[nginx-ingress-controller] Initialize proxy_upstream_name variable

[aledbf]

fixes #1801

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This change is

[kayrus]

two notes:

• set empty value to -, otherwise log parsing will be broken
• please remove whitespaces

[aledbf]

set empty value to -, otherwise log parsing will be broken

It's inside []

[kayrus]

@aledbf true. LGTM then.

[bprashanth]

LGTM, please send the documentation pr that describs log format output so people can leverage it for greater good (and it keeps un honest about changing the format)

[kayrus]

Issue still exists:

2016/09/29 18:25:16 [warn] 25#25: *67 using uninitialized "proxy_upstream_name" variable while logging request, client: 1.2.3.4, server: example.com, request: "HEAD / HTTP/1.0", host: "example.com"

[aledbf]

@kayrus example.com is defined in an Ingress rule?

[k8s-github-robot]

Automatic merge from submit-queue

[kayrus]

@aledbf Yep

[kayrus]

It is reproducible within non-https request.

[aledbf]

@kayrus please change

            {{- buildProxyPass $location }}
            set $proxy_upstream_name "{{ $location.Upstream.Name }}";

to

            set $proxy_upstream_name "{{ $location.Upstream.Name }}";
            {{- buildProxyPass $location }}

[kayrus]

It is not easy without this fix :) #1498
just wonder whether it is reasonable to change these strings too:

         location / {
             set $proxy_upstream_name "upstream-default-backend";
             proxy_pass             http://upstream-default-backend;
         }

to

         set $proxy_upstream_name "upstream-default-backend";
         location / {
             proxy_pass             http://upstream-default-backend;
         }

[kayrus]

@aledbf no, your last suggestion doesn't resolve this issue. you can easily reproduce it using:

curl -v -X HEAD example.com

[aledbf]

@kayrus I cannot reproduce the error. Can you test with the mentioned image #1805 (comment) ?