Add source property and default to SQLAlchemy

Author: hovaesco

README.md

@@ -89,6 +89,20 @@ nodes = Table(
 rows = connection.execute(select(nodes)).fetchall()
 ```
 
+In order to pass additional connection attributes use [connect_args](https://docs.sqlalchemy.org/en/14/core/engines.html#sqlalchemy.create_engine.params.connect_args) method.
+
+```python
+from sqlalchemy import create_engine
+
+engine = create_engine(
+    'trino://user@localhost:8080/system',
+    connect_args={
+      "session_properties": {'query_max_run_time': '1d'},
+      "client_tags": ["tag1", "tag2"]
+    }
+)
+```
+
 ## Authentications
 
 ### Basic Authentication

tests/unit/sqlalchemy/test_dialect.py

@@ -22,15 +22,15 @@ def setup(self):
             (
                 make_url("trino://user@localhost"),
                 list(),
-                dict(host="localhost", catalog="system", user="user"),
+                dict(host="localhost", catalog="system", user="user", source="trino-sqlalchemy"),
             ),
             (
                 make_url("trino://user@localhost:8080"),
                 list(),
-                dict(host="localhost", port=8080, catalog="system", user="user"),
+                dict(host="localhost", port=8080, catalog="system", user="user", source="trino-sqlalchemy"),
             ),
             (
-                make_url("trino://user:pass@localhost:8080"),
+                make_url("trino://user:pass@localhost:8080?source=trino-rulez"),
                 list(),
                 dict(
                     host="localhost",
@@ -39,6 +39,7 @@ def setup(self):
                     user="user",
                     auth=BasicAuthentication("user", "pass"),
                     http_scheme="https",
+                    source="trino-rulez"
                 ),
             ),
         ],

trino/sqlalchemy/dialect.py

@@ -96,6 +96,11 @@ def create_connect_args(self, url: URL) -> Tuple[Sequence[Any], Mapping[str, Any
             kwargs["http_scheme"] = "https"
             kwargs["auth"] = JWTAuthentication(url.query["access_token"])
 
+        if "source" in url.query:
+            kwargs["source"] = url.query["source"]
+        else:
+            kwargs["source"] = "trino-sqlalchemy"
+
         return args, kwargs
 
     def get_columns(self, connection: Connection, table_name: str, schema: str = None, **kw) -> List[Dict[str, Any]]: