Add preupgrade check for RPP (#2014)

* Add preupgrade check for RPP

Signed-off-by: Harsh Thakur <harshthakur9030@gmail.com>

* Change from panic to error, and better logging

Signed-off-by: Harsh Thakur <harshthakur9030@gmail.com>

* Minor changes

Signed-off-by: Harsh Thakur <harshthakur9030@gmail.com>

* Modify function to return CRD

Signed-off-by: Harsh Thakur <harshthakur9030@gmail.com>

* Remove redundant error logging

Signed-off-by: Harsh Thakur <harshthakur9030@gmail.com>

cmd/preupgradechecks/main.go

@@ -65,11 +65,15 @@ Options:
 			zap.Error(err))
 	}
 
-	installed := crdBackedClient.IsFissionReInstall()
-	if !installed {
+	crd := crdBackedClient.GetFunctionCRD()
+	if crd == nil {
 		logger.Info("nothing to do since CRDs are not present on the cluster")
 		return
 	}
 
+	err = crdBackedClient.LatestSchemaApplied()
+	if err != nil {
+		logger.Fatal("New CRDs are not applied")
+	}
 	crdBackedClient.VerifyFunctionSpecReferences()
 }

cmd/preupgradechecks/preupgradechecks.go

@@ -18,10 +18,12 @@ package main
 
 import (
 	"fmt"
+	"strings"
 
 	multierror "github.com/hashicorp/go-multierror"
 	"github.com/pkg/errors"
 	"go.uber.org/zap"
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
 	apiextensionsclient "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
 	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -63,18 +65,32 @@ func makePreUpgradeTaskClient(logger *zap.Logger, fnPodNs, envBuilderNs string)
 	}, nil
 }
 
-// IsFissionReInstall checks if there is at least one fission CRD, i.e. function in this case, on this cluster.
-// We need this to find out if fission had been previously installed on this cluster
-func (client *PreUpgradeTaskClient) IsFissionReInstall() bool {
+// GetFunctionCRD checks if function CRD is present on the cluster and returns it. It returns nil if not found
+// We can use this to find out if fission had been previously installed on this cluster too.
+func (client *PreUpgradeTaskClient) GetFunctionCRD() *v1beta1.CustomResourceDefinition {
 	for i := 0; i < maxRetries; i++ {
-		_, err := client.apiExtClient.ApiextensionsV1beta1().CustomResourceDefinitions().Get(FunctionCRD, metav1.GetOptions{})
+		crd, err := client.apiExtClient.ApiextensionsV1beta1().CustomResourceDefinitions().Get(FunctionCRD, metav1.GetOptions{})
 		if err != nil && k8serrors.IsNotFound(err) {
-			return false
-
+			continue
 		}
+		return crd
 	}
+	return nil
+}
 
-	return false
+// LatestSchemaApplied ensures that the end user has applied the latest CRDs generated to the cluster.
+// For future reference: whenever a new field is added, we need to check for that field's existence in this function
+func (client *PreUpgradeTaskClient) LatestSchemaApplied() error {
+	client.logger.Info("Checking if user has applied the latest CRDs")
+	crd := client.GetFunctionCRD()
+	if crd == nil {
+		return errors.New("Could not get the Function CRD")
+	}
+	// Any new field added in Function spec can be checked here provided the substring matches the description in CRD Validation of the field
+	if !strings.Contains(crd.Spec.String(), "RequestsPerPod") {
+		return errors.New("Apply the newer CRDs before upgrading")
+	}
+	return nil
 }
 
 // VerifyFunctionSpecReferences verifies that a function references secrets, configmaps, pkgs in its own namespace and