remove need for configuration file #3

add method to attach volume at instance launch #4

Added a configuration object allowing multiple ways to do
configuration. A new argument to launch_new_instance allows attaching
 a volume snapshot at launch.

Author: bekozi

simple-aws.conf.TEMPLATE

@@ -1,15 +1,17 @@
 [simple-aws]
 # AWS access key identifier
-aws_access_key_id =
+aws_access_key =
 # AWS secret access key
-aws_secret_access_key =
+aws_secret_key =
 # default image identifier to launch
-image_id =
+aws_image_id = ami-6ac2a85a
 # default instance type to launch
-instance_type =
+aws_instance_type = t1.micro
 # default region to connect to
-region =
+aws_region = us-west-2
 # default security group to use
-security_group =
+aws_security_group = sosecure
 # name of key file to use for instance filtering
-key_name =
+aws_key_name = sosecure-key
+# path to the key file
+aws_key_path = ~/.ssh/sosecure-key.pem

src/saws/__init__.py

@@ -1 +1 @@
-from manager import AwsManager
+from manager import AwsManager, AwsManagerConfiguration

src/saws/manager.py

@@ -6,29 +6,31 @@
 from boto import ses
 import boto.ec2
 from boto.ec2.address import Address
+from boto.ec2.blockdevicemapping import BlockDeviceMapping, BlockDeviceType
 from exc import InstanceNameNotAvailable
 
 
+SIMPLEAWS_SECTION_TITLE = 'simple-aws'
+
+
 class AwsManager(object):
     """
-    :param str conf_path: Path to the configuration file. See *simple-aws.conf.TEMPLATE* for structure.
+    :param str conf_path: See :class:`saws.manager.AwsManagerConfiguration`.
     :param bool filtered: If ``True``, only consider instances attached to ``key_name`` in the configuration file.
     :param bool only_running: If ``True``, only consider running instances.
-    :param str section_title: The title of the section in the configuration file to read values from.
+    :param str section_title: See :class:`saws.manager.AwsManagerConfiguration`.
+    :param conf: Configuration object used in place of configuration file.
+    :type conf: :class:`saws.manager.AwsManagerConfiguration`
     """
 
-    def __init__(self, conf_path=None, filtered=True, only_running=True, section_title='simple-aws'):
-        if conf_path is None:
-            msg = 'Path to configuration file required.'
-            raise ValueError(msg)
-
-        self.conf_path = conf_path or os.path.expanduser(os.getenv('SIMPLEAWS_CONF_PATH'))
+    def __init__(self, conf_path=None, filtered=True, only_running=True, section_title=SIMPLEAWS_SECTION_TITLE,
+                 conf=None):
+        if conf is None:
+            conf = AwsManagerConfiguration(conf_path=conf_path, section_title=section_title)
+        self.conf = conf
         self.filtered = filtered
         self.only_running = only_running
         self._conn = None
-        self._parser = SafeConfigParser()
-        self._parser.read(self.conf_path)
-        self._cfg = dict(self._parser.items(section_title))
 
     @property
     def conn(self):
@@ -50,7 +52,7 @@ def _get_key_(instance):
                 raise NotImplementedError(key)
             return ret
 
-        reservations = self.conn.get_all_reservations()
+        reservations = self.conn.get_all_instances()
         instances = [i for r in reservations for i in r.instances]
         instances = {i.id: i for i in instances}
         if self.only_running:
@@ -69,18 +71,28 @@ def get_instance_by_name(self, name):
         else:
             return ret
 
-    def launch_new_instance(self, name, image_id=None, instance_type=None, placement=None, elastic_ip=None, wait=True):
-        image_id = image_id or self._cfg['image_id']
-        instance_type = instance_type or self._cfg['instance_type']
-        security_group = self._cfg['security_group']
-        key_name = self._cfg['key_name']
+    def launch_new_instance(self, name, image_id=None, instance_type=None, placement=None, elastic_ip=None, wait=True,
+                            ebs_snapshot_id=None, ebs_mount_name='/dev/xvdg'):
+        image_id = image_id or self.conf.aws_image_id
+        instance_type = instance_type or self.conf.aws_instance_type
+        security_group = self.conf.aws_security_group
+        key_name = self.conf.aws_key_name
 
         if not self._get_is_unique_tag_(name, 'Name'):
             msg = 'The assigned instance name "{0}" is not unique.'.format(name)
             raise ValueError(msg)
 
+        block_device_map = None
+        if ebs_snapshot_id is not None:
+            block_device_map = BlockDeviceMapping()
+            block_dev_type = BlockDeviceType()
+            block_dev_type.delete_on_termination = True
+            block_dev_type.snapshot_id = ebs_snapshot_id
+            block_device_map[ebs_mount_name] = block_dev_type
+
         reservation = self.conn.run_instances(image_id, key_name=key_name, instance_type=instance_type,
-                                              security_groups=[security_group], placement=placement)
+                                              security_groups=[security_group], placement=placement,
+                                              block_device_map=block_device_map)
         instance = reservation.instances[0]
 
         if wait:
@@ -101,10 +113,10 @@ def send_email(self, fromaddr, recipient, subject, body):
         msg['From'] = fromaddr
         msg['To'] = recipient
 
-        aws_access_key_id = self._cfg['aws_access_key_id']
-        aws_secret_access_key = self._cfg['aws_secret_access_key']
-        conn = ses.connect_to_region(self._cfg['region'], aws_access_key_id=aws_access_key_id,
-                                     aws_secret_access_key=aws_secret_access_key)
+        aws_access_key = self.conf.aws_access_key
+        aws_secret_key = self.conf.aws_secret_key
+        conn = ses.connect_to_region(self.conf.aws_region, aws_access_key_id=aws_access_key,
+                                     aws_secret_access_key=aws_secret_key)
         conn.send_raw_email(msg.as_string())
 
     def start_instance_by_name(self, name, wait=True):
@@ -123,31 +135,25 @@ def start_instance_by_name(self, name, wait=True):
             self.only_running = prev_only_running
 
     @staticmethod
-    def wait_for_status(target, status_target, sleep=1, pad=None):
+    def wait_for_status(instance, status_target, sleep=1, pad=3):
         time.sleep(sleep)
-        while target.update() != status_target:
+        while instance.update() != status_target:
             time.sleep(sleep)
         if pad is not None:
             time.sleep(pad)
 
     def _filter_(self, instance):
-        if instance.key_name == self._cfg['key_name']:
+        if instance.key_name == self.conf.aws_key_name:
             ret = True
         else:
             ret = False
         return ret
 
     def _get_aws_connection_(self):
-        region = self._cfg['region']
-
-        aws_access_key_id = self._cfg['aws_access_key_id']
-        aws_secret_access_key = self._cfg['aws_secret_access_key']
-
-        conn = boto.ec2.connect_to_region(region, aws_access_key_id=aws_access_key_id, aws_secret_access_key=aws_secret_access_key)
-
+        conn = boto.ec2.connect_to_region(self.conf.aws_region, aws_access_key_id=self.conf.aws_access_key,
+                                          aws_secret_access_key=self.conf.aws_secret_key)
         if conn is None:
             raise RuntimeError('Unable to launch instance.')
-
         return conn
 
     def _get_is_unique_tag_(self, tag_value, tag_key):
@@ -157,3 +163,55 @@ def _get_is_unique_tag_(self, tag_value, tag_key):
             if i.tags.get(tag_key) == tag_value:
                 ret = False
         return ret
+
+
+class AwsManagerConfiguration(object):
+    """
+    :class:`saws.AwsManager` configuration object. Any of the keywords arguments found in
+    :attr:`saws.AwsManagerConfiguration._kwargs` may be set in the following ways (in order of precedence):
+     * Passed as keyword arguments to the constructor.
+     * Set as uppercase environment variables.
+     * Set in the configuration file.
+
+    :keyword str conf_path: (``=None``) Path to the configuration file. The environment variable
+     ``'SIMPLEAWS_CONF_PATH'`` may also be used.
+    :keyword str section_title: (``='simple-aws'``) Name of the section in the configuration file to look for values.
+    :keyword kwargs: Any keyword from :attr:`saws.AwsManagerConfiguration._kwargs`.
+    :raises: ValueError
+    """
+
+    _kwargs = {'aws_access_key': False, 'aws_secret_key': False, 'aws_image_id': True, 'aws_instance_type': True,
+               'aws_region': False, 'aws_security_group': True, 'aws_key_name': True, 'aws_key_path': False}
+
+    def __init__(self, **kwargs):
+        self.conf_path = kwargs.pop('conf_path', None)
+        if self.conf_path is None:
+            self.conf_path = os.environ.get('SIMPLEAWS_CONF_PATH')
+        self.section_title = kwargs.pop('section_title', SIMPLEAWS_SECTION_TITLE)
+
+        cfg_kwargs = {}
+        for kwarg in self._kwargs.iterkeys():
+            value = kwargs.get(kwarg)
+            if value is None:
+                value = os.environ.get(kwarg)
+                if value is None:
+                    value = os.environ.get(kwarg.upper())
+            cfg_kwargs[kwarg] = value
+
+        cfg_conf = {}
+        if self.conf_path is not None:
+            self.conf_path = os.path.expanduser(self.conf_path)
+            parser = SafeConfigParser()
+            parser.read(self.conf_path)
+            cfg_conf = dict(parser.items(self.section_title))
+
+        for k, v in cfg_conf.iteritems():
+            if cfg_kwargs.get(k) is None:
+                cfg_kwargs[k] = v
+
+        for k, v in cfg_kwargs.iteritems():
+            if v is None and not self._kwargs[k]:
+                msg = 'The configuration key "{0}" may not be None.'.format(k)
+                raise ValueError(msg)
+            else:
+                setattr(self, k, v)