diff --git a/pkg/engine/funcs.go b/pkg/engine/funcs.go index dac105e74..eb4a398f4 100644 --- a/pkg/engine/funcs.go +++ b/pkg/engine/funcs.go @@ -53,6 +53,7 @@ func funcMap() template.FuncMap { "fromYaml": fromYAML, "toJson": toJSON, "fromJson": fromJSON, + "lookup" : lookup, // This is a placeholder for the "include" function, which is // late-bound to a template. By declaring it here, we preserve the diff --git a/pkg/engine/lookup_func.go b/pkg/engine/lookup_func.go new file mode 100644 index 000000000..fe127d8f3 --- /dev/null +++ b/pkg/engine/lookup_func.go @@ -0,0 +1,118 @@ +package engine + +import ( + "flag" + "log" + "os" + "path/filepath" + "strings" + + metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" + "k8s.io/apimachinery/pkg/runtime/schema" + "k8s.io/client-go/discovery" + "k8s.io/client-go/dynamic" + "k8s.io/client-go/rest" + "k8s.io/client-go/tools/clientcmd" +) + +var config *rest.Config +var addLookupFunction = false + +func init() { + // try the out-cluster config, this will default to the in-cluster config is not successful + var kubeconfig *string + if home := homeDir(); home != "" { + kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file") + } else { + kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file") + } + flag.Parse() + + // use the current context in kubeconfig + config1, err := clientcmd.BuildConfigFromFlags("", *kubeconfig) + if err == nil { + addLookupFunction = true + config = config1 + } + return +} + +func homeDir() string { + if h := os.Getenv("HOME"); h != "" { + return h + } + return os.Getenv("USERPROFILE") // windows +} + +func lookup(apiversion string, resource string, namespace string, name string) (map[string]interface{}, error) { + var client dynamic.ResourceInterface + c, err := getDynamicClientOnKind(apiversion, resource) + if err != nil { + return map[string]interface{}{}, err + } + if namespace != "" { + client = c.Namespace(namespace) + } else { + client = c + } + if name != "" { + //this will return a single object + obj, err := client.Get(name, metav1.GetOptions{}) + if err != nil { + return map[string]interface{}{}, err + } + return obj.Object, nil + } + //this will return a list + obj, err := client.List(metav1.ListOptions{}) + if err != nil { + return map[string]interface{}{}, err + } + return obj.Object, nil + +} + +// GetDynamicClientOnUnstructured returns a dynamic client on an Unstructured type. This client can be further namespaced. +func getDynamicClientOnKind(apiversion string, kind string) (dynamic.NamespaceableResourceInterface, error) { + gvk := schema.FromAPIVersionAndKind(apiversion, kind) + apiRes, err := getAPIReourceForGVK(gvk) + if err != nil { + log.Printf("[ERROR] unable to get apiresource from unstructured: %s , error %s", gvk.String(), err) + return nil, err + } + gvr := schema.GroupVersionResource{ + Group: apiRes.Group, + Version: apiRes.Version, + Resource: apiRes.Name, + } + intf, err := dynamic.NewForConfig(config) + if err != nil { + log.Printf("[ERROR] unable to get dynamic client %s", err) + return nil, err + } + res := intf.Resource(gvr) + return res, nil +} + +func getAPIReourceForGVK(gvk schema.GroupVersionKind) (metav1.APIResource, error) { + res := metav1.APIResource{} + discoveryClient, err := discovery.NewDiscoveryClientForConfig(config) + if err != nil { + log.Printf("[ERROR] unable to create discovery client %s", err) + return res, err + } + resList, err := discoveryClient.ServerResourcesForGroupVersion(gvk.GroupVersion().String()) + if err != nil { + log.Printf("[ERROR] unable to retrieve resouce list for: %s , error: %s", gvk.GroupVersion().String(), err) + return res, err + } + for _, resource := range resList.APIResources { + if resource.Kind == gvk.Kind && !strings.Contains(resource.Name, "/") { + res = resource + res.Group = gvk.Group + res.Version = gvk.Version + break + } + } + return res, nil +}