Install drush 9

.gitignore

+*.env

Dockerfile

@@ -2,15 +2,14 @@ FROM cern/cc7-base
 MAINTAINER drupal-admins@cern.ch
 
 ARG APP_ROOT=/app
+ARG DRUSH_VERSION=9.2.1
 
-# Set the Drush version.
-ENV DRUSH_VERSION 8.1.17
 ENV DRUPAL_VERSION 8.8.4
 
 ENV PHP_VERSION=7.1 \
     PHP_VER_SHORT=71 \
     NAME=drush-php-apache \
-    PATH=$PATH:/opt/rh/rh-php71/root/usr/bin
+    PATH=/opt/rh/rh-php71/root/usr/bin:$PATH
 
 ### 1. Install PHP & Apache
 
@@ -55,12 +54,14 @@ COPY drush/settings.php /drush/settings.php
 
 COPY drupal/ /drupal/$DRUPAL_VERSION/
 
-RUN a2enmod php7.1
-
 ### 3. Drush 9 from composer
 
+# enable software collections on startup
 RUN cp "/opt/app-root/etc/scl_enable" "/etc/profile.d/"
 
+RUN composer global require drush/drush:"$DRUSH_VERSION" --prefer-dist
+ENV PATH=/root/.composer/vendor/bin:$PATH
+
 CMD ["/bin/docker-sleep"]
 
 ENTRYPOINT prepare-enviroment.sh && rm /usr/bin/prepare-enviroment.sh && /usr/bin/scl enable rh-php71 bash