feat: add oras feature

src/oras/devcontainer-feature.json

@@ -0,0 +1,15 @@
+{
+  "name": "ORAS",
+  "id": "oras",
+  "version": "1.0.0",
+  "description": "Install ORAS ( https://oras.land ), an OCI Artifact tool",
+  "options": {
+    "version": {
+      "type": "string",
+      "proposals": ["1.0.0"],
+      "default": "1.0.0",
+      "description": "The specific version to install"
+    }
+  },
+  "installsAfter": ["ghcr.io/devcontainers/features/common-utils"]
+}

src/oras/ensure_command.sh

@@ -0,0 +1,28 @@
+ensure_apt_updated() {
+    if [ "${_apt_updated:-}" != "true" ]; then
+        apt-get update
+        _apt_updated=true
+    fi
+}
+
+ensure_command() {
+    command=${1:?}
+    package=${2:-$command}
+
+    if ! which "$command" >/dev/null; then
+        ensure_package "$package"
+    fi
+}
+
+ensure_package() {
+    package=${1:?}
+    if which apt-get >/dev/null; then
+        ensure_apt_updated
+        apt-get -y install "$package"
+    elif which apk >/dev/null; then
+        apk add "${package}"
+    else
+        echo "Unable to install $package, no supported package manager found" >&2
+        exit 1
+    fi
+}

src/oras/install.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+set -euo pipefail
+
+. ./ensure_command.sh
+ensure_command curl
+
+VERSION="${VERSION:-1.0.0}"
+if [[ ! $VERSION =~ ^[a-zA-Z0-9.-]+$ ]]; then
+  echo "Error: invalid version: $VERSION" >&2
+  exit 1
+fi
+
+declare -A uname_platforms=([aarch64]=arm64 [x86_64]=amd64)
+platform=${uname_platforms[$(uname -m)]:?"Error: unsupported platform: $(uname -m)"}
+
+curl --fail --location -# -o oras.tar.gz \
+  "https://github.com/oras-project/oras/releases/download/v${VERSION?}/oras_${VERSION:?}_linux_${platform:?}.tar.gz"
+mkdir -p oras-install/
+tar -zxf oras.tar.gz -C oras-install/
+mv oras-install/oras /usr/local/bin/
+rm -rf oras.tar.gz oras-install/

test/oras/scenarios.json

@@ -0,0 +1 @@
+{}

test/oras/test.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+set -e
+
+# https://github.com/devcontainers/cli/blob/main/docs/features/test.md
+source dev-container-features-test-lib
+
+check "oras command available" oras version
+
+reportResults