hg: Redirect Mercurial stdout/stderr to logging when running as WSGI Any "console" output from Mercurial when Kallithea is running from WSGI should end up in Kallithea's logs. That seems like a nice general feature. This will however also solve another rare but more critical problem: Mercurial is writing to sys.stdout / sys.stderr, using several layers of wrapping. Since Mercurial 5.5 (with https://repo.mercurial-scm.org/hg/rev/8e04607023e5 ), all writes are given a memoryview. Apache httpd mod_wsgi is invoking the WSGI with a custom mod_wsgi.Log injected in sys.stdout / sys.stderr . This logger can however not handle memoryview - https://github.com/GrahamDumpleton/mod_wsgi/issues/863 .