In the Drupal 7 migrate module, you can use 'csvrownum' as the mapping key when migrating content from a CSV (https://www.drupal.org/node/1152158). For the Drupal 8 version, I am not sure what the equivalent is. Here is my yml file configuration (migrate plus):
id: timesheet_data
label: Importing Timesheet
migration_group: csvimport
migration_tags:
- node
- csvimport
source:
plugin: csv
path: 'somepath/timesheet.csv'
header_row_count: 1
keys:
- csvrownum
column_names:
0:
name: Name of Contact
1:
address: Address
destination:
plugin: 'entity:node'
default_bundle: timesheets
process:
title: name
I tried this approach thinking it might be similar to the drupal 7 migrate module. I also tried not specifying a key, both resulted in an error.