app: first draft of dash app

src/arcmapper/__init__.py

@@ -1,8 +1,24 @@
+import os
+import time
+import socket
+import logging
+import threading
+import subprocess
+import webbrowser
+
 import pandas as pd
+from waitress import serve
+from .app import app
 from .arc import read_arc_schema
 from .dictionary import read_data_dictionary
 from .strategies import tf_idf, sbert
 
+__version__ = "0.1.0"
+
+ARCMAPPER_HOST = os.getenv("ARCMAPPER_HOST", "127.0.0.1")
+ARCMAPPER_PORT = int(os.getenv("ARCMAPPER_PORT", 8050))
+ARCMAPPER_TIMEOUT = 30
+
 
 def map(
     method: str,
@@ -20,4 +36,63 @@ def map(
             raise ValueError(f"Unknown mapping method: {method}")
 
 
-__all__ = ["read_arc_schema", "map", "read_data_dictionary"]
+def launch_app():
+    logging.getLogger("waitress.queue").setLevel(logging.ERROR)
+    serve(app.server, host=ARCMAPPER_HOST, port=ARCMAPPER_PORT)
+
+
+def launch_subprocess():
+    logging.getLogger("waitress.queue").setLevel(logging.ERROR)
+    return subprocess.Popen(
+        [
+            "waitress-serve",
+            "--host",
+            ARCMAPPER_HOST,
+            "--port",
+            str(ARCMAPPER_PORT),
+            "arcmapper.app:app.server",
+        ]
+    )
+
+
+def check_port(host: str, port: int) -> bool:
+    try:
+        with socket.create_connection((host, port), timeout=1):
+            return True
+    except (OSError, ConnectionRefusedError):
+        return False
+
+
+def wait_for_server(
+    host=ARCMAPPER_HOST, port=ARCMAPPER_PORT, timeout=ARCMAPPER_TIMEOUT
+) -> bool:
+    start_time = time.time()
+    while time.time() - start_time < timeout:
+        try:
+            if check_port(host, port):
+                return True
+        except (OSError, ConnectionRefusedError):
+            time.sleep(1)
+    raise TimeoutError(f"Server did not start within {timeout} seconds")
+
+
+def main():
+    if check_port(ARCMAPPER_HOST, ARCMAPPER_PORT):
+        logging.info("Port is already in use. Opening browser.")
+        webbrowser.open(f"http://{ARCMAPPER_HOST}:{ARCMAPPER_PORT}")
+        return
+    # Launch the server in a separate thread
+    server_thread = threading.Thread(target=launch_app)
+    server_thread.start()
+    # Wait for startup before opening web browser
+    wait_for_server(
+        ARCMAPPER_HOST,
+        ARCMAPPER_PORT,
+        ARCMAPPER_TIMEOUT,
+    )
+    webbrowser.open(f"http://{ARCMAPPER_HOST}:{ARCMAPPER_PORT}")
+    # Join the server thread and wait for it to finish or be closed
+    server_thread.join()
+
+
+__all__ = ["read_arc_schema", "map", "read_data_dictionary", "main"]

src/arcmapper/__main__.py

@@ -0,0 +1,21 @@
+import logging
+import argparse
+from . import main
+from .app import app
+
+
+if __name__ == "__main__":
+    p = argparse.ArgumentParser()
+    p.add_argument("--debug", action="store_true")
+    args = p.parse_args()
+
+    if args.debug:
+        # Dash launches a Flask development server
+        root_logger = logging.getLogger()
+        if root_logger.hasHandlers():
+            root_logger.handlers.clear()
+        logging.basicConfig(level=logging.INFO)
+        app.run(debug=True)
+    else:
+        # Otherwise, launch the production server
+        main()

src/arcmapper/app.py

@@ -0,0 +1,39 @@
+"""Dash frontend for the arcmapper library"""
+
+import dash
+from dash import html
+import dash_bootstrap_components as dbc
+
+
+app = dash.Dash("arcmapper", external_stylesheets=[dbc.themes.BOOTSTRAP])
+app.title = "ARCMapper"
+
+navbar = dbc.Navbar(
+    dbc.Container(
+        [
+            html.A(
+                # Use row and col to control vertical alignment of logo / brand
+                dbc.Row(
+                    [
+                        dbc.Col(
+                            html.Img(src="assets/ISARIC_logo_wh.png", height="60px")
+                        ),
+                        dbc.Col(dbc.NavbarBrand("ARCMapper", className="ms-2")),
+                    ],
+                    align="center",
+                    className="g-0",
+                ),
+                href="https://isaric.org/",
+                style={"textDecoration": "none"},
+            ),
+            dbc.NavbarToggler(id="navbar-toggler", n_clicks=0),
+        ]
+    ),
+    color="#BA0225",
+    dark=True,
+)
+
+main_content = dbc.Container([dbc.Row([html.H1("Hello world")])])
+
+app.layout = dbc.Container([navbar, main_content])
+server = app.server