#12452 Python: Replace logger.error with raise RipsError in instance.py

Error conditions in launch() and find() now raise RipsError instead of
logging and returning None, making failures explicit. Updated test to
expect the exception.

GrpcInterface/Python/rips/instance.py

@@ -30,6 +30,7 @@ from .project import Project
 from .retry_policy import ExponentialBackoffRetryPolicy
 from .grpc_retry_interceptor import RetryOnRpcErrorClientInterceptor
 from .generated.generated_classes import CommandRouter
+from .exception import RipsError
 
 from typing import List, Optional, Tuple
 from pathlib import Path
@@ -148,20 +149,18 @@ class Instance:
         if not resinsight_executable:
             resinsight_executable_from_env = os.environ.get("RESINSIGHT_EXECUTABLE")
             if not resinsight_executable_from_env:
-                logger.error(
+                raise RipsError(
                     "Could not launch ResInsight because the environment variable"
                     " RESINSIGHT_EXECUTABLE is not set"
                 )
-                return None
             else:
                 resinsight_executable = resinsight_executable_from_env
 
         # Check if executable file exists
         if not os.path.isfile(resinsight_executable):
-            logger.error(
-                "ResInsight executable not found at path: %s", resinsight_executable
+            raise RipsError(
+                f"ResInsight executable not found at path: {resinsight_executable}"
             )
-            return None
 
         logger.info("Trying to launch %s", resinsight_executable)
         with tempfile.TemporaryDirectory() as tmp_dir_path:
@@ -188,9 +187,9 @@ class Instance:
                     port_number_file, init_timeout
                 )
                 if port == -1:
-                    logger.error("Unable to read port number. Launch failed.")
-                    # Need to kill the process using PID since there is no  GRPC connection to use.
+                    # Need to kill the process using PID since there is no GRPC connection to use.
                     Instance.__kill_process(pid)
+                    raise RipsError("Unable to read port number. Launch failed.")
                 else:
                     instance = Instance(port=port, launched=True)
                     return instance
@@ -221,12 +220,9 @@ class Instance:
             ):
                 return Instance(port=try_port)
 
-        logger.error(
-            "Could not find any ResInsight instances responding between ports %d and %d",
-            start_port,
-            end_port,
+        raise RipsError(
+            f"Could not find any ResInsight instances responding between ports {start_port} and {end_port}"
         )
-        return None
 
     def __execute_command(self, **command_params):
         return self.commands.Execute(Commands_pb2.CommandParams(**command_params))