Looks for a tenant-devices.json file in it's current directory, and uses it to produce a bit of config for dhcpd. See code comment block for expected json object.

dhcpd-client-gen.js

#!/usr/bin/env node
'use strict';

/*
Parses tenant-devices.json file. For each tenant and client named in the array
in the form of:

[
  "tenantName": "my-tenant",
  "clients": [
    {
    "name": "my-client-name",
    "mac" : "00:11:22:33:44:55"
    }
  ]
]

...it will produce an entry in a clients config file in the form of:

host <name> {
  option dhcp-client-identifier 1:<mac>;
  hardware ethernet <mac>;
  option host-name "<name>.<domain>";
}
subclass "<tenant>" 1:<mac>;
subclass "<tenant>" <mac>;

*/

const fs = require('fs')
const domain = "my.domain.com"
const outputFile = "dhcpd-clients.conf"
var outputString = ""
try {
	var tenants = require("./tenant-devices.json")
} catch (e) {
  console.log(e);
	process.stdout.write(`\n\nCould not process 'tenant-devices.json' file.\n\n`);
	process.exit(1);
}

tenants.forEach((tenant)=>{

  tenant.clients.forEach((client)=>{

    outputString += `host ${client.name} {
  option dhcp-client-identifier 1:${client.mac};
  hardware ethernet ${client.mac};
  option host-name "${client.name}.${domain}";
}
subclass "${tenant.tenantName}" 1:${client.mac};
subclass "${tenant.tenantName}" ${client.mac};

`

  })
})

fs.writeFile(outputFile, outputString, (err)=>{
    if (err) console.log(err);
    console.log(`Successfully Written to ${outputFile}.`);
});