Implement oc set route-backend and A/B to describers / printers

[smarterclayton]

oc set route-backends foo a=10 b=20 c=0

Adds describer and printer support for router.

$ oc set route-backends --all
NAME         KIND     TO    WEIGHT
routes/bar   Service  bar   100 (100%)
routes/bar2  Service  bar2  100 (100%)
routes/foo   Service  a1    0
routes/foo   Service  b2    0
routes/foo   Service  c3    0

$ oc set route-backends foo a=10 b=30
route "foo" updated

$ oc set route-backends foo
NAME        KIND     TO  WEIGHT
routes/foo  Service  a   10 (25%)
routes/foo  Service  b   30 (75%)

$ oc describe route foo
Name:           foo
Namespace:      default
Created:        4 minutes ago
Labels:         <none>
Annotations:        openshift.io/host.generated=true
Requested Host:     foo-default.router.default.svc.cluster.local
Path:           <none>
TLS Termination:    edge
Insecure Policy:    <none>
Endpoint Port:      8080

Service:    a
Weight:     10 (25%)
Endpoints:  <error: endpoints "a" not found>

Service:    b
Weight:     30 (75%)
Endpoints:  <error: endpoints "b" not found>

$ oc get route
NAME      HOST/PORT                                       PATH      SERVICES        PORT      TERMINATION
bar       bar-default.router.default.svc.cluster.local              bar(100%)       9090      edge
bar2      bar2-default.router.default.svc.cluster.local             bar2(100%)      9090      edge
foo       foo-default.router.default.svc.cluster.local              a(25%),b(75%)   8080      edge

Primary use cases for set route-backend:

1. Allow someone to easily set a number of backends at a time: oc set route-backends foo a=N b=N c=N
2. Allow someone to script tweaking a particular backend up: oc set route-backends foo --adjust a=+10%
3. Allow someone to reset to even: oc set route-backends foo --equal
4. Allow someone to zero out the weights: oc set route-backends foo --zero

[smarterclayton]

[test]

[openshift-bot]

Evaluated for origin test up to 1aac6c3

[openshift-bot]

continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/8286/)

[smarterclayton]

[merge] @jwforres / @fabianofranz if you can do a retroactive - we'll consider this experimental / new

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/8288/) (Image: devenv-rhel7_4888)

[openshift-bot]

Evaluated for origin merge up to 1aac6c3

[0xmichalis]

cp error?

[smarterclayton]

Yeah

[smarterclayton]

Follow up

• warn if service doesn't exist
• error if user provides percentages to "set" and they don't equal 100%
• --allow-headers doesn't work