ntopng/scripts/lua/modules/alert_endpoints/email.lua
2018-04-13 11:57:28 +02:00

109 lines
3.1 KiB
Lua

--
-- (C) 2018 - ntop.org
--
local email = {}
email.EXPORT_FREQUENCY = 60
local MAX_ALERTS_PER_EMAIL = 100
local MAX_NUM_SEND_ATTEMPTS = 5
local NUM_ATTEMPTS_KEY = "ntopng.alerts.modules_notifications_queue.email.num_attemps"
local function buildMessageHeader(now_ts, from, to, subject, body)
local now = os.date("%a, %d %b %Y %X", now_ts) -- E.g. "Tue, 3 Apr 2018 14:58:00"
local msg_id = "<" .. now_ts .. "." .. os.clock() .. "@ntopng>"
local lines = {
"From: " .. from,
"To: " .. to,
"Subject: " .. subject,
"Date: " .. now,
"Message-ID: " .. msg_id,
"Content-Type: text/html; charset=UTF-8",
}
return table.concat(lines, "\r\n") .. "\r\n\r\n" .. body .. "\r\n"
end
function email.sendEmail(subject, message_body)
local smtp_server = ntop.getPref("ntopng.prefs.alerts.smtp_server")
local from_addr = ntop.getPref("ntopng.prefs.alerts.email_sender")
local to_addr = ntop.getPref("ntopng.prefs.alerts.email_recipient")
if isEmptyString(from_addr) or isEmptyString(to_addr) or isEmptyString(smtp_server) then
return false
end
local from = from_addr:gsub(".*<(.*)>", "%1")
local to = to_addr:gsub(".*<(.*)>", "%1")
local product = ntop.getInfo(false).product
local info = ntop.getHostInformation()
subject = product .. " [" .. info.instance_name .. "@" .. info.ip .. "] " .. subject
if not string.find(smtp_server, "://") then
smtp_server = "smtp://" .. smtp_server
end
local parts = string.split(to, "@")
if #parts == 2 then
local sender_domain = parts[2]
smtp_server = smtp_server .. "/" .. sender_domain
end
local message = buildMessageHeader(os.time(), from_addr, to_addr, subject, message_body)
return ntop.sendMail(from, to, message, smtp_server)
end
function email.dequeueAlerts(queue)
while true do
local notifications = ntop.lrangeCache(queue, 0, MAX_ALERTS_PER_EMAIL-1)
if not notifications then
break
end
local subject = ""
if #notifications > 1 then
subject = "(" .. i18n("alert_messages.x_alerts", {num=#notifications}) .. ")"
end
local message_body = {}
-- Multiple notifications
for _, json_message in ipairs(notifications) do
local notif = alertNotificationToObject(json_message)
message_body[#message_body + 1] = formatAlertNotification(notif, {nohtml=true})
end
message_body = table.concat(message_body, "<br>")
local rv = email.sendEmail(subject, message_body)
if not rv then
local num_attemps = (tonumber(ntop.getCache(NUM_ATTEMPTS_KEY)) or 0) + 1
if num_attemps >= MAX_NUM_SEND_ATTEMPTS then
ntop.delCache(NUM_ATTEMPTS_KEY)
-- Prevent alerts starvation if the plugin is not working after max num attempts
ntop.delCache(queue)
return {success=false, error_message="Unable to send mails"}
else
ntop.setCache(NUM_ATTEMPTS_KEY, tostring(num_attemps))
return {success=true}
end
else
ntop.delCache(NUM_ATTEMPTS_KEY)
end
-- Remove the processed messages from the queue
ntop.ltrimCache(queue, MAX_ALERTS_PER_EMAIL, -1)
end
return {success=true}
end
return email