ---
+
+class ConfigOptionNotFound ( ConfigException ):
+   pass
+# --- end of ConfigOptionNotFound ---
+
+class ConfigTreeUsageError ( ConfigException ):
+   def __init__ ( self, message=None ):
+      super ( ConfigTreeUsageError, self ).__init__ (
+         "bad usage" if message is None else message
+      )
+# --- end of ConfigTreeUsageError ---

diff --git a/roverlay/config/tree.py b/roverlay/config/tree.py
index d9f1900..0aeb86c 100644
--- a/roverlay/config/tree.py
+++ b/roverlay/config/tree.py
@@ -1,6 +1,6 @@
 # R overlay -- config package, tree
 # -*- coding: utf-8 -*-
-# Copyright (C) 2012 André Erdmann <dywi@×××××××.de>
+# Copyright (C) 2012-2014 André Erdmann <dywi@×××××××.de>
 # Distributed under the terms of the GNU General Public License;
 # either version 2 of the License, or (at your option) any later version.
 
@@ -20,9 +20,11 @@ __all__ = [ 'ConfigTree', ]
 
 import logging
 
-from roverlay.config        import const
-from roverlay.config.loader import ConfigLoader
-from roverlay.config.util   import get_config_path
+import roverlay.config.exceptions
+from roverlay.config           import const
+from roverlay.config.loader    import ConfigLoader
+from roverlay.config.util      import get_config_path
+from roverlay.config.entryutil import find_config_path
 
 CONFIG_INJECTION_IS_BAD = True
 
@@ -115,7 +117,7 @@ class ConfigTree ( object ):
          pass
 
       else:
-         raise Exception ( "bad usage" )
+         raise roverlay.config.exceptions.ConfigUsageError()
 
    # --- end of merge_with (...) ---
 
@@ -207,6 +209,9 @@ class ConfigTree ( object ):
       * key --
       * fallback_value --
       * fail_if_unset  -- fail if key is neither in config nor const
+
+      raises:
+      * ConfigKeyError -- key does not exist and fail_if_unset is True
       """
 
       config_value = self._findpath ( key )
@@ -219,7 +224,7 @@ class ConfigTree ( object ):
             config_value = fallback
 
          if config_value is None and fail_if_unset:
-            raise Exception ( "config key '%s' not found but required." % key )
+            raise roverlay.config.exceptions.ConfigKeyError ( key )
 
       return config_value
 
@@ -230,6 +235,81 @@ class ConfigTree ( object ):
       return self.get ( key, fail_if_unset=True )
    # --- end of get_or_fail ---
 
+   def get_by_name ( self, option_name, *args, **kwargs ):
+      """Searches for an option referenced by name (e.g. OVERLAY_DIR)
+      and returns its value. See ConfigTree.get() for details.
+
+      This is an inefficient operation meant for setup/query scripts.
+      Use get() where possible.
+
+      arguments:
+      * option_name
+      * *args, **kwargs -- passed to get()
+
+      raises:
+      * ConfigOptionNotFound    -- option_name is unknown or hidden
+      * ConfigEntryMapException -- config entry is broken
+      * ConfigKeyError          -- key does not exist and fail_if_unset is True
+      """
+      return self.get ( find_config_path ( option_name ), *args, **kwargs )
+   # --- end of get_by_name (...) ---
+
+   def get_by_name_or_fail ( self, option_name ):
+      """Alias to self.get_by_name ( key, fail_if_unset=True )."""
+      return self.get_by_name ( option_name, fail_if_unset=True )
+   # --- end of get_by_name_or_fail (...) ---
+
+   def query_by_name ( self,
+      request, empty_missing=False, convert_value=None
+   ):
+      """Creates a dict<var_name,value> of config options, referenced by name
+
+      Returns: 2-tuple ( # of missing options, var dict ).
+
+      arguments:
+      * request       -- an iterable containing strings
+                         or 2-tuples(option_name,var_name)
+      * empty_missing -- whether to create empty entries for missing options
+                         or not. Defaults to False.
+      * convert_value -- if set and not None: convert config values using
+                         this function before adding them to the resulting
+                         dict
+      """
+      num_missing = 0
+      retvars     = dict()
+
+      for k in request:
+         if (
+            not isinstance ( k, str ) and hasattr ( k, '__iter__' )
+            and len ( k ) > 1
+         ):
+
+            option_name = k[0]
+            var_name    = k[1]
+         else:
+            option_name = str(k)
+            var_name    = option_name
+         # -- end if <set option_name/var_name>
+
+         try:
+            value = self.get_by_name_or_fail ( option_name )
+         except (
+            roverlay.config.exceptions.ConfigOptionNotFound,
+            roverlay.config.exceptions.ConfigKeyError
+         ):
+            num_missing += 1
+            if empty_missing:
+               retvars [var_name] = ""
+         else:
+            if convert_value is not None:
+               retvars [var_name] = convert_value ( value )
+            else:
+               retvars [var_name] = value
+      # -- end for <request>
+
+      return ( num_missing, retvars )
+   # --- end of query_by_name (...) ---
+
    def get_field_definition ( self, force_update=False ):
       """Gets the field definition stored in this ConfigTree.