From 8dcace4bfdf1bb513b5f5ab5aada1bd9e8f8c5d0 Mon Sep 17 00:00:00 2001
From: palmtree5 <3577255+palmtree5@users.noreply.github.com>
Date: Sun, 19 Nov 2017 14:17:01 -0900
Subject: [PATCH] [Core V3] add instance listing cli flag (#1079)

* [Core] add instance listing cli flag

* Alphabetically sort instance names
---
 redbot/__main__.py | 22 +++++++++++++++++++++-
 redbot/core/cli.py |  5 ++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/redbot/__main__.py b/redbot/__main__.py
index 7ce9a5cc3..560b9b200 100644
--- a/redbot/__main__.py
+++ b/redbot/__main__.py
@@ -6,7 +6,8 @@ import sys
 import discord
 from redbot.core.bot import Red, ExitCodes
 from redbot.core.cog_manager import CogManagerUI
-from redbot.core.data_manager import load_basic_configuration
+from redbot.core.data_manager import load_basic_configuration, config_file
+from redbot.core.json_io import JsonIO
 from redbot.core.global_checks import init_global_checks
 from redbot.core.events import init_events
 from redbot.core.sentry_setup import init_sentry_logging
@@ -81,8 +82,27 @@ async def _get_prefix_and_token(red, indict):
     indict['enable_sentry'] = await red.db.enable_sentry()
 
 
+def list_instances():
+    if not config_file.exists():
+        print("No instances have been configured! Configure one "
+              "using `redbot-setup` before trying to run the bot!")
+        sys.exit(1)
+    else:
+        data = JsonIO(config_file)._load_json()
+        text = "Configured Instances:\n\n"
+        for instance_name in sorted(data.keys()):
+            text += "{}\n".format(instance_name)
+        print(text)
+        sys.exit(0)
+
+
 def main():
     cli_flags = parse_cli_flags(sys.argv[1:])
+    if cli_flags.list_instances:
+        list_instances()
+    elif not cli_flags.instance_name:
+        print("Error: No instance name was provided!")
+        sys.exit(1)
     load_basic_configuration(cli_flags.instance_name)
     log, sentry_log = init_loggers(cli_flags)
     description = "Red - Version {}".format(__version__)
diff --git a/redbot/core/cli.py b/redbot/core/cli.py
index fe6e00185..87c58cb92 100644
--- a/redbot/core/cli.py
+++ b/redbot/core/cli.py
@@ -63,6 +63,9 @@ def ask_sentry(red: Red):
 
 def parse_cli_flags(args):
     parser = argparse.ArgumentParser(description="Red - Discord Bot")
+    parser.add_argument("--list-instances", action="store_true",
+                        help="List all instance names setup "
+                             "with 'redbot-setup'")
     parser.add_argument("--owner", type=int,
                         help="ID of the owner. Only who hosts "
                              "Red should be owner, this has "
@@ -106,7 +109,7 @@ def parse_cli_flags(args):
                         action="store_true",
                         help="Enables the built-in RPC server. Please read the docs"
                              "prior to enabling this!")
-    parser.add_argument("instance_name",
+    parser.add_argument("instance_name", nargs="?",
                         help="Name of the bot instance created during `redbot-setup`.")
 
     args = parser.parse_args(args)