init

.venv/lib/python3.8/site-packages/pyflyby/_log.py

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+# pyflyby/_log.py.
+# Copyright (C) 2011, 2012, 2013, 2014, 2015, 2018 Karl Chen.
+# License: MIT http://opensource.org/licenses/MIT
+
+from __future__ import (absolute_import, division, print_function,
+                        with_statement)
+
+from   contextlib               import contextmanager
+import logging
+from   logging                  import Handler, Logger
+import os
+from   six.moves                import builtins
+import sys
+
+
+class _PyflybyHandler(Handler):
+
+    _pre_log_function = None
+    _logged_anything_during_context = False
+
+    _interactive_prefix    = "\033[0m\033[33m[PYFLYBY]\033[0m "
+    _noninteractive_prefix = "[PYFLYBY] "
+
+    def emit(self, record):
+        """
+        Emit a log record.
+        """
+        try:
+            # Call pre-log hook.
+            if self._pre_log_function is not None:
+                if not self._logged_anything_during_context:
+                    self._pre_log_function()
+                    self._logged_anything_during_context = True
+            # Format (currently a no-op).
+            msg = self.format(record)
+            # Add prefix per line.
+            if _is_ipython() or _is_interactive(sys.stderr):
+                prefix = self._interactive_prefix
+            else:
+                prefix = self._noninteractive_prefix
+            msg = ''.join(["%s%s\n" % (prefix, line) for line in msg.splitlines()])
+            # First, flush stdout, to make sure that stdout and stderr don't get
+            # interleaved.  Normally this is automatic, but when stdout is piped,
+            # it can be necessary to force a flush to avoid interleaving.
+            sys.stdout.flush()
+            # Write log message.
+            if sys.stderr.__class__.__module__.startswith("prompt_toolkit"):
+                with _PromptToolkitStdoutProxyRawCtx(sys.stderr):
+                    sys.stderr.write(msg)
+                    sys.stderr.flush()
+            else:
+                sys.stderr.write(msg)
+                # Flush now - we don't want any interleaving of stdout/stderr.
+                sys.stderr.flush()
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except:
+            self.handleError(record)
+
+    @contextmanager
+    def HookCtx(self, pre, post):
+        """
+        Enter a context where:
+          * ``pre`` is called before the first time a log record is emitted
+            during the context, and
+          * ``post`` is called at the end of the context, if any log records
+            were emitted during the context.
+
+        :type pre:
+          ``callable``
+        :param pre:
+          Function to call before the first time something is logged during
+          this context.
+        :type post:
+          ``callable``
+        :param post:
+          Function to call before returning from the context, if anything was
+          logged during the context.
+        """
+        assert self._pre_log_function is None
+        self._pre_log_function = pre
+        try:
+            yield
+        finally:
+            if self._logged_anything_during_context:
+                post()
+                self._logged_anything_during_context = False
+            self._pre_log_function = None
+
+
+def _is_interactive(file):
+    filemod = type(file).__module__
+    if filemod.startswith("IPython.") or filemod.startswith("prompt_toolkit."):
+        # Inside IPython notebook/kernel
+        return True
+    try:
+        fileno = file.fileno()
+    except Exception:
+        return False # dunno
+    return os.isatty(fileno)
+
+
+def _is_ipython():
+    """
+    Returns true if we're currently running inside IPython.
+    """
+    # This currently only works for versions of IPython that are modern enough
+    # to install 'builtins.get_ipython()'.
+    if 'IPython' not in sys.modules:
+        return False
+    if not hasattr(builtins, "get_ipython"):
+        return False
+    ip = builtins.get_ipython()
+    if ip is None:
+        return False
+    return True
+
+
+@contextmanager
+def _PromptToolkitStdoutProxyRawCtx(proxy):
+    """
+    Hack to defeat the "feature" where
+    prompt_toolkit.interface._StdoutProxy(sys.stderr) causes ANSI escape codes
+    to not be written.
+    """
+    # prompt_toolkit replaces sys.stderr with a proxy object.  This proxy
+    # object replaces ESC (\xb1) with '?'.  That breaks our colorization of
+    # the [PYFLYBY] log prefix.  To work around this, we need to temporarily
+    # set _StdoutProxy._raw to True during the write() call.  However, the
+    # write() call actually just stores a lambda to be executed later, and
+    # that lambda references self._raw by reference.  So we can't just set
+    # _raw before we call sys.stderr.write(), since the _raw variable is not
+    # read yet at that point.  We need to hook the internals so that we store
+    # a wrapped lambda which temporarily sets _raw to True.  Yuck, this is so
+    # brittle.  Tested with prompt_toolkit 1.0.15.
+    if not hasattr(type(proxy), '_do') or not hasattr(proxy, '_raw'):
+        yield
+        return
+    MISSING = object()
+    prev = proxy.__dict__.get('_do', MISSING)
+    original_do = proxy._do
+    def wrapped_do_raw(self, func):
+        def wrapped_func():
+            prev_raw = self._raw
+            try:
+                self._raw = True
+                func()
+            finally:
+                self._raw = prev_raw
+        original_do(wrapped_func)
+    try:
+        proxy._do = wrapped_do_raw.__get__(proxy)
+        yield
+    finally:
+        if prev is MISSING:
+            proxy.__dict__.pop('_do', None)
+        else:
+            proxy.__dict__ = prev
+
+
+@contextmanager
+def _NoRegisterLoggerHandlerInHandlerListCtx():
+    """
+    Work around a bug in the ``logging`` module for Python 2.x-3.2.
+
+    The Python stdlib ``logging`` module has a bug where you sometimes get the
+    following warning at exit::
+
+      Exception TypeError: "'NoneType' object is not callable" in <function
+      _removeHandlerRef at 0x10a1b3f50> ignored
+
+    This is caused by shutdown ordering affecting which globals in the logging
+    module are available to the _removeHandlerRef function.
+
+    Python 3.3 fixes this.
+
+    For earlier versions of Python, this context manager works around the
+    issue by avoiding registering a handler in the _handlerList.  This means
+    that we no longer call "flush()" from the atexit callback.  However, that
+    was a no-op anyway, and even if we needed it, we could call it ourselves
+    atexit.
+
+    :see:
+      http://bugs.python.org/issue9501
+    """
+    if not hasattr(logging, "_handlerList"):
+        yield
+        return
+    if sys.version_info >= (3, 3):
+        yield
+        return
+    try:
+        orig_handlerList = logging._handlerList[:]
+        yield
+    finally:
+        logging._handlerList[:] = orig_handlerList
+
+
+
+class PyflybyLogger(Logger):
+
+    _LEVELS = dict( (k, getattr(logging, k))
+                    for k in ['DEBUG', 'INFO', 'WARNING', 'ERROR'] )
+
+    def __init__(self, name, level):
+        Logger.__init__(self, name)
+        with _NoRegisterLoggerHandlerInHandlerListCtx():
+            handler = _PyflybyHandler()
+        self.addHandler(handler)
+        self.set_level(level)
+
+    def set_level(self, level):
+        """
+        Set the pyflyby logger's level to ``level``.
+
+        :type level:
+          ``str``
+        """
+        if isinstance(level, int):
+            level_num = level
+        else:
+            try:
+                level_num = self._LEVELS[level.upper()]
+            except KeyError:
+                raise ValueError("Bad log level %r" % (level,))
+        Logger.setLevel(self, level_num)
+
+    @property
+    def debug_enabled(self):
+        return self.level <= logging.DEBUG
+
+    @property
+    def info_enabled(self):
+        return self.level <= logging.INFO
+
+    def HookCtx(self, pre, post):
+        return self.handlers[0].HookCtx(pre, post)
+
+
+logger = PyflybyLogger('pyflyby', os.getenv("PYFLYBY_LOG_LEVEL") or "INFO")