Only log slurm node list if it's been modified

Signed-off-by: Tim Lane <tilne@amazon.com>

src/sqswatcher/plugins/slurm.py

@@ -13,6 +13,7 @@
 # This file has a special meaning for pytest. See https://docs.pytest.org/en/2.7.3/plugins.html for
 # additional details.
 
+import filecmp
 import logging
 import os
 import os.path
@@ -76,14 +77,18 @@ def _read_node_list(config_file):
 
 
 def _write_node_list_to_file(generic_node_list, config_file_path):
-    log.info("Writing updated {0} with the following nodes: {1}".format(config_file_path, generic_node_list))
     with tempfile.NamedTemporaryFile(mode="w", delete=False) as file:
         abs_path = file.name
         # Adding a comment to the file so that Slurm does not display warnings in case of empty file
         file.write("# This file is automatically generated by ParallelCluster\n\n")
         for node in generic_node_list:
             file.write("{0}".format(node))
 
+    # Only log the updated node list if it's different from the previous version,
+    # because it can get quite long.
+    if not filecmp.cmp(config_file_path, abs_path, shallow=False):
+        log.info("Writing updated {0} with the following nodes: {1}".format(config_file_path, generic_node_list))
+
     # Update permissions on new file
     os.chmod(abs_path, 0o744)
     # Move new file