Add basic debugging capabilities

If debug is set to True, then custodia's own Exception handlers will
print a stack trace to standard output to aid debugging.

Signed-off-by: Simo Sorce <simo@redhat.com>

7 files changed, 63 insertions, 18 deletions

diff --git a/custodia.conf b/custodia.conf
index 1f9dff9..c3c56a5 100644
--- a/custodia.conf
+++ b/custodia.conf
@@ -1,5 +1,6 @@
 [global]
 server_version = "Secret/0.0.7"
+debug = True
 
 #[auth:simple]
 #handler = custodia.httpd.authenticators.SimpleCredsAuth
diff --git a/custodia/custodia b/custodia/custodia
index 0fd621b..0aa7986 100755
--- a/custodia/custodia
+++ b/custodia/custodia
@@ -7,6 +7,7 @@ try:
 except ImportError:
     from configparser import RawConfigParser
 from custodia.httpd.server import LocalHTTPServer
+from custodia import log
 import importlib
 import os
 import six
@@ -103,6 +104,8 @@ def parse_config(cfgfile):
 if __name__ == '__main__':
     cfgfile = source_config()
     config = parse_config(cfgfile)
+    if config.get('debug') == 'True':
+        log.DEBUG = True
 
     if 'server_socket' in config:
         address = config['server_socket']
diff --git a/custodia/httpd/server.py b/custodia/httpd/server.py
index dc88aef..240e3b6 100644
--- a/custodia/httpd/server.py
+++ b/custodia/httpd/server.py
@@ -10,14 +10,13 @@ except ImportError:
     from http.server import BaseHTTPRequestHandler
     from socketserver import ForkingMixIn, UnixStreamServer
     from urllib.parse import urlparse, parse_qs
-import io
+from custodia.log import stacktrace
+from custodia.log import debug as log_debug
 import os
 import shutil
 import six
 import socket
 import struct
-import sys
-import traceback
 
 SO_PEERCRED = 17
 MAX_REQUEST_SIZE = 10*1024*1024  # For now limit body to 10MiB
@@ -28,15 +27,9 @@ class HTTPError(Exception):
     def __init__(self, code=None, message=None):
         self.code = code if code is not None else 500
         self.mesg = message
-        super(HTTPError, self).__init__('%d: %s' % (self.code, self.mesg))
-
-
-def stacktrace():
-    with io.BytesIO() as f:
-        _, _, tb = sys.exc_info()
-        traceback.print_tb(tb, None, file=f)
-        del tb
-        return f.getvalue()
+        errstring = '%d: %s' % (self.code, self.mesg)
+        log_debug(errstring)
+        super(HTTPError, self).__init__(errstring)
 
 
 class ForkingLocalHTTPServer(ForkingMixIn, UnixStreamServer):
diff --git a/custodia/log.py b/custodia/log.py
new file mode 100644
index 0000000..12a6ba7
--- /dev/null
+++ b/custodia/log.py
@@ -0,0 +1,31 @@
+# Copyright (C) 2015  Custodia Project Contributors - see LICENSE file
+
+import io
+import sys
+import traceback
+import time
+
+
+DEBUG = False
+
+
+def stacktrace():
+    with io.BytesIO() as f:
+        _, _, tb = sys.exc_info()
+        traceback.print_tb(tb, None, file=f)
+        del tb
+        return f.getvalue()
+
+
+def error(msg, head=None):
+    if head is not None:
+        t = time.gmtime(time.time())
+        head = '%04d/%02d/%02d %02d:%02d:%02d' % (
+            t[0], t[1], t[2], t[3], t[4], t[5])
+    sys.stderr.write('[%s] %s\n' % (head, msg))
+
+
+def debug(msg):
+    if DEBUG:
+        error(msg, 'DEBUG')
+        sys.stderr.write(stacktrace())
diff --git a/custodia/message/common.py b/custodia/message/common.py
index 25ce4e7..c538a57 100644
--- a/custodia/message/common.py
+++ b/custodia/message/common.py
@@ -1,5 +1,7 @@
 # Copyright (C) 2015  Custodia Project Contributors - see LICENSE file
 
+from custodia import log
+
 
 class InvalidMessage(Exception):
     """Invalid Message.
@@ -7,7 +9,9 @@ class InvalidMessage(Exception):
     This exception is raised when a message cannot be parsed
     or validated.
     """
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(InvalidMessage, self).__init__(message)
 
 
 class UnknownMessageType(Exception):
@@ -16,7 +20,9 @@ class UnknownMessageType(Exception):
     This exception is raised when a message is of an unknown
     type.
     """
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(UnknownMessageType, self).__init__(message)
 
 
 class UnallowedMessage(Exception):
@@ -25,7 +31,9 @@ class UnallowedMessage(Exception):
     This exception is raise when the message type is know but
     is not allowed.
     """
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(UnallowedMessage, self).__init__(message)
 
 
 class MessageHandler(object):
diff --git a/custodia/message/kem.py b/custodia/message/kem.py
index 3d15e2f..343cb90 100644
--- a/custodia/message/kem.py
+++ b/custodia/message/kem.py
@@ -3,6 +3,7 @@
 from custodia.httpd.authorizers import SimplePathAuthz
 from custodia.message.common import InvalidMessage
 from custodia.message.common import MessageHandler
+from custodia import log
 from jwcrypto.common import json_decode
 from jwcrypto.common import json_encode
 from jwcrypto.jwe import JWE
@@ -19,7 +20,9 @@ KEY_USAGE_MAP = {KEY_USAGE_SIG: 'sig', KEY_USAGE_ENC: 'enc'}
 
 
 class UnknownPublicKey(Exception):
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(UnknownPublicKey, self).__init__(message)
 
 
 class KEMKeysStore(SimplePathAuthz):
diff --git a/custodia/store/interface.py b/custodia/store/interface.py
index 5a7db93..11c2e36 100644
--- a/custodia/store/interface.py
+++ b/custodia/store/interface.py
@@ -1,12 +1,18 @@
 # Copyright (C) 2015  Custodia Project Contributors - see LICENSE file
 
+from custodia import log
+
 
 class CSStoreError(Exception):
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(CSStoreError, self).__init__(message)
 
 
 class CSStoreExists(Exception):
-    pass
+    def __init__(self, message=None):
+        log.debug(message)
+        super(CSStoreExists, self).__init__(message)
 
 
 class CSStore(object):