feat(docker): enhance Dockerfiles with user creation and health check

* Added non-root user creation for SteamCMD in Dockerfiles for Ubuntu 18.04, 20.04, 22.04, and 24.04.
* Included a basic health check to ensure SteamCMD is operational.
* Updated README to correct "docker cli" to "Docker cli".

Dockerfile.ubuntu-1804

@@ -24,5 +24,15 @@ RUN locale-gen en_US.UTF-8
 ENV LANG=en_US.UTF-8
 ENV LANGUAGE=en_US:en
 
+# Create non-root user
+RUN useradd -m -d /home/steam -s /bin/bash steam \
+  && mkdir -p /home/steam/Steam \
+  && chown -R steam:steam /home/steam
+USER steam
+WORKDIR /home/steam
+
 ENTRYPOINT ["steamcmd"]
 CMD ["+help", "+quit"]
+
+# Basic health check: run a no-op steamcmd help then quit
+HEALTHCHECK --interval=30m --timeout=30s --start-period=30s --retries=3 CMD steamcmd +login anonymous +app_info_update 1 +quit > /dev/null 2>&1 || exit 1

Dockerfile.ubuntu-2004

@@ -24,5 +24,15 @@ RUN locale-gen en_US.UTF-8
 ENV LANG=en_US.UTF-8
 ENV LANGUAGE=en_US:en
 
+# Create non-root user
+RUN useradd -m -d /home/steam -s /bin/bash steam \
+  && mkdir -p /home/steam/Steam \
+  && chown -R steam:steam /home/steam
+USER steam
+WORKDIR /home/steam
+
 ENTRYPOINT ["steamcmd"]
 CMD ["+help", "+quit"]
+
+# Basic health check: run a no-op steamcmd help then quit
+HEALTHCHECK --interval=30m --timeout=30s --start-period=30s --retries=3 CMD steamcmd +login anonymous +app_info_update 1 +quit > /dev/null 2>&1 || exit 1

Dockerfile.ubuntu-2204

@@ -24,5 +24,15 @@ RUN locale-gen en_US.UTF-8
 ENV LANG=en_US.UTF-8
 ENV LANGUAGE=en_US:en
 
+# Create non-root user
+RUN useradd -m -d /home/steam -s /bin/bash steam \
+  && mkdir -p /home/steam/Steam \
+  && chown -R steam:steam /home/steam
+USER steam
+WORKDIR /home/steam
+
 ENTRYPOINT ["steamcmd"]
 CMD ["+help", "+quit"]
+
+# Basic health check: run a no-op steamcmd help then quit
+HEALTHCHECK --interval=30m --timeout=30s --start-period=30s --retries=3 CMD steamcmd +login anonymous +app_info_update 1 +quit > /dev/null 2>&1 || exit 1

Dockerfile.ubuntu-2404

@@ -24,5 +24,15 @@ RUN locale-gen en_US.UTF-8
 ENV LANG=en_US.UTF-8
 ENV LANGUAGE=en_US:en
 
+# Create non-root user
+RUN useradd -m -d /home/steam -s /bin/bash steam \
+  && mkdir -p /home/steam/Steam \
+  && chown -R steam:steam /home/steam
+USER steam
+WORKDIR /home/steam
+
 ENTRYPOINT ["steamcmd"]
 CMD ["+help", "+quit"]
+
+# Basic health check: run a no-op steamcmd help then quit
+HEALTHCHECK --interval=30m --timeout=30s --start-period=30s --retries=3 CMD steamcmd +login anonymous +app_info_update 1 +quit > /dev/null 2>&1 || exit 1

README.md

@@ -23,7 +23,7 @@ SteamCMD is a command-line version of the Steam client. It allows you to downloa
 
 ## Usage
 
-docker cli
+Docker cli
 
 ```bash
 docker run -it gameservermanagers/steamcmd:latest