octant: add update script

pkgs/applications/networking/cluster/octant/update.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p curl gnused gawk nix-prefetch
+
+set -euo pipefail
+
+ROOT="$(dirname "$(readlink -f "$0")")"
+NIX_DRV="$ROOT/default.nix"
+if [ ! -f "$NIX_DRV" ]; then
+  echo "ERROR: cannot find default.nix in $ROOT"
+  exit 1
+fi
+
+fetch_arch() {
+  VER="$1"; ARCH="$2"
+  URL="https://github.com/vmware-tanzu/octant/releases/download/v${VER}/octant_${VER}_${ARCH}.tar.gz"
+  nix-prefetch "{ stdenv, fetchzip }:
+stdenv.mkDerivation rec {
+  pname = \"octant\"; version = \"${VER}\";
+  src = fetchzip { url = \"$URL\"; };
+}
+"
+}
+
+replace_sha() {
+  sed -i "s#$1 = \"sha256-.\{44\}\"#$1 = \"$2\"#" "$NIX_DRV"
+}
+
+OCTANT_VER=$(curl -Ls -w "%{url_effective}" -o /dev/null https://github.com/vmware-tanzu/octant/releases/latest | awk -F'/' '{print $NF}' | sed 's/v//')
+
+OCTANT_LINUX_X64_SHA256=$(fetch_arch "$OCTANT_VER" "Linux-64bit")
+OCTANT_DARWIN_X64_SHA256=$(fetch_arch "$OCTANT_VER" "Linux-arm64")
+OCTANT_LINUX_AARCH64_SHA256=$(fetch_arch "$OCTANT_VER" "macOS-64bit")
+
+sed -i "s/version = \".*\"/version = \"$OCTANT_VER\"/" "$NIX_DRV"
+
+replace_sha "x86_64-linux" "$OCTANT_LINUX_X64_SHA256"
+replace_sha "x86_64-darwin" "$OCTANT_LINUX_AARCH64_SHA256"
+replace_sha "aarch64-linux" "$OCTANT_DARWIN_X64_SHA256"