Make libvirt-python an extra requirement

This patch moves libvirt-python to extras.

Change-Id: Id129ab0a280b12e1bd0bfc1214c76a087c572a0d

README.rst

@@ -14,6 +14,20 @@ IPMI driver).
 * Source: https://github.com/openstack/os-faults
 * Bugs: http://bugs.launchpad.net/os-faults
 
+
+Installation
+------------
+
+Reqular installation::
+
+    pip install os-faults
+
+The library contains optional libvirt driver, if you plan to use it,
+please use the following command to install os-faults with extra dependencies::
+
+    pip install os-faults[libvirt]
+
+
 Configuration
 -------------
 

doc/source/installation.rst

@@ -10,3 +10,8 @@ Or, if you have virtualenvwrapper installed::
 
     $ mkvirtualenv os-faults
     $ pip install os-faults
+
+The library contains optional libvirt driver, if you plan to use it,
+please use the following command to install os-faults with extra dependencies::
+
+    pip install os-faults[libvirt]

os_faults/drivers/libvirt_driver.py

@@ -13,8 +13,6 @@
 
 import logging
 
-import libvirt
-
 from os_faults.api import error
 from os_faults.api import power_management
 from os_faults import utils
@@ -44,6 +42,11 @@ class LibvirtDriver(power_management.PowerManagement):
 
     def _get_connection(self):
         if self._cached_conn is None:
+            try:
+                import libvirt
+            except ImportError:
+                raise error.OSFError('libvirt-python is required '
+                                     'to use LibvirtDriver')
             self._cached_conn = libvirt.open(self.connection_uri)
 
         return self._cached_conn

requirements.txt

@@ -12,7 +12,6 @@ oslo.i18n>=1.5.0 # Apache-2.0
 oslo.log>=1.12.0 # Apache-2.0
 oslo.serialization>=1.10.0 # Apache-2.0
 oslo.utils!=2.6.0,>=2.4.0 # Apache-2.0
-libvirt-python>=1.2.5 # LGPLv2+
 pyghmi>=1.0.3 # Apache-2.0
 PyYAML>=3.1.0 # MIT
 six>=1.9.0

setup.cfg

@@ -24,6 +24,10 @@ packages =
 console_scripts =
     os-inject-fault = os_faults.cmd.cmd:main
 
+[extras]
+libvirt =
+    libvirt-python>=1.2.5 # LGPLv2+
+
 [build_sphinx]
 source-dir = doc/source
 build-dir = doc/build

tox.ini

@@ -11,7 +11,10 @@ install_command =
 setenv =
    VIRTUAL_ENV={envdir}
 whitelist_externals = find
-deps = -r{toxinidir}/test-requirements.txt
+# TODO(astudenov): replace libvirt-python with extras option from tox 2.4
+deps =
+    -r{toxinidir}/test-requirements.txt
+    libvirt-python>=1.2.5
 commands =
   find . -type f -name "*.pyc" -delete
   py.test -vvvv --html={envlogdir}/pytest_results.html --self-contained-html --durations=10 "os_faults/tests/unit" {posargs}