Update

Dockerfile

@@ -1,14 +1,18 @@
 # official Python image as the base image
 FROM python:3.8-slim
 
-# referencing docker compose (find wiki) #
-ENV port ${port}
-ENV port ${host}
+# referencing docker compose (see wiki) #
+ENV PORT ${port}
+ENV HOST ${host}
+
 
 WORKDIR /app
+
 COPY . .
+
 RUN pip install -r requirements.txt
-EXPOSE ${PORT}
+
+EXPOSE ${port}
 
 # run dash application
-CMD ["python3", "app.py"]
+CMD ["python", "app.py"]

app.py

@@ -9,8 +9,8 @@
 
 if (__name__ == '__main__'):
 
-   host = environ.get('host')
-   port = environ.get('port')
+   host = environ.get('HOST')
+   port = environ.get('PORT')
 
    objLayout = layout()
    objCallbacks = callbacks()