Update check for existing table (#71)

* Update check for existing table

A change in sqlalchemy 1.4 changed how to check
whether a table exists. This enables the new check
and the old check, tested on sqlalchemy 1.3 and 1.4.

Co-authored-by: Jordi Aranda <jarandaf@users.noreply.github.com>

* Fix mypy errors

Newer versions of mypy complain when named tuple is passed the wrong name.
Also added types-cachetools as a test dependency to ensure mypy checks pass.

* version bump

Co-authored-by: Jordi Aranda <jarandaf@users.noreply.github.com>

pyproject.toml

@@ -52,6 +52,7 @@ test = [
     "black>=19.3b0",
     "flake8>=3.7",
     "mypy",
+    "types-cachetools",
 ]
 doc = [
     "sphinx>=2.0,<3.0",

src/superintendent/__init__.py

@@ -4,4 +4,4 @@
 from .base import Labeller
 
 __all__ = ["MultiClassLabeller", "ClassLabeller", "Labeller"]
-__version__ = "0.5.2"
+__version__ = "0.5.3"

src/superintendent/distributed/queueing.py

@@ -59,7 +59,7 @@ class DatabaseQueue(BaseLabellingQueue):
     """
 
     worker_id = None
-    item = namedtuple("QueueItem", ["id", "data", "label"])
+    item = namedtuple("item", ["id", "data", "label"])
 
     def __init__(
         self,
@@ -86,9 +86,18 @@ def __init__(
         self.engine = sa.create_engine(connection_string)
         self._popped = deque([])
 
-        if not self.engine.dialect.has_table(
-            self.engine, self.data.__tablename__
-        ):
+        try:
+            # works with sqlalchemy >= 1.4
+            table_exists = sa.inspect(self.engine).has_table(
+                self.data.__tablename__
+            )
+        except AttributeError:
+            # works with sqlalchemy < 1.3
+            table_exists = self.engine.dialect.has_table(
+                self.engine, self.data.__tablename__
+            )
+
+        if not table_exists:
             self.data.metadata.create_all(bind=self.engine)
 
         try:

src/superintendent/queueing/in_memory.py

@@ -13,7 +13,7 @@
 
 class SimpleLabellingQueue(BaseLabellingQueue):
 
-    item = namedtuple("QueueItem", ["id", "data", "label"])
+    item = namedtuple("item", ["id", "data", "label"])
 
     def __init__(self, features: Any = None, labels: Any = None):
         """Create an in-memory labelling queue.