reload env file on hot reload in granian (#5510)

Author: adhami3310

pyproject.toml

@@ -22,7 +22,7 @@ requires-python = ">=3.10,<4.0"
 dependencies = [
   "alembic >=1.15.2,<2.0",
   "fastapi >=0.115.0",
-  "granian[reload] >=2.2.5",
+  "granian[reload] >=2.4.0",
   "httpx >=0.28.0,<1.0",
   "jinja2 >=3.1.2,<4.0",
   "packaging >=24.2,<26",

reflex/config.py

@@ -19,48 +19,18 @@
 from reflex.constants.base import LogLevel
 from reflex.environment import EnvironmentVariables as EnvironmentVariables
 from reflex.environment import EnvVar as EnvVar
-from reflex.environment import ExistingPath, interpret_env_var_value
+from reflex.environment import (
+    ExistingPath,
+    _load_dotenv_from_str,
+    interpret_env_var_value,
+)
 from reflex.environment import env_var as env_var
 from reflex.environment import environment as environment
 from reflex.plugins import Plugin
 from reflex.utils import console
 from reflex.utils.exceptions import ConfigError
 from reflex.utils.types import true_type_for_pydantic_field
 
-try:
-    from dotenv import load_dotenv
-except ImportError:
-    load_dotenv = None
-
-
-def _load_dotenv_from_str(env_files: str) -> None:
-    if not env_files:
-        return
-
-    if load_dotenv is None:
-        console.error(
-            """The `python-dotenv` package is required to load environment variables from a file. Run `pip install "python-dotenv>=1.1.0"`."""
-        )
-        return
-
-    # load env files in reverse order if they exist
-    for env_file_path in [
-        Path(p) for s in reversed(env_files.split(os.pathsep)) if (p := s.strip())
-    ]:
-        if env_file_path.exists():
-            load_dotenv(env_file_path, override=True)
-
-
-def _load_dotenv_from_env():
-    """Load environment variables from paths specified in REFLEX_ENV_FILE."""
-    env_env_file = os.environ.get("REFLEX_ENV_FILE")
-    if env_env_file:
-        _load_dotenv_from_str(env_env_file)
-
-
-# Load the env files at import time if they are set in the ENV_FILE environment variable.
-_load_dotenv_from_env()
-
 
 class DBConfig(Base):
     """Database config."""

reflex/environment.py

@@ -606,3 +606,39 @@ class EnvironmentVariables:
 
 
 environment = EnvironmentVariables()
+
+try:
+    from dotenv import load_dotenv
+except ImportError:
+    load_dotenv = None
+
+
+def _load_dotenv_from_str(env_files: str) -> None:
+    from reflex.utils import console
+
+    if not env_files:
+        return
+
+    if load_dotenv is None:
+        console.error(
+            """The `python-dotenv` package is required to load environment variables from a file. Run `pip install "python-dotenv>=1.1.0"`."""
+        )
+        return
+
+    # load env files in reverse order if they exist
+    for env_file_path in [
+        Path(p) for s in reversed(env_files.split(os.pathsep)) if (p := s.strip())
+    ]:
+        if env_file_path.exists():
+            load_dotenv(env_file_path, override=True)
+
+
+def _load_dotenv_from_env():
+    """Load environment variables from paths specified in REFLEX_ENV_FILE."""
+    env_env_file = os.environ.get("REFLEX_ENV_FILE")
+    if env_env_file:
+        _load_dotenv_from_str(env_env_file)
+
+
+# Load the env files at import time if they are set in the ENV_FILE environment variable.
+_load_dotenv_from_env()

reflex/utils/exec.py

@@ -502,6 +502,13 @@ def run_uvicorn_backend(host: str, port: int, loglevel: LogLevel):
 )
 
 
+def _reload_hook():
+    """Hook to load environment variables from .env file."""
+    from reflex.environment import _load_dotenv_from_env
+
+    _load_dotenv_from_env()
+
+
 def run_granian_backend(host: str, port: int, loglevel: LogLevel):
     """Run the backend in development mode using Granian.
 
@@ -521,7 +528,7 @@ def run_granian_backend(host: str, port: int, loglevel: LogLevel):
     from granian.log import LogLevels
     from granian.server import MPServer as Granian
 
-    Granian(
+    granian_app = Granian(
         target=get_app_instance_from_file(),
         factory=True,
         address=host,
@@ -534,7 +541,11 @@ def run_granian_backend(host: str, port: int, loglevel: LogLevel):
         reload_ignore_patterns=HOTRELOAD_IGNORE_PATTERNS,
         reload_tick=100,
         workers_kill_timeout=2,
-    ).serve()
+    )
+
+    granian_app.on_reload(_reload_hook)
+
+    granian_app.serve()
 
 
 def run_backend_prod(