#164 Send events on image change

[magmax]

Sends an event on any image change (fixes #164)

I thought in re-using some argo-cd code, but finally I decided to copy and adapt it. It is the code related to send the event.

The namespace used is the one where argocd-image-updater is running in order to reduce the permissions required (a Role instead a ClusterRole).

I had to add some argo-cd dependencies to the kubernetes package, what is... ugly. Maybe you know a better way to do it.

Finally, understand this is my first golang contribution... I'm open to changes XD

NOTE: I didn't tested it under real fire. I have no docker repository accessible from my laptop.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #167 (8d2b15f) into master (21df300) will increase coverage by 0.65%.
The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master     #167      +/-   ##
==========================================
+ Coverage   68.20%   68.85%   +0.65%     
==========================================
  Files          19       19              
  Lines        1343     1384      +41     
==========================================
+ Hits          916      953      +37     
- Misses        344      346       +2     
- Partials       83       85       +2     

Impacted Files	Coverage Δ
pkg/argocd/update.go	72.26% <86.66%> (+0.66%)	⬆️
pkg/kube/kubernetes.go	85.29% <93.10%> (+5.29%)	⬆️

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[jannfis]

Hey, awesome @magmax! Pretty great for your first lines of Go, actually! I only have a few comments (see inline) and also the following:

• We need to give the ServiceAccount for the Image Updater appropriate Kubernetes RBAC permissions to create Events. The Role is part of the manifests and can be found here. Can you please provide proper authorization there?
• I feel that emitting events should be enabled by default, but optionally can be disabled. It would be great to have a command line switch to disable it (e.g. --disable-kube-events). The main command can be found here and the flags are defined here. We provide default values to most flags that are override-able using environment variables (e.g. using env.GetBoolVal()), and then map those to keys in the argocd-image-updater-config ConfigMap, as shown here. I think this one should be settable by IMAGE_UPDATER_KUBE_EVENTS with a ConfigMap key of kube.events.

[magmax]

I did the change.
My brains's python section says that I should have created an object for that.
The C section says it won't work due to memory weaks and misunderstanding.
But the Golang section says that everything is fine XD

I didn't tested it under real fire because I have no repository accessible from this computer and it would take me a while to do it.

[jannfis]

On a second thought, I'm not sure whether this will work reliably. The name parts of annotations are rather strict, and must follow a rule:

regex used for validation is '([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9]') with an optional DNS subdomain prefix and '/' (e.g. 'example.com/MyName')

Also, the name must be max 63 characters long. I think we must either make sure that the image name is properly normalized, look for another name for the annotation (and put the image name in its value) or think about a completely another solution (e.g. putting the details into the event's Message).

Is there a specific reason that you use an annotation for storing the updated images?

[magmax]

Not really. I want just to "pass parameters" between the argocd-image-updater and a listener through events.

[magmax]

New approach. Now annotations have less randomness and a fixed size around 40 characters

[jannfis]

Awesome! I tested it successfully, the event now looks like:

Name:             guestbook-multi.166fdad08646fd49
Namespace:        argocd
Labels:           <none>
Annotations:      argocd-image-updater.image-0/image-name: heptio-images/ks-guestbook-demo
                  argocd-image-updater.image-0/new-tag: 0.2
                  argocd-image-updater.image-0/old-tag: 0.1
                  argocd-image-updater.image-1/image-name: coredns/coredns
                  argocd-image-updater.image-1/new-tag: 1.8.3
                  argocd-image-updater.image-1/old-tag: 1.8.0
API Version:      v1               
Count:            1   
...
Involved Object:                
  API Version:       argoproj.io/v1alpha1
  Kind:              Application
  Name:              guestbook-multi                                                                     
  Namespace:         argocd                                                                                                                                                                                        
...
Message:             Successfully updated application 'guestbook-multi'
...
Source:
  Component:  ArgocdImageUpdater
Type:         Normal

I'm not sure whether it's intended to use the image name without the registry prefix (the Image Updater's API is possibly not good documented in that regard), but I'd suggest to change

changeList = append(changeList, change{updateableImage.ImageName, updateableImage.ImageTag, containerImageNew.ImageTag})

to

changeList = append(changeList, change{updateableImage.GetFullNameWithoutTag(), updateableImage.ImageTag, containerImageNew.ImageTag})

at the place where you store the image information to be propagated to the event.

And I also guess this would be the last change required before merge 🎉

[magmax]

I'm thinking in using annotations to compose a message on slack. So allowing the user to decide might be a really cool idea :)

So, I finally decided to add both.

[jannfis]

I'm fine with that solution as well 👍

[jannfis]

LGTM!

Thanks for this contribution @magmax - much appreciated!

Also, you said it's your first steps into Golang, but I have to say great job on the code and thanks for constructively working through the review with me!

[magmax]

Thank you very much for your comments and support.

[axot]

If argocd is running in a different namespace as involvedObject.namespace, the event can't be sent.

"Event could not be sent: Event "xxxx" is invalid: involvedObject.namespace: Invalid value: "yyyy": does not match event.namespace" application=zzzz