Add --reload-dir command line option

Author: jcheng5

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### New features
 
+* `shiny run` now takes zero or more `--reload-dir` arguments that can be used with `--reload` to indicate what directories should be (recursively) monitored for reload. If zero such arguments are passed, then the directory containing the app will be recursively monitored.
 
 ### Bug fixes
 

shiny/_main.py

@@ -1,12 +1,13 @@
 import copy
 import importlib
 import importlib.util
+import inspect
 import os
 import shutil
 import sys
 import types
 from pathlib import Path
-from typing import Any, Dict, Optional, Tuple, Union
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 import click
 import uvicorn
@@ -67,6 +68,14 @@ def main() -> None:
     "--debug", is_flag=True, default=False, help="Enable debug mode.", hidden=True
 )
 @click.option("--reload", is_flag=True, default=False, help="Enable auto-reload.")
+@click.option(
+    "--reload-dir",
+    "reload_dirs",
+    multiple=True,
+    help="Set reload directories explicitly, instead of using the current working"
+    " directory.",
+    type=click.Path(exists=True),
+)
 @click.option(
     "--ws-max-size",
     type=int,
@@ -110,6 +119,7 @@ def run(
     autoreload_port: int,
     debug: bool,
     reload: bool,
+    reload_dirs: Tuple[str, ...],
     ws_max_size: int,
     log_level: str,
     app_dir: str,
@@ -123,6 +133,7 @@ def run(
         autoreload_port=autoreload_port,
         debug=debug,
         reload=reload,
+        reload_dirs=list(reload_dirs),
         ws_max_size=ws_max_size,
         log_level=log_level,
         app_dir=app_dir,
@@ -138,6 +149,7 @@ def run_app(
     autoreload_port: int = 0,
     debug: bool = False,
     reload: bool = False,
+    reload_dirs: Optional[List[str]] = None,
     ws_max_size: int = 16777216,
     log_level: Optional[str] = None,
     app_dir: Optional[str] = ".",
@@ -220,11 +232,16 @@ def run_app(
 
     log_config: Dict[str, Any] = copy.deepcopy(uvicorn.config.LOGGING_CONFIG)
 
-    if reload and app_dir is not None:
-        reload_dirs = [app_dir]
-    else:
+    if reload_dirs is None:
         reload_dirs = []
 
+    if reload and len(reload_dirs) == 0 and app_dir is not None:
+        reload_dirs.append(app_dir)
+
+    if reload and os.getenv("SHINY_PKG_AUTORELOAD"):
+        shinypath = Path(inspect.getfile(shiny)).parent
+        reload_dirs.append(str(shinypath))
+
     if reload:
         if autoreload_port == 0:
             autoreload_port = _utils.random_port(host=host)
@@ -242,6 +259,15 @@ def run_app(
 
     maybe_setup_rsw_proxying(log_config)
 
+    if "WEB_CONCURRENCY" in os.environ:
+        # WEB_CONCURRENCY is one way to set uvicorn's worker count; we don't support
+        # this, let's make that perfectly clear.
+        wc = os.environ["WEB_CONCURRENCY"]
+        if wc != "1":
+            sys.stderr.write(
+                f"Ignoring WEB_CONCURRENCY value of {wc}. Shiny does not support gunicorn-style concurrency; instead, run multiple Shiny processes behind a load balancer that supports sticky sessions.\n"
+            )
+
     uvicorn.run(  # pyright: ignore[reportUnknownMemberType]
         app,  # pyright: ignore[reportGeneralTypeIssues]
         host=host,
@@ -254,6 +280,7 @@ def run_app(
         log_config=log_config,
         app_dir=app_dir,
         factory=factory,
+        workers=1,
     )