Merge "Read configuration from file or standard location"

README.rst

@@ -47,6 +47,13 @@ Build the connection to the cloud deployment and verify it:
     distractor = os_faults.connect(cloud_config)
     distractor.verify()
 
+The library can also read configuration from the file specified in
+`OS_FAULTS_CONFIG` environment variable or read it from one of default
+locations:
+ * current directory
+ * ~/.config/os-faults
+ * /etc/openstack
+
 Make some distraction:
 
 .. code-block:: python

os_faults/__init__.py

@@ -10,8 +10,13 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import pbr.version
+import os
 
+import appdirs
+import pbr.version
+import yaml
+
+from os_faults.api import error
 from os_faults.drivers import devstack
 from os_faults.drivers import fuel
 from os_faults.drivers import ipmi
@@ -20,7 +25,38 @@ from os_faults.drivers import libvirt_driver
 __version__ = pbr.version.VersionInfo('os_faults').version_string()
 
 
-def connect(cloud_config):
+APPDIRS = appdirs.AppDirs(appname='openstack', appauthor='OpenStack')
+UNIX_SITE_CONFIG_HOME = '/etc/openstack'
+CONFIG_SEARCH_PATH = [
+    os.getcwd(),
+    APPDIRS.user_config_dir,
+    UNIX_SITE_CONFIG_HOME,
+]
+CONFIG_FILES = [
+    os.path.join(d, 'os-faults' + s)
+    for d in CONFIG_SEARCH_PATH
+    for s in ['.json', '.yaml', '.yml']
+]
+
+
+def _read_config():
+    os_faults_config = os.environ.get('OS_FAULTS_CONFIG')
+    if os_faults_config:
+        CONFIG_FILES.insert(0, os_faults_config)
+
+    for config_file in CONFIG_FILES:
+        if os.path.exists(config_file):
+            with open(config_file) as fd:
+                return yaml.safe_load(fd.read())
+
+    msg = 'Config file is not found on any of paths: {}'.format(CONFIG_FILES)
+    raise error.OSFError(msg)
+
+
+def connect(cloud_config=None):
+    if not cloud_config:
+        cloud_config = _read_config()
+
     cloud_management = None
     cloud_management_params = cloud_config.get('cloud_management') or {}
 

requirements.txt

@@ -5,6 +5,7 @@
 pbr>=1.6
 
 ansible>=2.0
+appdirs>=1.3.0 # MIT License
 iso8601>=0.1.9
 oslo.i18n>=1.5.0 # Apache-2.0
 oslo.log>=1.12.0 # Apache-2.0
@@ -12,4 +13,5 @@ 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