db.Session: Add

Add database session API to db. This is a breaking change, because
from this commit on, a session object has to be passed to every
query.

This commit also removes any reference to Cmds / App objects. An
instantiated database object can be worked with outside of an App.

Signed-off-by: Jan Lindemann <jan@janware.com>

tools/python/jwutils/db/DataBase.py

@@ -3,21 +3,27 @@
 from typing import Any
 
 import abc
+from contextlib import contextmanager
 
 from jwutils.Config import Config
 from jwutils.db.schema.Schema import Schema
 from jwutils import Cmds
+from .Session import Session
+from ..log import *
 
 class DataBase(abc.ABC):
 
-    def __init__(self, schema: Schema, conf: Config, app: Any) -> None:
+    def __init__(self, schema: Schema, conf: Config) -> None:
         self.__conf = conf
-        self.__app = app
         self.__schema = schema
+        conf.dump(NOTICE, "Initializing database with configuration")
 
-    @property
-    def app(self) -> Cmds:
-        return self.__app
+    @abc.abstractmethod
+    def _create_session(self):
+        pass
+
+    def _delete_session(self, session: Session):
+        del session
 
     @property
     def schema(self):
@@ -26,3 +32,11 @@ class DataBase(abc.ABC):
     @property
     def conf(self):
         return self.__conf
+
+    @contextmanager
+    def session(self):
+        ret = self._create_session()
+        try:
+           yield ret
+        finally:
+            self._delete_session(ret)

tools/python/jwutils/db/Session.py

@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+
+import abc
+
+class Session(abc.ABC): # export
+
+    def __init__(self, db):
+        self.__db = db
+
+    @property
+    def db(self):
+        return self.__db

tools/python/jwutils/db/query/Queries.py

@@ -24,8 +24,8 @@ class Queries(abc.ABC): # export
 
         # -- implement API
 
-        def _run(self, *args, **kwargs) -> QueryResult:
-            return self.__func(*args, **kwargs)
+        def _run(self, session, *args, **kwargs) -> QueryResult:
+            return self.__func(session, *args, **kwargs)
 
         def _register(self):
             raise Exception('Can\'t call register on this object')
@@ -57,10 +57,6 @@ class Queries(abc.ABC): # export
     def db(self) -> DataBase:
         return self.__db
 
-    @property
-    def app(self) -> Cmds:
-        return self.__db.app
-
     def load(self, modules: list[str], cls=QueryBase):
         for path in modules:
             slog(INFO, f'Loading modules from {path}')

tools/python/jwutils/db/query/Query.py

@@ -8,6 +8,7 @@ from jwutils.log import *
 from jwutils.misc import load_classes
 from jwutils.Cmds import Cmds
 from jwutils.db.DataBase import DataBase
+from jwutils.db.Session import Session
 from jwutils.db.query.QueryResult import QueryResult
 #from jwutils.db.query.Queries import Queries
 
@@ -19,7 +20,7 @@ class Query(abc.ABC): # export
     # -- pure virtuals
 
     @abc.abstractmethod
-    def _run(self, *args, **kwargs) -> QueryResult:
+    def _run(self, session: Session, *args, **kwargs) -> QueryResult:
         raise Exception('Called pure virtual _run()')
 
     @abc.abstractmethod
@@ -40,8 +41,8 @@ class Query(abc.ABC): # export
     def _add(self, query_name: str, location: str, func: Any):
         return self.__parent.add(self, query_name, location, func)
 
-    def run(self, *args, **kwargs) -> QueryResult:
-        return self._run(*args, **kwargs)
+    def run(self, session: Session, *args, **kwargs) -> QueryResult:
+        return self._run(session, *args, **kwargs)
 
     @property
     def parent(self):
@@ -55,10 +56,6 @@ class Query(abc.ABC): # export
     def schema(self):
         return self.__parent.db.schema
 
-    @property
-    def app(self) -> Cmds:
-        return self.__parent.app
-
     @property
     def column_names(self) -> list[str]:
         return self._column_names()

tools/python/jwutils/db/query/QueryResult.py

@@ -8,6 +8,7 @@ from enum import Enum, auto
 from jwutils.log import *
 from jwutils.Cmds import Cmds
 from jwutils.db.DataBase import DataBase
+from jwutils.db.Session import Session
 
 class ResType(Enum): # export
     Statement    = auto()
@@ -18,17 +19,22 @@ class ResType(Enum): # export
 
 class QueryResult(abc.ABC): # export
 
-    def __init__(self, query: Any) -> None:
+    def __init__(self, session: Session, query: Any) -> None:
         self.__query = query
-
-    @property
-    def app(self) -> Cmds:
-        return self.__query.app
+        self.__session = session
 
     @property
     def db(self) -> DataBase:
         return self.__query.db
 
+    @property
+    def query(self) -> DataBase:
+        return self.__query
+
+    @property
+    def session(self) -> DataBase:
+        return self.__session
+
     @property
     def schema(self):
         return self.__query.db.schema
@@ -36,8 +42,8 @@ class QueryResult(abc.ABC): # export
     def rows(self) -> list[Any]:
         return self._cast(ResType.Scalars)
 
-    def pages(self, per_page=20) -> Any:
-        return self._cast(ResType.Pages, per_page=per_page)
+    def pages(self, per_page=20, page=1) -> Any:
+        return self._cast(ResType.Pages, per_page=per_page, page=page)
 
     def one(self) -> Any:
         return self._cast(ResType.One)
@@ -52,5 +58,5 @@ class QueryResult(abc.ABC): # export
     # -- pure virtuals
 
     @abc.abstractmethod
-    def _cast(self, res_type: ResType, **kwargs) -> Union[Any|list[Any]]:
+    def _cast(self, session: Session, res_type: ResType, **kwargs) -> Union[Any|list[Any]]:
         pass