Fix the log levels mapping

The libssh provides the most verbose logging with SSH_LOG_TRACE, which
was not mapped to any of the standard values so the users are unable
to get full debug logs. These are critical for libssh developers to be
able to investigate issues.

Signed-off-by: Jakub Jelen <[email protected]>

Author: Jakuje

src/pylibsshext/includes/callbacks.pxd

@@ -127,3 +127,10 @@ cdef extern from "libssh/callbacks.h":
     ctypedef ssh_channel_callbacks_struct * ssh_channel_callbacks
 
     int ssh_set_channel_callbacks(ssh_channel channel, ssh_channel_callbacks cb)
+
+    ctypedef void(*ssh_logging_callback)(
+        int priority,
+        const char *function,
+        const char *buffer,
+        void *userdata)
+    int ssh_set_log_callback(ssh_logging_callback cb)

src/pylibsshext/logging.pxd

@@ -0,0 +1,23 @@
+# distutils: libraries = ssh
+#
+# This file is part of the pylibssh library
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, see file LICENSE.rst in this
+# repository.
+#
+from pylibsshext.includes cimport callbacks, libssh
+
+
+cdef class Logging:
+    pass

src/pylibsshext/logging.pyx

@@ -0,0 +1,101 @@
+#
+# This file is part of the pylibssh library
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, see file LICENSE.rst in this
+# repository.
+
+import logging
+
+from pylibsshext.errors cimport LibsshSessionException
+
+
+ANSIBLE_PYLIBSSH_TRACE = 5
+
+LOG_MAP = {
+    logging.NOTSET: libssh.SSH_LOG_NONE,
+    ANSIBLE_PYLIBSSH_TRACE: libssh.SSH_LOG_TRACE,
+    logging.DEBUG: libssh.SSH_LOG_DEBUG,
+    logging.INFO: libssh.SSH_LOG_INFO,
+    logging.WARNING: libssh.SSH_LOG_WARN,
+    logging.ERROR: libssh.SSH_LOG_WARN,
+    logging.CRITICAL: libssh.SSH_LOG_WARN
+}
+
+LOG_MAP_REV = {
+    libssh.SSH_LOG_NONE: logging.NOTSET,
+    libssh.SSH_LOG_TRACE: ANSIBLE_PYLIBSSH_TRACE,
+    libssh.SSH_LOG_DEBUG: logging.DEBUG,
+    libssh.SSH_LOG_INFO: logging.INFO,
+    libssh.SSH_LOG_WARN: logging.WARNING,
+}
+
+logger = logging.getLogger("libssh")
+
+
+def add_trace_log_level():
+    level_num = ANSIBLE_PYLIBSSH_TRACE
+    level_name = "TRACE"
+    method_name = level_name.lower()
+    logger_class = logging.getLoggerClass()
+
+    if hasattr(logging, level_name):
+        raise AttributeError('{} already defined in logging module'.format(level_name))
+    if hasattr(logging, method_name):
+        raise AttributeError('{} already defined in logging module'.format(method_name))
+    if hasattr(logger_class, method_name):
+        raise AttributeError('{} already defined in logger class'.format(method_name))
+
+    def logForLevel(self, message, *args, **kwargs):
+        if self.isEnabledFor(level_num):
+            self._log(level_num, message, args, **kwargs)
+
+    def logToRoot(message, *args, **kwargs):
+        logging.log(level_num, message, *args, **kwargs)
+
+    logging.addLevelName(level_num, level_name)
+    setattr(logging, level_name, level_num)
+    setattr(logging, method_name, logToRoot)
+    setattr(logger_class, method_name, logForLevel)
+
+
+cdef void _pylibssh_log_wrapper(int priority,
+                                const char *function,
+                                const char *buffer,
+                                void *userdata) noexcept nogil:
+    with gil:
+        log_level = LOG_MAP_REV[priority]
+        logger.log(log_level, f"{buffer}")
+
+
+def set_log_callback():
+    callbacks.ssh_set_log_callback(_pylibssh_log_wrapper)
+
+
+def logging_init():
+    try:
+        add_trace_log_level()
+    except AttributeError:
+        pass
+    set_log_callback()
+
+
+def set_level(level):
+    logging_init()
+    if level in LOG_MAP.keys():
+        rc = libssh.ssh_set_log_level(LOG_MAP[level])
+        if rc != libssh.SSH_OK:
+            raise LibsshSessionException("Failed to set log level [%d] with error [%d]" % (level, rc))
+        logger.setLevel(level)
+    else:
+        raise LibsshSessionException("Invalid log level [%d]" % level)

src/pylibsshext/session.pyx

@@ -15,12 +15,14 @@
 # License along with this library; if not, see file LICENSE.rst in this
 # repository.
 import inspect
-import logging
 
 from cpython.bytes cimport PyBytes_AS_STRING
 
 from pylibsshext.channel import Channel
+
 from pylibsshext.errors cimport LibsshSessionException
+
+from pylibsshext.logging import set_level
 from pylibsshext.scp import SCP
 from pylibsshext.sftp import SFTP
 
@@ -44,15 +46,6 @@ OPTS_DIR_MAP = {
     "add_identity": libssh.SSH_OPTIONS_ADD_IDENTITY,
 }
 
-LOG_MAP = {
-    logging.NOTSET: libssh.SSH_LOG_NONE,
-    logging.DEBUG: libssh.SSH_LOG_DEBUG,
-    logging.INFO: libssh.SSH_LOG_INFO,
-    logging.WARNING: libssh.SSH_LOG_WARN,
-    logging.ERROR: libssh.SSH_LOG_WARN,
-    logging.CRITICAL: libssh.SSH_LOG_TRACE
-}
-
 KNOW_HOST_MSG_MAP = {
     libssh.SSH_KNOWN_HOSTS_CHANGED: "Host key for server has changed: ",
     libssh.SSH_KNOWN_HOSTS_OTHER: "Host key type for server has changed: ",
@@ -334,6 +327,7 @@ cdef class Session(object):
         if rc != libssh.SSH_OK:
             return
 
+        # FIXME The SHA1 hashes are non-standard -- the most common these days are SHA256 hashes for fingerprints
         rc = libssh.ssh_get_publickey_hash(srv_pubkey, libssh.SSH_PUBLICKEY_HASH_SHA1, &hash, &hash_len)
 
         cdef libssh.ssh_keytypes_e key_type = libssh.ssh_key_type(srv_pubkey)
@@ -520,12 +514,7 @@ cdef class Session(object):
         return SFTP(self)
 
     def set_log_level(self, level):
-        if level in LOG_MAP.keys():
-            rc = libssh.ssh_set_log_level(LOG_MAP[level])
-            if rc != libssh.SSH_OK:
-                raise LibsshSessionException("Failed to set log level [%d] with error [%d]" % (level, rc))
-        else:
-            raise LibsshSessionException("Invalid log level [%d]" % level)
+        set_level(level)
 
     def close(self):
         if self._libssh_session is not NULL: