RAHHH

backend/lib/python3.12/site-packages/twisted/logger/_util.py

@@ -0,0 +1,51 @@
+# -*- test-case-name: twisted.logger.test.test_util -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Logging utilities.
+"""
+
+from typing import List
+
+from ._interfaces import LogTrace
+from ._logger import Logger
+
+
+def formatTrace(trace: LogTrace) -> str:
+    """
+    Format a trace (that is, the contents of the C{log_trace} key of a log
+    event) as a visual indication of the message's propagation through various
+    observers.
+
+    @param trace: the contents of the C{log_trace} key from an event.
+
+    @return: A multi-line string with indentation and arrows indicating the
+        flow of the message through various observers.
+    """
+
+    def formatWithName(obj: object) -> str:
+        if hasattr(obj, "name"):
+            return f"{obj} ({obj.name})"
+        else:
+            return f"{obj}"
+
+    result = []
+    lineage: List[Logger] = []
+
+    for parent, child in trace:
+        if not lineage or lineage[-1] is not parent:
+            if parent in lineage:
+                while lineage[-1] is not parent:
+                    lineage.pop()
+
+            else:
+                if not lineage:
+                    result.append(f"{formatWithName(parent)}\n")
+
+                lineage.append(parent)
+
+        result.append("  " * len(lineage))
+        result.append(f"-> {formatWithName(child)}\n")
+
+    return "".join(result)