Re: [Libguestfs] [PATCH nbdkit] python: Turn python exceptions into nbdkit errors properly.

--- configure.ac | 8 +++++++ plugins/python/python.c | 51 +++++++++++++++++++++++++++++++++++++++--- tests/Makefile.am | 1 + tests/python-exception.py | 45 +++++++++++++++++++++++++++++++++++++ tests/test-python-exception.sh | 42 ++++++++++++++++++++++++++++++++++ 5 files changed, 144 insertions(+), 3 deletions(-)

+/* Convert bytes/str/unicode into a string. Caller must free. */ +static char * +python_to_string (PyObject *str) +{ + char *r; + + if (str) { +#ifdef HAVE_PYUNICODE_ASUTF8 + if (PyUnicode_Check (str)) { + r = PyUnicode_AsUTF8 (str); + r = strdup (r); + return r;

static int check_python_failure (const char *callback) { if (PyErr_Occurred ()) { - nbdkit_error ("%s: callback failed: %s", script, callback); - /* How to turn this into a string? XXX */ - PyErr_Print (); + PyObject *type, *error, *traceback, *error_str; + char *error_cstr; + + /* Convert the Python exception to a string. + * https://stackoverflow.com/a/1418703 + * But forget about the traceback, it's very hard to print. + * https://stackoverflow.com/q/1796510 + */ + PyErr_Fetch (&type, &error, &traceback); + PyErr_NormalizeException (&type, &error, &traceback); + error_str = PyObject_Str (error); + error_cstr = python_to_string (error_str); + nbdkit_error ("%s: %s: error: %s", + script, callback, error_cstr ? : "<unknown>");