Add hack/module.sh script to run module tasks

The script knows `tidy`, `lint`, and `test`

hack/module.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+root_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )/.." && pwd )"
+
+function tidy_cmd() {
+  echo 'go mod tidy'
+}
+
+function lint_cmd() {
+  if [ -x "$(command -v golangci-lint)" ]; then
+    cmd='golangci-lint'
+  else
+    cmd='go run github.com/golangci/golangci-lint/cmd/golangci-lint'
+  fi
+  echo "${cmd} run --modules-download-mode=readonly --timeout=10m"
+}
+
+function test_cmd() {
+  if [ -x "$(command -v gotest)" ]; then
+    cmd='gotest'
+  else
+    cmd='go test'
+  fi
+  echo "${cmd} -race ./..."
+}
+
+function with_modules() {
+  local cmd_function="${1}"
+  cmd="$(${cmd_function})"
+
+  pushd "${root_dir}"
+  for mod_file in $(find . -maxdepth 3 -name go.mod); do
+    mod_dir="$(dirname "${mod_file}")"
+    (
+      echo "=> " && \
+      echo "   cd ${mod_dir} && ${cmd}" && \
+      cd "${mod_dir}" && ${cmd}
+    )
+  done
+  popd
+}
+
+function usage() {
+  echo "Error: <task> must be specified"
+  echo "       do.sh <task> [tidy, lint, test]"
+  exit 1
+}
+
+function main() {
+  case "${1:-invalid}" in
+    'tidy') with_modules 'tidy_cmd' ;;
+    'lint') with_modules 'lint_cmd' ;;
+    'test') with_modules 'test_cmd' ;;
+    *) usage ;;
+  esac
+}
+
+main "$@"