Added select_host_states

neat/db.py

@@ -220,3 +220,27 @@ class Database(object):
                      for k, v in hosts.items()]        
         self.connection.execute(
             self.host_states.insert(), to_insert)
+
+    @contract
+    def select_host_states(self):
+        """ Select the current states of all the hosts.
+
+        :return: A dict of host names to states.
+         :rtype: dict(str: int)
+        """
+        hs1 = self.host_states
+        hs2 = self.host_states.alias()
+        sel = select([hs1.c.host_id, hs1.c.state], from_obj=[
+            hs1.outerjoin(hs2, and_(
+                hs1.c.host_id == hs2.c.host_id,
+                hs1.c.id < hs2.c.id))]). \
+             where(hs2.c.id == None)
+        data = dict(self.connection.execute(sel).fetchall())
+        host_ids = self.select_host_ids()
+        host_states = {}
+        for host, id in host_ids.items():
+            if id in data:
+                host_states[str(host)] = int(data[id])
+            else:
+                host_states[str(host)] = 1
+        return host_states

tests/test_db.py

@@ -185,3 +185,22 @@ class Db(TestCase):
                     lambda x: x[1] == hosts['host2'], 
                     result), key=lambda x: x[0])]
         self.assertEqual(host1, [0, 0, 1])        
+
+    @qc(1)
+    def select_host_states(
+        hosts=dict_(
+            keys=str_(of='abc123', min_length=1, max_length=5),
+            values=list_(of=int_(min=0, max=1),
+                         min_length=0, max_length=10),
+            min_length=0, max_length=3
+        )
+    ):
+        db = db_utils.init_db('sqlite:///:memory:')
+        res = {}
+        for host, data in hosts.items():
+            db.update_host(host, 1, 1, 1)
+            for state in data:
+                db.insert_host_states({host: state})
+            if data:
+                res[host] = data[-1]
+        assert db.select_host_states() == res