ksconf merge: add '--in-place' option

docs/source/changelog.rst

@@ -38,7 +38,9 @@ Ksconf v0.12.1 (DRAFT)
    Use ``--attr-matches`` and/or ``--attr-not-matches`` to match specific attribute and value combinations for stanza matching.
    This can be used to find props with a specific ``KV_MODE``, find saved search containing a specific search command, or list indexes not using ``volume:`` designation.
    See the `ksconf_cmd_filter` docs for example usage.
+*  Add ``--in-place`` processing behavior for :ref:`ksconf_cmd_merge` to simplify the process of merging new content into an existing conf file.
 *  Fixed documentation generation bug that prevented command line options from showing up in the docs.
+*  Fixed some CLI file handling bug that resulted in broken use of ``-`` (stdin) and/or fancy shell commands involving ``<(some command)`` syntax, which can be a helpful trick to reduce the number of temporary files.
 
 
 

ksconf/commands/merge.py

@@ -15,7 +15,7 @@
 from ksconf.commands import ConfFileProxy, ConfFileType, KsconfCmd, dedent
 from ksconf.conf.merge import merge_conf_files
 from ksconf.conf.parser import PARSECONF_MID, PARSECONF_STRICT
-from ksconf.consts import EXIT_CODE_SUCCESS
+from ksconf.consts import EXIT_CODE_BAD_ARGS, EXIT_CODE_SUCCESS
 from ksconf.util.completers import conf_files_completer
 
 
@@ -44,6 +44,12 @@ def register_args(self, parser):
         parser.add_argument("--ignore-missing", "-s", default=False, action="store_true",
                             help="Silently ignore any missing CONF files.")
 
+        parser.add_argument("--in-place", "-i", default=False, action="store_true",
+                            help=dedent("""
+            Enable in-place update mode.  When selected, the target file will also be considered as
+            the base of the merge operation.  All conf files will be merged with target.  When disabled,
+            any existing content within target is ignored and overwritten."""))
+
         parser.add_argument("--dry-run", "-D", default=False, action="store_true", help=dedent("""\
             Enable dry-run mode.
             Instead of writing to TARGET, preview changes in 'diff' format.
@@ -52,6 +58,14 @@ def register_args(self, parser):
             A banner or warning comment added to the top of the TARGET file.
             Used to discourage Splunk admins from editing an auto-generated file."""))
 
+    def pre_run(self, args):
+        if args.in_place:
+            if args.target.name == "<stdout>":
+                self.stderr.write("In-place mode require '--target=FILE'.\n")
+                return EXIT_CODE_BAD_ARGS
+            # Insert target as the first source CONF file to parse
+            args.conf.insert(0, args.target.name)
+
     def run(self, args):
         ''' Merge multiple configuration files into one '''
         self.parse_profile = PARSECONF_MID