avoid service restart prompt during Dockerfile builds

https://unix.stackexchange.com/questions/146283/how-to-prevent-prompt-that-ask-to-restart-services-when-installing-libpq-dev

Author: dzuelke

Dockerfile

@@ -3,7 +3,8 @@ FROM heroku/heroku:16-build
 WORKDIR /app
 ENV WORKSPACE_DIR="/app/builds" \
     S3_BUCKET="lang-python" \
-    S3_PREFIX="heroku-16/"
+    S3_PREFIX="heroku-16/" \
+    DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y python-pip && rm -rf /var/lib/apt/lists/*
 

Dockerfile.heroku-18

@@ -3,7 +3,8 @@ FROM heroku/heroku:18-build
 WORKDIR /app
 ENV WORKSPACE_DIR="/app/builds" \
     S3_BUCKET="lang-python" \
-    S3_PREFIX="heroku-18/"
+    S3_PREFIX="heroku-18/" \
+    DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && apt-get install -y python-pip && rm -rf /var/lib/apt/lists/*