internalised connection to database and added main routine

src/wattanalyse/external_interface.py

@@ -1,6 +1,8 @@
+from __future__ import annotations
+
 import sys
 import time
-from typing import Final
+from typing import TYPE_CHECKING, Final
 
 import dopt_basics.datetime as dopt_dt
 import oracledb
@@ -11,28 +13,13 @@ from wattanalyse import db, pipelines
 from wattanalyse.constants import USER_CFG
 from wattanalyse.logging import logger_base, logger_database, logger_pipeline
 
-try:
-    ORACLE_CONN = oracledb.connect(
-        user=USER_CFG.Datenbank.Nutzer,
-        password=USER_CFG.Datenbank.Passwort,
-        host=USER_CFG.Datenbank.Host,
-        port=USER_CFG.Datenbank.Port,
-        service_name=USER_CFG.Datenbank.Service_Name,
-    )
-except OperationalError as err:
-    logger_base.error(
-        (
-            "[Oracle Database] Could not establish connection. Check if the database "
-            "online, fully functional and reachable. Check the configuration parameters.\n"
-            ">>> Exception:\n%s"
-        ),
-        err,
-        stack_info=True,
-    )
-    sys.exit(1)
+if TYPE_CHECKING:
+    from wattanalyse.pipelines import OracleConnection
 
 
-def pipeline_KPI_calculation() -> int:
+def pipeline_KPI_calculation(
+    conn: OracleConnection,
+) -> int:
     return_code: int = 0
     PIPELINE_NAME: Final[str] = "KPI_calculation"
     logger_pipeline.info("Start pipeline >%s<", PIPELINE_NAME)
@@ -40,7 +27,7 @@ def pipeline_KPI_calculation() -> int:
     start = dopt_dt.current_time_tz()
     t1 = time.perf_counter_ns()
 
-    res_pipe = pipelines.KPI_calculation(ORACLE_CONN)
+    res_pipe = pipelines.KPI_calculation(conn)
 
     t2 = time.perf_counter_ns()
 
@@ -89,14 +76,34 @@ def pipeline_KPI_calculation() -> int:
     return return_code
 
 
-if __name__ == "__main__":
+def main() -> None:
     try:
-        code = pipeline_KPI_calculation()
+        ORACLE_CONN = oracledb.connect(
+            user=USER_CFG.Datenbank.Nutzer,
+            password=USER_CFG.Datenbank.Passwort,
+            host=USER_CFG.Datenbank.Host,
+            port=USER_CFG.Datenbank.Port,
+            service_name=USER_CFG.Datenbank.Service_Name,
+        )
+    except OperationalError as err:
+        logger_base.critical(
+            (
+                "[Oracle Database] Could not establish connection. Check if the database "
+                "is online, fully functional and reachable. Check the configuration "
+                "parameters.\n>>> Exception:\n%s"
+            ),
+            err,
+            stack_info=True,
+        )
+        sys.exit(1)
+
+    try:
+        code = pipeline_KPI_calculation(ORACLE_CONN)
         sys.exit(code)
     except Exception as err:
-        logger_base.error(
+        logger_base.critical(
             (
-                "[BASE ERROR] An unexpected and unwrapped error occurred during the "
+                "[BASE] An unexpected and unwrapped error occurred during the "
                 "execution of the pipeline function.\n>>> Exception:\n%s"
             ),
             err,
@@ -105,3 +112,7 @@ if __name__ == "__main__":
         sys.exit(1)
     finally:
         ORACLE_CONN.close()
+
+
+if __name__ == "__main__":
+    main()