Add basic program scaffolding

glassy/__main__.py

@@ -0,0 +1,36 @@
+"""Main program entrypoint and CLI interface"""
+
+import argparse
+import sys
+from pathlib import Path
+
+from glassy import __about__
+
+
+def get_args() -> argparse.Namespace:
+    """Parse the CLI arguments"""
+
+    parser = argparse.ArgumentParser(prog=__about__.__title__, description=__about__.__summary__)
+
+    parser.add_argument("--version", help="Show program version and exit", action="store_true")
+    parser.add_argument("-c", "--config", help="Path to the program config file", default=Path("~", ".config", "glassy.yaml").resolve())
+    parser.add_argument("--check", help="Check syntax of the config file and diagram without running network tests", action="store_true")
+    parser.add_argument("-o", "--output", help="Path to a file to output the rendered result, or one of the magic values 'stdout' or 'stderr'", default="stdout")
+    parser.add_argument("template", help="Path to the template diagram to render and output")
+
+    return parser.parse_args()
+    
+
+def main() -> int:
+    args = get_args()
+
+    if args.version:
+        print(f"{__about__.__title__} {__about__.__version__}", file=sys.stderr)
+        return 0
+
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())