Request log: a hook's secret is masked in uvicorn's lines and the tunnel connector's failure line

backend/fluksio/main.py

@@ -66,26 +66,35 @@ logger = logging.getLogger(__name__)
 #: worker's `?token=`, the pairing poll's `?secret=`.
 _CREDENTIAL_IN_QUERY = re.compile(r"([?&](?:[\w-]*token|[\w-]*secret|ticket)=)[^&\s]+")
 
+#: A hook's secret, the last segment of `/hooks/<flow>/<path>/<secret>`. A hook
+#: without one loses its last path segment from the log too, since the log
+#: cannot tell which hooks carry a secret.
+_SECRET_IN_HOOK_PATH = re.compile(r"(/hooks/[^/\s?]+/(?:[^/\s?]*/)*)[^/\s?]+")
+
+
+def _redact(text: str) -> str:
+    return _SECRET_IN_HOOK_PATH.sub(r"\1***", _CREDENTIAL_IN_QUERY.sub(r"\1***", text))
+
 
 class _RedactTokens(logging.Filter):
-    """Keep query-string credentials out of uvicorn's request lines.
+    """Keep credentials out of request lines, from the query string or the path.
 
-    uvicorn logs each request and websocket handshake with its query string,
-    and the live socket, a worker's attach and a device polling for its
-    pairing carry their credential there.
+    uvicorn logs each request and websocket handshake with its URL, and the
+    live socket, a worker's attach and a device polling for its pairing carry
+    their credential in the query, a webhook or served socket in the path.
     """
 
     def filter(self, record: logging.LogRecord) -> bool:
         if isinstance(record.args, tuple):
             record.args = tuple(
-                _CREDENTIAL_IN_QUERY.sub(r"\1***", arg) if isinstance(arg, str) else arg
-                for arg in record.args
+                _redact(arg) if isinstance(arg, str) else arg for arg in record.args
             )
         return True
 
 
-# The handshake lines go to `uvicorn.error`, the request lines to `uvicorn.access`.
-for _name in ("uvicorn.access", "uvicorn.error"):
+# The handshake lines go to `uvicorn.error`, the request lines to `uvicorn.access`,
+# and the tunnel connector names the path of a call it could not proxy.
+for _name in ("uvicorn.access", "uvicorn.error", "fluksio.cloud.connector"):
     logging.getLogger(_name).addFilter(_RedactTokens())
 
 

backend/tests/test_access_log.py

@@ -1,4 +1,4 @@
-"""A credential in a query string stays out of uvicorn's request lines."""
+"""A credential in a query string or a hook's path stays out of uvicorn's request lines."""
 
 import logging
 
@@ -52,3 +52,29 @@ def test_the_pairing_secret_is_not_logged() -> None:
     assert [record.getMessage() for record in records] == [
         '192.0.2.1:0 - "GET /api/v1/devices/pair/ABCD2345?secret=*** HTTP/1.1" 202'
     ]
+
+
+def test_a_hooks_secret_is_not_logged() -> None:
+    records: list[logging.LogRecord] = []
+    handler = logging.Handler()
+    handler.emit = records.append  # type: ignore[method-assign]
+    log = logging.getLogger("uvicorn.access")
+    level = log.level
+    log.addHandler(handler)
+    log.setLevel(logging.INFO)
+    try:
+        for path in (
+            "/hooks/home/tick/s3cr3t",
+            "/hooks/home/a/b/s3cr3t?x=1",
+            "/hooks/home//s3cr3t",
+        ):
+            log.info('%s - "%s %s HTTP/%s" %d', "192.0.2.1:0", "POST", path, "1.1", 202)
+    finally:
+        log.removeHandler(handler)
+        log.setLevel(level)
+
+    assert [record.getMessage() for record in records] == [
+        '192.0.2.1:0 - "POST /hooks/home/tick/*** HTTP/1.1" 202',
+        '192.0.2.1:0 - "POST /hooks/home/a/b/***?x=1 HTTP/1.1" 202',
+        '192.0.2.1:0 - "POST /hooks/home//*** HTTP/1.1" 202',
+    ]

docs/reference/node-types.md

@@ -83,6 +83,10 @@ publishes nothing.
     Through the [portal](../interface/portal.md#hooks-and-agents-through-the-portal)
     a webhook or served socket answers only with a secret.
 
+The secret is part of the URL of a webhook or a served socket. The engine's own
+request log prints it as `***` (and the last path segment of a hook without
+one), while a reverse proxy in front of the engine logs the path as it sees it.
+
 ### WebSocket
 
 **`websocket`** — listen on a socket, or send to it, as a client or a server.