more logging

src/h2/config.py

@@ -6,6 +6,8 @@
 Objects for controlling the configuration of the HTTP/2 stack.
 """
 
+import sys
+
 
 class _BooleanConfigOption:
     """
@@ -27,7 +29,7 @@ def __set__(self, instance, value):
 
 class DummyLogger:
     """
-    An Logger object that does not actual logging, hence a DummyLogger.
+    A Logger object that does not actual logging, hence a DummyLogger.
 
     For the class the log operation is merely a no-op. The intent is to avoid
     conditionals being sprinkled throughout the h2 code for calls to
@@ -49,6 +51,29 @@ def trace(self, *vargs, **kwargs):
         pass
 
 
+class OutputLogger:
+    """
+    A Logger object that prints to stderr or any other file-like object.
+
+    This class is provided for convinience and not part of the stable API.
+
+    :param file: A file-like object passed to the print function.
+        Defaults to ``sys.stderr``.
+    :param trace: Enables trace-level output. Defaults to ``False``.
+    """
+    def __init__(self, file=sys.stderr, trace=False):
+        super().__init__()
+        self.file = file
+        self.trace = trace
+
+    def debug(self, fmtstr, *args):
+        print(f"h2 (debug): {fmtstr % args}", file=self.file)
+
+    def trace(self, fmtstr, *args):
+        if self.trace:
+            print(f"h2 (trace): {fmtstr % args}", file=self.file)
+
+
 class H2Configuration:
     """
     An object that controls the way a single HTTP/2 connection behaves.

src/h2/connection.py

@@ -1481,6 +1481,7 @@ def _receive_frame(self, frame):
         .. versionchanged:: 2.0.0
            Removed from the public API.
         """
+        self.config.logger.trace("Received frame: %s", repr(frame))
         try:
             # I don't love using __class__ here, maybe reconsider it.
             frames, events = self._frame_dispatch_table[frame.__class__](frame)

src/h2/utilities.py

@@ -203,7 +203,7 @@ def validate_headers(headers, hdr_validation_flags):
     # checking remains somewhat expensive, and attempts should be made wherever
     # possible to reduce the time spent doing them.
     #
-    # For example, we avoid tuple upacking in loops because it represents a
+    # For example, we avoid tuple unpacking in loops because it represents a
     # fixed cost that we don't want to spend, instead indexing into the header
     # tuples.
     headers = _reject_uppercase_header_fields(