use docker exec to compare backends, rather than querying nginx

[tgross]

For #45

Rather than waiting for CNS to catch up, we can instead check the Nginx config files directly against what's expected. This means we don't quite test the Nginx SIGHUP but honestly that should be pretty solid short of a syntax error in the config. Test output:

----------------------------------------------------------------------
NginxStackTest.test_scaleup_and_down
----------------------------------------------------------------------
elapsed  | task
12.75874 | docker-compose -f triton/docker-compose.yml -p nginx stop
16.73752 | docker-compose -f triton/docker-compose.yml -p nginx rm -f
35.06248 | docker-compose -f triton/docker-compose.yml -p nginx up -d
1.950042 | docker-compose -f triton/docker-compose.yml -p nginx ps
1.952207 | docker-compose -f triton/docker-compose.yml -p nginx ps
1.952496 | wait_for_containers: {'consul': 1, 'backend': 1, 'nginx': 1}
0.707822 | docker inspect nginx_consul_1
0.762927 | wait_for_service: backend
1.033709 | wait_for_service: containerpilot
6.161812 | wait_for_service: nginx
0.020028 | wait_for_service: nginx-public
0.096123 | wait_for_cns:
33.31035 | docker-compose -f triton/docker-compose.yml -p nginx scale backend=2
2.719624 | docker-compose -f triton/docker-compose.yml -p nginx ps
2.720015 | wait_for_containers: {'consul': 1, 'backend': 2, 'nginx': 1}
2.066465 | wait_for_service: backend
1.809874 | docker exec nginx_backend_1 ip -o addr
2.784050 | docker exec nginx_backend_2 ip -o addr
2.905334 | docker exec nginx_nginx_1 cat /etc/nginx/conf.d/site.conf
2.706559 | docker exec nginx_backend_2 ifconfig eth0 down
9.237921 | wait_for_service: backend
3.227224 | docker exec nginx_nginx_1 cat /etc/nginx/conf.d/site.conf
2.630694 | docker exec nginx_backend_2 ifconfig eth0 up
7.188679 | wait_for_service: backend
2.902231 | docker exec nginx_nginx_1 cat /etc/nginx/conf.d/site.conf
.
----------------------------------------------------------------------
Ran 1 test in 150.036s

OK

[jasonpincin]

👍

[geek]

Is this a reliable way to get the site.conf... will 'nginx_1' always exist?

[tgross]

It should, but if nginx_1 doesn't exist at this point, the test should fail anyways.