Validate trigger filters are immutable

[benmoss]

Changes

• 🎁 Add a validating webhook for triggers that will enforce that spec.filters are immutable

/kind enhancement

Fixes #338

Release Note

:page_facing_up: Trigger filters are now enforced to be immutable, since the underlying RMQ binding is immutable

[benmoss]

/hold

I want to see if we can actually swap the binding instead of restricting users

[codecov]

Codecov Report

Merging #468 (6c0b1e0) into main (226facb) will decrease coverage by 0.17%.
The diff coverage is 56.00%.

@@            Coverage Diff             @@
##             main     #468      +/-   ##
==========================================
- Coverage   75.99%   75.82%   -0.18%     
==========================================
  Files          44       45       +1     
  Lines        2691     2713      +22     
==========================================
+ Hits         2045     2057      +12     
- Misses        525      533       +8     
- Partials      121      123       +2     

Impacted Files	Coverage Δ
pkg/apis/eventing/v1/trigger_validation.go	54.54% <54.54%> (ø)
pkg/apis/eventing/v1/broker_validation.go	81.48% <66.66%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 226facb...6c0b1e0. Read the comment docs.

[benmoss]

/hold cancel

I think it's too much work to tackle right now, we can add immutability and change it later if we can figure out how to enable it

[benmoss]

ready for review

/assign @knative-sandbox/eventing-rabbitmq-approvers

[xtreme-sameer-vohra]

thanks @benmoss
I'll take a look at this

[xtreme-sameer-vohra]

Test case - Update trigger and change filter

Before Change

% kn trigger create some-trigger --broker default --sink ksvc:event-display --filter source=some-source --filter type=some-type
Trigger 'some-trigger' successfully created in namespace 'default'.

% kn trigger update some-trigger --filter bar=foo
Trigger 'some-trigger' updated in namespace 'default'.

But things are not happy

% kn trigger list
NAME           BROKER    SINK                 AGE   CONDITIONS   READY   REASON
some-trigger   default   ksvc:event-display   29s   4 OK / 6     False   BindingFailure : admission webhook "vbinding.kb.io" denied the request: Binding.rabbitmq.com "t.default.some-trigger.853a4d0d-4a81-4836-88ff-cd0270365df0" is invalid: spec.arguments: Invalid value: runtime.RawExtension{Raw:[]uint8{0x7b, 0x22, 0x62, 0x61, 0x72, 0x22, 0x3a, 0x22, 0x66, 0x6f, 0x6f, 0x22, 0x2c, 0x22, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x22, 0x3a, 0x22, 0x73, 0x6f, 0x6d, 0x65, 0x2d, 0x73, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x22, 0x2c, 0x22, 0x74, 0x79, 0x70, 0x65, 0x22, 0x3a, 0x22, 0x73, 0x6f, 0x6d, 0x65, 0x2d, 0x74, 0x79, 0x70, 0x65, 0x22, 0x2c, 0x22, 0x78, 0x2d, 0x6b, 0x6e, 0x61, 0x74, 0x69, 0x76, 0x65, 0x2d, 0x74, 0x72, 0x69, 0x67, 0x67, 0x65, 0x72, 0x22, 0x3a, 0x22, 0x73, 0x6f, 0x6d, 0x65, 0x2d, 0x74, 0x72, 0x69, 0x67, 0x67, 0x65, 0x72, 0x22, 0x2c, 0x22, 0x78, 0x2d, 0x6d, 0x61, 0x74, 0x63, 0x68, 0x22, 0x3a, 0x22, 0x61, 0x6c, 0x6c, 0x22, 0x7d}, Object:runtime.Object(nil)}: arguments cannot be updated


% kn trigger describe some-trigger
Name:         some-trigger
Namespace:    default
Labels:       eventing.knative.dev/broker=default
Annotations:  eventing.knative.dev/creator=kubernetes-admin, eventing.knative.dev/lastModifier=ku ...
Age:          34s
Broker:       default
Filter:
  bar:        foo
  source:     some-source
  type:       some-type

Sink:
  Name:      event-display
  Resource:  Service (serving.knative.dev/v1)

Conditions:
  OK TYPE                      AGE REASON
  !! Ready                     28s BindingFailure
  ++ BrokerReady               34s
  ++ DeadLetterSinkResolved    34s DeadLetterSinkNotConfigured
  !! DependencyReady           28s BindingFailure
  ++ SubscriberResolved        34s
  ++ SubscriptionReady         34s

With Change

% kn trigger create some-trigger --broker default --sink ksvc:event-display --filter source=some-source --filter type=some-type
Trigger 'some-trigger' successfully created in namespace 'default'.

% kn trigger update some-trigger --filter bar=foo
Error: admission webhook "validation.webhook.rabbitmq.eventing.knative.dev" denied the request: validation callback failed: Immutable fields changed (-old +new): filter, spec
{*v1.TriggerFilter}.Attributes["bar"]:
	+: "foo"

[xtreme-sameer-vohra]

nit: is this if check required 🤔

[xtreme-sameer-vohra]

cc @benmoss

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: benmoss, xtreme-sameer-vohra

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [benmoss,xtreme-sameer-vohra]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment