Remove ucloud_common and put its files under ucloud.common subpackage.

Remove individual config.py used by every component and put them into single config.py ucloud/config.py
Use /etc/ucloud/ucloud.conf for Environment Variables
Refactoring and a lot of it
Make ucloud repo a package and different components of ucloud a subpackage for avoiding code duplication.
Improved logging.

common/vm.py

@@ -0,0 +1,110 @@
+from contextlib import contextmanager
+from datetime import datetime
+from os.path import join
+
+from .classes import SpecificEtcdEntryBase
+
+
+class VMStatus:
+    # Must be only assigned to brand new VM
+    requested_new = "REQUESTED_NEW"
+
+    # Only Assigned to already created vm
+    requested_start = "REQUESTED_START"
+
+    # These all are for running vms
+    requested_shutdown = "REQUESTED_SHUTDOWN"
+    requested_migrate = "REQUESTED_MIGRATE"
+    requested_delete = "REQUESTED_DELETE"
+    # either its image is not found or user requested
+    # to delete it
+    deleted = "DELETED"
+
+    stopped = "STOPPED"  # After requested_shutdown
+    killed = "KILLED"  # either host died or vm died itself
+
+    running = "RUNNING"
+
+    error = "ERROR"  # An error occurred that cannot be resolved automatically
+
+
+class VMEntry(SpecificEtcdEntryBase):
+
+    def __init__(self, e):
+        self.owner = None  # type: str
+        self.specs = None  # type: dict
+        self.hostname = None  # type: str
+        self.status = None  # type: str
+        self.image_uuid = None  # type: str
+        self.log = None  # type: list
+        self.in_migration = None  # type: bool
+
+        super().__init__(e)
+
+    @property
+    def uuid(self):
+        return self.key.split("/")[-1]
+
+    def declare_killed(self):
+        self.hostname = ""
+        self.in_migration = False
+        if self.status == VMStatus.running:
+            self.status = VMStatus.killed
+
+    def declare_stopped(self):
+        self.hostname = ""
+        self.in_migration = False
+        self.status = VMStatus.stopped
+
+    def add_log(self, msg):
+        self.log = self.log[:5]
+        self.log.append("{} - {}".format(datetime.now().isoformat(), msg))
+
+    @property
+    def path(self):
+        return "rbd:uservms/{}".format(self.uuid)
+
+
+class VmPool:
+    def __init__(self, etcd_client, vm_prefix):
+        self.client = etcd_client
+        self.prefix = vm_prefix
+
+    @property
+    def vms(self):
+        _vms = self.client.get_prefix(self.prefix, value_in_json=True)
+        return [VMEntry(vm) for vm in _vms]
+
+    def by_host(self, host, _vms=None):
+        if _vms is None:
+            _vms = self.vms
+        return list(filter(lambda x: x.hostname == host, _vms))
+
+    def by_status(self, status, _vms=None):
+        if _vms is None:
+            _vms = self.vms
+        return list(filter(lambda x: x.status == status, _vms))
+
+    def except_status(self, status, _vms=None):
+        if _vms is None:
+            _vms = self.vms
+        return list(filter(lambda x: x.status != status, _vms))
+
+    def get(self, key):
+        if not key.startswith(self.prefix):
+            key = join(self.prefix, key)
+        v = self.client.get(key, value_in_json=True)
+        if v:
+            return VMEntry(v)
+        return None
+
+    def put(self, obj: VMEntry):
+        self.client.put(obj.key, obj.value, value_in_json=True)
+
+    @contextmanager
+    def get_put(self, key) -> VMEntry:
+        # Updates object at key on exit
+        obj = self.get(key)
+        yield obj
+        if obj:
+            self.put(obj)