feat: base flask x gunicorn server

app/params.py

@@ -1,20 +1,70 @@
 import argparse
 import dataclasses
+import os
 import typing
 
-from . import PKG_NAME
+from app import PKG_NAME
 
 
 @dataclasses.dataclass(frozen=True, slots=True)
 class Parameters:
     debug: bool = False
     quiet: bool = False
+    env: str = "production"
+    bind: str = "0.0.0.0"
+    port: int = 5000
+    workers: int = 4
+    timeout: int = 120
 
     @classmethod
     def from_namespace(cls, args: argparse.Namespace) -> Parameters:
         return Parameters(**vars(args))
 
 
+def __get_env_str(var: str, default: str) -> str:
+    if (result := os.getenv(var)) is None:
+        return default
+    return result
+
+
+def __get_env_int(var: str, default: int) -> int:
+    value = __get_env_str(var, str(default))
+    if value.isdecimal():
+        return int(value)
+    return default
+
+
+def __add_arg_str(
+    parser: argparse.ArgumentParser,
+    *flags: str,
+    env_var: str,
+    default: str,
+    help_txt: str,
+) -> None:
+    parser.add_argument(
+        *flags,
+        metavar=env_var,
+        default=__get_env_str(env_var, default),
+        help=f"{help_txt} (default: {default})" if len(default) else help_txt,
+    )
+
+
+def __add_arg_int(
+    parser: argparse.ArgumentParser,
+    *flags: str,
+    env_var: str,
+    default: int,
+    help_txt: str,
+) -> None:
+    parser.add_argument(
+        *flags,
+        type=int,
+        metavar=env_var,
+        default=__get_env_int(env_var, default),
+        help=f"{help_txt} (default: {default})",
+    )
+
+
 def parse_parameters(args: typing.Sequence[str]) -> Parameters:
     default_values = Parameters()
     parser = argparse.ArgumentParser(
@@ -27,5 +77,40 @@ def parse_parameters(args: typing.Sequence[str]) -> Parameters:
     parser.add_argument(
         "--quiet", action=argparse.BooleanOptionalAction, default=default_values.quiet
     )
+    __add_arg_str(
+        parser,
+        "--env",
+        env_var="APP_ENV",
+        default=default_values.env,
+        help_txt="environnement",
+    )
+    __add_arg_str(
+        parser,
+        "--bind",
+        env_var="BIND",
+        default=default_values.bind,
+        help_txt="server bind address",
+    )
+    __add_arg_int(
+        parser,
+        "--port",
+        env_var="PORT",
+        default=default_values.port,
+        help_txt="server http port",
+    )
+    __add_arg_int(
+        parser,
+        "--workers",
+        env_var="WORKERS",
+        default=default_values.workers,
+        help_txt="WSGI workers",
+    )
+    __add_arg_int(
+        parser,
+        "--timeout",
+        env_var="TIMEOUT",
+        default=default_values.timeout,
+        help_txt="WSGI timeout",
+    )
     parsed_args = parser.parse_args(args)
     return Parameters.from_namespace(parsed_args)