Fix #66 by adding always_resolve_dns config option

[CLAassistant]

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[mschurenko]

Is anyone around that can merge this PR?

[JeremyGrosser]

I'm waiting to merge it until you've confirmed that it solves your problem

[mschurenko]

Oh sorry. I'll try to test it this week. Thanks again!

[mschurenko]

It doesn't look to be working. After I change the IP address of the backend I get this in the logs:

Dec 21 20:03:43 statsrelay1: tcpclient: Error resolving backend address (null): Unknown error

[JeremyGrosser]

I think this new patch should fix that issue. 896e817

[mschurenko]

It looks like the ip address actually does not get updated. I added a bit of debugging (CLIENT ADDR IS: ) :

https://github.com/mschurenko/statsrelay/blob/testing/src/tcpclient.c#L329

When I run it I get this in the logs:

Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: statsrelay 1.6.8
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: carbon has no backends, skipping
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: CLIENT ADDR IS: 127.0.0.1
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: State transition INIT -> CONNECTING
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: tcpserver: Listening on frontend 127.0.0.1[:9126], fd = 7
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: udpserver: Listening on frontend 127.0.0.1[:9126], fd = 8
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: main: Starting event loop
Jan  3 21:17:18 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: State transition CONNECTING -> CONNECTED
Jan  3 21:17:52 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: Server closed connection
Jan  3 21:17:52 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: State transition CONNECTED -> INIT
Jan  3 21:17:57 pipes-vagrant-v1-2 statsrelay: CLIENT ADDR IS: 127.0.0.1
Jan  3 21:17:57 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: State transition INIT -> CONNECTING
Jan  3 21:17:57 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: Connect failed: Connection refused
Jan  3 21:17:57 pipes-vagrant-v1-2 statsrelay: tcpclient[host1/9600/tcp]: State transition CONNECTING -> BACKOFF

In my test I am changing the IP for host1 from 127.0.0.1 to 127.0.0.2. The second occurrence of "CLIENT ADDR IS:" should be "127.0.0.2" and not "127.0.0.1". (Unless my debug logging is incorrect. I don't really know C so that's possible.)

[JeremyGrosser]

I can't reproduce this issue... I setup statsrelay in a container on kubernetes, pointed it at a service name "carbon.default.svc.cluster.local", then changed the IP that name points to several times and saw statsrelay resolve the new IP each time after the record's TTL expired. The test config I'm using is here: https://storage.googleapis.com/statsrelay-config.legitdata.co/statsrelay.yaml

[mschurenko]

Ok I tested it using a DNS server instead of /etc/hosts and it does work. I'm not sure why it wasn't picking up the IP address change when just using the hosts file. Thanks

[mschurenko]

Hey. Just wondering if you are ok to merge this now? Thanks

[JeremyGrosser]

I've merged it into JeremyGrosser/master, but it looks like Uber's removed my commit access to uber/statsrelay, so there's that.

[mschurenko]

I tried emailing and tweeting @eklitzke but haven't got a response.