Use a completely custom usage mesage for plain --help

Keep argparse in place for --help <TOPIC>, but try to make that match
the customised short help as much as possible.

letsencrypt/cli.py

@@ -25,22 +25,30 @@ from letsencrypt import reporter
 
 from letsencrypt.display import util as display_util
 from letsencrypt.display import ops as display_ops
-
 from letsencrypt.plugins import disco as plugins_disco
 
-USAGE = """
+# Argparse's help formatting has a lot of unhelpful peculiarities, so we want
+# to replace as much of it as we can...
+
+# This is the stub to include in help generated by argparse
+
+SHORT_USAGE = """
   letsencrypt [SUBCOMMAND] [options] [domains]
 
 The Let's Encrypt agent can obtain and install HTTPS/TLS/SSL certificates.  By
 default, it will attempt to use a webserver both for obtaining and installing
-the cert.  Major SUBCOMMANDS are:
+the cert.  """
 
-  (default)         Obtain & install a cert in your current webserver
-  auth              Authenticate & obtain cert, but do not install it
-  install           Install a previously obtained cert in a server
-  revoke            Revoke a previously obtained certificate
-  rollback          Rollback server configuration changes made during install
-  config-changes    Show changes made to server config during installation
+# This is the short help for letsencrypt --help, where we disable argparse
+# altogether
+USAGE = SHORT_USAGE + """Major SUBCOMMANDS are:
+
+  (default) everything Obtain & install a cert in your current webserver
+  auth                 Authenticate & obtain cert, but do not install it
+  install              Install a previously obtained cert in a server
+  revoke               Revoke a previously obtained certificate
+  rollback             Rollback server configuration changes made during install
+  config-changes       Show changes made to server config during installation
 
 Choice of server for authentication/installation:
 
@@ -142,7 +150,7 @@ def run(args, config, plugins):
 
 
 def auth(args, config, plugins):
-    """Obtain a certificate (no install)."""
+    """Authenticate & obtain cert, but do not install it"""
     # XXX: Update for renewer / RenewableCert
     acc = _account_init(args, config)
     if acc is None:
@@ -167,7 +175,7 @@ def auth(args, config, plugins):
 
 
 def install(args, config, plugins):
-    """Install cert in server software (no auth)."""
+    """Install a previously obtained cert in a server"""
     # XXX: Update for renewer/RenewableCert
     acc = _account_init(args, config)
     if acc is None:
@@ -184,7 +192,7 @@ def install(args, config, plugins):
 
 
 def revoke(args, unused_config, unused_plugins):
-    """Revoke."""
+    """Revoke a previously obtained certificate"""
     if args.rev_cert is None and args.rev_key is None:
         return "At least one of --certificate or --key is required"
 
@@ -196,12 +204,12 @@ def revoke(args, unused_config, unused_plugins):
 
 
 def rollback(args, config, plugins):
-    """Rollback."""
+    """Rollback server configuration changes made during install"""
     client.rollback(args.installer, args.checkpoints, config, plugins)
 
 
 def config_changes(unused_args, config, unused_plugins):
-    """View config changes.
+    """Show changes made to server config during installation
 
     View checkpoints and associated configuration changes.
 
@@ -210,7 +218,7 @@ def config_changes(unused_args, config, unused_plugins):
 
 
 def plugins_cmd(args, config, plugins):  # TODO: Use IDiplay rathern than print
-    """List plugins."""
+    """List server software plugins"""
     logging.debug("Expected interfaces: %s", args.ifaces)
 
     ifaces = [] if args.ifaces is None else args.ifaces
@@ -285,16 +293,22 @@ class HelpfulArgumentParser(object):
         plugin_names = [name for name, _p in plugins.iteritems()]
         self.help_topics = HELP_TOPICS + plugin_names
         self.parser = configargparse.ArgParser(
-            description=__doc__,
+            usage=SHORT_USAGE,
             formatter_class=argparse.ArgumentDefaultsHelpFormatter,
             args_for_setting_config_path=["-c", "--config"],
             default_config_files=flag_default("config_files"))
+
+        self.parser._add_config_file_help = False
         self.silent_parser = SilentParser(self.parser)
 
         h1 = self.prescan_for_flag("-h", self.help_topics)
         h2 = self.prescan_for_flag("--help", self.help_topics)
         assert max(True, "a") == "a", "Gravity changed direction"
         help_arg = max(h1, h2)
+        if help_arg == True:
+          # just --help with no topic; avoid argparse altogether
+          print USAGE
+          sys.exit(0)
         self.visible_topics = self.determine_help_topics(help_arg)
         #print self.visible_topics
         self.groups = {}  # elements are added by .add_group()