Add CLI for running Shattered apps

examples/chat/Dockerfile

@@ -2,6 +2,7 @@ FROM python:3
 
 ENV FLASK_APP=chat.py
 ENV FLASK_ENV=development
+ENV SHATTERED_APP=chat.py
 
 COPY requirements.txt /src/requirements.txt
 

examples/chat/chat.py

@@ -21,7 +21,3 @@ def echo(headers, body, conn):
     data = dict(parse_qsl(body))
     email = data["email"]
     conn.send(body=f'<li>{email}: {data["message"]}</li>', destination="/topic/chat")
-
-
-if __name__ == "__main__":
-    shattered_app.run()

examples/chat/docker-compose.yml

@@ -15,8 +15,8 @@ services:
         "300",
         "rabbitmq:61613",
         "--",
-        "python",
-        "chat.py",
+        "shattered",
+        "run",
       ]
   chat:
     build: .

pyproject.toml

@@ -1,12 +1,15 @@
 [tool.poetry]
 name = "shattered"
-version = "0.2.0"
+version = "0.3.0"
 description = "STOMP meets bottle.py"
 authors = ["Jimmy Bradshaw <[email protected]>"]
 repository = "https://github.com/bradshjg/shattered"
 license = "MIT"
 readme = "README-PYPI.md"
 
+[tool.poetry.scripts]
+shattered = "shattered.cli:main"
+
 [tool.poetry.dependencies]
 python = "^3.6"
 "stomp.py" = "^5.0.0"

src/shattered/__init__.py

@@ -1,3 +1,3 @@
-__version__ = "0.2.0"
+__version__ = "0.3.0"
 
 from shattered.shattered import Shattered

src/shattered/cli.py

@@ -0,0 +1,47 @@
+import argparse
+import os
+import sys
+
+from .shattered import Shattered
+
+
+def load_app(args):
+    sys.path.insert(0, os.getcwd())
+    module_file = args.app or os.getenv("SHATTERED_APP", "app.py")
+    module_name = os.path.splitext(module_file)[0]
+    __import__(module_name)
+    module = sys.modules[module_name]
+    matches = [v for v in module.__dict__.values() if isinstance(v, Shattered)]
+    if len(matches) == 1:
+        return matches[0]
+    else:
+        raise EnvironmentError("Detected multiple Shattered applications.")
+
+
+def run_app(args):
+    app = load_app(args)
+    app.run()
+
+
+def print_config(args):
+    app = load_app(args)
+    for k, v in app.config.items():
+        print(f"{k}: {v}")
+
+
+def parse_arguments():
+    parser = argparse.ArgumentParser(prog="shattered")
+    parser.add_argument("-a", "--app", help="shattered app")
+    subparsers = parser.add_subparsers(
+        title="subcommands", description="valid subcommands", help="additional help"
+    )
+    parser_run = subparsers.add_parser("run", help="run shattered app")
+    parser_run.set_defaults(func=run_app)
+    parser_config = subparsers.add_parser("config", help="show shattered app config")
+    parser_config.set_defaults(func=print_config)
+    return parser.parse_args()
+
+
+def main():
+    args = parse_arguments()
+    args.func(args)

src/shattered/shattered.py

@@ -27,16 +27,25 @@ def on_message(self, headers, body):
 class Shattered:
     def __init__(self, **config):
         self.config = config
-        self.host = self.config.get("host", "localhost")
-        self.port = self.config.get("port", 61613)
-        self.username = self.config.get("username", "guest")
-        self.password = self.config.get("password", "guest")
-        self.vhost = self.config.get("vhost", "/")
+        self._set_config_defaults()
+
+        self.host = self.config["host"]
+        self.port = self.config["port"]
+        self.username = self.config["username"]
+        self.password = self.config["password"]
+        self.vhost = self.config["vhost"]
 
         self.subscriptions = {}
         self.conn = None
         self.listener = ShatteredListener(self)
 
+    def _set_config_defaults(self):
+        self.config.setdefault("host", "localhost")
+        self.config.setdefault("port", 61613)
+        self.config.setdefault("username", "guest")
+        self.config.setdefault("password", "guest")
+        self.config.setdefault("vhost", "/")
+
     def add_subscription(self, destination, callback):
         if destination not in self.subscriptions:
             self.subscriptions[destination] = []