Configurable protocol on Service Discovery

[MDS-Info]

Hello,

Environment info:

• KrakenD version: devopsfaith/krakend:2.1.2
• System info: Ubuntu 20.04 LTS / docker engine 20.10.17
• Hardware specs: 16CPU/10Go Memory

Describe the bug

I want to set the Service Discovery by using DNS SRV RECORD, but I have this issue :

{"@timestamp":"2023-04-13T15:44:16.922+00:00", "@Version": 1, "level": "ERROR", "message": "[ENDPOINT: xxx] no hosts available", "module": "KRAKEND"}
[GIN] 2023/04/13 - 15:44:16 | 500 | 86.964µs | 192.168.107.1 | GET "xxx"
Error #1: no hosts available

Nevertheless, the DNS server return the correct information :

17:44:26.586003 IP 172.18.0.12.44657 > xxx.local.domain: 4478+ [1au] SRV? _api.._tcp.mds.local. (50)
17:44:26.586017 IP 172.18.0.12.55777 > xxx.local.domain: 34244+ [1au] SRV? _api.._tcp.mds.local. (50)
17:44:26.587021 IP xxx.local.domain > 172.18.0.12.55777: 34244* 1/0/2 SRV xxx.domain.:5001 0 0 (105)

from the docker host, the resolution is correct:

nslookup

set type=srv
_api._tcp.mds.local

_api._tcp.mds.local service = 0 0 5001 xxx.domain.

by using curl, the service is responding

172.18.0.12 : container's IP
xxx.local.domain : DNS server

Your configuration file:
"endpoint": "xxx",
"input_headers": [
"*"
],
"input_query_strings": [],
"method": "Get",
"output_encoding": "no-op",
"extra_config": {},
"backend": [
{
"url_pattern": "xxx",
"encoding": "json",
"sd": "dns",
"method": "Get",
"extra_config": {},
"disable_host_sanitize": true,
"host": [
"_api._tcp.mds.local"
]
}
]

thanks for you help

[MDS-Info]

@alombarte @kpacha
Hello team,

i fixed it by using priority and weigth on my SRV record.

but now i have a new issue

Error #1: Get "http://XXX.:XXX/v1/XXX/XXX": EOF

Now, krakend send the request to the good destination host by used http schema, how to switch to https

i suspect the schema to be hard coded : https://github.com/luraproject/lura/blob/master/sd/dnssrv/subscriber.go
line 136

thanks for your help

[alombarte]

Hello @MDS-Info,

You are right, the protocol is hardcoded. We can add a new flag in the configuration sd_protocol that would default to the value http but you could change it to https.

There would still the limitation that you couldn't mix http and https servers, but the DNS SRV does not provide any mechanism to prevent that.

We will have a look at this issue in the next release.

[alombarte]

The attribute sd_scheme was added in KrakenD 2.4
https://www.krakend.io/docs/backends/service-discovery/#sd_scheme

Thanks!

[github-actions]

This issue was marked as resolved a long time ago and now has been automatically locked as there has not been any recent activity after it. You can still open a new issue and reference this link.