ECR login helper for fish.

ecr_login.fish

function ecr_login -d \
    "ecr_login [profile_name] [region]: Log in to ECR via the AWS CLI." \
    -a profile_name region

  set -l args
  if [ -n "$profile_name" ]
    set args $args "--profile=$profile_name"
  end
  if [ -n "$region" ]
    set args $args "--region=$region"
  end
  set -l auth_result (aws $args ecr get-authorization-token --output text)
  if [ -z "$auth_result" ]
    return
  end
  set -l token (echo "$auth_result" | cut -f2 | base64 --decode | cut -d: -f2)
  set -l url (echo "$auth_result" | cut -f4)
  echo "$token" | docker login --password-stdin -u AWS "$url"
end