Support 'nilmtool help command' just like 'nilmtool command --help'

nilmdb/cmdline/cmdline.py

@@ -12,8 +12,8 @@ from argparse import ArgumentDefaultsHelpFormatter as def_form
 
 # Valid subcommands.  Defined in separate files just to break
 # things up -- they're still called with Cmdline as self.
-subcommands = [ "info", "create", "list", "metadata", "insert", "extract",
-                "remove", "destroy" ]
+subcommands = [ "help", "info", "create", "list", "metadata",
+                "insert", "extract", "remove", "destroy" ]
 
 # Import the subcommand modules
 subcmd_mods = {}
@@ -31,6 +31,7 @@ class Cmdline(object):
         self.argv = argv or sys.argv[1:]
         self.client = None
         self.def_url = os.environ.get("NILMDB_URL", "http://localhost:12380")
+        self.subcmd = {}
 
     def arg_time(self, toparse):
         """Parse a time string argument"""
@@ -55,15 +56,14 @@ class Cmdline(object):
                            default=self.def_url,
                            help="NilmDB server URL (default: %(default)s)")
 
-        sub = self.parser.add_subparsers(title="Commands",
-                                         dest="command",
-                                         description="Specify --help after "
-                                         "the command for command-specific "
-                                         "options.")
+        sub = self.parser.add_subparsers(
+            title="Commands", dest="command",
+            description="Use 'help command' or 'command --help' for more "
+            "details on a particular command.")
 
         # Set up subcommands (defined in separate files)
         for cmd in subcommands:
-            subcmd_mods[cmd].setup(self, sub)
+            self.subcmd[cmd] = subcmd_mods[cmd].setup(self, sub)
 
     def die(self, formatstr, *args):
         fprintf(sys.stderr, formatstr + "\n", *args)
@@ -86,11 +86,13 @@ class Cmdline(object):
 
         self.client = nilmdb.Client(self.args.url)
 
-        # Make a test connection to make sure things work
-        try:
-            server_version = self.client.version()
-        except nilmdb.client.Error as e:
-            self.die("error connecting to server: %s", str(e))
+        # Make a test connection to make sure things work,
+        # unless the particular command requests that we don't.
+        if "no_test_connect" not in self.args:
+            try:
+                server_version = self.client.version()
+            except nilmdb.client.Error as e:
+                self.die("error connecting to server: %s", str(e))
 
         # Now dispatch client request to appropriate function.  Parser
         # should have ensured that we don't have any unknown commands

nilmdb/cmdline/create.py

@@ -26,6 +26,7 @@ Layout types are of the format: type_count
                        help="Path (in database) of new stream, e.g. /foo/bar")
     group.add_argument("layout",
                        help="Layout type for new stream, e.g. float32_8")
+    return cmd
 
 def cmd_create(self):
     """Create new stream"""

nilmdb/cmdline/destroy.py

@@ -16,6 +16,7 @@ def setup(self, sub):
     group = cmd.add_argument_group("Required arguments")
     group.add_argument("path",
                        help="Path of the stream to delete, e.g. /foo/bar")
+    return cmd
 
 def cmd_destroy(self):
     """Destroy stream"""

nilmdb/cmdline/extract.py

@@ -30,6 +30,7 @@ def setup(self, sub):
                        help="Show raw timestamps in annotated information")
     group.add_argument("-c", "--count", action="store_true",
                        help="Just output a count of matched data points")
+    return cmd
 
 def cmd_extract_verify(self):
     if self.args.start is not None and self.args.end is not None:

nilmdb/cmdline/help.py

@@ -0,0 +1,26 @@
+from nilmdb.utils.printf import *
+
+import argparse
+import sys
+
+def setup(self, sub):
+    cmd = sub.add_parser("help", help="Show detailed help for a command",
+                         description="""
+                         Show help for a command. 'help command' is
+                         the same as 'command --help'.
+                         """)
+    cmd.set_defaults(handler = cmd_help)
+    cmd.set_defaults(no_test_connect = True)
+    cmd.add_argument("command", nargs="?",
+                     help="Command to get help about")
+    cmd.add_argument("rest", nargs=argparse.REMAINDER,
+                     help=argparse.SUPPRESS)
+    return cmd
+
+def cmd_help(self):
+    if self.args.command in self.subcmd:
+        self.subcmd[self.args.command].print_help()
+    else:
+        self.parser.print_help()
+
+    return

nilmdb/cmdline/info.py

@@ -12,6 +12,7 @@ def setup(self, sub):
                          version.
                          """)
     cmd.set_defaults(handler = cmd_info)
+    return cmd
 
 def cmd_info(self):
     """Print info about the server"""

nilmdb/cmdline/insert.py

@@ -47,6 +47,7 @@ def setup(self, sub):
                        help="Path of stream, e.g. /foo/bar")
     group.add_argument("file", nargs="*", default=['-'],
                        help="File(s) to insert (default: - (stdin))")
+    return cmd
 
 def cmd_insert(self):
     # Find requested stream

nilmdb/cmdline/list.py

@@ -35,6 +35,7 @@ def setup(self, sub):
     group.add_argument("-e", "--end",
                        metavar="TIME", type=self.arg_time,
                        help="Ending timestamp (free-form, noninclusive)")
+    return cmd
 
 def cmd_list_verify(self):
     # A hidden "path_positional" argument lets the user leave off the

nilmdb/cmdline/metadata.py

@@ -26,6 +26,7 @@ def setup(self, sub):
     exc.add_argument("-u", "--update", nargs="+", metavar="key=value",
                      help="Update metadata using provided "
                      "key=value pairs")
+    return cmd
 
 def cmd_metadata(self):
     """Manipulate metadata"""

nilmdb/cmdline/remove.py

@@ -23,6 +23,7 @@ def setup(self, sub):
     group = cmd.add_argument_group("Output format")
     group.add_argument("-c", "--count", action="store_true",
                        help="Output number of data points removed")
+    return cmd
 
 def cmd_remove(self):
     try:

tests/test_cmdline.py

@@ -193,6 +193,20 @@ class TestCmdline(object):
             self.fail("extract --start 2000-01-01 --start 2001-01-02")
             self.contain("duplicated argument")
 
+        # Verify that "help command" and "command --help" are identical
+        # for all commands.
+        self.fail("")
+        m = re.search(r"{(.*)}", self.captured)
+        for command in [""] + m.group(1).split(','):
+            self.ok(command + " --help")
+            cap1 = self.captured
+            self.ok("help " + command)
+            cap2 = self.captured
+            self.ok("help " + command + " asdf --url --zxcv -")
+            cap3 = self.captured
+            eq_(cap1, cap2)
+            eq_(cap2, cap3)
+
     def test_02_parsetime(self):
         os.environ['TZ'] = "America/New_York"
         test = datetime_tz.datetime_tz.now()