Add annotation for client-body-buffer-size per location

[diazjf]

Adds an annotation which allows for client-body-buffer-size to
be configured per specific locations specified in the ingress
resource yaml. Fixes #826

[k8s-reviewable]

This change is 

[coveralls]

Coverage increased (+0.03%) to 44.509% when pulling 8caeb5b on diazjf:client-body-buffer-size into 7010627 on kubernetes:master.

[diazjf]

Currently only working on creation, but update is not configuring the client_body_buffer_size.

Annotation name was changed to ingress.kubernetes.io/client-body-buffer-size to avoid conflicts with the already existing ingress.kubernetes.io/proxy-body-size which configures client_max_body_size.

[diazjf]

If invalid value is provided ingress-controller will fail as follows:

Error: exit status 1
2017/08/21 01:52:57 [emerg] 596#596: "client_body_buffer_size" directive invalid value in /tmp/nginx-cfg431539895:277
nginx: [emerg] "client_body_buffer_size" directive invalid value in /tmp/nginx-cfg431539895:277
nginx: configuration file /tmp/nginx-cfg431539895 test failed

Would this be expected behavior?

[coveralls]

Coverage decreased (-0.02%) to 44.398% when pulling ff83a35 on diazjf:client-body-buffer-size into a0e4661 on kubernetes:master.

[diazjf]

@aledbf two questions:

1.) Do annotation values regularly need validation, for example in client_body_buffer_size it must be in the format of an int which can be followed by a k or m. Should we check this before generating a template and if it is incorrect set a default of "" so that nothing is generated in the config or let it of to the error:

Error: exit status 1
2017/08/21 01:52:57 [emerg] 596#596: "client_body_buffer_size" directive invalid value in /tmp/nginx-cfg431539895:277
nginx: [emerg] "client_body_buffer_size" directive invalid value in /tmp/nginx-cfg431539895:277
nginx: configuration file /tmp/nginx-cfg431539895 test failed

2.) Should the location parameter for client_body_buffer_size be updated each time the annotation is updated? I'm thinking this would require us to reload the ingress backend anytime there is a change detected from the current value in the location parameter and whats in the annotation for a particular location.

Thanks again and have a good night!

[coveralls]

Coverage decreased (-0.02%) to 44.363% when pulling 30d4cca on diazjf:client-body-buffer-size into 6ef6343 on kubernetes:master.

[aledbf]

1.) yes, we need to add that feature but not in this PR :)

2.) this is done each time the sync loop is executed
https://github.com/kubernetes/ingress/blob/master/core/pkg/ingress/controller/controller.go#L373

[diazjf]

Ingress Resource YAML:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ok-ingress
  annotations:
    ingress.kubernetes.io/client-body-buffer-size: 4k
spec:
  tls:
  - hosts:
    - ok.com
  rules:
  - host: ok.com
    http:
      paths:
      - path: /tea
        backend:
          serviceName: tea-svc
          servicePort: 80

produces https://pastebin.com/0eSbjHfx in which you can see that client_body_buffer_size is 4k for location/ and location/tea.

It also updates each time a change is made.

[diazjf]

@aledbf ready for review. My only question is if client_body_buffer_size shouldn't be applied to location / as well.

[coveralls]

Coverage increased (+0.003%) to 44.463% when pulling e9ffbf0 on diazjf:client-body-buffer-size into 1da974f on kubernetes:master.

[aledbf]

My only question is if client_body_buffer_size shouldn't be applied to location / as well.

No, only the the paths in the ingress.

[aledbf]

/lgtm

[aledbf]

@diazjf thanks!