SF patch #761519: Fixes for bugs 760703 and 757821

rhettinger · rhettinger · commit 6f3eaa67e51e · 2003-06-27T21:43:39.000Z
SF bug #760703: SocketHandler and LogRecord don't work well together
SF bug #757821: logging module docs

Applied Vinay Sajip's patch with a few minor fixups and a NEWS item.

Patched __init__.py - added new function
makeLogRecord (for bug report 760703).

Patched handlers.py - updated some docstrings and
deleted some old commented-out code.

Patched test_logging.py to make use of makeLogRecord.

Patched liblogging.tex to fill documentation gaps (both
760703 and bug 757821).
diff --git a/Doc/lib/liblogging.tex b/Doc/lib/liblogging.tex
@@ -52,7 +52,7 @@ \section{\module{logging} ---
 \class{Handler} class. Handlers are responsible for ensuring that a logged
 message (in the form of a \class{LogRecord}) ends up in a particular
 location (or set of locations) which is useful for the target audience for
-that message (e.g. end users, support desk staff, system administrators,
+that message (such as end users, support desk staff, system administrators,
 developers). Handlers are passed \class{LogRecord} instances intended for
 particular destinations. Each logger can have zero, one or more handlers
 associated with it (via the \method{addHandler} method of \class{Logger}).
@@ -204,6 +204,13 @@ \section{\module{logging} ---
 returned.
 \end{funcdesc}
 
+\begin{funcdesc}{makeLogRecord}{attrdict}
+Creates and returns a new \class{LogRecord} instance whose attributes are
+defined by \var{attrdict}. This function is useful for taking a pickled
+\class{LogRecord} attribute dictionary, sent over a socket, and reconstituting
+it as a \class{LogRecord} instance at the receiving end.
+\end{funcdesc}
+
 \begin{funcdesc}{basicConfig}{}
 Does basic configuration for the logging system by creating a
 \class{StreamHandler} with a default \class{Formatter} and adding it to
@@ -266,7 +273,7 @@ \subsection{Logger Objects}
 Indicates the effective level for this logger. If a value other than
 \constant{NOTSET} has been set using \method{setLevel()}, it is returned.
 Otherwise, the hierarchy is traversed towards the root until a value
-other than \constant{NOTSET} is found,and that value is returned.
+other than \constant{NOTSET} is found, and that value is returned.
 \end{methoddesc}
 
 \begin{methoddesc}{debug}{msg\optional{, *args\optional{, **kwargs}}}
@@ -535,9 +542,11 @@ \subsubsection{SocketHandler}
 \end{methoddesc}
 
 \begin{methoddesc}{emit}{}
-Pickles the record and writes it to the socket in binary format.
-If there is an error with the socket, silently drops the packet.
-If the connection was previously lost, re-establishes the connection.
+Pickles the record's attribute dictionary and writes it to the socket in
+binary format. If there is an error with the socket, silently drops the
+packet. If the connection was previously lost, re-establishes the connection.
+To unpickle the record at the receiving end into a LogRecord, use the
+\function{makeLogRecord} function.
 \end{methoddesc}
 
 \begin{methoddesc}{handleError}{}
@@ -553,8 +562,8 @@ \subsubsection{SocketHandler}
 \end{methoddesc}
 
 \begin{methoddesc}{makePickle}{record}
-Pickles the record in binary format with a length prefix, and returns
-it ready for transmission across the socket.
+Pickles the record's attribute dictionary in binary format with a length
+prefix, and returns it ready for transmission across the socket.
 \end{methoddesc}
 
 \begin{methoddesc}{send}{packet}
@@ -574,8 +583,11 @@ \subsubsection{DatagramHandler}
 \end{classdesc}
 
 \begin{methoddesc}{emit}{}
-Pickles the record and writes it to the socket in binary format.
-If there is an error with the socket, silently drops the packet.
+Pickles the record's attribute dictionary and writes it to the socket in
+binary format. If there is an error with the socket, silently drops the
+packet.
+To unpickle the record at the receiving end into a LogRecord, use the
+\function{makeLogRecord} function.
 \end{methoddesc}
 
 \begin{methoddesc}{makeSocket}{}
@@ -584,8 +596,7 @@ \subsubsection{DatagramHandler}
 \end{methoddesc}
 
 \begin{methoddesc}{send}{s}
-Send a pickled string to a socket. This function allows for
-partial sends which can happen when the network is busy.
+Send a pickled string to a socket.
 \end{methoddesc}
 
 \subsubsection{SysLogHandler}
@@ -789,8 +800,8 @@ \subsection{Formatter Objects}
 supplied, the default value of "\%s(message)\\n" is used.
 
 A Formatter can be initialized with a format string which makes use of
-knowledge of the \class{LogRecord} attributes - e.g. the default value
-mentioned above makes use of the fact that the user's message and
+knowledge of the \class{LogRecord} attributes - such as the default value
+mentioned above making use of the fact that the user's message and
 arguments are pre- formatted into a LogRecord's \var{message}
 attribute. Currently, the useful attributes in a LogRecord are
 described by:
@@ -916,7 +927,11 @@ \subsection{Configuration}
 
 \subsubsection{Configuration functions}
 
-The following functions allow the logging module to be configured.
+The following functions allow the logging module to be configured. Before
+they can be used, you must import \module{logging.config}. Their use is optional -
+you can configure the logging module entirely by making calls to the main
+API (defined in \module{logging} itself) and defining handlers which are declared
+either in \module{logging} or \module{logging.handlers}.
 
 \begin{funcdesc}{fileConfig}{fname\optional{, defaults}}
 Reads the logging configuration from a ConfigParser-format file named
@@ -1013,7 +1028,7 @@ \subsubsection{Configuration file format}
 higher up the logger hierarchy from this logger, or 0 to indicate that
 messages are \strong{not} propagated to handlers up the hierarchy. The
 \code{qualname} entry is the hierarchical channel name of the logger,
-i.e. the name used by the application to get the logger.
+for example, the name used by the application to get the logger.
 
 Sections which specify handler configuration are exemplified by the
 following.
diff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
@@ -36,8 +36,8 @@
 
 __author__  = "Vinay Sajip <vinay_sajip@red-dove.com>"
 __status__  = "beta"
-__version__ = "0.4.8"
-__date__    = "22 April 2003"
+__version__ = "0.4.8.1"
+__date__    = "26 June 2003"
 
 #---------------------------------------------------------------------------
 #   Miscellaneous module data
@@ -233,6 +233,17 @@ def getMessage(self):
             msg = msg % self.args
         return msg
 
+def makeLogRecord(dict):
+    """
+    Make a LogRecord whose attributes are defined by the specified dictionary,
+    This function is useful for converting a logging event received over
+    a socket connection (which is sent as a dictionary) into a LogRecord
+    instance.
+    """
+    rv = LogRecord(None, None, "", 0, "", (), None)
+    rv.__dict__.update(dict)
+    return rv
+
 #---------------------------------------------------------------------------
 #   Formatter classes and functions
 #---------------------------------------------------------------------------
diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py
@@ -111,8 +111,12 @@ class SocketHandler(logging.Handler):
     A handler class which writes logging records, in pickle format, to
     a streaming socket. The socket is kept open across logging calls.
     If the peer resets it, an attempt is made to reconnect on the next call.
-    Note that the very simple wire protocol used means that packet sizes
-    are expected to be encodable within 16 bits (i.e. < 32767 bytes).
+    The pickle which is sent is that of the LogRecord's attribute dictionary
+    (__dict__), so that the receiver does not need to have the logging module
+    installed in order to process the logging event.
+
+    To unpickle the record at the receiving end into a LogRecord, use the
+    makeLogRecord function.
     """
 
     def __init__(self, host, port):
@@ -208,9 +212,12 @@ def close(self):
 class DatagramHandler(SocketHandler):
     """
     A handler class which writes logging records, in pickle format, to
-    a datagram socket. Note that the very simple wire protocol used means
-    that packet sizes are expected to be encodable within 16 bits
-    (i.e. < 32767 bytes).
+    a datagram socket.  The pickle which is sent is that of the LogRecord's
+    attribute dictionary (__dict__), so that the receiver does not need to
+    have the logging module installed in order to process the logging event.
+
+    To unpickle the record at the receiving end into a LogRecord, use the
+    makeLogRecord function.
 
     """
     def __init__(self, host, port):
@@ -236,14 +243,6 @@ def send(self, s):
         when the network is busy - UDP does not guarantee delivery and
         can deliver packets out of sequence.
         """
-        #old code
-        #sentsofar = 0
-        #left = len(s)
-        #addr = (self.host, self.port)
-        #while left > 0:
-        #    sent = self.sock.sendto(s[sentsofar:], addr)
-        #    sentsofar = sentsofar + sent
-        #    left = left - sent
         self.sock.sendto(s, (self.host, self.port))
 
 class SysLogHandler(logging.Handler):
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
@@ -70,8 +70,7 @@ def handle(self):
                 while len(chunk) < slen:
                     chunk = chunk + self.connection.recv(slen - len(chunk))
                 obj = self.unPickle(chunk)
-                record = logging.LogRecord(None, None, "", 0, "", (), None)
-                record.__dict__.update(obj)
+                record = logging.makeLogRecord(obj)
                 self.handleLogRecord(record)
             except:
                 raise
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -83,6 +83,9 @@ Extension modules
 Library
 -------
 
+- The logging module now has a new function, makeLogRecord() making
+  LogHandler easier to interact with DatagramHandler and SocketHandler.
+
 - For compatibility with doctests created before 2.3, if an expected
   output block consists solely of "1" and the actual output block
   consists solely of "True", it's accepted as a match; similarly
