anchor.diff:  
     ec2-autohostname = ''
       ${ip} route delete blackhole 169.254.169.254 2>/dev/null || true
  -
  -    export CURL_CA_BUNDLE=${pkgs.cacert}/etc/ca-bundle.crt
  -
       # registering route 53 hostnames if any:
       echo ${concatStringsSep " " (
           mapAttrsToList (_: args: retry-wrapper (register-hostname {
  
positive.code:     useLocalHostname,
      query ? if useLocalHostname then "local-ipv4" else "public-hostname",
      recordType ? if useLocalHostname then "A" else "CNAME"
    }: pkgs.writeScript "ec2-register-hostname-${zone}" ''
      #!${bash}
      date=$(${curl} -I https://route53.amazonaws.com/date | ${awk} '/^Date: / {sub("Date: ", "", $0); sub("\\r", "", $0); print $0}')
  
      iam="${iamCredentialName}"
  
negative.code:     set -- $(${wget} http://169.254.169.254/latest/meta-data/iam/security-credentials/${iamCredentialName} \
                | ${jq} -r '.SecretAccessKey, .AccessKeyId, .Token')
  
      signature="$(echo -n "$date" | ${openssl} dgst -binary -sha1 -hmac "$1" | ${base64})"
      auth_header="X-Amzn-Authorization: AWS3-HTTPS AWSAccessKeyId=$2,Algorithm=HmacSHA1,Signature=$signature"
      record_value=$(${wget} http://169.254.169.254/latest/meta-data/${query})
  
  