add app.py & server.py

Quite obviously inspired (a.k.a. copied from) my other project,
linux-status. The same goes for test/.

1 files changed, 127 insertions, 0 deletions

diff --git a/server.py b/server.py
new file mode 100755
index 0000000..9fa7530
--- /dev/null
+++ b/server.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2022 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "void" project.
+# For details, see https://github.com/egor-tensin/void.
+# Distributed under the MIT License.
+
+import argparse
+from contextlib import contextmanager
+import http.server
+import os
+import signal
+import sys
+from threading import Condition, Lock, Thread
+import traceback
+
+from app import Request, Response, Void
+
+
+DEFAULT_PORT = 23666
+EXITING = False
+
+
+def script_dir():
+    return os.path.dirname(os.path.realpath(__file__))
+
+
+def set_exiting():
+    global EXITING
+    with SignalHandler.LOCK:
+        EXITING = True
+        SignalHandler.CV.notify()
+
+
+class SignalHandler:
+    LOCK = Lock()
+    CV = Condition(LOCK)
+
+    def __init__(self, httpd):
+        self.httpd = httpd
+        self.thread = Thread(target=self.run)
+
+    def __enter__(self):
+        self.thread.start()
+        return self
+
+    def __exit__(self, type, value, traceback):
+        self.thread.join()
+
+    def run(self):
+        with SignalHandler.CV:
+            while not EXITING:
+                SignalHandler.CV.wait()
+            self.httpd.shutdown()
+
+
+def handle_sigterm(signum, frame):
+    print('\nSIGTERM received, exiting...')
+    set_exiting()
+
+
+@contextmanager
+def setup_signal_handlers(httpd):
+    handler_thread = SignalHandler(httpd)
+    with handler_thread:
+        signal.signal(signal.SIGTERM, handle_sigterm)
+        yield
+        # TODO: cleanup signal handlers?
+
+
+class RequestHandler(http.server.SimpleHTTPRequestHandler):
+    VOID = None
+
+    def do_GET(self):
+        try:
+            request = Request.from_http_path(self.path)
+        except ValueError:
+            return super().do_GET()
+        try:
+            response = request.process(RequestHandler.VOID)
+            response.write_to_request_handler(self)
+        except:
+            status = http.server.HTTPStatus.INTERNAL_SERVER_ERROR
+            response = Response(traceback.format_exc(), status)
+            response.write_to_request_handler(self)
+            return
+
+
+def make_server(port):
+    addr = ('', port)
+    server = http.server.HTTPServer
+    if sys.version_info >= (3, 7):
+        server = http.server.ThreadingHTTPServer
+    return server(addr, RequestHandler)
+
+
+def parse_args(args=None):
+    if args is None:
+        args = sys.argv[1:]
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-p', '--port', metavar='PORT',
+                        type=int, default=DEFAULT_PORT,
+                        help='set port number')
+    parser.add_argument('-v', '--void', metavar='PATH', dest='backup',
+                        help='set path to the void')
+    return parser.parse_args(args)
+
+
+def main(args=None):
+    # It's a failsafe; this script is only allowed to serve the directory it
+    # resides in.
+    os.chdir(script_dir())
+
+    args = parse_args(args)
+    with Void(args.backup) as void:
+        RequestHandler.VOID = void
+        httpd = make_server(args.port)
+        with setup_signal_handlers(httpd):
+            try:
+                httpd.serve_forever()
+            except KeyboardInterrupt:
+                print('\nKeyboard interrupt received, exiting...')
+                set_exiting()
+
+
+if __name__ == '__main__':
+    main()