make the php memory limit configurable via environment variable

also set a sensible default of 512M

Author: Kevin Buchholz

Dockerfile

@@ -3,7 +3,8 @@ FROM php:7.3.8-fpm-alpine3.10
 ENV PHP_OPCACHE_VALIDATE_TIMESTAMPS="0" \
     PHP_OPCACHE_MAX_ACCELERATED_FILES="10000" \
     PHP_OPCACHE_MEMORY_CONSUMPTION="192" \
-    PHP_OPCACHE_MAX_WASTED_PERCENTAGE="10"
+    PHP_OPCACHE_MAX_WASTED_PERCENTAGE="10" \
+    PHP_MEMORY_LIMIT="512M"
 
 RUN apk info \
     && echo @edge http://nl.alpinelinux.org/alpine/edge/community >> /etc/apk/repositories \

usr/local/etc/php/php.ini

@@ -6,7 +6,7 @@
 
 max_execution_time = 60
 max_input_time = 60
-memory_limit = 512M
+memory_limit = ${PHP_MEMORY_LIMIT}
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; Error handling and logging ;