Adding pp_lib/obj.py

diff --git a/pp_lib/obj.py b/pp_lib/obj.py
new file mode 100644 (file)
index 0000000..7da42a9
--- /dev/null
+++ b/pp_lib/obj.py
@@ -0,0 +1,332 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+@author: Frank Brehm
+@contact: frank.brehm@pixelpark.com
+@copyright: © 2010 - 2017 by Frank Brehm, Publicies Pixelpark GmbH, Berlin
+"""
+
+# Standard modules
+import sys
+import os
+import logging
+import datetime
+import traceback
+
+# Third party modules
+import six
+
+# Own modules
+from pp_tools import pp
+
+from pp_tools.errors import PpError
+
+
+__version__ = '0.1.1'
+
+LOG = logging.getLogger(__name__)
+
+
+# =============================================================================
+class PpBaseObjectError(PpError):
+    """
+    Base error class useable by all descendand objects.
+    """
+
+    pass
+
+
+# =============================================================================
+class PpBaseObject(object):
+    """
+    Base class for all objects.
+    """
+
+    # -------------------------------------------------------------------------
+    def __init__(
+        self, appname=None, verbose=0, version=__version__, base_dir=None,
+            initialized=False):
+        """
+        Initialisation of the base object.
+
+        Raises an exception on a uncoverable error.
+        """
+
+        self._appname = None
+        """
+        @ivar: name of the current running application
+        @type: str
+        """
+        if appname:
+            v = str(appname).strip()
+            if v:
+                self._appname = v
+        if not self._appname:
+            self._appname = os.path.basename(sys.argv[0])
+
+        self._version = version
+        """
+        @ivar: version string of the current object or application
+        @type: str
+        """
+
+        self._verbose = int(verbose)
+        """
+        @ivar: verbosity level (0 - 9)
+        @type: int
+        """
+        if self._verbose < 0:
+            msg = _("Wrong verbose level %r, must be >= 0") % (verbose)
+            raise ValueError(msg)
+
+        self._initialized = False
+        """
+        @ivar: initialisation of this object is complete
+               after __init__() of this object
+        @type: bool
+        """
+
+        self._base_dir = base_dir
+        """
+        @ivar: base directory used for different purposes, must be an existent
+               directory. Defaults to directory of current script daemon.py.
+        @type: str
+        """
+        if base_dir:
+            if not os.path.exists(base_dir):
+                msg = _("Base directory %r does not exists.") % (base_dir)
+                self.handle_error(msg)
+                self._base_dir = None
+            elif not os.path.isdir(base_dir):
+                msg = _("Base directory %r is not a directory.") % (base_dir)
+                self.handle_error(msg)
+                self._base_dir = None
+        if not self._base_dir:
+            self._base_dir = os.path.dirname(os.path.abspath(sys.argv[0]))
+
+        self._initialized = bool(initialized)
+
+    # -----------------------------------------------------------
+    @property
+    def appname(self):
+        """The name of the current running application."""
+        return self._appname
+
+    @appname.setter
+    def appname(self, value):
+        if value:
+            v = str(value).strip()
+            if v:
+                self._appname = v
+
+    # -----------------------------------------------------------
+    @property
+    def version(self):
+        """The version string of the current object or application."""
+        return self._version
+
+    # -----------------------------------------------------------
+    @property
+    def verbose(self):
+        """The verbosity level."""
+        return getattr(self, '_verbose', 0)
+
+    @verbose.setter
+    def verbose(self, value):
+        v = int(value)
+        if v >= 0:
+            self._verbose = v
+        else:
+            log.warn(_("Wrong verbose level %r, must be >= 0"), value)
+
+    # -----------------------------------------------------------
+    @property
+    def initialized(self):
+        """The initialisation of this object is complete."""
+        return getattr(self, '_initialized', False)
+
+    @initialized.setter
+    def initialized(self, value):
+        self._initialized = bool(value)
+
+    # -----------------------------------------------------------
+    @property
+    def base_dir(self):
+        """The base directory used for different purposes."""
+        return self._base_dir
+
+    @base_dir.setter
+    def base_dir(self, value):
+        if value.startswith('~'):
+            value = os.path.expanduser(value)
+        if not os.path.exists(value):
+            msg = _("Base directory %r does not exists.") % (value)
+            log.error(msg)
+        elif not os.path.isdir(value):
+            msg = _("Base directory %r is not a directory.") % (value)
+            log.error(msg)
+        else:
+            self._base_dir = value
+
+    # -------------------------------------------------------------------------
+    def __str__(self):
+        """
+        Typecasting function for translating object structure
+        into a string
+
+        @return: structure as string
+        @rtype:  str
+        """
+
+        return pp(self.as_dict(short=True))
+
+    # -------------------------------------------------------------------------
+    def __repr__(self):
+        """Typecasting into a string for reproduction."""
+
+        out = "<%s(" % (self.__class__.__name__)
+
+        fields = []
+        fields.append("appname=%r" % (self.appname))
+        fields.append("verbose=%r" % (self.verbose))
+        fields.append("version=%r" % (self.version))
+        fields.append("base_dir=%r" % (self.base_dir))
+        fields.append("initialized=%r" % (self.initialized))
+
+        out += ", ".join(fields) + ")>"
+        return out
+
+    # -------------------------------------------------------------------------
+    def as_dict(self, short=False):
+        """
+        Transforms the elements of the object into a dict
+
+        @param short: don't include local properties in resulting dict.
+        @type short: bool
+
+        @return: structure as dict
+        @rtype:  dict
+        """
+
+        res = self.__dict__
+        res = {}
+        for key in self.__dict__:
+            if short and key.startswith('_') and not key.startswith('__'):
+                continue
+            val = self.__dict__[key]
+            if isinstance(val, PbBaseObject):
+                res[key] = val.as_dict(short=short)
+            else:
+                res[key] = val
+        res['__class_name__'] = self.__class__.__name__
+        res['appname'] = self.appname
+        res['version'] = self.version
+        res['verbose'] = self.verbose
+        res['initialized'] = self.initialized
+        res['base_dir'] = self.base_dir
+
+        return res
+
+    # -------------------------------------------------------------------------
+    def handle_error(
+            self, error_message=None, exception_name=None, do_traceback=False):
+        """
+        Handle an error gracefully.
+
+        Print a traceback and continue.
+
+        @param error_message: the error message to display
+        @type error_message: str
+        @param exception_name: name of the exception class
+        @type exception_name: str
+        @param do_traceback: allways show a traceback
+        @type do_traceback: bool
+
+        """
+
+        msg = 'Exception happened: '
+        if exception_name is not None:
+            exception_name = exception_name.strip()
+            if exception_name:
+                msg = exception_name + ': '
+            else:
+                msg = ''
+        if error_message:
+            msg += str(error_message)
+        else:
+            msg += _('undefined error.')
+
+        root_log = logging.getLogger()
+        has_handlers = False
+        if root_log.handlers:
+            has_handlers = True
+
+        if has_handlers:
+            log.error(msg)
+            if do_traceback:
+                log.error(traceback.format_exc())
+
+        if not has_handlers:
+            curdate = datetime.datetime.now()
+            curdate_str = "[" + curdate.isoformat(' ') + "]: "
+            msg = curdate_str + msg + "\n"
+            if hasattr(sys.stderr, 'buffer'):
+                sys.stderr.buffer.write(msg)
+            else:
+                sys.stderr.write(msg)
+            if do_traceback:
+                traceback.print_exc()
+
+        return
+
+    # -------------------------------------------------------------------------
+    def handle_info(self, message, info_name=None):
+        """
+        Shows an information. This happens both to STDERR and to all
+        initialized log handlers.
+
+        @param message: the info message to display
+        @type message: str
+        @param info_name: Title of information
+        @type info_name: str
+
+        """
+
+        msg = ''
+        if info_name is not None:
+            info_name = info_name.strip()
+            if info_name:
+                msg = info_name + ': '
+        msg += str(message).strip()
+
+        root_log = logging.getLogger()
+        has_handlers = False
+        if root_log.handlers:
+            has_handlers = True
+
+        if has_handlers:
+            log.info(msg)
+
+        if not has_handlers:
+            curdate = datetime.datetime.now()
+            curdate_str = "[" + curdate.isoformat(' ') + "]: "
+            msg = curdate_str + msg + "\n"
+            if hasattr(sys.stderr, 'buffer'):
+                sys.stderr.buffer.write(msg)
+            else:
+                sys.stderr.write(msg)
+
+        return
+
+# =============================================================================
+
+if __name__ == "__main__":
+
+    pass
+
+# =============================================================================
+
+# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+
+
+