Make run.sh more robust

run.sh

@@ -11,11 +11,23 @@
 #   export MTG_IMAGENAME="nineseconds/mtg:latest"
 #   curl -sfL --compressed https://raw.githubusercontent.com/9seconds/mtg/master/run.sh | bash
 
-set -eu -o pipefail
+set -eu
 
 export XDG_CONFIG_HOME="${XDG_CONFIG_HOME:-$HOME/.config}"
 export MTG_CONFIG="${MTG_CONFIG:-$XDG_CONFIG_HOME/mtg}"
 
+if ! [ -x "$(command -v docker)" ]; then
+    echo 'Error: docker is not installed.' >&2
+    exit 1
+fi
+
+id -Gn "$USER" | grep -qw 'docker' > /dev/null
+if [ $? -eq 0 ] || [ "$(id -u)" -eq '0' ]; then
+    DOCKER_CMD="$(command -v docker)"
+else
+    DOCKER_CMD="sudo $(command -v docker)"
+fi
+
 mkdir -p "$MTG_CONFIG" || true
 
 MTG_SECRET="$MTG_CONFIG/secret"
@@ -26,33 +38,31 @@ if [ ! -f "$MTG_ENV" ]; then
     MTG_PORT="${MTG_PORT:-3128}"
     MTG_CONTAINER="${MTG_CONTAINER:-mtg}"
 
-    echo "MTG_IMAGENAME=${MTG_IMAGENAME}" > "$MTG_ENV"
-    echo "MTG_PORT=${MTG_PORT}" >> "$MTG_ENV"
-    echo "MTG_CONTAINER=${MTG_CONTAINER}" >> "$MTG_ENV"
+    echo "MTG_IMAGENAME=$MTG_IMAGENAME" > "$MTG_ENV"
+    echo "MTG_PORT=$MTG_PORT" >> "$MTG_ENV"
+    echo "MTG_CONTAINER=$MTG_CONTAINER" >> "$MTG_ENV"
 fi
 
 set -a
 source "$MTG_ENV"
 set +a
 
-docker pull "$MTG_IMAGENAME"
+$DOCKER_CMD pull "$MTG_IMAGENAME" > /dev/null
 if [ ! -f "$MTG_SECRET" ]; then
-    docker run \
+    $DOCKER_CMD run \
             --rm \
             "$MTG_IMAGENAME" \
         generate-secret tls -c "$(openssl rand -hex 16).com" \
     > "$MTG_SECRET"
 fi
 
-echo
 echo "Proxy secret is $(cat "$MTG_SECRET"). Port is $MTG_PORT."
-echo
 
-docker ps --filter "Name=$MTG_CONTAINER" -aq | xargs -r docker rm -fv
-docker run \
+$DOCKER_CMD ps --filter "Name=$MTG_CONTAINER" -aq | xargs -r $DOCKER_CMD rm -fv > /dev/null
+$DOCKER_CMD run \
         -d \
         --restart=unless-stopped \
         --name "$MTG_CONTAINER" \
         --ulimit nofile=51200:51200 \
         -p "$MTG_PORT:3128" \
-    "$MTG_IMAGENAME" run "$(cat "$MTG_SECRET")"
+    "$MTG_IMAGENAME" run "$(cat "$MTG_SECRET")" > /dev/null