From 7ea411b9234f58c0632ef8b0c2632ee55dd9f2d0 Mon Sep 17 00:00:00 2001
From: helmutm <helmutm@fd906abe-77d9-0310-91a1-e0d9ade77398>
Date: Wed, 1 Aug 2007 13:05:27 +0000
Subject: [PATCH] set up Configurator stuff

git-svn-id: svn://svn.cy55.de/Zope3/src/loops/trunk@1858 fd906abe-77d9-0310-91a1-e0d9ade77398
---
 agent/README.txt | 98 ++++++++++++++++++++++++++++++++++++++++++------
 agent/config.py  | 79 ++++++++++++++++++++++++++++++++------
 agent/core.py    |  4 +-
 agent/tests.py   |  1 +
 4 files changed, 156 insertions(+), 26 deletions(-)

diff --git a/agent/README.txt b/agent/README.txt
index b6dfa6a..9767b50 100644
--- a/agent/README.txt
+++ b/agent/README.txt
@@ -26,8 +26,92 @@ This means that all calls to services (like crawler, transporter, ...)
 return a deferred that must be supplied with a callback method (and in
 most cases also an errback method).
 
-  >>> from loops.agent.core import Agent
-  >>> agent = Agent()
+  >>> from loops.agent import core
+  >>> agent = core.Agent()
+
+
+Configuration Management
+========================
+
+Functionality
+
+- Storage of configuration parameters
+- Interface to the browser-based user interface that allows the
+  editing of configuration parameters
+
+All configuration parameters are always accessible via the ``config``
+attribute of the agent object.
+
+  >>> config = agent.config
+
+This already provides all needed sections (transport, crawl, ui), so
+we can directly put information into these sections by loading a
+string with the corresponding assignment.
+
+  >>> config.load('transport.url = "http://loops.cy55.de"')
+  >>> config.transport.url
+  'http://loops.cy55.de'
+
+This setting may also contain indexed access; thus we can model
+configuration parameters with multiple instances (like crawling
+jobs).
+
+  >>> config.load('''
+  ... crawl[0].type = "filesystem"
+  ... crawl[0].directory = "documents/projects"
+  ... ''')
+  >>> config.crawl[0].type
+  'filesystem'
+  >>> config.crawl[0].directory
+  'documents/projects'
+
+Subsections are created automatically when they are first accessed.
+
+  >>> config.load('ui.web.port = 8081')
+  >>> config.ui.web.port
+  8081
+
+The ``setdefault()`` method allows to retrieve a value and set
+it with a default if not found, in one statement.
+
+  >>> config.ui.web.setdefault('port', 8080)
+  8081
+  >>> config.transport.setdefault('user', 'loops')
+  'loops'
+
+We can output a configuration in a form that is ready for loading
+just by converting it to a string representation.
+
+  >>> print config
+  crawl[0].directory = 'documents/projects'
+  crawl[0].type = 'filesystem'
+  transport.url = 'http://loops.cy55.de'
+  transport.user = 'loops'
+  ui.web.port = 8081
+
+The configuration may also be saved to a file -
+for testing purposes let's use the loops.agent package directory
+for storage; normally it would be stored in the users home directory.
+
+  >>> import os
+  >>> os.environ['HOME'] = os.path.dirname(core.__file__)
+
+  >>> config.save()
+
+  >>> fn = config.getDefaultConfigFile()
+  >>> fn
+  '....loops.agent.cfg'
+
+  >>> print open(fn).read()
+  crawl[0].directory = 'documents/projects'
+  crawl[0].type = 'filesystem'
+  transport.url = 'http://loops.cy55.de'
+  transport.user = 'loops'
+  ui.web.port = 8081
+
+Cleaning up up...
+
+  >>> os.unlink(fn)
 
 
 Scheduling
@@ -185,16 +269,6 @@ Configuration (per install/update job)
 - package names
 
 
-Configuration Management
-========================
-
-Functionality
-
-- Storage of configuration parameters
-- Interface to the browser-based user interface that allows the
-  editing of configuration parameters
-
-
 Browser-based User Interface
 ============================
 
diff --git a/agent/config.py b/agent/config.py
index b201788..887af3e 100644
--- a/agent/config.py
+++ b/agent/config.py
@@ -22,6 +22,7 @@ Management of agent configuration.
 $Id$
 """
 
+import os
 from zope.interface import implements
 from loops.agent.interfaces import IConfigurator
 
@@ -30,21 +31,75 @@ class Configurator(object):
 
     implements(IConfigurator)
 
-    def loadConfiguration(self):
-        pass
+    def __init__(self, *sections, **kw):
+        for s in sections:
+            setattr(self, s, ConfigSection())
+        self.filename = kw.get('filename')
 
-    def addConfigOption(self, key, value):
-        setattr(self, key, value)
+    def load(self, p=None, filename=None):
+        if p is None:
+            fn = self.getConfigFile(filename)
+            if fn is not None:
+                f = open(fn, 'r')
+                p = f.read()
+                f.close()
+        if p is None:
+            return
+        exec p in self.__dict__
 
-    def getConfigOption(self, key, value):
-        return getattr(self, key, None)
+    def save(self, filename=None):
+        fn = self.getConfigFile(filename)
+        if fn is None:
+            fn = self.getDefaultConfigFile()
+        if fn is not None:
+            f = open(fn, 'w')
+            f.write(repr(self))
+            f.close()
+
+    def __repr__(self):
+        result = []
+        for name, value in self.__dict__.items():
+            if isinstance(value, ConfigSection):
+                value.collect(name, result)
+        return '\n'.join(sorted(result))
+
+    def getConfigFile(self, filename=None):
+        if filename is not None:
+            self.filename = filename
+        if self.filename is None:
+            fn = self.getDefaultConfigFile()
+            if os.path.isfile(fn):
+                self.filename = fn
+        return self.filename
+
+    def getDefaultConfigFile(self):
+        return os.path.join(os.path.expanduser('~'), '.loops.agent.cfg')
 
 
-conf = Configurator()
+class ConfigSection(list):
 
-# this is just for convenience during the development phase,
-# thus we can retrieve the port easily via ``conf.ui.web.port``
-conf.addConfigOption('ui', Configurator())
-conf.ui.addConfigOption('web', Configurator())
-conf.ui.web.addConfigOption('port', 10095)
+    def __getattr__(self, attr):
+        value = ConfigSection()
+        setattr(self, attr, value)
+        return value
+
+    def __getitem__(self, idx):
+        while idx >= len(self):
+            self.append(ConfigSection())
+        return list.__getitem__(self, idx)
+
+    def setdefault(self, attr, value):
+        if attr not in self.__dict__:
+            setattr(self, attr, value)
+            return value
+        return getattr(self, attr)
+
+    def collect(self, ident, result):
+        for idx, element in enumerate(self):
+            element.collect('%s[%i]' % (ident, idx), result)
+        for name, value in self.__dict__.items():
+            if isinstance(value, ConfigSection):
+                value.collect('%s.%s' % (ident, name), result)
+            elif isinstance(value, (str, int)):
+                result.append('%s.%s = %s' % (ident, name, repr(value)))
 
diff --git a/agent/core.py b/agent/core.py
index 9df60ea..2b85374 100644
--- a/agent/core.py
+++ b/agent/core.py
@@ -33,7 +33,7 @@ class Agent(object):
     implements(IAgent)
 
     def __init__(self):
-        configurator = self.configurator = Configurator()
-        configurator.loadConfiguration()
+        config = self.config = Configurator('ui', 'crawl', 'transport')
+        config.load()
         self.scheduler = Scheduler()
 
diff --git a/agent/tests.py b/agent/tests.py
index 01f8ff7..7feff39 100755
--- a/agent/tests.py
+++ b/agent/tests.py
@@ -1,3 +1,4 @@
+#! /usr/bin/env python
 #
 #  Run with ``trial2.4 tests.py`` to execute the twisted unit tests.
 #  Run with ``python tests.py`` to execute the doctests.