Merge pull request #138 from clarku/main

Adds support for custom-columns on omc get, close #94

cmd/get/get.go

@@ -74,7 +74,7 @@ var yamlData []byte
 
 var GetCmd = &cobra.Command{
 	Use:   "get",
-	Short: "Get kubernetes/openshift object in tabular format or wide|yaml|json|jsonpath.",
+	Short: "Get kubernetes/openshift object in tabular format or wide|yaml|json|jsonpath|custom-columns.",
 	Run: func(cmd *cobra.Command, args []string) {
 		if len(args) == 0 {
 			cmd.Help()
@@ -117,7 +117,7 @@ func init() {
 	GetCmd.PersistentFlags().BoolVar(&vars.NoHeaders, "no-headers", false, "When using the default or custom-column output format, don't print headers (default print headers).")
 	GetCmd.PersistentFlags().BoolVar(&vars.ShowManagedFields, "show-managed-fields", false, "If true, show the managedFields when printing objects in JSON or YAML format.")
 	GetCmd.PersistentFlags().BoolVarP(&vars.ShowLabelsBoolVar, "show-labels", "", false, "When printing, show all labels as the last column (default hide labels column)")
-	GetCmd.PersistentFlags().StringVarP(&vars.OutputStringVar, "output", "o", "", "Output format. One of: json|yaml|wide|jsonpath=...")
+	GetCmd.PersistentFlags().StringVarP(&vars.OutputStringVar, "output", "o", "", "Output format. One of: json|yaml|wide|jsonpath|custom-columns=...")
 	GetCmd.PersistentFlags().StringVarP(&vars.LabelSelectorStringVar, "selector", "l", "", "selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2)")
 }
 
@@ -392,23 +392,31 @@ func handleObject(obj unstructured.Unstructured) error {
 	}
 	klog.V(3).Info("INFO deserializing ", obj.GetKind(), " ", obj.GetName())
 	var objectTable *metav1.Table
-	_, ok := vars.KnownResources[strings.ToLower(obj.GetKind())]
-	if ok {
-		runtimeObjectType := deserializer.RawObjectToRuntimeObject(rawObject, vars.Schema)
-		if err := yaml.Unmarshal(rawObject, runtimeObjectType); err != nil {
-			klog.V(3).Info(err, err.Error())
-		}
-		objectTable, err = tablegenerator.InternalResourceTable(runtimeObjectType, &obj)
+	if strings.HasPrefix(vars.OutputStringVar, "custom-columns=") {
+		objectTable, err = tablegenerator.CustomColumnsTable(&obj)
 		if err != nil {
-			klog.V(3).Info("INFO ", fmt.Sprintf("%s: %s, %s", err.Error(), obj.GetKind(), obj.GetAPIVersion()))
 			klog.V(1).ErrorS(err, err.Error())
 			return err
 		}
 	} else {
-		objectTable, err = tablegenerator.GenerateCustomResourceTable(obj)
-		if err != nil {
-			klog.V(1).ErrorS(err, err.Error())
-			return err
+		_, ok := vars.KnownResources[strings.ToLower(obj.GetKind())]
+		if ok {
+			runtimeObjectType := deserializer.RawObjectToRuntimeObject(rawObject, vars.Schema)
+			if err := yaml.Unmarshal(rawObject, runtimeObjectType); err != nil {
+				klog.V(3).Info(err, err.Error())
+			}
+			objectTable, err = tablegenerator.InternalResourceTable(runtimeObjectType, &obj)
+			if err != nil {
+				klog.V(3).Info("INFO ", fmt.Sprintf("%s: %s, %s", err.Error(), obj.GetKind(), obj.GetAPIVersion()))
+				klog.V(1).ErrorS(err, err.Error())
+				return err
+			}
+		} else {
+			objectTable, err = tablegenerator.GenerateCustomResourceTable(obj)
+			if err != nil {
+				klog.V(1).ErrorS(err, err.Error())
+				return err
+			}
 		}
 	}
 

docs/subcmds/get.md

@@ -16,3 +16,4 @@ omc get pod my-pod -o yaml                # Get a pod's YAML
 | `-o=name`                 | Print only the resource name and nothing else                                                             | 
 | `-o=wide`                 | Output in the plain-text format with any additional information, and for pods, the node name is included  | 
 | `-o=yaml`                 | Output a YAML formatted API object                                                                        | 
+| `-o=custom-columns`       | Allows a user to customise the fields that are output and their corresponding header names                | 

pkg/tablegenerator/tablegenerator.go

@@ -2,6 +2,7 @@ package tablegenerator
 
 import (
 	"fmt"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -18,6 +19,35 @@ import (
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
 )
 
+func CustomColumnsTable(unstruct *unstructured.Unstructured) (*metav1.Table, error) {
+	// Matches .metadata.name and metadata.name formats
+	format := regexp.MustCompile(`^\.?([^{}]+)$`)
+	fieldSelectors := map[string]string{}
+	prefix := "custom-columns="
+	table := &metav1.Table{}
+	args := vars.OutputStringVar[len(prefix):]
+	fields := strings.Split(args, ",")
+
+	for _, field := range fields {
+		fieldPair := strings.Split(field, ":")
+		if len(fieldPair) != 2 {
+			return nil, fmt.Errorf("error processing column '%s': expected format <name>:<selector>", field)
+		}
+		name, selector := fieldPair[0], fieldPair[1]
+		name = strings.Title(strings.ToLower(name))
+		column := metav1.TableColumnDefinition{Name: name, Type: "string"}
+		table.ColumnDefinitions = append(table.ColumnDefinitions, column)
+		fieldSelectors[name] = selector
+	}
+	cells := make([]interface{}, 0)
+	for _, column := range table.ColumnDefinitions {
+		matches := format.FindStringSubmatch(fieldSelectors[column.Name])
+		cells = append(cells, helpers.GetFromJsonPath(unstruct.Object, fmt.Sprintf("%s%s%s", "{.", matches[1], "}")))
+	}
+	table.Rows = []metav1.TableRow{{Cells: cells}}
+	return table, nil
+}
+
 func InternalResourceTable(runtimeObject runtime.Object, unstruct *unstructured.Unstructured) (*metav1.Table, error) {
 	resourceKind := strings.ToLower(unstruct.GetKind())
 	table, err := vars.TableGenerator.GenerateTable(runtimeObject, printers.GenerateOptions{Wide: vars.Wide, NoHeaders: false})