Store qe_stats_file in output directory (#262)

Function log_execution_env_state is used to gather information about the execution environment and store this together with the experiment log.  Recently we've added saving the compression schedule YAML file in the same logs directory.
This commit expands the log_execution_env_state interface to accept a list of paths to arbitrary files that may contribute to the experiment configuration and that you (the experiment owner) deem important for recreating the experiment.

In the sample classifier_compression.py app, we now store both the compression schedule YAML file and quantization statistics collateral file (qe_stats_file).

distiller/apputils/execution_env.py

@@ -20,7 +20,6 @@ This is helpful if you want to recreate an experiment at a later time, or if
 you want to understand the environment in which you execute the training.
 """
 
-import contextlib
 import logging
 import logging.config
 import os
@@ -41,16 +40,16 @@ except ImportError:
 logger = logging.getLogger("app_cfg")
 
 
-def log_execution_env_state(config_path=None, logdir=None, gitroot='.'):
+def log_execution_env_state(config_paths=None, logdir=None, gitroot='.'):
     """Log information about the execution environment.
 
-    File 'config_path' will be copied to directory 'logdir'. A common use-case
+    Files in 'config_paths' will be copied to directory 'logdir'. A common use-case
     is passing the path to a (compression) schedule YAML file. Storing a copy
     of the schedule file, with the experiment logs, is useful in order to
     reproduce experiments.
 
     Args:
-        config_path: path to config file, used only when logdir is set
+        config_paths: path(s) to config file(s), used only when logdir is set
         logdir: log directory
         git_root: the path to the .git root directory
     """
@@ -89,21 +88,25 @@ def log_execution_env_state(config_path=None, logdir=None, gitroot='.'):
     log_git_state()
     logger.debug("Command line: %s", " ".join(sys.argv))
 
-    if (logdir is None) or (config_path is None):
+    if (logdir is None) or (config_paths is None):
         return
+
     # clone configuration files to output directory
     configs_dest = os.path.join(logdir, 'configs')
-    with contextlib.suppress(FileExistsError):
-        os.makedirs(configs_dest)
-    if os.path.exists(os.path.join(configs_dest,
-                                   os.path.basename(config_path))):
-        logger.debug('{} already exists in logdir'.format(
-            os.path.basename(config_path) or config_path))
-    else:
-        try:
-            shutil.copy(config_path, configs_dest)
-        except OSError as e:
-            logger.debug('Failed to copy of config file: {}'.format(str(e)))
+
+    if isinstance(config_paths, str) or not hasattr(config_paths, '__iter__'):
+        config_paths = [config_paths]
+    for cpath in config_paths:
+        os.makedirs(configs_dest, exist_ok=True)
+
+        if os.path.exists(os.path.join(configs_dest, os.path.basename(cpath))):
+            logger.debug('{} already exists in logdir'.format(
+                os.path.basename(cpath) or cpath))
+        else:
+            try:
+                shutil.copy(cpath, configs_dest)
+            except OSError as e:
+                logger.debug('Failed to copy of config file: {}'.format(str(e)))
 
 
 def config_pylogger(log_cfg_file, experiment_name, output_dir='logs'):

examples/classifier_compression/compress_classifier.py

@@ -97,7 +97,9 @@ def main():
 
     # Log various details about the execution environment.  It is sometimes useful
     # to refer to past experiment executions and this information may be useful.
-    apputils.log_execution_env_state(args.compress, msglogger.logdir, gitroot=module_path)
+    apputils.log_execution_env_state(
+        filter(None, [args.compress, args.qe_stats_file]),  # remove both None and empty strings
+        msglogger.logdir, gitroot=module_path)
     msglogger.debug("Distiller: %s", distiller.__version__)
 
     start_epoch = 0