feat: hot-reload configuration file

app/main.py

@@ -1,20 +1,27 @@
 """FastAPI module to serve the backend API and all frontend sites."""
 
 from contextlib import asynccontextmanager
-from fastapi import FastAPI, Depends, Request, Path as FasAPIPath
-from fastapi.staticfiles import StaticFiles
-from fastapi.responses import Response
-from pydantic import EmailStr, Field, BaseModel
-from os import getenv
 from datetime import datetime
+from os import getenv
 from pathlib import Path
 
+from fastapi import Depends, FastAPI
+from fastapi import Path as FasAPIPath
+from fastapi import Request
+from fastapi.responses import Response
+from fastapi.staticfiles import StaticFiles
+from modules.config_handler import ConfigHandler
+from pydantic import BaseModel, EmailStr, Field
+from watchdog.observers import Observer
+
 API_PREFIX: str = getenv("API_PREFIX", "/api")
 DATA_PATH: Path = Path(getenv("DATA_PATH", "./data"))
 CSV_HEADER: str = "email,timestamp\n"
 ADMIN_SECRET: str = getenv("ADMIN_SECRET", "admin")
 STATIC_PAGES_DIR: Path = Path(getenv("STATIC_PAGES_DIR", "./static_pages"))
 
+CONF_PATH: Path = Path("./conf/config.yaml")
+
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
@@ -99,3 +106,8 @@ async def get_emails(
 
 
 app.mount("/", StaticFiles(directory=STATIC_PAGES_DIR, html=True), name="static")
+
+observer = Observer()
+config_handler = ConfigHandler()
+observer.schedule(config_handler, path=CONF_PATH, recursive=False)
+observer.start()

app/modules/config_handler.py

@@ -0,0 +1,18 @@
+from pathlib import Path
+
+from modules.site_renderer import SiteRenderer
+from watchdog.events import FileSystemEventHandler
+
+TEMPLATE_SRC: Path = Path("./template/src/")
+CONF_PATH: Path = Path("./conf/config.yaml")
+STATIC_PAGES_DIR: Path = Path("./static_pages")
+
+
+class ConfigHandler(FileSystemEventHandler):
+
+    def __init__(self):
+        self.site_renderer = SiteRenderer(CONF_PATH, TEMPLATE_SRC, STATIC_PAGES_DIR)
+
+    def on_modified(self, event):
+        if event.src_path == str(CONF_PATH):
+            self.site_renderer.render_sites()

app/scripts/render_sites.py → app/modules/site_renderer.py

@@ -1,26 +1,33 @@
 """Module to render the template for the configured sites."""
 
-import yaml
-from pathlib import Path
+import os
 import shutil
+from pathlib import Path
+
+import yaml
 from jinja2 import Environment, FileSystemLoader
 from loguru import logger
 
 TEMPLATE_SRC: Path = Path("./template/src/")
 CONF_PATH: Path = Path("./conf/config.yaml")
 STATIC_PAGES_DIR: Path = Path("./static_pages")
 
-if __name__ == "__main__":
-    with open(CONF_PATH, "r") as conf_file:
-        conf = yaml.safe_load(conf_file)
 
-    for site in conf["sites"]:
+class SiteRenderer:
+    def __init__(self, conf_path: Path, template_src: Path, static_pages_dir: Path):
+        self.conf_path = conf_path
+        self.template_src = template_src
+        self.static_pages_dir = static_pages_dir
+
+    def render_site(self, site: dict) -> None:
         page_identifier = site["page_identifier"]
         logger.info(f"Rendering site: {page_identifier}")
-        site_path: Path = STATIC_PAGES_DIR / page_identifier
+        site_path: Path = self.static_pages_dir / page_identifier
 
         # recursive copy of template files to site directory
-        shutil.copytree(TEMPLATE_SRC, site_path)
+        if os.path.exists(site_path):
+            shutil.rmtree(site_path)
+        shutil.copytree(self.template_src, site_path)
 
         # replace jinja variables in index.html
         env = Environment(loader=FileSystemLoader(site_path))
@@ -29,3 +36,14 @@
 
         with open(site_path / "index.html", "w") as f:
             f.write(rendered)
+
+    def render_sites(self) -> None:
+        with open(self.conf_path, "r") as conf_file:
+            conf = yaml.safe_load(conf_file)
+
+        for site in conf["sites"]:
+            self.render_site(site)
+
+
+if __name__ == "__main__":
+    SiteRenderer(CONF_PATH, TEMPLATE_SRC, STATIC_PAGES_DIR).render_sites()

app/prestart.sh

@@ -1,4 +1,4 @@
 #! /usr/bin/env bash
 
-cd /app
-python scripts/render_sites.py
+cd /app || exit
+python modules/site_renderer.py

requirements.in

@@ -6,3 +6,4 @@ loguru
 pydantic
 pyyaml
 uvicorn
+watchdog

requirements.txt

@@ -1,5 +1,5 @@
 #
-# This file is autogenerated by pip-compile with Python 3.11
+# This file is autogenerated by pip-compile with Python 3.12
 # by the following command:
 #
 #    pip-compile
@@ -51,3 +51,5 @@ typing-extensions==4.11.0
     #   pydantic-core
 uvicorn==0.29.0
     # via -r requirements.in
+watchdog==4.0.0
+    # via -r requirements.in