diff hgext/lfs/wireprotolfsserver.py @ 37690:726c4102db9e

lfs: log information about Internal Server Errors reported in the Batch API

Reporting a 500 and then not leaving any traces on the server seems like a
receipe for frustration.  There's similar log writing in hgweb.server.do_POST().
That doesn't write directly to the wsgi.errors object, so it doesn't seem worth
trying to refactor.

It does seem like earlier stack frames are missing for some reason.

--- a/hgext/lfs/wireprotolfsserver.py	Sat Apr 07 12:48:21 2018 -0400
+++ b/hgext/lfs/wireprotolfsserver.py	Fri Apr 13 12:39:54 2018 -0400
@@ -10,6 +10,7 @@
 import datetime
 import errno
 import json
+import traceback
 
 from mercurial.hgweb import (
     common as hgwebcommon,
@@ -63,6 +64,19 @@
     res.headers[b'Content-Type'] = b'text/plain; charset=utf-8'
     res.setbodybytes(b'')
 
+def _logexception(req):
+    """Write information about the current exception to wsgi.errors."""
+    tb = pycompat.sysbytes(traceback.format_exc())
+    errorlog = req.rawenv[r'wsgi.errors']
+
+    uri = b''
+    if req.apppath:
+        uri += req.apppath
+    uri += b'/' + req.dispatchpath
+
+    errorlog.write(b"Exception happened while processing request '%s':\n%s" %
+                   (uri, tb))
+
 def _processbatchrequest(repo, req, res):
     """Handle a request for the Batch API, which is the gateway to granting file
     access.
@@ -179,6 +193,8 @@
             verifies = store.verify(oid)
         except IOError as inst:
             if inst.errno != errno.ENOENT:
+                _logexception(req)
+
                 rsp['error'] = {
                     'code': 500,
                     'message': inst.strerror or 'Internal Server Server'