Handle exceptions in wait_for_table_activation

LowVoltage/compounds/wait_for_table_activation.py

@@ -33,16 +33,27 @@ def wait_for_table_activation(connection, table):
         wait_for_table_deletion(connection, table)
     """
 
-    r = connection(_lv.DescribeTable(table))
-    while not _table_is_fully_active(r.table):
+    desc = _describe(connection, table)
+    while desc is None or not _table_is_fully_active(desc):
         time.sleep(3)
-        r = connection(_lv.DescribeTable(table))
+        desc = _describe(connection, table)
     # Unfortunately, DescribeTable seems to perform an eventually consistent read.
     # Without the next line, I've seen the doctest fail with a table status == "CREATING"
     # after the wait. So, let's wait a bit more :-/
     time.sleep(3)
 
 
+def _describe(connection, table):
+    try:
+        return connection(_lv.DescribeTable(table)).table
+    except _lv.ResourceNotFoundException:
+        # DescribeTable seems to perform an eventually consistent read.
+        # So from time to time you create a table (on server A), then ask for its description
+        # (on server B) and server B doesn't know yet it exists.
+        # Seen in https://travis-ci.org/jacquev6/LowVoltage/jobs/61754722#L962
+        return None
+
+
 def _table_is_fully_active(table):
     if table.global_secondary_indexes is not None:
         for gsi in table.global_secondary_indexes:
@@ -57,6 +68,22 @@ def setUp(self):
         self.connection = self.mocks.create("connection")
         self.sleep = self.mocks.replace("time.sleep")
 
+    def test_table_not_yet_created_on_first_describe(self):
+        self.connection.expect._call_.withArguments(
+            self.ActionChecker("DescribeTable", {"TableName": "Table"})
+        ).andRaise(
+            _lv.ResourceNotFoundException
+        )
+        self.sleep.expect(3)
+        self.connection.expect._call_.withArguments(
+            self.ActionChecker("DescribeTable", {"TableName": "Table"})
+        ).andReturn(
+            _lv.DescribeTableResponse(Table={"TableStatus": "ACTIVE"})
+        )
+        self.sleep.expect(3)
+
+        wait_for_table_activation(self.connection.object, "Table")
+
     def test_table_creating(self):
         self.connection.expect._call_.withArguments(
             self.ActionChecker("DescribeTable", {"TableName": "Table"})