From 4262dc8564fa915b6090a9709e1a44de3565db44 Mon Sep 17 00:00:00 2001
From: Olivier Mehani <shtrom@ssji.net>
Date: Wed, 5 Jan 2022 22:51:16 +1100
Subject: [PATCH] snmp__if_combined: add support for multiple instances

This allows to split the data into smaller groups, e.g., per ifType.

Signed-off-by: Olivier Mehani <shtrom@ssji.net>
---
 plugins/snmp/snmp__if_combined | 52 ++++++++++++++++++++++++++--------
 1 file changed, 40 insertions(+), 12 deletions(-)

diff --git a/plugins/snmp/snmp__if_combined b/plugins/snmp/snmp__if_combined
index 6d06619a..7b6e3cb1 100755
--- a/plugins/snmp/snmp__if_combined
+++ b/plugins/snmp/snmp__if_combined
@@ -74,6 +74,28 @@ would normally be for VPNs.  A minor horde of different interface types
 are supposted, please see IANAifType-MIB (on your system or find with
 Google) for a full list.
 
+=head2 MULTIPLE INSTANCES
+
+It is possible to run multiple instances of the plugin for the same host. This
+is most useful to generate separate views for groups of ifTypes (e.g.,
+ethernetCsmacd, ieee82011, l2vlan, ...).
+
+New instances should be symlinked to the script with an underscore-separated
+suffix. A matching configuration file should be present to specify the required
+ifTypes (or any other relevant parameters).
+
+    $ readlink /etc/munin/plugins/snmp_192.2.0.1_if_combined_vlan
+    /path/to/munin-contrib/plugins/snmp/snmp__if_combined
+
+    $ sudo cat /etc/munin/plugin-conf.d/snmp_192.2.0.1_if_combined_vlan
+    env.ifTypeOnly l2vlan
+
+The suffix will be appended to the graph base name, e.g.,
+`snmp_<HOST>_if_combined_<SUFFIX>` will generate the `snmp_if_combined_<SUFFIX>`
+multigraph and associated series for the selected `<HOST>`.
+
+=head2 STACKED ROOT GRAPH
+
 The `stackedRoot` option determines whether the root summary graph shows the
 traffic on each interface separately, or stacks them on top of one another to
 show the total traffic through the device.
@@ -211,6 +233,12 @@ use strict;
 use Munin::Plugin;
 use Munin::Plugin::SNMP;
 
+my $scriptname='snmp_if_combined';
+my @scriptname_components= split(/_/,$0);
+if ($scriptname_components[-1] ne 'combined') {
+    $scriptname .= "_${scriptname_components[-1]}";
+}
+
 my $response;
 my $iface;
 
@@ -611,7 +639,7 @@ sub do_config_root {
 
     print <<END;
 
-multigraph snmp_if_combined
+multigraph $scriptname
 graph_title All interfaces traffic
 graph_args --base 1000
 graph_vlabel bits in (-) / out (+) per \${graph_period}
@@ -622,8 +650,8 @@ END
     print "graph_order";
     my @ifs;
     foreach my $if (sort {$a <=> $b} keys %{$snmpinfo}) {
-        print " recv$if=snmp_if_combined.$if.recv send$if=snmp_if_combined.$if.send";
-        push @ifs, "snmp_if_combined.$if";
+        print " recv$if=$scriptname.$if.recv send$if=$scriptname.$if.send";
+        push @ifs, "$scriptname.$if";
     }
     if ($stackedRoot) {
         print " recv_bits send_bits";
@@ -679,7 +707,7 @@ END
     }
 
     print <<END;
-multigraph snmp_if_combined_err
+multigraph ${scriptname}_err
 graph_title All interfaces errors
 graph_args --base 1000
 graph_vlabel errors in (-) / out (+) per \${graph_period}
@@ -688,7 +716,7 @@ END
 
     print "graph_order";
     foreach my $if (sort {$a <=> $b} keys %{$snmpinfo}) {
-        print " recv$if=snmp_if_combined_err.$if.total_in send$if=snmp_if_combined_err.$if.total_out";
+        print " recv$if=${scriptname}_err.$if.total_in send$if=${scriptname}_err.$if.total_out";
     }
     print "\n";
 
@@ -761,7 +789,7 @@ sub do_config_if {
     $extrainfo .= " This is a '".$ifTypeByNum{$response}."' interface.";
 
     print <<END;
-multigraph snmp_if_combined.$if
+multigraph $scriptname.$if
 graph_title $alias traffic
 graph_info This graph shows traffic for the \"$alias\" network interface.$extrainfo
 graph_args --base 1000
@@ -787,7 +815,7 @@ END
     }
 
     print <<END;
-multigraph snmp_if_combined_err.$if
+multigraph ${scriptname}_err.$if
 graph_title $alias errors
 graph_info This graph shows errors for the \"$alias\" network interface.$extrainfo
 graph_args --base 1000
@@ -836,11 +864,11 @@ sub do_fetch_if {
     if ($status != 1) {
         # Interface is down
         print <<END;
-multigraph snmp_if_combined.$if
+multigraph $scriptname.$if
 recv.value U
 send.value U
 send.extinfo This interface is currently down.
-multigraph snmp_if_combined_err.$if
+multigraph ${scriptname}_err.$if
 errors_in.value U
 errors_out.value U
 discards_in.value U
@@ -856,7 +884,7 @@ END
     my $recv;
     my $send;
 
-    print "multigraph snmp_if_combined.$if\n";
+    print "multigraph $scriptname.$if\n";
 
     $response = $snmpinfoX->{$if}->{ifHCInOctets} || $snmpinfo->{$if}->{ifInOctets};
     $recv = defined($response) ? ($response * 8) : undef;
@@ -866,7 +894,7 @@ END
     $send = defined($response) ? ($response * 8) : undef;
     printf("send.value %s\n", $send || "U");
 
-    print "multigraph snmp_if_combined_err.$if\n";
+    print "multigraph ${scriptname}_err.$if\n";
 
     my $errors = $snmpinfo->{$if}->{ifInErrors};
     my $discards = $snmpinfo->{$if}->{ifInDiscards};
@@ -925,7 +953,7 @@ foreach my $if (sort {$a <=> $b} keys %{$snmpinfo}) {
     $send += ($send_if || 0);
 }
 if ($stackedRoot) {
-    print "multigraph snmp_if_combined\n";
+    print "multigraph $scriptname\n";
     print "recv_bits.value $recv\n";
     print "send_bits.value $send\n";
 }