INSTALL_MultiProtocol.md

Support hosts without http server

Add protocol features to allow to read traffic XML data via the other protocols.

a 'file' protocol is added to support all of the other protocols, three methods can be used:

Firstly

a daemon can be called to get the XML traffic data from the other services directly and forward the XML output to proxy.sh.

<iface>
  <name>eth0</name>
  <description>Local Host</description>
  <host>localhost</host>
  <protocol>file</protocol>
  <dump_tool>/usr/lib/cgi-bin/vnstat.sh</dump_tool>
</iface>

Second

A daemon can be run periodically to collect the XML data and put them into a directory. Another program can be called by proxy.sh to output the data.

It is very similar to above method, but need extra 'dump_tool' here may have not need to access remote host while getting data, but get local data directly for a daemon have collected data for us.

The following method is similar but works better for it can reuse local interfaces. So, thie method is not recommendded, see below one.

Third

The data from the other servers can be stored to the same directory of local data but map to different local 'virtual' interfaces.

For example, download the remote test.org data to local /var/lib/vnstat/eth5, and then, we can get the output with localhost directly. Or, even you can use something like /var/lib/vnstat/test.org-eth0, for example:

$ cp /var/lib/vnstat/eth0 /var/lib/vnstat/test.org-eth0
$ vnstat -i test.org-eth0

Let's write a simple daemon below, use ssh protocol (with public key) as an example:

# collect-data.sh
hosts="a b c d e"
ifaces="eth0 eth1"
while :;
do
	for h in $hosts
	do
                for i in $ifaces
                do
                    scp ${h}:/var/lib/vnstat/${i} /var/lib/vnstat/${h}-${i}
                done
	done
	sleep 5
done

Based on the above shell script, you can write a simple cron script.

Then, we can add the following lines into sidebar.xml:

<iface>
   <name>a-eth0</name>
   <description>Remote Host</description>
   <host>localhost</host>
   <protocol>http</protocol>
   <dump_tool>/cgi-bin/vnstat.sh</dump_tool>
</iface>
<iface>
   <name>b-eth0</name>
   <description>Remote Host</description>
   <host>localhost</host>
   <protocol>http</protocol>
   <dump_tool>/cgi-bin/vnstat.sh</dump_tool>
</iface>
<iface>
   <name>c-eth0</name>
   <description>Remote Host</description>
   <host>localhost</host>
   <protocol>http</protocol>
   <dump_tool>/cgi-bin/vnstat.sh</dump_tool>
</iface>
<iface>
   <name>d-eth0</name>
   <description>Remote Host</description>
   <host>localhost</host>
   <protocol>http</protocol>
   <dump_tool>/cgi-bin/vnstat.sh</dump_tool>
</iface>
<iface>
   <name>e-eth0</name>
   <description>Remote Host</description>
   <host>localhost</host>
   <protocol>http</protocol>
   <dump_tool>/cgi-bin/vnstat.sh</dump_tool>
</iface>

Note: To get the second data from remote host, we must collect second(s) data with collect-data.sh:

# collect-data.sh
hosts="a b c d e"
ifaces="eth0 eth1"
while :;
do
	for h in hosts
	do
                for i in $ifaces
                do
                    scp ${h}:/var/lib/vnstat/${i} /var/lib/vnstat/${h}-${i}
                    scp ${h}:/proc/net/dev > /var/lib/vnstat/${h}-${i}-second
                done
	done
	sleep 5
done