feat: init docker-pussh CLI plugin for Docker

Author: psviderski

docker-pussh

@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Return metadata expected by the Docker CLI plugin framework: https://github.com/docker/cli/pull/1564
+# TODO: update ShortDescription and Version as needed.
+if [ "${1:-}" = "docker-cli-plugin-metadata" ]; then
+    cat <<EOF
+{
+  "SchemaVersion": "0.1.0",
+  "Vendor": "https://github.com/psviderski",
+  "Version": "0.1.0",
+  "ShortDescription": "Push Docker images to remote daemons via SSH using unregistry"
+}
+EOF
+    exit 0
+fi
+
+# Colors for output.
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[0;33m'
+NC='\033[0m' # no color
+
+info() {
+    echo -e "${GREEN}[INFO]${NC} $1"
+}
+
+warning() {
+    echo -e "${YELLOW}[WARNING]${NC} $1"
+}
+
+error() {
+    echo -e "${RED}[ERROR]${NC} $1" >&2
+    exit 1
+}
+
+usage() {
+    echo "Usage: docker pussh [OPTIONS] IMAGE[:TAG] [USER@]HOST[:PORT]"
+    echo ""
+    echo "Upload a Docker image to a remote Docker daemon via SSH."
+    echo ""
+    echo "Options:"
+    echo "  -h, --help              Show this help message."
+    echo "  -i, --ssh-key path      Path to SSH private key for remote login (if not already added to SSH agent)."
+    echo "      --platform string   Push a specific platform for a multi-platform image (e.g., linux/amd64, linux/arm64)."
+    echo "                          Local Docker has to use containerd image store to support multi-platform images."
+    echo ""
+    echo "Examples:"
+    echo "  docker pussh myimage:latest user@host"
+    echo "  docker pussh --platform linux/amd64 myimage:latest host"
+    echo "  docker pussh myimage:latest user@host:2222 -i ~/.ssh/id_ed25519"
+}
+
+DOCKER_PLATFORM=""
+SSH_KEY=""
+IMAGE=""
+SSH_ADDRESS=""
+
+# Skip 'pussh' if called as Docker CLI plugin.
+if [ "${1:-}" = "pussh" ]; then
+    shift
+fi
+
+# Parse options and arguments.
+help_command="Run 'docker pussh --help' for usage information."
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -i|--ssh-key)
+            if [ -z "${2:-}" ]; then
+                error "-i/--ssh-key option requires an argument.\n${help_command}"
+            fi
+            SSH_KEY="$2"
+            shift 2
+            ;;
+        --platform)
+            if [ -z "${2:-}" ]; then
+                error "--platform option requires an argument.\n${help_command}"
+            fi
+            DOCKER_PLATFORM="$2"
+            shift 2
+            ;;
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        -*)
+            error "unknown option: $1\n${help_command}"
+            ;;
+        *)
+            # First non-option argument is the image.
+            if [ -z "$IMAGE" ]; then
+                IMAGE="$1"
+            # Second non-option argument is the SSH address.
+            elif [ -z "$SSH_ADDRESS" ]; then
+                SSH_ADDRESS="$1"
+            else
+                error "too many arguments.\n${help_command}"
+            fi
+            shift
+            ;;
+    esac
+done
+
+# Validate required arguments.
+if [ -z "$IMAGE" ] || [ -z "$SSH_ADDRESS" ]; then
+    error "IMAGE and HOST are required.\n${help_command}"
+fi
+# Validate SSH key file exists if provided.
+if [ -n "$SSH_KEY" ] && [ ! -f "$SSH_KEY" ]; then
+    error "SSH key file not found: $SSH_KEY"
+fi