Upgrade Go modules with Dockerfile builds

upgrade-go.sh

#!/bin/bash
set -o errexit

# Assumes the latest version of Go is installed on the PATH.

# Finds all go.mod files under the current working directory and upgrades the
# Go modules to the latest version of Go and upgrades all their Go dependencies
# too.

# Then finds the Dockerfile in the go.mod file's parent directory and updates
# the "FROM golang" line to the latest version of Go and also updates the "RUN"
# line that installs golangci-lint to use the latest version of that tool.

find_golangci_lint_version () {
  curl -sL \
  -H "Accept: application/vnd.github+json" \
  -H "X-GitHub-Api-Version: 2022-11-28" \
  https://api.github.com/repos/golangci/golangci-lint/releases \
    | grep -m1 -Eo 'https://api\.github\.com/repos/golangci/golangci-lint/tarball/v[^"]*' \
    | cut -d'/' -f8
}

process_dockerfile () {
  local dockerfile="$1"

  printf 'Processing %s...\n' "${dockerfile}"

  # Set FROM golang line to new golang version
  sed -E -e 's/^FROM\s+golang:\S+/FROM golang:'"${GO_VERSION}"'/i' -i "${dockerfile}"

  # Ensure golangci-lint install is done on one lint
  sed -E -e '\,^RUN\s.*golangci-lint/master/install\.sh\s*\|\s*\\$,{N;s,\s*\\\n\s*, ,}' -i "${dockerfile}"

  # Set golangci-lint install to new version
  sed -E -e 's,^(RUN\s.*golangci-lint/master/install\.sh\s*\|\s*sh\s.*\s)v[0-9\.]+\s*$,\1'"${GOLANGCI_LINT_VERSION}"',' -i "${dockerfile}"
}

process_go_mod () {
  local go_mod="$1" app_dir dockerfile
  app_dir=$(dirname "${go_mod}")

  printf 'Processing %s...\n' "${go_mod}"
  (
      cd "${app_dir}"
      go mod download
      go mod tidy
      go get go@"${GO_VERSION}"
      go get -u ./...
      go mod tidy
  )

  dockerfile="${app_dir}/Dockerfile"
  if [ ! -s "${dockerfile}" ]; then
    dockerfile="${app_dir}/../Dockerfile"
  fi
  if [ -s "${dockerfile}" ]; then
    process_dockerfile "${dockerfile}"
  fi
}

main () {
  declare -g GO_VERSION GOLANGCI_LINT_VERSION
  GO_VERSION=$(
    go version \
      | awk '/^go version go1/ {print $3}' \
      | head -n1 \
      | sed 's/^go//'
  )
  if [ -z "${GO_VERSION}" ]; then
    printf 'Local Go version not found. Installed desired version of Go locally.\n' >&2
    return 1
  fi

  GOLANGCI_LINT_VERSION=$(find_golangci_lint_version)
  if [ -z "${GOLANGCI_LINT_VERSION}" ]; then
    printf 'Latest golangci-lint version not found on GitHub.\n' >&2
    return 1
  fi

  printf 'Searching under %s...\n' "${PWD}"
  printf 'Upgrading Go apps to v%s \n' "${GO_VERSION}"
  printf 'Upgrading golangci-lint to v%s \n' "${GOLANGCI_LINT_VERSION}"

  local go_mod
  while IFS= read -d '' -r go_mod; do
    process_go_mod "${go_mod}"
  done < <(
    find . -xdev -type f -name go.mod -print0 | sort -z
  )
}

main "$@"

# TODO go install golang.org/x/vuln/cmd/[email protected]
# TODO RUN go run github.com/google/wire/cmd/wire diff