Switch to using set -euxo pipefail for better error handling

-e immediately exit when a command fails. No further commands are processed.
-o pipefail, if a series of piped commands fail, do NOt return the last commands returncode, but DO return the return code of the failing command in the pipeline series
-u, raise an error when an unset variable is used. Not using this results in an empty value being used and the script being executed differently without you knowing why.
-x, print each command before executing it. Actual arguments are expanded. So you see the command with the actual parameter values. This is printed in red in the buildx log output.

webmails/roundcube/Dockerfile

@@ -6,33 +6,34 @@ FROM base
 ARG VERSION
 LABEL version=$VERSION
 
-RUN apk add --no-cache \
+RUN set -euxo pipefail \
+  ; apk add --no-cache \
     nginx gpg gpg-agent \
     php8 php8-fpm php8-mbstring php8-zip php8-xml php8-simplexml \
     php8-dom php8-curl php8-exif gd php8-gd php8-iconv php8-intl php8-openssl \
     php8-pdo_sqlite php8-pdo_mysql php8-pdo_pgsql php8-pdo php8-sodium libsodium php8-tidy php8-pecl-uuid \
     php8-pspell php8-pecl-imagick php8-opcache php8-session php8-sockets php8-fileinfo \
-    && rm /etc/nginx/http.d/default.conf \
-    && rm /etc/php8/php-fpm.d/www.conf \
-    && mkdir -p /run/nginx \
-    && mkdir -p /conf
+  ; rm /etc/nginx/http.d/default.conf \
+  ; rm /etc/php8/php-fpm.d/www.conf \
+  ; mkdir -p /run/nginx \
+  ; mkdir -p /conf
 
 ENV ROUNDCUBE_URL https://github.com/roundcube/roundcubemail/releases/download/1.5.3/roundcubemail-1.5.3-complete.tar.gz
 ENV CARDDAV_URL https://github.com/mstilkerich/rcmcarddav/releases/download/v4.4.3/carddav-v4.4.3.tar.gz
 
-RUN \
- cd /var/www \
- && curl -sL ${ROUNDCUBE_URL} | tar xz \
- && curl -sL ${CARDDAV_URL} | tar xz \
- && mv roundcubemail-* webmail \
- && mkdir -p /var/www/webmail/config \
- && mv carddav webmail/plugins/ \
- && cd webmail \
- && rm -rf CHANGELOG.md SECURITY.md INSTALL LICENSE README.md UPGRADING composer.json-dist installer composer.* \
- && ln -sf index.php /var/www/webmail/sso.php \
- && chmod -R u+w,a+rX /var/www/webmail \
- && chown -R nginx:nginx /var/www/webmail \
- && rm -rf plugins/{autologon,example_addressbook,http_authentication,krb_authentication,new_user_identity,password,redundant_attachments,squirrelmail_usercopy,userinfo,virtuser_file,virtuser_query}
+RUN set -euxo pipefail \
+  ; cd /var/www \
+  ; curl -sL ${ROUNDCUBE_URL} | tar xz \
+  ; curl -sL ${CARDDAV_URL} | tar xz \
+  ; mv roundcubemail-* webmail \
+  ; mkdir -p /var/www/webmail/config \
+  ; mv carddav webmail/plugins/ \
+  ; cd webmail \
+  ; rm -rf CHANGELOG.md SECURITY.md INSTALL LICENSE README.md UPGRADING composer.json-dist installer composer.* \
+  ; ln -sf index.php /var/www/webmail/sso.php \
+  ; chmod -R u+w,a+rX /var/www/webmail \
+  ; chown -R nginx:nginx /var/www/webmail \
+  ; rm -rf plugins/{autologon,example_addressbook,http_authentication,krb_authentication,new_user_identity,password,redundant_attachments,squirrelmail_usercopy,userinfo,virtuser_file,virtuser_query}
 
 
 # nginx / PHP config files

webmails/snappymail/Dockerfile

@@ -34,16 +34,17 @@ LABEL version=$VERSION
 #     xxtea (PECL)      not found on alpine repo
 #     zip               php7-zip
 #php7-curl php7-iconv php7-json php7-xml php7-simplexml php7-dom php7-openssl php7-pdo php7-pdo_sqlite php7-mbstring \
-RUN apk add --no-cache \
+RUN set -euxo pipefail \
+  ; apk add --no-cache \
     nginx curl \
     php8 php8-fpm php8-mbstring php8-zip php8-xml php8-simplexml \
     php8-dom php8-curl php8-exif gd php8-gd php8-iconv php8-intl php8-openssl \
     php8-pdo_sqlite php8-pdo php8-sodium libsodium php8-tidy php8-pecl-uuid \
- && rm /etc/nginx/http.d/default.conf \
- && rm /etc/php8/php-fpm.d/www.conf \
- && mkdir -p /run/nginx \
- && mkdir -p /var/www/webmail \
- && mkdir -p /config
+  ; rm /etc/nginx/http.d/default.conf \
+  ; rm /etc/php8/php-fpm.d/www.conf \
+  ; mkdir -p /run/nginx \
+  ; mkdir -p /var/www/webmail \
+  ; mkdir -p /config
 
 # nginx / PHP config files
 COPY config/nginx-snappymail.conf /config/nginx-snappymail.conf
@@ -55,12 +56,13 @@ COPY defaults/application.ini /defaults/application.ini
 COPY defaults/default.ini /defaults/default.ini
 
 # Install Snappymail from source
-ENV SNAPPYMAIL_URL https://github.com/the-djmaze/snappymail/releases/download/v2.13.4/snappymail-2.13.4.zip
+ENV SNAPPYMAIL_URL https://github.com/the-djmaze/snappymail/releases/download/v2.13.4/snappymail-2.13.4.tar.gz
 
-RUN cd /var/www/webmail \
- && busybox wget ${SNAPPYMAIL_URL} -O - | busybox unzip - \
- && chmod -R u+w,a+rX /var/www/webmail \
- && chown -R nginx:nginx /var/www/webmail
+RUN set -euxo pipefail \
+  ; cd /var/www/webmail \
+  ; curl -sL  ${SNAPPYMAIL_URL} | tar xz \
+  ; chmod -R u+w,a+rX /var/www/webmail \
+  ; chown -R nginx:nginx /var/www/webmail
 
 # SnappyMail login
 COPY login/include.php /var/www/webmail/include.php