uchiwa outputs "Uchiwa is now listening on" before attempting to open port

[LeslieCarr]

Background - I was attempting to run uchiwa on port 80 and it seemed to silently exit, however uchiwa would successfully run as root. I would see {"Date":"2015-07-02T17:55:22.798964641Z","Level":"info","Src":{"Func":"github.com/sensu/uchiwa/uchiwa.(*Uchiwa).WebServer","Line":274},"Output":"Uchiwa is now listening on 0.0.0.0:80"} in the logs, however the service would immediately exit.

Interesting part of the strace is below --

write(1, "{\"Date\":\"2015-07-02T18:05:08.028"..., 188{"Date":"2015-07-02T18:05:08.028877731Z","Level":"info","Src":{"Func":"github.com/sensu/uchiwa/uchiwa/config.Load","Line":73},"Output":"Loading configuration file /etc/sensu/uchiwa.json"}
) = 188
open("/etc/sensu/uchiwa.json", O_RDONLY|O_CLOEXEC) = 3
clock_gettime(CLOCK_MONOTONIC, {153818, 237067041}) = 0
clock_gettime(CLOCK_MONOTONIC, {153818, 237104019}) = 0
read(3, "{\n\"sensu\": [\n    {\n      \"name\":"..., 512) = 336
clock_gettime(CLOCK_MONOTONIC, {153818, 237190242}) = 0
clock_gettime(CLOCK_MONOTONIC, {153818, 237280045}) = 0
clock_gettime(CLOCK_MONOTONIC, {153818, 237369835}) = 0
clock_gettime(CLOCK_REALTIME, {1435860308, 29873923}) = 0
write(1, "{\"Date\":\"2015-07-02T18:05:08.029"..., 185{"Date":"2015-07-02T18:05:08.029873923Z","Level":"info","Src":{"Func":"github.com/sensu/uchiwa/uchiwa.(*Uchiwa).WebServer","Line":274},"Output":"Uchiwa is now listening on 0.0.0.0:80"}
) = 185
socket(PF_INET6, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 4
setsockopt(4, SOL_IPV6, IPV6_V6ONLY, [0], 4) = 0
setsockopt(4, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
setsockopt(4, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(4, {sa_family=AF_INET6, sin6_port=htons(80), inet_pton(AF_INET6, "::", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EACCES (Permission denied)
close(4)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++

You can see that the message that uchiwa is listening on a port comes before the attempt to open the port. Can you please move the message after the port is opened so that this is easier to debug.

[palourde]

Hi @LeslieCarr,

Unfortunately it isn't possible to add anything after the http.ListenAndServe function. However, we could wrap it with logger.Fatal like this so if you attempt to start Uchiwa on a privileged port with an unprivileged user, the following error would be thrown:

{"Date":"2015-07-06T13:53:35.276351058-04:00","Level":"info","Src":{"Func":"github.com/sensu/uchiwa/uchiwa/config.Load","Line":75},"Output":"Loading configuration file ./config.json"}
{"Date":"2015-07-06T13:53:35.276992056-04:00","Level":"info","Src":{"Func":"github.com/sensu/uchiwa/uchiwa.(*Uchiwa).WebServer","Line":286},"Output":"Uchiwa is now listening on 0.0.0.0:80"}
{"Date":"2015-07-06T13:53:35.277079942-04:00","Level":"fatal","Src":{"Func":"github.com/sensu/uchiwa/uchiwa.(*Uchiwa).WebServer","Line":288},"Output":"listen tcp 0.0.0.0:80: bind: permission denied"}

Do you think it would be an appropriate solution?

[LeslieCarr]

That would definitely help in troubleshooting!