Update build docker image actions, fix username

cannot build the image automatically

This reverts commit fc7840efef.

.github/workflows/build.yml

@@ -0,0 +1,35 @@
+name: Build Images
+
+on:
+  push:
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Log into DockerHub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          username: ${{ github.actor }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ github.actor }}/ufw-docker-agent
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          push: ${{ github.event_name != 'pull_request' }}
+          platforms: linux/amd64,linux/arm64/v8
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

Dockerfile

@@ -1,18 +1,18 @@
-FROM ubuntu:20.04
+FROM ubuntu:24.04
 
-ARG docker_version="19.03.12"
+ARG docker_version="27.3.1"
 
 ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update \
-    && apt-get install -y --no-install-recommends apt-transport-https \
-               ca-certificates curl software-properties-common gnupg dirmngr \
-    && apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9DC858229FC7DD38854AE2D88D81803C0EBFCD88 \
-    && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
-                          $(lsb_release -cs) stable" \
+    && apt-get install -y ca-certificates curl gnupg lsb-release \
+    && mkdir -p /etc/apt/keyrings \
+    && curl -fsSL https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg \
+    && echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg]" \
+            "https://download.docker.com/linux/ubuntu" "$(lsb_release -cs) stable" \
+            | tee /etc/apt/sources.list.d/docker.list > /dev/null \
     && apt-get update \
     && apt-get install -y --no-install-recommends locales ufw \
-    && ( apt-get install -y --no-install-recommends "docker-ce=5:${docker_version}~*" || \
-         apt-get install -y --no-install-recommends "docker-ce=${docker_version}~*" ) \
+    && apt-get install -y --no-install-recommends "docker-ce=$(apt-cache madison docker-ce | grep -m1 -F "${docker_version}" | cut -d'|' -f2 | tr -d '[[:blank:]]')" \
     && locale-gen en_US.UTF-8 \
     && apt-get clean autoclean \
     && apt-get autoremove --yes \

Vagrantfile

@@ -3,16 +3,29 @@
 # -*- mode: ruby -*-
 # vi: set ft=ruby :
 
-Vagrant.configure('2') do |config|
+ENV['VAGRANT_NO_PARALLEL']="true"
 
-  config.vm.box = "chaifeng/ubuntu-20.04-docker-19.03.13"
-  #config.vm.box = "chaifeng/ubuntu-16.04-docker-18.03"
+Vagrant.configure('2') do |config|
+  ubuntu_version = File.readlines("Dockerfile").filter { |line|
+    line.start_with?("FROM ")
+  }.first.match(/\d\d\.\d\d/)[0]
+
+  docker_version = File.readlines("Dockerfile").filter { |line|
+    line.start_with?("ARG docker_version=")
+  }.first.match(/"([\d\.]+)"/)[1]
+
+  config.vm.box = "chaifeng/ubuntu-#{ubuntu_version}-docker-#{docker_version}"
 
   config.vm.provider 'virtualbox' do |vb|
     vb.memory = '1024'
     vb.default_nic_type = "virtio"
   end
 
+  config.vm.provider 'parallels' do |prl|
+    prl.memory = '1024'
+    prl.check_guest_tools = false
+  end
+
   ip_prefix="192.168.56"
 
   config.vm.provision 'docker-daemon-config', type: 'shell', inline: <<-SHELL
@@ -57,15 +70,16 @@ Vagrant.configure('2') do |config|
   private_registry="#{ip_prefix}.130:5000"
 
   config.vm.define "master" do |master|
+    master_ip_address = "#{ip_prefix}.130"
     master.vm.hostname = "master"
-    master.vm.network "private_network", ip: "#{ip_prefix}.130"
+    master.vm.network "private_network", ip: "#{master_ip_address}"
 
-    master.vm.provision "unit-testing", type: 'shell', inline: <<-SHELL
+    master.vm.provision "unit-testing", preserve_order: true, type: 'shell', inline: <<-SHELL
         set -euo pipefail
         /vagrant/test.sh
     SHELL
 
-    master.vm.provision "docker-registry", type: 'docker' do |d|
+    master.vm.provision "docker-registry", preserve_order: true, type: 'docker' do |d|
       d.run "registry",
             image: "registry:2",
             args: "-p 5000:5000",
@@ -73,35 +87,38 @@ Vagrant.configure('2') do |config|
             daemonize: true
     end
 
-    ufw_docker_agent_image = "#{private_registry}/chaifeng/ufw-docker-agent:test"
+    ufw_docker_agent_image = "#{private_registry}/chaifeng/ufw-docker-agent:test-legacy"
 
-    master.vm.provision "docker-build-ufw-docker-agent", type: 'shell', inline: <<-SHELL
+    master.vm.provision "docker-build-ufw-docker-agent", preserve_order: true, type: 'shell', inline: <<-SHELL
       set -euo pipefail
-      docker build -t #{ufw_docker_agent_image} /vagrant
-      docker push #{ufw_docker_agent_image}
+      suffix="$(iptables --version | grep -o '\\(nf_tables\\|legacy\\)')"
+      docker build -t "#{ufw_docker_agent_image}-${suffix}" /vagrant
+      docker push "#{ufw_docker_agent_image}-${suffix}"
 
-      echo "export UFW_DOCKER_AGENT_IMAGE=#{ufw_docker_agent_image}" > /etc/profile.d/ufw-docker.sh
+      echo "export UFW_DOCKER_AGENT_IMAGE=#{ufw_docker_agent_image}-${suffix}" > /etc/profile.d/ufw-docker.sh
       echo "export DEBUG=true" >> /etc/profile.d/ufw-docker.sh
 
       echo "Defaults env_keep += UFW_DOCKER_AGENT_IMAGE" > /etc/sudoers.d/98_ufw-docker
       echo "Defaults env_keep += DEBUG" >> /etc/sudoers.d/98_ufw-docker
     SHELL
 
-    master.vm.provision "swarm-init", type: 'shell', inline: <<-SHELL
+    master.vm.provision "swarm-init", preserve_order: true, type: 'shell', inline: <<-SHELL
       set -euo pipefail
       docker info | fgrep 'Swarm: active' && exit 0
 
-      docker swarm init --advertise-addr eth1
+      docker swarm init --advertise-addr "#{master_ip_address}"
       docker swarm join-token worker --quiet > /vagrant/.vagrant/docker-join-token
     SHELL
 
-    master.vm.provision "build-webapp", type: 'shell', inline: <<-SHELL
+    master.vm.provision "build-webapp", preserve_order: true, type: 'shell', inline: <<-SHELL
         set -euo pipefail
         docker build -t #{private_registry}/chaifeng/hostname-webapp - <<\\DOCKERFILE
 FROM httpd:alpine
 
 RUN { echo '#!/bin/sh'; \\
     echo 'set -e; (echo -n "${name:-Hi} "; hostname;) > /usr/local/apache2/htdocs/index.html'; \\
+    echo 'grep "^Listen 7000" || echo Listen 7000 >> /usr/local/apache2/conf/httpd.conf'; \\
+    echo 'grep "^Listen 8080" || echo Listen 8080 >> /usr/local/apache2/conf/httpd.conf'; \\
     echo 'exec "$@"'; \\
     } > /entrypoint.sh; chmod +x /entrypoint.sh
 
@@ -111,7 +128,7 @@ DOCKERFILE
         docker push #{private_registry}/chaifeng/hostname-webapp
     SHELL
 
-    master.vm.provision "local-webapp", type: 'shell', inline: <<-SHELL
+    master.vm.provision "local-webapp", preserve_order: true, type: 'shell', inline: <<-SHELL
         set -euo pipefail
         for name in public:18080 local:8000; do
             webapp="${name%:*}_webapp"
@@ -125,7 +142,7 @@ DOCKERFILE
         ufw-docker allow public_webapp
     SHELL
 
-    master.vm.provision "multiple-network", type: 'shell', inline: <<-SHELL
+    master.vm.provision "multiple-network", preserve_order: true, type: 'shell', inline: <<-SHELL
       set -euo pipefail
       if ! docker network ls | grep -F foo-internal; then
           docker network create --internal foo-internal
@@ -148,7 +165,7 @@ DOCKERFILE
       ufw-docker allow internal-multinet-app 80 foo-internal
     SHELL
 
-    master.vm.provision "swarm-webapp", type: 'shell', inline: <<-SHELL
+    master.vm.provision "swarm-webapp", preserve_order: true, type: 'shell', inline: <<-SHELL
       set -euo pipefail
         for name in public:29090 local:9000; do
             webapp="${name%:*}_service"
@@ -159,6 +176,14 @@ DOCKERFILE
         done
 
         ufw-docker service allow public_service 80/tcp
+
+        docker service inspect "public_multiport" ||
+            docker service create --name "public_multiport" \
+                --publish "40080:80" --publish "47000:7000" --publish "48080:8080" \
+                --env name="public_multiport" --replicas 3 #{private_registry}/chaifeng/hostname-webapp
+
+        ufw-docker service allow public_multiport 80/tcp
+        ufw-docker service allow public_multiport 8080/tcp
     SHELL
   end
 
@@ -167,7 +192,7 @@ DOCKERFILE
       node.vm.hostname = "node#{ip}"
       node.vm.network "private_network", ip: "#{ip_prefix}.#{ 130 + ip }"
 
-      node.vm.provision "swarm-join", type: 'shell', inline: <<-SHELL
+      node.vm.provision "swarm-join", preserve_order: true, type: 'shell', inline: <<-SHELL
         set -euo pipefail
         docker info | fgrep 'Swarm: active' && exit 0
 
@@ -177,15 +202,25 @@ DOCKERFILE
     end
   end
 
+  config.vm.define "node-internal" do |node|
+    node.vm.hostname = "node-internal"
+    node.vm.network "private_network", ip: "#{ip_prefix}.142"
+  end
+
   config.vm.define "external" do |external|
     external.vm.hostname = "external"
     external.vm.network "private_network", ip: "#{ip_prefix}.127"
 
-    external.vm.provision "testing", type: 'shell', inline: <<-SHELL
+    external.vm.provision "testing", preserve_order: true, type: 'shell', inline: <<-SHELL
         set -euo pipefail
         set -x
         server="http://#{ip_prefix}.130"
-        function test-webapp() { timeout 3 curl --silent "$@"; }
+        function test-webapp() {
+          if timeout 3 curl --silent "$@"
+          then echo "Success: $*"
+          else echo "Cannot visit: $*"; return 1
+          fi
+        }
         test-webapp "$server:18080"
         ! test-webapp "$server:8000"
 
@@ -195,6 +230,10 @@ DOCKERFILE
         test-webapp "$server:29090"
         ! test-webapp "$server:9000"
 
+        test-webapp "$server:40080"
+        test-webapp "$server:48080"
+        ! test-webapp "$server:47000"
+
         echo "====================="
         echo "      TEST DONE      "
         echo "====================="

test/bach

@@ -1 +1 @@
-Subproject commit 447edb60db232d3dbc2267f37c49bd7a070cc83d
+Subproject commit 27885eb79c11e4652dede994c886ae5f9e30994f

test/ufw-docker.test.sh

@@ -12,12 +12,20 @@ source "$working_dir"/bach/bach.sh
     @mocktrue ufw status
     @mocktrue grep -Fq "Status: active"
 
-    @ignore remove_blank_lines
+    @mock iptables --version
+    @mocktrue grep -F '(legacy)'
+
+    @mocktrue docker -v
+    @mock docker -v === @stdout Docker version 0.0.0, build dummy
+
+    @mockpipe remove_blank_lines
     @ignore echo
     @ignore err
 
     DEFAULT_PROTO=tcp
     GREP_REGEXP_INSTANCE_NAME="[-_.[:alnum:]]\\+"
+
+    UFW_DOCKER_AGENT_IMAGE=chaifeng/ufw-docker-agent:090502-legacy
 }
 
 function ufw-docker() {
@@ -30,6 +38,41 @@ function load-ufw-docker-function() {
     @load_function "$working_dir/../ufw-docker" "$1"
 }
 
+test-ufw-docker-init-legacy() {
+    @mocktrue grep -F '(legacy)'
+    @source <(@sed '/PATH=/d' "$working_dir/../ufw-docker") help
+}
+test-ufw-docker-init-legacy-assert() {
+    iptables --version
+    test -n chaifeng/ufw-docker-agent:090502-legacy
+    trap on-exit EXIT INT TERM QUIT ABRT ERR
+    @dryrun cat
+}
+
+
+test-ufw-docker-init-nf_tables() {
+    @mockfalse grep -F '(legacy)'
+    @source <(@sed '/PATH=/d' "$working_dir/../ufw-docker") help
+}
+test-ufw-docker-init-nf_tables-assert() {
+    iptables --version
+    test -n chaifeng/ufw-docker-agent:090502-nf_tables
+    trap on-exit EXIT INT TERM QUIT ABRT ERR
+    @dryrun cat
+}
+
+
+test-ufw-docker-init() {
+    UFW_DOCKER_AGENT_IMAGE=chaifeng/ufw-docker-agent:100917
+    @source <(@sed '/PATH=/d' "$working_dir/../ufw-docker") help
+}
+test-ufw-docker-init-assert() {
+    test -n chaifeng/ufw-docker-agent:100917
+    trap on-exit EXIT INT TERM QUIT ABRT ERR
+    @dryrun cat
+}
+
+
 test-ufw-docker-help() {
     ufw-docker help
 }
@@ -48,11 +91,23 @@ test-ufw-docker-without-parameters-assert() {
 
 test-ufw-is-disabled() {
     @mockfalse grep -Fq "Status: active"
+    @mock iptables --version === @stdout 'iptables v1.8.4 (legacy)'
 
     ufw-docker
 }
 test-ufw-is-disabled-assert() {
-    die "UFW is disabled or you are not root user."
+    die "UFW is disabled or you are not root user, or mismatched iptables legacy/nf_tables, current iptables v1.8.4 (legacy)"
+    ufw-docker--help
+}
+
+
+test-docker-is-installed() {
+    @mockfalse docker -v
+
+    ufw-docker
+}
+test-docker-is-installed-assert() {
+    die "Docker executable not found."
     ufw-docker--help
 }
 
@@ -410,7 +465,7 @@ test-ufw-docker--instance-name-found-a-name() {
 }
 test-ufw-docker--instance-name-found-a-name-assert() {
     docker inspect --format="{{.Name}}" foo
-    echo -n foo
+    @dryrun echo -n foo
 }
 
 
@@ -433,7 +488,7 @@ test-ufw-docker--list-name() {
     ufw-docker--list foo
 }
 test-ufw-docker--list-name-assert() {
-    grep "# allow foo\\( [[:digit:]]\\+\\/\\(tcp\\|udp\\)\\)\\?\\( [[:graph:]]*\\)\\?\$"
+    grep "# allow foo\\( [[:digit:]]\\+\\/\\(tcp\\|udp\\)\\)\\( [[:graph:]]*\\)\$"
 }
 
 test-ufw-docker--list-name-udp() {
@@ -442,7 +497,7 @@ test-ufw-docker--list-name-udp() {
     ufw-docker--list foo "" udp
 }
 test-ufw-docker--list-name-udp-assert() {
-    grep "# allow foo\\( [[:digit:]]\\+\\/\\(tcp\\|udp\\)\\)\\?\\( [[:graph:]]*\\)\\?\$"
+    grep "# allow foo\\( [[:digit:]]\\+\\/\\(tcp\\|udp\\)\\)\\( [[:graph:]]*\\)\$"
 }
 
 
@@ -452,7 +507,7 @@ test-ufw-docker--list-name-80() {
     ufw-docker--list foo 80
 }
 test-ufw-docker--list-name-80-assert() {
-    grep "# allow foo\\( 80\\/tcp\\)\\?\\( [[:graph:]]*\\)\\?\$"
+    grep "# allow foo\\( 80\\/tcp\\)\\( [[:graph:]]*\\)\$"
 }
 
 
@@ -462,7 +517,30 @@ test-ufw-docker--list-name-80-udp() {
     ufw-docker--list foo 80 udp
 }
 test-ufw-docker--list-name-80-udp-assert() {
-    grep "# allow foo\\( 80\\/udp\\)\\?\\( [[:graph:]]*\\)\\?\$"
+    grep "# allow foo\\( 80\\/udp\\)\\( [[:graph:]]*\\)\$"
+}
+
+
+test-ufw-docker--list-grep-without-network() {
+    @mocktrue ufw status numbered
+    @mockfalse grep "# allow foo\\( 80\\/udp\\)\\( [[:graph:]]*\\)\$"
+    load-ufw-docker-function ufw-docker--list
+    ufw-docker--list foo 80 udp
+}
+test-ufw-docker--list-grep-without-network-assert() {
+    grep "# allow foo\\( 80\\/udp\\)\$"
+}
+
+
+test-ufw-docker--list-grep-without-network-and-port() {
+    @mocktrue ufw status numbered
+    @mockfalse grep "# allow foo\\( 80\\/udp\\)\\( [[:graph:]]*\\)\$"
+    @mockfalse grep "# allow foo\\( 80\\/udp\\)\$"
+    load-ufw-docker-function ufw-docker--list
+    ufw-docker--list foo 80 udp
+}
+test-ufw-docker--list-grep-without-network-and-port-assert() {
+    grep "# allow foo\$"
 }
 
 
@@ -479,7 +557,7 @@ test-ufw-docker--list-number-assert() {
 
 test-ufw-docker--delete-empty-result() {
     @mock ufw-docker--list-number webapp 80 tcp === @stdout ""
-    @mock sort -rn
+    @mockpipe sort -rn
 
     load-ufw-docker-function ufw-docker--delete
     ufw-docker--delete webapp 80 tcp
@@ -491,7 +569,7 @@ test-ufw-docker--delete-empty-result-assert() {
 
 test-ufw-docker--delete-all() {
     @mock ufw-docker--list-number webapp 80 tcp === @stdout 5 8 9
-    @mock sort -rn
+    @mockpipe sort -rn
 
     load-ufw-docker-function ufw-docker--delete
     ufw-docker--delete webapp 80 tcp

ufw-docker

@@ -5,13 +5,23 @@ set -euo pipefail
 LANG=en_US.UTF-8
 LANGUAGE=en_US:
 LC_ALL=en_US.UTF-8
-PATH="/bin:/usr/bin:/sbin:/usr/sbin"
+PATH="/bin:/usr/bin:/sbin:/usr/sbin:/snap/bin/"
 
 GREP_REGEXP_INSTANCE_NAME="[-_.[:alnum:]]\\+"
 DEFAULT_PROTO=tcp
 
 ufw_docker_agent=ufw-docker-agent
-ufw_docker_agent_image="${UFW_DOCKER_AGENT_IMAGE:-chaifeng/${ufw_docker_agent}:210925}"
+ufw_docker_agent_image="${UFW_DOCKER_AGENT_IMAGE:-chaifeng/${ufw_docker_agent}:221002-nf_tables}"
+
+if [[ "${ufw_docker_agent_image}" = *-@(legacy|nf_tables) ]]; then
+    if iptables --version | grep -F '(legacy)' &>/dev/null; then
+        ufw_docker_agent_image="${ufw_docker_agent_image%-*}-legacy"
+    else
+        ufw_docker_agent_image="${ufw_docker_agent_image%-*}-nf_tables"
+    fi
+fi
+
+test -n "$ufw_docker_agent_image"
 
 function ufw-docker--status() {
     ufw-docker--list "$GREP_REGEXP_INSTANCE_NAME"
@@ -32,7 +42,9 @@ function ufw-docker--list() {
        NETWORK="[[:graph:]]*"
     fi
 
-    ufw status numbered | grep "# allow ${INSTANCE_NAME}\\( ${INSTANCE_PORT}\\/${PROTO}\\)\\?\\( ${NETWORK}\\)\\?\$"
+    ufw status numbered | grep "# allow ${INSTANCE_NAME}\\( ${INSTANCE_PORT}\\/${PROTO}\\)\\( ${NETWORK}\\)\$" ||  \
+    ufw status numbered | grep "# allow ${INSTANCE_NAME}\\( ${INSTANCE_PORT}\\/${PROTO}\\)\$" || \
+    ufw status numbered | grep "# allow ${INSTANCE_NAME}\$"
 }
 
 function ufw-docker--list-number() {
@@ -72,12 +84,11 @@ function ufw-docker--allow() {
         if [[ -z "$INSTANCE_PORT" || "$PORT_PROTO" = "${INSTANCE_PORT}/${PROTO}" ]]; then
             ITER=0
             for IP in "${INSTANCE_IP_ADDRESSES[@]}"; do
-	        INSTANCE_NETWORK="${INSTANCE_NETWORK_NAMES[$ITER]}"
-		      ITER=$((ITER+1))
-	        if [[ -n "$NETWORK" ]] && [[ "$NETWORK" != "$INSTANCE_NETWORK" ]]; then
-		  continue
-		fi
-	    
+                INSTANCE_NETWORK="${INSTANCE_NETWORK_NAMES[$ITER]}"
+                ITER=$((ITER+1))
+                if [[ -n "$NETWORK" ]] && [[ "$NETWORK" != "$INSTANCE_NETWORK" ]]; then
+                    continue
+                fi
                 ufw-docker--add-rule "$INSTANCE_NAME" "$IP" "${PORT_PROTO%/*}" "${PORT_PROTO#*/}" "${INSTANCE_NETWORK}"
                 RETVAL="$?"
             done
@@ -281,34 +292,34 @@ function ufw-docker--raw-command() {
 after_rules="/etc/ufw/after.rules"
 
 function ufw-docker--check() {
-  err "\\n########## iptables -n -L DOCKER-USER ##########"
-  iptables -n -L DOCKER-USER
+    err "\\n########## iptables -n -L DOCKER-USER ##########"
+    iptables -n -L DOCKER-USER
 
-  err "\\n\\n########## diff $after_rules ##########"
-  ufw-docker--check-install && err "\\nCheck done."
+    err "\\n\\n########## diff $after_rules ##########"
+    ufw-docker--check-install && err "\\nCheck done."
 }
 
 declare -a files_to_be_deleted
 
 function rm-on-exit() {
-  [[ $# -gt 0 ]] && files_to_be_deleted+=("$@")
+    [[ $# -gt 0 ]] && files_to_be_deleted+=("$@")
 }
 
 function on-exit() {
-  for file in "${files_to_be_deleted[@]:-}"; do
-    [[ -f "$file" ]] && rm -r "$file"
-  done
-  files_to_be_deleted=()
+    for file in "${files_to_be_deleted[@]:-}"; do
+        [[ -f "$file" ]] && rm -r "$file"
+    done
+    files_to_be_deleted=()
 }
 
 trap on-exit EXIT INT TERM QUIT ABRT ERR
 
 function ufw-docker--check-install() {
-	after_rules_tmp="${after_rules_tmp:-$(mktemp)}"
-	rm-on-exit "$after_rules_tmp"
+    after_rules_tmp="${after_rules_tmp:-$(mktemp)}"
+    rm-on-exit "$after_rules_tmp"
 
-	sed "/^# BEGIN UFW AND DOCKER/,/^# END UFW AND DOCKER/d" "$after_rules" > "$after_rules_tmp"
-	>> "${after_rules_tmp}" cat <<-\EOF
+    sed "/^# BEGIN UFW AND DOCKER/,/^# END UFW AND DOCKER/d" "$after_rules" > "$after_rules_tmp"
+    >> "${after_rules_tmp}" cat <<-\EOF
 	# BEGIN UFW AND DOCKER
 	*filter
 	:ufw-user-forward - [0:0]
@@ -338,27 +349,27 @@ function ufw-docker--check-install() {
 	# END UFW AND DOCKER
 	EOF
 
-	diff -u --color=auto "$after_rules" "$after_rules_tmp"
+    diff -u --color=auto "$after_rules" "$after_rules_tmp"
 }
 
 function ufw-docker--install() {
-  if ! ufw-docker--check-install; then
-	  local after_rules_bak
-    after_rules_bak="${after_rules}-ufw-docker~$(date '+%Y-%m-%d-%H%M%S')~"
-	  err "\\nBacking up $after_rules to $after_rules_bak"
-	  cp "$after_rules" "$after_rules_bak"
-	  cat "$after_rules_tmp" > "$after_rules"
-    err "Please restart UFW service manually by using the following command:"
-    if type systemctl &>/dev/null; then
-      err "    sudo systemctl restart ufw"
-    else
-      err "    sudo service ufw restart"
+    if ! ufw-docker--check-install; then
+        local after_rules_bak
+        after_rules_bak="${after_rules}-ufw-docker~$(date '+%Y-%m-%d-%H%M%S')~"
+        err "\\nBacking up $after_rules to $after_rules_bak"
+        cp "$after_rules" "$after_rules_bak"
+        cat "$after_rules_tmp" > "$after_rules"
+        err "Please restart UFW service manually by using the following command:"
+        if type systemctl &>/dev/null; then
+            err "    sudo systemctl restart ufw"
+        else
+            err "    sudo service ufw restart"
+        fi
     fi
-  fi
 }
 
 function ufw-docker--help() {
-	cat <<-EOF >&2
+    cat <<-EOF >&2
 	Usage:
 	  ufw-docker <list|allow> [docker-instance-id-or-name [port[/tcp|/udp]] [network]]
 	  ufw-docker delete allow [docker-instance-id-or-name [port[/tcp|/udp]] [network]]
@@ -410,7 +421,11 @@ function die() {
 # __main__
 
 if ! ufw status 2>/dev/null | grep -Fq "Status: active" ; then
-    die "UFW is disabled or you are not root user."
+    die "UFW is disabled or you are not root user, or mismatched iptables legacy/nf_tables, current $(iptables --version)"
+fi
+
+if ! docker -v &> /dev/null; then
+  die "Docker executable not found."
 fi
 
 ufw_action="${1:-help}"
@@ -438,9 +453,9 @@ case "$ufw_action" in
         if [[ "$INSTANCE_PORT" = */udp ]]; then
             PROTO=udp
         fi
-	shift || true
+        shift || true
 
-	NETWORK="${1:-}"	
+        NETWORK="${1:-}"
 
         INSTANCE_PORT="${INSTANCE_PORT%/*}"