/* Copyright 2014 The Kubernetes Authors. 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 explain import ( "fmt" "github.com/spf13/cobra" "k8s.io/apimachinery/pkg/api/meta" "k8s.io/apimachinery/pkg/runtime/schema" "k8s.io/cli-runtime/pkg/genericiooptions" openapiclient "k8s.io/client-go/openapi" cmdutil "k8s.io/kubectl/pkg/cmd/util" "k8s.io/kubectl/pkg/explain" openapiv3explain "k8s.io/kubectl/pkg/explain/v2" "k8s.io/kubectl/pkg/util/i18n" "k8s.io/kubectl/pkg/util/openapi" "k8s.io/kubectl/pkg/util/templates" ) var ( explainLong = templates.LongDesc(i18n.T(` Describe fields and structure of various resources. This command describes the fields associated with each supported API resource. Fields are identified via a simple JSONPath identifier: .[.] Information about each field is retrieved from the server in OpenAPI format.`)) explainExamples = templates.Examples(i18n.T(` # Get the documentation of the resource and its fields kubectl explain pods # Get all the fields in the resource kubectl explain pods --recursive # Get the explanation for deployment in supported api versions kubectl explain deployments --api-version=apps/v1 # Get the documentation of a specific field of a resource kubectl explain pods.spec.containers # Get the documentation of resources in different format kubectl explain deployment --output=plaintext-openapiv2`)) ) const ( plaintextTemplateName = "plaintext" plaintextOpenAPIV2TemplateName = "plaintext-openapiv2" ) // ExplainFlags directly reflect the information that CLI is gathering via flags. // They will be converted to Options, which reflect the runtime requirements for // the command. type ExplainFlags struct { APIVersion string OutputFormat string Recursive bool genericiooptions.IOStreams } // NewExplainFlags returns a default ExplainFlags func NewExplainFlags(streams genericiooptions.IOStreams) *ExplainFlags { return &ExplainFlags{ OutputFormat: plaintextTemplateName, IOStreams: streams, } } // AddFlags registers flags for a cli func (flags *ExplainFlags) AddFlags(cmd *cobra.Command) { cmd.Flags().BoolVar(&flags.Recursive, "recursive", flags.Recursive, "Print the fields of fields (Currently only 1 level deep)") cmd.Flags().StringVar(&flags.APIVersion, "api-version", flags.APIVersion, "Get different explanations for particular API version (API group/version)") cmd.Flags().StringVarP(&flags.OutputFormat, "output", "o", plaintextTemplateName, "Format in which to render the schema (plaintext, plaintext-openapiv2)") } // ToOptions converts from CLI inputs to runtime input func (flags *ExplainFlags) ToOptions(f cmdutil.Factory, parent string, args []string) (*ExplainOptions, error) { mapper, err := f.ToRESTMapper() if err != nil { return nil, err } // Only openapi v3 needs the discovery client. openAPIV3Client, err := f.OpenAPIV3Client() if err != nil { return nil, err } o := &ExplainOptions{ IOStreams: flags.IOStreams, Recursive: flags.Recursive, APIVersion: flags.APIVersion, OutputFormat: flags.OutputFormat, CmdParent: parent, args: args, Mapper: mapper, openAPIGetter: f, OpenAPIV3Client: openAPIV3Client, } return o, nil } // NewCmdExplain returns a cobra command for swagger docs func NewCmdExplain(parent string, f cmdutil.Factory, streams genericiooptions.IOStreams) *cobra.Command { flags := NewExplainFlags(streams) cmd := &cobra.Command{ Use: "explain TYPE [--recursive=FALSE|TRUE] [--api-version=api-version-group] [-o|--output=plaintext|plaintext-openapiv2]", DisableFlagsInUseLine: true, Short: i18n.T("Get documentation for a resource"), Long: explainLong + "\n\n" + cmdutil.SuggestAPIResources(parent), Example: explainExamples, Run: func(cmd *cobra.Command, args []string) { o, err := flags.ToOptions(f, parent, args) cmdutil.CheckErr(err) cmdutil.CheckErr(o.Validate()) cmdutil.CheckErr(o.Run()) }, } flags.AddFlags(cmd) return cmd } type ExplainOptions struct { genericiooptions.IOStreams Recursive bool APIVersion string // Name of the template to use with the openapiv3 template renderer. OutputFormat string CmdParent string args []string Mapper meta.RESTMapper openAPIGetter openapi.OpenAPIResourcesGetter // Client capable of fetching openapi documents from the user's cluster OpenAPIV3Client openapiclient.Client } func (o *ExplainOptions) Validate() error { if len(o.args) == 0 { return fmt.Errorf("You must specify the type of resource to explain. %s\n", cmdutil.SuggestAPIResources(o.CmdParent)) } if len(o.args) > 1 { return fmt.Errorf("We accept only this format: explain RESOURCE\n") } return nil } // Run executes the appropriate steps to print a model's documentation func (o *ExplainOptions) Run() error { var fullySpecifiedGVR schema.GroupVersionResource var fieldsPath []string var err error if len(o.APIVersion) == 0 { fullySpecifiedGVR, fieldsPath, err = explain.SplitAndParseResourceRequestWithMatchingPrefix(o.args[0], o.Mapper) if err != nil { return err } } else { // TODO: After we figured out the new syntax to separate group and resource, allow // the users to use it in explain (kubectl explain ). // Refer to issue #16039 for why we do this. Refer to PR #15808 that used "/" syntax. fullySpecifiedGVR, fieldsPath, err = explain.SplitAndParseResourceRequest(o.args[0], o.Mapper) if err != nil { return err } } // Fallback to openapiv2 implementation using special template name switch o.OutputFormat { case plaintextOpenAPIV2TemplateName: return o.renderOpenAPIV2(fullySpecifiedGVR, fieldsPath) case plaintextTemplateName: // Check whether the server reponds to OpenAPIV3. if _, err := o.OpenAPIV3Client.Paths(); err != nil { // Use v2 renderer if server does not support v3 return o.renderOpenAPIV2(fullySpecifiedGVR, fieldsPath) } fallthrough default: if len(o.APIVersion) > 0 { apiVersion, err := schema.ParseGroupVersion(o.APIVersion) if err != nil { return err } fullySpecifiedGVR.Group = apiVersion.Group fullySpecifiedGVR.Version = apiVersion.Version } return openapiv3explain.PrintModelDescription( fieldsPath, o.Out, o.OpenAPIV3Client, fullySpecifiedGVR, o.Recursive, o.OutputFormat, ) } } func (o *ExplainOptions) renderOpenAPIV2( fullySpecifiedGVR schema.GroupVersionResource, fieldsPath []string, ) error { var err error gvk, _ := o.Mapper.KindFor(fullySpecifiedGVR) if gvk.Empty() { gvk, err = o.Mapper.KindFor(fullySpecifiedGVR.GroupResource().WithVersion("")) if err != nil { return err } } if len(o.APIVersion) != 0 { apiVersion, err := schema.ParseGroupVersion(o.APIVersion) if err != nil { return err } gvk = apiVersion.WithKind(gvk.Kind) } resources, err := o.openAPIGetter.OpenAPISchema() if err != nil { return err } schema := resources.LookupResource(gvk) if schema == nil { return fmt.Errorf("couldn't find resource for %q", gvk) } return explain.PrintModelDescription(fieldsPath, o.Out, schema, gvk, o.Recursive) }