[fixup] Missing earthly.sh script

Author: vector-of-bool

tools/earthly.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+: "${EARTHLY_VERSION:=0.8.16}"
+
+this_file=${BASH_SOURCE[0]}
+this_dir=$(readlink -f "$(dirname "$this_file")")
+repo_dir=$(dirname "$this_dir")
+scratch_dir="$repo_dir/_build"
+mkdir -p "$scratch_dir"
+
+# Calc the arch of the executable we want
+case "$HOSTTYPE" in
+    x64|x86_64)
+        arch=amd64
+        ;;
+    arm64)
+        arch=arm64
+        ;;
+    *)
+        echo "Unsupported architecture for automatic Earthly download: $HOSTTYPE" 1>&1
+        exit 99
+        ;;
+esac
+
+# The location where the Earthly executable will live
+cache_dir="$scratch_dir/_earthly/$EARTHLY_VERSION"
+mkdir -p "$cache_dir"
+
+exe_filename="earthly-$(uname | tr '[:upper:]' '[:lower:]')-$arch"
+EARTHLY_EXE="$cache_dir/$exe_filename"
+
+# Download if it isn't already present
+if ! test -f "$EARTHLY_EXE"; then
+    echo "Downloading $exe_filename $EARTHLY_VERSION"
+    url="https://github.com/earthly/earthly/releases/download/v$EARTHLY_VERSION/$exe_filename"
+    curl --retry 5 -LsS --max-time 120 --fail "$url" --output "$EARTHLY_EXE"
+    chmod a+x "$EARTHLY_EXE"
+fi
+
+"$EARTHLY_EXE" "$@"