Add interactive -i flag to k4run.

README.md

@@ -43,7 +43,7 @@ Service generating unique, reproducible numbers to be used for seeding RNG used
 ## k4run
 ```
 $ k4run --help
-usage: k4run [--dry-run] [-v] [-n NUM_EVENTS] [-l] [--gdb] [--interactive-root] [-h] [config_files ...]
+usage: k4run [--dry-run] [-v] [-n NUM_EVENTS] [-l] [--gdb] [--interactive-root] [--log-level {VERBOSE,DEBUG,INFO,WARNING,ERROR}] [-i] [-h] [config_files ...]
 
 Run job in the Key4hep framework
 
@@ -58,6 +58,9 @@ options:
   -l, --list            Print all the configurable components available in the framework and exit
   --gdb                 Attach gdb debugger
   --interactive-root    Run with ROOT in interactive mode (e.g. to see plots)
+  --log-level {VERBOSE,DEBUG,INFO,WARNING,ERROR}
+                        Set the log (output) level for python and the ApplicationMgr
+  -i,--interactive      Start a Python command loop after reading the configuration files
   -h, --help            show this help message and exit
 ```
 When supplied with a Gaudi steering file `k4run --help file.py` also shows the settable properties of the Gaudi algorithms used in the file. Additionally, it is possible to add further arguments and use them in the steering file by using the Python `argparse.ArgumentParser` shared by `k4run`.

k4FWCore/scripts/k4run

@@ -129,6 +129,21 @@ class DeprecatedStoreTrueAction(argparse.Action):
         setattr(namespace, self.dest, True)
 
 
+def startInteractive(vars):
+    """Start an interactive session"""
+    import code
+
+    # collect all global and local variables
+    vars = vars.copy()
+
+    # start the interpreter
+    code.interact(
+        local=vars,
+        banner="Starting interactive Python session.  Exit with Ctrl-D to resume the job.",
+    )
+    return
+
+
 def main():
     # ensure that we (and the subprocesses) use the C standard localization
     os.environ["LC_ALL"] = "C"
@@ -180,6 +195,14 @@ def main():
         choices=LOG_LEVELS,
     )
 
+    parser.add_argument(
+        "-i",
+        "--interactive",
+        action="store_true",
+        help="Start a Python command loop after reading the configuration files",
+        default=False,
+    )
+
     # Once to parse the files and another time below to have the new parameters
     # in the namespace since parsing of the file happens when the namespace
     # has already been filled
@@ -202,8 +225,9 @@ def main():
             print(f"{item} (from {cfgdb[item]['lib']}), path: {path_to_component}")
         sys.exit()
 
+    config_ns = {}
     for file in opts[0].config_files:
-        load_file(file)
+        config_ns.update(load_file(file))
 
     from Configurables import ApplicationMgr
 
@@ -260,6 +284,9 @@ def main():
 
     from Gaudi.Main import gaudimain
 
+    if opts.interactive:
+        startInteractive(config_ns)
+
     gaudi = gaudimain()
     if not opts.dry_run:
         if not opts.interactive_root:

python/k4FWCore/utils.py

@@ -93,6 +93,7 @@ def load_file(opt_file: Union[str, os.PathLike]) -> None:
 
     check_wrong_imports(code)
     exec(compile(code, ofile.name, "exec"), namespace)
+    return namespace
 
 
 _logger = None