[REVERT] back up and do the try thingys

Author: emmuhamm

src/daqpytools/apps/logging_demonstrator.py

@@ -181,6 +181,34 @@ def test_handlertypes(main_logger: logging.Logger) -> None:
         extra={"handlers": [HandlerType.Rich, HandlerType.Protobufstream]}
     )
 
+ers_envs = {
+    "DUNEDAQ_ERS_WARNING" : "erstrace,throttle,lstdout",
+    "DUNEDAQ_ERdS_INFO" : "erstrace,throttle,lstdout",
+    "DUNEDAQ_ERS_FATAL" : "erstrace,lstdout",
+    "DUNEDAQ_ERS_ERROR" : (
+            "erstrace,"
+            "throttle,"
+            "lstdout,"
+            "protobufstream(monkafka.cern.ch:30092)"
+        )
+}
+
+def obtain_original_envs(envs: dict) -> dict:
+    return {
+        key: os.environ.get(key)
+        for key in envs
+    }
+
+
+
+def restore_original_envs(original:dict) -> None:
+    for var_name, original_value in original.items():
+        if original_value is None:
+            os.environ.pop(var_name, None)
+        else:
+            os.environ[var_name] = original_value
+
+
 
 def test_handlerconf(main_logger: logging.Logger) -> None:
     """Demonstrates the main functionality of the handlerconf. With ERS support.
@@ -194,15 +222,12 @@ def test_handlerconf(main_logger: logging.Logger) -> None:
     main_logger.warning("Handlerconf Opmon", extra=handlerconf.Opmon)
 
     #* Interlude: Inject sample environment variables
-    os.environ["DUNEDAQ_ERS_WARNING"] = "erstrace,throttle,lstdout"
-    os.environ["DUNEDAQ_ERS_INFO"] = "erstrace,throttle,lstdout"
-    os.environ["DUNEDAQ_ERS_FATAL"] = "erstrace,lstdout"
-    os.environ["DUNEDAQ_ERS_ERROR"] = (
-        "erstrace,"
-        "throttle,"
-        "lstdout,"
-        "protobufstream(monkafka.cern.ch:30092)"
-    )
+    # Save envs from current shell before we rewrite
+    saved_envs = obtain_original_envs(ers_envs)
+
+    for key, value in ers_envs.items():
+        # Inject ERS envs into the python shell
+        os.environ[key] = value
 
     info_out = f"{os.getenv('DUNEDAQ_ERS_ERROR')=}"
     main_logger.info(info_out)
@@ -214,17 +239,33 @@ def test_handlerconf(main_logger: logging.Logger) -> None:
     # HandlerConf will require that these variables are defined!
     # They come from the OKS, so whatever tools you have should have this up
     # You can also initialise via handlerconf = LogHandlerConf(init_ers=True)
-    handlerconf.init_ers_stream()
+    try:
+        handlerconf.init_ers_stream()
+        
+        #* Test ERS Streams
+        main_logger.warning("ERS Warning erstrace,throttle,lstdout", extra=handlerconf.ERS)
+        main_logger.info("ERS Info erstrace,throttle,lstdout", extra=handlerconf.ERS)
+        main_logger.critical("ERS Fatal erstrace,lstdout", extra=handlerconf.ERS)
+        main_logger.debug("ERS Debug none", extra=handlerconf.ERS)
+        main_logger.error("ERS Error erstrace,throttle,lstdout,"
+            "protobufstream(monkafka.cern.ch:30092)", 
+            extra=handlerconf.ERS
+    ) 
+    except Exception as e:
+        main_logger.error(f"UHhhh not sure what happened here {e}")
+    finally:
+        
+        # Restore original environment variables
+        ## Note that in https://dagster.io/blog/
+        ##   python-environment-variables#modifying-and-adding-environment-variables
+        ## It looks like os.environ only affects the local python shell, and doesn't 
+        ## "leak" out into the bash envs. 
+        ## However, for best practices this is still done
+        
+        restore_original_envs(saved_envs)
+    
+    
 
-    #* Test ERS Streams
-    main_logger.warning("ERS Warning erstrace,throttle,lstdout", extra=handlerconf.ERS)
-    main_logger.info("ERS Info erstrace,throttle,lstdout", extra=handlerconf.ERS)
-    main_logger.critical("ERS Fatal erstrace,lstdout", extra=handlerconf.ERS)
-    main_logger.debug("ERS Debug none", extra=handlerconf.ERS)
-    main_logger.error("ERS Error erstrace,throttle,lstdout,"
-        "protobufstream(monkafka.cern.ch:30092)", 
-        extra=handlerconf.ERS
-    )     
 
 
 def test_fallback_handlers(log_level: str) -> None: