Add the Pool's available_connections property

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## 0.2
 
+### 0.2.6
+
+- Add the `available_connections` property to the `Pool` class. The issue #121 by @itssimon. By @stankudrow in #122
+
 ### 0.2.5
 
 - Add more validation rules in the `parse_dsn` function. By @stankudrow in #113

asynch/pool.py

@@ -214,6 +214,20 @@ def acquired_connections(self) -> int:
 
         return len(self._acquired_connections)
 
+    @property
+    def available_connections(self) -> int:
+        """Returns the number of available connections in the pool.
+
+        The number of available connections means
+        those that can be acquired from the pool.
+        Equivalent to `pool.maxsize - pool.connections`.
+
+        :return: the number of connections available to be requested from the pool
+        :rtype: int
+        """
+
+        return self.maxsize - self.connections
+
     @property
     def free_connections(self) -> int:
         """Returns the number of free connections in the pool.

tests/test_pool.py

@@ -59,24 +59,29 @@ async def test_pool_connection_attributes(config):
     assert pool.connections == 0
     assert pool.free_connections == 0
     assert pool.acquired_connections == 0
+    assert pool.available_connections == constants.POOL_MAX_SIZE
 
     async with pool:
         assert pool.connections == constants.POOL_MIN_SIZE
         assert pool.free_connections == constants.POOL_MIN_SIZE
         assert pool.acquired_connections == 0
+        assert pool.available_connections == (constants.POOL_MAX_SIZE - constants.POOL_MIN_SIZE)
 
         async with pool.connection():
             assert pool.connections == constants.POOL_MIN_SIZE
             assert pool.free_connections == 0
             assert pool.acquired_connections == constants.POOL_MIN_SIZE
+            assert pool.available_connections == (constants.POOL_MAX_SIZE - constants.POOL_MIN_SIZE)
 
         assert pool.connections == constants.POOL_MIN_SIZE
         assert pool.free_connections == constants.POOL_MIN_SIZE
         assert pool.acquired_connections == 0
+        assert pool.available_connections == (constants.POOL_MAX_SIZE - constants.POOL_MIN_SIZE)
 
     assert pool.connections == 0
     assert pool.free_connections == 0
     assert pool.acquired_connections == 0
+    assert pool.available_connections == constants.POOL_MAX_SIZE
 
 
 @pytest.mark.asyncio