Rewrite plugin affects coredns_dns_request_size_bytes metric #7162
Description
I did 2 tests with and without rewrite plugin and the results are different. In the first test, coredns_dns_request_size_bytes is 90, which is the expected request size. But when I added the rewrite plugin, it affected the coredns_dns_request_size_bytes metric. I think this is not the expected behavior.
TC1: without rewrite
Corefile:
.:59 {
prometheus :8086
forward . 8.8.8.8
}
Request:
dig @localhost -p 59 somerequestthathaveasize90.123456789.123456789.1234567891.net
localhost:8086/metrics
...
coredns_dns_request_size_bytes_bucket{proto="udp",server="dns://:59",view="",zone=".",le="100"} 1
coredns_dns_request_size_bytes_bucket{proto="udp",server="dns://:59",view="",zone=".",le="200"} 1
...
coredns_dns_request_size_bytes_sum{proto="udp",server="dns://:59",view="",zone="."} 90
coredns_dns_request_size_bytes_count{proto="udp",server="dns://:59",view="",zone="."} 1
TC2: with rewrite
Corefile:
.:59 {
prometheus :8086
rewrite edns0 local set 0x13 test123456 revert
forward . 8.8.8.8
}
Request:
dig @localhost -p 59 somerequestthathaveasize90.123456789.123456789.1234567891.net
localhost:8086/metrics
...
coredns_dns_request_size_bytes_bucket{proto="udp",server="dns://:59",view="",zone=".",le="100"} 0
coredns_dns_request_size_bytes_bucket{proto="udp",server="dns://:59",view="",zone=".",le="200"} 1
...
coredns_dns_request_size_bytes_sum{proto="udp",server="dns://:59",view="",zone="."} 104
coredns_dns_request_size_bytes_count{proto="udp",server="dns://:59",view="",zone="."} 1
Environment:
The version of CoreDNS: CoreDNS-1.12.0