/
generic_lookup_func.go
216 lines (171 loc) · 5.98 KB
/
generic_lookup_func.go
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// Copyright (c) 2020 Red Hat, Inc.
// Copyright Contributors to the Open Cluster Management project
package templates
import (
"context"
"errors"
"fmt"
"github.com/golang/glog"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/client-go/discovery"
"k8s.io/client-go/dynamic"
)
// getNamespace checks that the target namespace is allowed based on the configured
// lookupNamespace. If it's not, an error is returned. It then returns the namespace
// that should be used. If the target namespace is not set and the lookupNamespace
// configuration is, then the namespace of lookupNamespace is returned for convenience.
func (t *TemplateResolver) getNamespace(funcName, namespace string) (string, error) {
// When lookupNamespace is an empty string, there are no namespace restrictions.
if t.config.LookupNamespace != "" {
// If lookupNamespace is set but namespace is an empty string, then default
// to lookupNamespace for convenience
if namespace == "" {
return t.config.LookupNamespace, nil
}
if t.config.LookupNamespace != namespace {
msg := fmt.Sprintf(
"the namespace argument passed to %s is restricted to %s",
funcName,
t.config.LookupNamespace,
)
glog.Error(msg)
return "", errors.New(msg)
}
}
return namespace, nil
}
func (t *TemplateResolver) lookup(
apiversion string, kind string, namespace string, rsrcname string,
) (
map[string]interface{}, error,
) {
glog.V(glogDefLvl).Infof("lookup : %v, %v, %v, %v", apiversion, kind, namespace, rsrcname)
result := make(map[string]interface{})
ns, err := t.getNamespace("lookup", namespace)
if err != nil {
return result, err
}
// get dynamic Client for the given GVK and namespace
dclient, dclientErr := t.getDynamicClient(apiversion, kind, ns)
if dclientErr != nil {
return result, dclientErr
}
// if resourcename is set then get the specific resource
// else get list of all resources for that (gvk, ns)
var lookupErr error
if rsrcname != "" {
getObj, getErr := dclient.Get(context.TODO(), rsrcname, metav1.GetOptions{})
if getErr == nil {
result = getObj.UnstructuredContent()
}
lookupErr = getErr
} else {
listObj, listErr := dclient.List(context.TODO(), metav1.ListOptions{})
if listErr == nil {
result = listObj.UnstructuredContent()
}
lookupErr = listErr
}
if lookupErr != nil {
if apierrors.IsNotFound(lookupErr) {
lookupErr = nil
}
}
glog.V(glogDefLvl).Infof("lookup result: %v", result)
return result, lookupErr
}
// this func finds the GVR for given GVK and returns a namespaced dynamic client.
func (t *TemplateResolver) getDynamicClient(
apiversion string, kind string, namespace string,
) (
dynamic.ResourceInterface, error,
) {
var dclient dynamic.ResourceInterface
gvk := schema.FromAPIVersionAndKind(apiversion, kind)
glog.V(glogDefLvl).Infof("GVK is: %v", gvk)
// we have GVK but We need GVR i.e resourcename for kind inorder to create dynamicClient
// find ApiResource for given GVK
apiResource, findErr := t.findAPIResource(gvk)
if findErr != nil {
return nil, findErr
}
// make GVR from ApiResource
gvr := schema.GroupVersionResource{
Group: apiResource.Group,
Version: apiResource.Version,
Resource: apiResource.Name,
}
glog.V(glogDefLvl).Infof("GVR is: %v", gvr)
// get Dynamic Client
dclientIntf, dclientErr := dynamic.NewForConfig(t.kubeConfig)
if dclientErr != nil {
glog.Errorf("Failed to get dynamic client with err: %v", dclientErr)
return nil, fmt.Errorf("failed to get the dynamic client: %w", dclientErr)
}
// get Dynamic Client for GVR
dclientNsRes := dclientIntf.Resource(gvr)
// get Dynamic Client for GVR for Namespace if namespaced
if apiResource.Namespaced && namespace != "" {
dclient = dclientNsRes.Namespace(namespace)
} else {
dclient = dclientNsRes
}
glog.V(glogDefLvl).Infof("dynamic client: %v", dclient)
return dclient, nil
}
func (t *TemplateResolver) findAPIResource(gvk schema.GroupVersionKind) (metav1.APIResource, error) {
glog.V(glogDefLvl).Infof("GVK is: %v", gvk)
apiResource := metav1.APIResource{}
// check if an apiresource list is available already (i.e provided as input to templates)
// if not available use api discovery client to get api resource list
apiResList := t.config.KubeAPIResourceList
if apiResList == nil {
var ddErr error
apiResList, ddErr = t.discoverAPIResources()
if ddErr != nil {
return apiResource, fmt.Errorf("")
}
}
// find apiResourcefor given GVK
var groupVersion string
if gvk.Group != "" {
groupVersion = gvk.Group + "/" + gvk.Version
} else {
groupVersion = gvk.Version
}
glog.V(glogDefLvl).Infof("GroupVersion is: %v", groupVersion)
for _, apiResGroup := range apiResList {
if apiResGroup.GroupVersion == groupVersion {
for _, apiRes := range apiResGroup.APIResources {
if apiRes.Kind == gvk.Kind {
apiResource = apiRes
apiResource.Group = gvk.Group
apiResource.Version = gvk.Version
break
}
}
}
}
glog.V(glogDefLvl).Infof("found APIResource : %v", apiResource)
return apiResource, nil
}
// Configpolicycontroller sets the apiresource list on the template processor
// So this func shouldnt execute in the configpolicy flow
// including this just for completeness.
func (t *TemplateResolver) discoverAPIResources() ([]*metav1.APIResourceList, error) {
glog.V(glogDefLvl).Infof("discover APIResources")
dd, ddErr := discovery.NewDiscoveryClientForConfig(t.kubeConfig)
if ddErr != nil {
glog.Errorf("Failed to create the discovery client with err: %v", ddErr)
return nil, fmt.Errorf("failed to create the discovery client: %w", ddErr)
}
apiresourcelist, apiresourcelistErr := dd.ServerResources()
if apiresourcelistErr != nil {
glog.Errorf("Failed to retrieve apiresourcelist with err: %v", apiresourcelistErr)
return nil, fmt.Errorf("failed to retrieve apiresourcelist: %w", apiresourcelistErr)
}
glog.V(glogDefLvl).Infof("discovered APIResources: %v", apiresourcelist)
return apiresourcelist, nil
}