ARG should go INSIDE the FROM

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'weekly'

Dockerfile.base

@@ -1,4 +1,5 @@
-FROM tomcat:9.0.85-jre11
+FROM tomcat:9.0.88-jdk17
+ARG TARGETPLATFORM
 
 ENV GUAC_VER=1.5.5 \
     GUACAMOLE_HOME=/app/guacamole \
@@ -16,8 +17,10 @@ RUN useradd postgres
 # Cleanup default tomcat stuff
 RUN rm -rf /usr/local/tomcat/webapps.dist
 
+RUN echo $TARGETPLATFORM
+
 # Apply the s6-overlay
-RUN if [ "$TARGETPLATFORM" = "linux/amd64" ]; then ARCHITECTURE=amd64; elif [ "$TARGETPLATFORM" = "linux/arm/v7" ]; then ARCHITECTURE=arm; elif [ "$TARGETPLATFORM" = "linux/arm64" ]; then ARCHITECTURE=aarch64; else ARCHITECTURE=amd64; fi \
+RUN if [ "$TARGETPLATFORM" = "linux/amd64" ]; then ARCHITECTURE=amd64; elif [ "$TARGETPLATFORM" = "linux/arm/v7" ]; then ARCHITECTURE=armhf; elif [ "$TARGETPLATFORM" = "linux/arm/v8" ]; then ARCHITECTURE=aarch64; elif [ "$TARGETPLATFORM" = "linux/arm64" ]; then ARCHITECTURE=aarch64; fi \
     && curl -sS -L -O --output-dir /tmp/ --create-dirs "https://github.com/just-containers/s6-overlay/releases/download/v2.2.0.3/s6-overlay-${ARCHITECTURE}-installer" \
     && chmod +x /tmp/s6-overlay-${ARCHITECTURE}-installer && /tmp/s6-overlay-${ARCHITECTURE}-installer / \
     && rm -rf /tmp/s6-overlay-${ARCHITECTURE}-installer

README.md

@@ -18,7 +18,7 @@ This container runs the guacamole web client, the guacd server and a postgres da
 docker run \
   -p 8080:8080 \
   -v </path/to/config>:/config \
-  jwetzell/guacamole
+  jwetzell/guacamole:1.5.5
 ```
 
 ## Raspberry Pi / ARMv7
@@ -29,7 +29,7 @@ Now that the image has been converted to a multi-platform image the command for
 docker run \
   -p 8080:8080 \
   -v </path/to/config>:/config \
-  jwetzell/guacamole
+  jwetzell/guacamole:1.5.5
 ```
 
 ## Parameters
@@ -51,7 +51,7 @@ docker run \
   -p 8080:8080 \
   -v </path/to/config>:/config \
   -e "EXTENSIONS=auth-ldap,auth-duo"
-  jwetzell/guacamole
+  jwetzell/guacamole:1.5.5
 ```
 
 Currently the available extensions are:
@@ -85,7 +85,7 @@ Mapped volumes behave differently when running Docker for Windows and you may en
 version: "2"
 services:
   guacamole:
-    image: jwetzell/guacamole
+    image: jwetzell/guacamole:1.5.5
     container_name: guacamole
     volumes:
       - postgres:/config