run-sloth

#!/bin/bash

# This script is used to download and run the Sloth tooling as part of the catalog compile step
# Sloth (sloth.dev) is used to generate prometheus alerts and recording rules based on the SLO alerting standards defined in Google's SRE book

set -eu

basedir=$(dirname "$0")
version="${SLOTH_VERSION:-v0.10.0}"

ensure_sloth () {
  set -eu

  local dir="$1"
  # Version with leading `v`.
  local version="$2"

  local arch
  arch=$(uname -m)
  case $arch in
    aarch64|arm64) arch="arm64";;
    x86_64|amd64) arch="amd64";;
    *)
      >&2 echo "Unsupported arch: $arch"
      exit 5
    ::
  esac

  local os
  os=$(uname -s)
  case $os in
    Linux) os="linux";;
    Darwin) os="darwin";;
    *)
      >&2 echo "Unsupported os: $os"
      exit 5
    ::
  esac

  if [ ! -x "${dir}/sloth-${version}-${os}-${arch}" ]; then
    download_sloth "${dir}" "${version}" "${os}" "${arch}"
  else
    >&2 echo "sloth-${version}-${os}-${arch} already installed"
  fi

  echo "${dir}/sloth-${version}-${os}-${arch}"
}

download_sloth () {
  set -eu

  local dir="$1"
  local version="$2"
  local os="$3"
  local arch="$4"

  local url="https://github.com/slok/sloth/releases/download/${version}/sloth-${os}-${arch}"

  >&2 echo "Downloading sloth-${version}-${os}-${arch} from ${url}"

  curl -fsSLo "${dir}/sloth-${version}-${os}-${arch}" "${url}"
  chmod +x "${dir}/sloth-${version}-${os}-${arch}"

  >&2 echo "sloth-${version}-${os}-${arch} successfully installed"
}

sloth=$(ensure_sloth "$basedir" "$version")

"$sloth" "$@"