[RFC-0009] Add CEL custom healthchecks

Signed-off-by: Matheus Pimenta <matheuscscp@gmail.com>

api/go.mod

@@ -3,10 +3,10 @@ module github.com/fluxcd/kustomize-controller/api
 go 1.23.0
 
 require (
-	github.com/fluxcd/pkg/apis/kustomize v1.8.0
-	github.com/fluxcd/pkg/apis/meta v1.9.0
-	k8s.io/apiextensions-apiserver v0.32.0
-	k8s.io/apimachinery v0.32.0
+	github.com/fluxcd/pkg/apis/kustomize v1.9.0
+	github.com/fluxcd/pkg/apis/meta v1.10.0
+	k8s.io/apiextensions-apiserver v0.32.1
+	k8s.io/apimachinery v0.32.1
 	sigs.k8s.io/controller-runtime v0.19.3
 )
 
@@ -23,8 +23,8 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
-	golang.org/x/net v0.30.0 // indirect
-	golang.org/x/text v0.19.0 // indirect
+	golang.org/x/net v0.34.0 // indirect
+	golang.org/x/text v0.21.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/utils v0.0.0-20241104100929-3ea5e8cea738 // indirect

api/go.sum

@@ -3,10 +3,10 @@ github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/fluxcd/pkg/apis/kustomize v1.8.0 h1:HH6YRa3SMS72KK4cUyb9m5sK/dZH+Eti1qhjWDCgwKg=
-github.com/fluxcd/pkg/apis/kustomize v1.8.0/go.mod h1:QCKIFj1ocdndaWSkrLs5JKvdGNYyTzQX1ZB3lYTwma0=
-github.com/fluxcd/pkg/apis/meta v1.9.0 h1:wPgm7bWNJZ/ImS5GqikOxt362IgLPFBG73dZ27uWRiQ=
-github.com/fluxcd/pkg/apis/meta v1.9.0/go.mod h1:pMea8eEZcsFSI7ngRnTHFtDZk2CEZGgtrueNgI6Iu70=
+github.com/fluxcd/pkg/apis/kustomize v1.9.0 h1:SJpT1CK58AnTvCpDKeGfMNA0Xud/4VReZNvPe8XkTxo=
+github.com/fluxcd/pkg/apis/kustomize v1.9.0/go.mod h1:AZl2GU03oPVue6SUivdiIYd/3mvF94j7t1G2JO26d4s=
+github.com/fluxcd/pkg/apis/meta v1.10.0 h1:rqbAuyl5ug7A5jjRf/rNwBXmNl6tJ9wG2iIsriwnQUk=
+github.com/fluxcd/pkg/apis/meta v1.10.0/go.mod h1:n7NstXHDaleAUMajcXTVkhz0MYkvEXy1C/eLI/t1xoI=
 github.com/fxamacker/cbor/v2 v2.7.0 h1:iM5WgngdRBanHcxugY4JySA0nk1wZorNOpTgCMedv5E=
 github.com/fxamacker/cbor/v2 v2.7.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
 github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
@@ -65,20 +65,20 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.30.0 h1:AcW1SDZMkb8IpzCdQUaIq2sP4sZ4zw+55h6ynffypl4=
-golang.org/x/net v0.30.0/go.mod h1:2wGyMJ5iFasEhkwi13ChkO/t1ECNC4X4eBKkVFyYFlU=
+golang.org/x/net v0.34.0 h1:Mb7Mrk043xzHgnRM88suvJFwzVrRfHEHJEl5/71CKw0=
+golang.org/x/net v0.34.0/go.mod h1:di0qlW3YNM5oh6GqDGQr92MyTozJPmybPK4Ev/Gm31k=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
-golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
-golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
+golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
+golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
@@ -96,12 +96,12 @@ gopkg.in/inf.v0 v0.9.1 h1:73M5CoZyi3ZLMOyDlQh031Cx6N9NDJ2Vvfl76EDAgDc=
 gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-k8s.io/api v0.32.0 h1:OL9JpbvAU5ny9ga2fb24X8H6xQlVp+aJMFlgtQjR9CE=
-k8s.io/api v0.32.0/go.mod h1:4LEwHZEf6Q/cG96F3dqR965sYOfmPM7rq81BLgsE0p0=
-k8s.io/apiextensions-apiserver v0.32.0 h1:S0Xlqt51qzzqjKPxfgX1xh4HBZE+p8KKBq+k2SWNOE0=
-k8s.io/apiextensions-apiserver v0.32.0/go.mod h1:86hblMvN5yxMvZrZFX2OhIHAuFIMJIZ19bTvzkP+Fmw=
-k8s.io/apimachinery v0.32.0 h1:cFSE7N3rmEEtv4ei5X6DaJPHHX0C+upp+v5lVPiEwpg=
-k8s.io/apimachinery v0.32.0/go.mod h1:GpHVgxoKlTxClKcteaeuF1Ul/lDVb74KpZcxcmLDElE=
+k8s.io/api v0.32.1 h1:f562zw9cy+GvXzXf0CKlVQ7yHJVYzLfL6JAS4kOAaOc=
+k8s.io/api v0.32.1/go.mod h1:/Yi/BqkuueW1BgpoePYBRdDYfjPF5sgTr5+YqDZra5k=
+k8s.io/apiextensions-apiserver v0.32.1 h1:hjkALhRUeCariC8DiVmb5jj0VjIc1N0DREP32+6UXZw=
+k8s.io/apiextensions-apiserver v0.32.1/go.mod h1:sxWIGuGiYov7Io1fAS2X06NjMIk5CbRHc2StSmbaQto=
+k8s.io/apimachinery v0.32.1 h1:683ENpaCBjma4CYqsmZyhEzrGz6cjn1MY/X2jB2hkZs=
+k8s.io/apimachinery v0.32.1/go.mod h1:GpHVgxoKlTxClKcteaeuF1Ul/lDVb74KpZcxcmLDElE=
 k8s.io/klog/v2 v2.130.1 h1:n9Xl7H1Xvksem4KFG4PYbdQCQxqc/tTUyrgXaOhHSzk=
 k8s.io/klog/v2 v2.130.1/go.mod h1:3Jpz1GvMt720eyJH1ckRHK1EDfpxISzJ7I9OYgaDtPE=
 k8s.io/utils v0.0.0-20241104100929-3ea5e8cea738 h1:M3sRQVHv7vB20Xc2ybTt7ODCeFj6JSWYFzOFnYeS6Ro=

api/v1/kustomization_types.go

@@ -179,6 +179,11 @@ type KustomizationSpec struct {
 	// Components specifies relative paths to specifications of other Components.
 	// +optional
 	Components []string `json:"components,omitempty"`
+
+	// HealthCheckExprs is a list of healthcheck expressions for evaluating the
+	// health of custom resources using Common Expression Language (CEL).
+	// +optional
+	HealthCheckExprs []kustomize.CustomHealthCheck `json:"healthCheckExprs,omitempty"`
 }
 
 // CommonMetadata defines the common labels and annotations.

config/crd/bases/kustomize.toolkit.fluxcd.io_kustomizations.yaml

@@ -136,6 +136,41 @@ spec:
                   Force instructs the controller to recreate resources
                   when patching fails due to an immutable field change.
                 type: boolean
+              healthCheckExprs:
+                description: |-
+                  HealthCheckExprs is a list of healthcheck expressions for evaluating the
+                  health of custom resources using Common Expression Language (CEL).
+                items:
+                  description: CustomHealthCheck defines the health check for custom
+                    resources.
+                  properties:
+                    apiVersion:
+                      description: APIVersion of the custom resource under evaluation.
+                      type: string
+                    current:
+                      description: |-
+                        Current is the CEL expression that determines if the status
+                        of the custom resource has reached the desired state.
+                      type: string
+                    failed:
+                      description: |-
+                        Failed is the CEL expression that determines if the status
+                        of the custom resource has failed to reach the desired state.
+                      type: string
+                    inProgress:
+                      description: |-
+                        InProgress is the CEL expression that determines if the status
+                        of the custom resource has not yet reached the desired state.
+                      type: string
+                    kind:
+                      description: Kind of the custom resource under evaluation.
+                      type: string
+                  required:
+                  - apiVersion
+                  - current
+                  - kind
+                  type: object
+                type: array
               healthChecks:
                 description: A list of resources to be included in the health assessment.
                 items:

docs/api/v1/kustomize.md

@@ -395,6 +395,21 @@ resources. When enabled, the HealthChecks are ignored. Defaults to false.</p>
 <p>Components specifies relative paths to specifications of other Components.</p>
 </td>
 </tr>
+<tr>
+<td>
+<code>healthCheckExprs</code><br>
+<em>
+<a href="https://godoc.org/github.com/fluxcd/pkg/apis/kustomize#CustomHealthCheck">
+[]github.com/fluxcd/pkg/apis/kustomize.CustomHealthCheck
+</a>
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>HealthCheckExprs is a list of healthcheck expressions for evaluating the
+health of custom resources using Common Expression Language (CEL).</p>
+</td>
+</tr>
 </table>
 </td>
 </tr>
@@ -918,6 +933,21 @@ resources. When enabled, the HealthChecks are ignored. Defaults to false.</p>
 <p>Components specifies relative paths to specifications of other Components.</p>
 </td>
 </tr>
+<tr>
+<td>
+<code>healthCheckExprs</code><br>
+<em>
+<a href="https://godoc.org/github.com/fluxcd/pkg/apis/kustomize#CustomHealthCheck">
+[]github.com/fluxcd/pkg/apis/kustomize.CustomHealthCheck
+</a>
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>HealthCheckExprs is a list of healthcheck expressions for evaluating the
+health of custom resources using Common Expression Language (CEL).</p>
+</td>
+</tr>
 </tbody>
 </table>
 </div>

docs/spec/v1/kustomizations.md

@@ -339,6 +339,67 @@ spec:
 If all the HelmRelease objects are successfully installed or upgraded, then
 the Kustomization will be marked as ready.
 
+### Health check expressions
+
+`.spec.healthCheckExprs` can be used to define custom logic for performing
+health checks on custom resources. This is done through Common Expression
+Language (CEL) expressions. This field accepts a list of objects with the
+following fields:
+
+- `apiVersion`: The API version of the custom resource. Required.
+- `kind`: The kind of the custom resource. Required.
+- `current`: A required CEL expression that returns `true` if the resource is ready.
+- `inProgress`: An optional CEL expression that returns `true` if the resource
+  is still being reconciled.
+- `failed`: An optional CEL expression that returns `true` if the resource
+  failed to reconcile.
+
+The controller will evaluate the expressions in the following order:
+
+1. `inProgress` if specified
+2. `failed` if specified
+3. `current`
+
+The first expression that evaluates to `true` will determine the health
+status of the custom resource.
+
+For example, to define a set of health check expressions for the `SealedSecret`
+custom resource:
+
+```yaml
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
+metadata:
+  name: sealed-secrets
+  namespace: flux-system
+spec:
+  interval: 5m
+  path: ./path/to/sealed/secrets
+  prune: true
+  sourceRef:
+    kind: GitRepository
+    name: flux-system
+  timeout: 1m
+  wait: true # Tells the controller to wait for all resources to be ready by performing health checks.
+  healthCheckExprs:
+    - apiVersion: bitnami.com/v1alpha1
+      kind: SealedSecret
+      inProgress: has(status.observedGeneration) && status.observedGeneration != metadata.generation
+      failed: status.conditions.filter(e, e.type == 'Synced').all(e, e.status == 'False')
+      current: status.conditions.filter(e, e.type == 'Synced').all(e, e.status == 'True')
+```
+
+A common error is writing expressions that reference fields that do not
+exist in the custom resource. This will cause the controller to wait
+for the resource to be ready until the timeout is reached. To avoid this,
+make sure your CEL expressions are correct. The
+[CEL Playground](https://playcel.undistro.io/) is a useful resource for
+this task. The input passed to each expression is the custom resource
+object itself.
+
+It's worth checking if [the library](/flux/cheatsheets/cel-healthchecks/)
+has expressions for the custom resources you are using.
+
 ### Wait
 
 `.spec.wait` is an optional boolean field to perform health checks for __all__