new kubectl explain command

pkg/kubectl/explain.go

@@ -0,0 +1,260 @@
+/*
+Copyright 2014 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubectl
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/emicklei/go-restful/swagger"
+
+	"k8s.io/kubernetes/pkg/api/meta"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+)
+
+var allModels = make(map[string]*swagger.NamedModel)
+var recursive = false // this is global for convenience, can become int for multiple levels
+
+// GetSwaggerSchema returns the swagger spec from master
+func GetSwaggerSchema(apiVer string, kubeClient client.Interface) (*swagger.ApiDeclaration, error) {
+	swaggerSchema, err := kubeClient.SwaggerSchema(apiVer)
+	if err != nil {
+		return nil, fmt.Errorf("couldn't read swagger schema from server: %v", err)
+	}
+	return swaggerSchema, nil
+}
+
+// SplitAndParseResourceRequest separates the users input into a model and fields
+func SplitAndParseResourceRequest(inResource string, mapper meta.RESTMapper) (string, []string, error) {
+	inResource, fieldsPath := splitDotNotation(inResource)
+	inResource, _ = mapper.ResourceSingularizer(expandResourceShortcut(inResource))
+	return inResource, fieldsPath, nil
+}
+
+// PrintModelDescription prints the description of a specific model or dot path
+func PrintModelDescription(inModel string, fieldsPath []string, w io.Writer, swaggerSchema *swagger.ApiDeclaration, r bool) error {
+	recursive = r // this is global for convenience
+	apiVer := swaggerSchema.ApiVersion + "."
+
+	var pointedModel *swagger.NamedModel
+	for i := range swaggerSchema.Models.List {
+		name := swaggerSchema.Models.List[i].Name
+
+		allModels[name] = &swaggerSchema.Models.List[i]
+		if strings.ToLower(name) == strings.ToLower(apiVer+inModel) {
+			pointedModel = &swaggerSchema.Models.List[i]
+		}
+	}
+	if pointedModel == nil {
+		return fmt.Errorf("Requested resourse: %s doesn't exit", inModel)
+	}
+
+	if len(fieldsPath) == 0 {
+		return printTopLevelResourceInfo(w, pointedModel)
+	}
+
+	var pointedModelAsProp *swagger.NamedModelProperty
+	for _, field := range fieldsPath {
+		if prop, nextModel, isModel := getField(pointedModel, field); prop != nil {
+			if isModel {
+				pointedModelAsProp = prop
+				pointedModel = allModels[nextModel]
+			} else {
+				return printPrimitive(w, prop)
+			}
+		} else {
+			return fmt.Errorf("field: %s doesn't exist", field)
+		}
+	}
+	return printModelInfo(w, pointedModel, pointedModelAsProp)
+}
+
+func splitDotNotation(model string) (string, []string) {
+	var fieldsPath []string
+	dotModel := strings.Split(model, ".")
+	if len(dotModel) >= 1 {
+		fieldsPath = dotModel[1:]
+	}
+	return dotModel[0], fieldsPath
+}
+
+func getPointedModel(prop *swagger.ModelProperty) (string, bool) {
+	if prop.Ref != nil {
+		return *prop.Ref, true
+	} else if *prop.Type == "array" && prop.Items.Ref != nil {
+		return *prop.Items.Ref, true
+	}
+	return "", false
+}
+
+func getField(model *swagger.NamedModel, sField string) (*swagger.NamedModelProperty, string, bool) {
+	for _, prop := range model.Model.Properties.List {
+		if prop.Name == sField {
+			pointedModel, isModel := getPointedModel(&prop.Property)
+			return &prop, pointedModel, isModel
+		}
+	}
+	return nil, "", false
+}
+
+func printModelInfo(w io.Writer, model *swagger.NamedModel, modelProp *swagger.NamedModelProperty) error {
+	t, _ := getFieldType(&modelProp.Property)
+	fmt.Fprintf(w, "RESOURCE: %s <%s>\n\n", modelProp.Name, t)
+	fieldDesc, _ := wrapAndIndentText(modelProp.Property.Description, "    ", 80)
+	fmt.Fprintf(w, "DESCRIPTION:\n%s\n\n%s\n", fieldDesc, indentText(model.Model.Description, "    "))
+	return printFields(w, model)
+}
+
+func printPrimitive(w io.Writer, field *swagger.NamedModelProperty) error {
+	t, _ := getFieldType(&field.Property)
+	fmt.Fprintf(w, "FIELD: %s <%s>\n\n", field.Name, t)
+	d, _ := wrapAndIndentText(field.Property.Description, "    ", 80)
+	fmt.Fprintf(w, "DESCRIPTION:\n%s\n", d)
+	return nil
+}
+
+func printTopLevelResourceInfo(w io.Writer, model *swagger.NamedModel) error {
+	fmt.Fprintf(w, "DESCRIPTION:\n%s\n", model.Model.Description)
+	return printFields(w, model)
+}
+
+func printFields(w io.Writer, model *swagger.NamedModel) error {
+	fmt.Fprint(w, "\nFIELDS:\n")
+	for _, field := range model.Model.Properties.List {
+		fieldType, err := getFieldType(&field.Property)
+		if err != nil {
+			return err
+		}
+
+		if arrayContains(model.Model.Required, field.Name) {
+			fmt.Fprintf(w, "   %s\t<%s> -required-\n", field.Name, fieldType)
+		} else {
+			fmt.Fprintf(w, "   %s\t<%s>\n", field.Name, fieldType)
+		}
+
+		if recursive {
+			pointedModel, isModel := getPointedModel(&field.Property)
+			if isModel {
+				for _, nestedField := range allModels[pointedModel].Model.Properties.List {
+					t, _ := getFieldType(&nestedField.Property)
+					fmt.Fprintf(w, "       %s\t<%s>\n", nestedField.Name, t)
+				}
+			}
+		} else {
+			fieldDesc, _ := wrapAndIndentText(field.Property.Description, "    ", 80)
+			fmt.Fprintf(w, "%s\n\n", fieldDesc)
+		}
+	}
+	fmt.Fprint(w, "\n")
+	return nil
+}
+
+func getFieldType(prop *swagger.ModelProperty) (string, error) {
+	if prop.Type == nil {
+		return "Object", nil
+	} else if *prop.Type == "any" {
+		// Swagger Spec doesn't return information for maps.
+		return "map[string]string", nil
+	} else if *prop.Type == "array" {
+		if prop.Items == nil {
+			return "", fmt.Errorf("error in swagger spec. Property: %v contains an array without type", prop)
+		}
+		if prop.Items.Ref != nil {
+			fieldType := "[]Object"
+			return fieldType, nil
+		}
+		fieldType := "[]" + *prop.Items.Type
+		return fieldType, nil
+	}
+	return *prop.Type, nil
+}
+
+func wrapAndIndentText(desc, indent string, lim int) (string, error) {
+	words := strings.Split(strings.Replace(strings.TrimSpace(desc), "\n", " ", -1), " ")
+	n := len(words)
+
+	for i := 0; i < n; i++ {
+		if len(words[i]) > lim {
+			if strings.Contains(words[i], "/") {
+				s := breakURL(words[i])
+				words = append(words[:i], append(s, words[i+1:]...)...)
+				i = i + len(s) - 1
+			} else {
+				fmt.Println(len(words[i]))
+				return "", fmt.Errorf("there are words longer that the break limit is")
+			}
+		}
+	}
+
+	var lines []string
+	line := []string{indent}
+	lineL := len(indent)
+	for i := 0; i < len(words); i++ {
+		w := words[i]
+
+		if strings.HasSuffix(w, "/") && lineL+len(w)-1 < lim {
+			prev := line[len(line)-1]
+			if strings.HasSuffix(prev, "/") {
+				if i+1 < len(words)-1 && !strings.HasSuffix(words[i+1], "/") {
+					w = strings.TrimSuffix(w, "/")
+				}
+
+				line[len(line)-1] = prev + w
+				lineL += len(w)
+			} else {
+				line = append(line, w)
+				lineL += len(w) + 1
+			}
+		} else if lineL+len(w) < lim {
+			line = append(line, w)
+			lineL += len(w) + 1
+		} else {
+			lines = append(lines, strings.Join(line, " "))
+			line = []string{indent, w}
+			lineL = len(indent) + len(w)
+		}
+	}
+	lines = append(lines, strings.Join(line, " "))
+
+	return strings.Join(lines, "\n"), nil
+}
+
+func breakURL(url string) []string {
+	var buf []string
+	for _, part := range strings.Split(url, "/") {
+		buf = append(buf, part+"/")
+	}
+	return buf
+}
+
+func indentText(text, indent string) string {
+	lines := strings.Split(text, "\n")
+	for i := range lines {
+		lines[i] = indent + lines[i]
+	}
+	return strings.Join(lines, "\n")
+}
+
+func arrayContains(s []string, e string) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
+}