Make kerberos/sasl support optional

Since installing the python-krbV dependency requires the kerberos
libraries to be installed, this commit makes kerberos/sasl support
optional at time of installation.

To install snakebite with sasl/kerberos support run:

  pip install "snakebite[kerberos]"

This triggers the installation of the sasl and python-krbV
dependendies.

In the client, sasl and kerberos are only included when the
client is explicitly configured with SASL.

README.rst

@@ -31,6 +31,14 @@ To install snakebite 2.x run:
 
   pip install snakebite
 
+
+
+To install snakebite 2.x with Kerberos/SASL support, make sure you can install python-krbV (https://fedorahosted.org/python-krbV/) and then run:
+
+  pip install "snakebite[kerberos]"
+
+
+
 Documentation
 *************
 More information and documentation can be found at http://spotify.github.io/snakebite/

debian/changelog

@@ -1,3 +1,9 @@
+snakebite (2.7.0) unstable; urgency=low
+
+   * Make kerberos/sasl optional in python packaging
+
+ -- Wouter de Bie <[email protected]>  Tue, 24 Sep 2015 13:12:25 -0000
+
 snakebite (2.6.1) unstable; urgency=low
 
    * Wraps use of the Python 'pwd' module in a utility procedure for Windows compatibility

requirements.txt

@@ -1,4 +1,2 @@
 argparse
-protobuf>2.4.1
-sasl
-python-krbV
+protobuf>2.4.1

setup.py

@@ -42,9 +42,13 @@ def run_tests(self):
 
 install_requires = [
     'protobuf>2.4.1',
-    'argparse',
-    'sasl',
-    'python-krbV']
+    'argparse']
+
+extras_require = {
+    'kerberos': [
+        'python-krbV',
+        'sasl']
+}
 
 tests_require = [
     'tox',
@@ -74,6 +78,7 @@ def run_tests(self):
         ('', ['LICENSE'])
     ],
     install_requires=install_requires,
+    extras_require=extras_require,
     tests_require=tests_require,
     cmdclass={'test': Tox}
 )

snakebite/channel.py

@@ -60,10 +60,6 @@
 import google.protobuf.internal.encoder as encoder
 import google.protobuf.internal.decoder as decoder
 
-# SASL
-from snakebite.rpc_sasl import SaslRpcClient
-from snakebite.kerberos import Kerberos
-
 # Module imports
 
 import logger
@@ -178,6 +174,13 @@ def __init__(self, host, port, version, effective_user=None, use_sasl=False):
         self.client_id = str(uuid.uuid4())
         self.use_sasl = use_sasl
         if self.use_sasl:
+            try:
+                # Only import if SASL is enabled
+                from snakebite.rpc_sasl import SaslRpcClient
+                from snakebite.kerberos import Kerberos
+            except ImportError:
+                raise Exception("Kerberos libs not found. Please install snakebite using 'pip install snakebite[kerberos]'")
+
             kerberos = Kerberos()
             self.effective_user = effective_user or kerberos.user_principal().name
         else: 

snakebite/version.py

@@ -1,4 +1,4 @@
-VERSION = "2.6.1"
+VERSION = "2.7.0"
 
 
 def version():