feat: add install script that improves talosctl installation user experience

This install script detects the platform and architecture, and downloads the correct talosctl, and checks the gpg checksums.
It also installs and chmods the binary.

Signed-off-by: Andrew Rynhard <andrew@rynhard.io>

website/static/install

@@ -0,0 +1,135 @@
+#!/usr/bin/env sh
+
+set -eu
+
+INSTALLPATH=${INSTALLPATH:-/usr/local/bin}
+
+happyexit() {
+  echo "Installed version:"
+  echo "$(talosctl version 2>/dev/null )"
+  echo ""
+  echo "Now run:"
+  echo ""
+  echo "  talosctl cluster create                  # install a local test cluster"
+  echo "  talosctl dashboard                       # If you have created a cluster, launch the dashboard"
+  echo ""
+  echo "Looking for more? Visit https://talos.dev/latest"
+  echo ""
+  exit 0
+}
+
+validate_checksum() {
+  filename=$1
+  url="https://github.com/siderolabs/talos/releases/latest/download/sha256sum.txt"
+  SHA=$(curl --proto '=https' --tlsv1.2 -sSfL "${url}" | grep "${filename}" | awk '{print $1 }')
+  echo ""
+  echo "Validating checksum..."
+
+  case $checksumbin in
+    *openssl)
+      checksum=$($checksumbin dgst -sha256 "${filename}" | sed -e 's/^.* //')
+      ;;
+    *shasum)
+      checksum=$($checksumbin -a256 "${filename}" | sed -e 's/ .*$//')
+      ;;
+  esac
+
+  if [ "$checksum" != "$SHA" ]; then
+    echo "Checksum validation failed." >&2
+    return 1
+  fi
+  echo "Checksum valid."
+  return 0
+}
+
+OS=$(uname -s)
+arch=$(uname -m)
+cli_arch=""
+case $OS in
+  CYGWIN* | MINGW64*)
+    OS=windows-amd64.exe
+    ;;
+  Darwin | Linux | FreeBSD)
+    case $arch in
+      x86_64)
+        cli_arch=amd64
+        ;;
+      armv8*)
+        cli_arch=arm64
+        ;;
+      aarch64*)
+        cli_arch=arm64
+        ;;
+      amd64|arm64)
+        cli_arch=$arch
+        ;;
+      *)
+        echo "There is no talosctl $OS support for $arch. Please open an issue with your platform details."
+        exit 1
+        ;;
+    esac
+    ;;
+  *)
+    echo "There is no talosctl support for $OS/$arch. Please open an issue with your platform details."
+    exit 1
+    ;;
+esac
+OS=$(echo $OS | tr '[:upper:]' '[:lower:]')
+
+
+tmpdir=$(mktemp -d /tmp/talosctl.XXXXXX)
+srcfile="talosctl-${OS}"
+if [ -n "${cli_arch}" ]; then
+  srcfile="${srcfile}-${cli_arch}"
+fi
+
+
+
+dstfile="${INSTALLPATH}/talosctl"
+
+checksumbin=$(command -v openssl) || checksumbin=$(command -v shasum) || {
+  echo "Failed to find checksum binary. Please install openssl or shasum."
+  echo ""
+  echo "You can also elect to just download/install https://github.com/siderolabs/talos/releases/latest/download/${srcfile}"
+  echo "into ${dstfile}"
+  exit 1
+}
+
+url="https://github.com/siderolabs/talos/releases/latest/download/${srcfile}"
+
+if [ -e "${dstfile}" ]; then
+    echo ""
+    echo "talosctl was already downloaded;  🎉"
+    echo ""
+    echo "To force re-downloading, delete '${dstfile}' then run me again."
+    (
+      rm -rf "${tmpdir}"
+    )
+    happyexit
+fi
+
+(
+  cd "$tmpdir"
+
+  echo "Downloading ${srcfile}..."
+  curl --proto '=https' --tlsv1.2 -fLO "${url}"
+  echo "Download complete!"
+
+  if ! validate_checksum "${srcfile}"; then
+    exit 1
+  fi
+  echo ""
+  exit
+)
+
+(
+  mv "${tmpdir}/${srcfile}" "${dstfile}"
+  chmod +x "${dstfile}"
+)
+
+
+rm -r "$tmpdir"
+
+echo "talosctl was successfully installed 🎉"
+echo ""
+happyexit