Bazel + Gunicorn

__main__.py

from gunicorn.app.wsgiapp import run
run()

BUILD.bazel

gunicorn_binary(
    name = "hello",
    args = ["hello:app"],
    deps = [
        "@pypi_flask//:pkg",
    ],
)

guincorn.bzl

load("@rules_python//python:defs.bzl", "py_binary", "py_library")

def gunicorn_binary(name, deps = [], **kwargs):
    py_library(
        name = name + "_lib",
        srcs = [name + ".py"],
        deps = deps,
    )

    args = kwargs.pop("args", [name + ":app"])
    py_binary(
        name = name,
        srcs = ["//python/wrappers/gunicorn:__main__.py"],
        main = "//python/wrappers/gunicorn:__main__.py",
        deps = [
            "@pypi_gunicorn//:pkg",
            ":" + name + "_lib",
        ],
        args = args,
        **kwargs
    )