udp.go

// Copyright 2017 Inca Roads LLC.  All rights reserved.
// Use of this source code is governed by licenses granted by the
// copyright holder including that found in the LICENSE file.

// Inbound UDP support
package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"time"
)

// UDPInboundHandler kicks off UDP single-upload request server
func UDPInboundHandler() {

	fmt.Printf("Now handling inbound UDP on %s%s\n", ThisServerAddressIPv4, TTServerUDPPort)

	ServerAddr, err := net.ResolveUDPAddr("udp", TTServerUDPPort)
	if err != nil {
		fmt.Printf("Error resolving UDP port: \n%v\n", err)
		return
	}

	ServerConn, err := net.ListenUDP("udp", ServerAddr)
	if err != nil {
		fmt.Printf("Error listening on UDP port: \n%v\n", err)
		return
	}
	defer ServerConn.Close()

	for {
		buf := make([]byte, 8192)

		n, addr, err := ServerConn.ReadFromUDP(buf)
		if err != nil {
			fmt.Printf("UDP read error: \n%v\n", err)
		} else {

			ttg := &TTGateReq{}
			ttg.Payload = buf[0:n]
			ttg.Transport = "device-udp:" + ipv4(addr.String())
			data, err := json.Marshal(ttg)
			if err == nil {
				go UploadToWebLoadBalancer(data, n, ttg.Transport)
				stats.Count.UDP++
			}

		}

	}

}

// UploadToWebLoadBalancer uploads a UDP packet via a Safecast data structure the load balancer for the web service
func UploadToWebLoadBalancer(data []byte, datalen int, transport string) {

	if true {
		fmt.Printf("\n%s Received %d-byte payload from %s, routing to HTTP load balancer\n", LogTime(), datalen, transport)
	}

	url := "http://" + TTServerHTTPAddress + TTServerHTTPPort + TTServerTopicSend

	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(data))
	req.Header.Set("User-Agent", "TTSERVE")
	req.Header.Set("Content-Type", "text/plain")
	httpclient := &http.Client{
		Timeout: time.Second * 15,
	}
	resp, err := httpclient.Do(req)
	if err != nil {
		fmt.Printf("HTTP POST error: %v\n", err)
	} else {
		resp.Body.Close()
	}

}