test-mail.lua

local mail = require "resty.mail"

local mailer, err = mail.new({
  host = "smtp.gmail.com",
  port = 587,
  starttls = true,
  username = "YOUR.USERNAME@gmail.com",
  password = "YOUR.PASSWORD",
})
if err then
  ngx.log(ngx.ERR, "mail.new error: ", err)
  return
end

local ok, err = mailer:send({
  from = "Master Splinter <splinter@example.com>",
  to = { "michelangelo@example.com" },
  cc = { "leo@example.com", "Raphael <raph@example.com>", "donatello@example.com" },
  subject = "Pizza is here!",
  text = "There's pizza in the sewer.",
  html = "<h1>There's pizza in the sewer.</h1>",
  attachments = {
    {
      filename = "toppings.txt",
      content_type = "text/plain",
      content = "1. Cheese\n2. Pepperoni",
    },
  },
})
if err then
  ngx.log(ngx.ERR, "mailer:send error: ", err)
  return
end

print("mailer:send success: ", ok)