Merge pull request #2908 from martian0x80/eval-envvar-on-run

Evaluate HOST, PORT, and PROXY env vars when Dash.run() is invoked

CHANGELOG.md

@@ -13,6 +13,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - [#2898](https://github.com/plotly/dash/pull/2898) Fix error thrown when using non-existent components in callback running keyword. Fixes [#2897](https://github.com/plotly/dash/issues/2897).
 - [#2892](https://github.com/plotly/dash/pull/2860) Fix ensures dcc.Dropdown menu maxHeight option works with Datatable. Fixes [#2529](https://github.com/plotly/dash/issues/2529) [#2225](https://github.com/plotly/dash/issues/2225)
 - [#2896](https://github.com/plotly/dash/pull/2896) The tabIndex parameter of Div can accept number or string type. Fixes [#2891](https://github.com/plotly/dash/issues/2891)
+- [#2908](https://github.com/plotly/dash/pull/2908) Fix when environment variables are ignored by Dash.run() at runtime. Fixes [#2902](https://github.com/plotly/dash/issues/2902)
 
 ## [2.17.1] - 2024-06-12
 

dash/dash.py

@@ -1981,9 +1981,9 @@ def delete_resource(resources):
 
     def run(
         self,
-        host=os.getenv("HOST", "127.0.0.1"),
-        port=os.getenv("PORT", "8050"),
-        proxy=os.getenv("DASH_PROXY", None),
+        host="127.0.0.1",
+        port="8050",
+        proxy=None,
         debug=None,
         jupyter_mode: JupyterDisplayMode = None,
         jupyter_width="100%",
@@ -2109,6 +2109,12 @@ def run(
             dev_tools_prune_errors,
         )
 
+        # Evaluate the env variables at runtime
+
+        host = os.getenv("HOST", host)
+        port = os.getenv("PORT", port)
+        proxy = os.getenv("DASH_PROXY", proxy)
+
         # Verify port value
         try:
             port = int(port)