feat: Add frappe cmd and doctype to request headers for analytics and load balancing

[sachinhub]

Frappe CMD and Doctype details are deep inside the POSTed HTTP body. If brought at the HTTP header level would help in more powerful load balancing at the webserver level and also in logging.

e.g. following snippet in nginx config allows routing based on http header to different backend ERPNext servers -

map $http_x_frappe_cmd $backend_server {
  "frappe.desk.reportview.export_query" replica-first;
  "frappe.desk.reportview.get_sidebar_stats" replica-first;
  "frappe.desk.reportview.get" replica-first;
  "frappe.desk.query_report.run" replica-first;
  "frappe.model.db_query.get_list" replica-first;
  "frappe.client.get_count" replica-first;
  "frappe.desk.notifications.get_open_count" replica-first;
  "frappe.utils.print_format.download_multi_pdf" quarantine;
}

upstream primary-first {
  server wra01.ntex.com;
}

upstream replica-first {
  server wra01.ntex.com;
  server wra02.ntex.com;
  server wra03.ntex.com;
  server backup-wra.ntex.com backup;
}

upstream quarantine {
  server wra03.ntex.com;
  server backup-wra.ntex.com backup;
}


location / {
    if ( $backend_server ) {
      add_header x-served-from $backend_server;
      proxy_pass http://$backend_Server;
      break;
    }

    add_header x-served-from "master";
    proxy_pass http://primary-first;

  }

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed within a week if no further activity occurs, but it only takes a comment to keep a contribution alive :) Also, even if it is closed, you can always reopen the PR when you're ready. Thank you for contributing.

[sachinhub]

@rmehta can this PR be merged?

[sachinhub]

Thanks for merging. However, just noticed that changes suggested to use .get() does not work in JavaScript. Sent another merge request #7520

[surajshetty3416]

@sachinhub Sorry for that suggestion. For some reason, I thought that it was a python file.