update python.gunicorn.sh to WEB_CONCURRENCY.sh (#373)

* update python.gunicorn.sh to WEB_CONCURRENCY.sh

* don't remove WEB_CONCURRENCY for prefixed 0s

* split gunicorn functionality into its own file

* cleanup comments

* fix var ordering

* add retry to curl

* use proper url for buildpack stdlib

bin/compile

@@ -68,6 +68,7 @@ mkdir -p /app/.heroku
 PROFILE_PATH="$BUILD_DIR/.profile.d/python.sh"
 EXPORT_PATH="$BIN_DIR/../export"
 GUNICORN_PROFILE_PATH="$BUILD_DIR/.profile.d/python.gunicorn.sh"
+WEB_CONCURRENCY_PROFILE_PATH="$BUILD_DIR/.profile.d/WEB_CONCURRENCY.sh"
 
 # We'll need to send these statics to other scripts we `source`.
 export BUILD_DIR CACHE_DIR BIN_DIR PROFILE_PATH EXPORT_PATH
@@ -211,8 +212,10 @@ set-default-env PYTHONHASHSEED random
 set-default-env PYTHONPATH /app/
 
 # Install sane-default script for $WEB_CONCURRENCY and $FORWARDED_ALLOW_IPS.
+cp $ROOT_DIR/vendor/WEB_CONCURRENCY.sh $WEB_CONCURRENCY_PROFILE_PATH
 cp $ROOT_DIR/vendor/python.gunicorn.sh $GUNICORN_PROFILE_PATH
 
+
 # Experimental post_compile hook.
 source $BIN_DIR/steps/hooks/post_compile
 

bin/utils

@@ -3,7 +3,7 @@ shopt -s extglob
 
 # The standard library.
 if [[ ! -f  /tmp/stdlib.sh ]]; then
-  curl -s https://raw.githubusercontent.com/heroku/buildpack-stdlib/v2/stdlib.sh > /tmp/stdlib.sh
+  curl --retry 3 -s https://lang-common.s3.amazonaws.com/buildpack-stdlib/v2/stdlib.sh > /tmp/stdlib.sh
 fi
 source /tmp/stdlib.sh