Merge pull request #164 from brendanjryan/bjr-output

expose output formatter

docs/index.md

@@ -87,23 +87,57 @@ The file fixtures/test_crd.yaml containing a SealedSecret was not validated agai
 Helm chart configurations generally have a reference to the source template in a comment
 like so:
 
-```
+```console
 # Source: chart/templates/frontend.yam
 ```
 
 When kubeval detects these comments it will report the relevant chart template files in
 the output.
 
-```
+```console
 $ kubeval fixtures/multi_valid_source.yaml
 The file chart/templates/primary.yaml contains a valid Service
 The file chart/templates/primary.yaml contains a valid ReplicationControlle
 ```
 
+## Configuring Output
 
-## Full usage instructions
+ The output of `kubeval` can be configured using the `--output` flag (`-o`).
 
+ As of today `kubeval` supports the following output types:
+
+ - Plaintext `--output=stdout`
+- JSON: `--output=json`
+
+ ### Example Output
+
+ #### Plaintext
+
+ ```console
+$ kubeval my-invalid-rc.yaml
+The document my-invalid-rc.yaml contains an invalid ReplicationController
+--> spec.replicas: Invalid type. Expected: integer, given: string
+```
+
+ #### JSON
+
+ ```console
+ $ kubeval fixtures/invalid.yaml -o json
+ [
+         {
+                 "filename": "fixtures/invalid.yaml",
+                 "kind": "ReplicationController",
+                 "status": "invalid",
+                 "errors": [
+                         "spec.replicas: Invalid type. Expected: [integer,null], given: string"
+                 ]
+         }
+ ]
 ```
+
+## Full usage instructions
+
+```console
 $ kubeval --help
 Validate a Kubernetes YAML file against the relevant schema
 
@@ -119,7 +153,8 @@ Flags:
       --ignore-missing-schemas      Skip validation for resource definitions without a schema
   -v, --kubernetes-version string   Version of Kubernetes to validate against (default "master")
       --openshift                   Use OpenShift schemas instead of upstream Kubernetes
-      --schema-location string      Base URL used to download schemas. Can also be specified with the environment variable KUBEVAL_SCHEMA_LOCATION (default "https://kubernetesjsonschema.dev")
+  -o, --output string               The format of the output of this script. Options are: [stdout json]
+      --schema-location string      Base URL used to download schemas. Can also be specified with the environment variable KUBEVAL_SCHEMA_LOCATION
       --skip-kinds strings          Comma-separated list of case-sensitive kinds to skip when validating against schemas
       --strict                      Disallow additional properties not in schema
       --version                     version for kubeval

kubeval/config.go

@@ -1,6 +1,10 @@
 package kubeval
 
-import "github.com/spf13/cobra"
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
 
 // DefaultSchemaLocation is the default location to search for schemas
 const DefaultSchemaLocation = "https://kubernetesjsonschema.dev"
@@ -40,13 +44,16 @@ type Config struct {
 
 	// FileName is the name to be displayed when testing manifests read from stdin
 	FileName string
-}
 
+	// OutputFormat is the name of the output formatter which will be used when
+	// reporting results to the user.
+	OutputFormat string
+}
 
 // NewDefaultConfig creates a Config with default values
 func NewDefaultConfig() *Config {
 	return &Config{
-		FileName: "stdin",
+		FileName:          "stdin",
 		KubernetesVersion: "master",
 	}
 }
@@ -61,5 +68,7 @@ func AddKubevalFlags(cmd *cobra.Command, config *Config) *cobra.Command {
 	cmd.Flags().StringSliceVar(&config.KindsToSkip, "skip-kinds", []string{}, "Comma-separated list of case-sensitive kinds to skip when validating against schemas")
 	cmd.Flags().StringVar(&config.SchemaLocation, "schema-location", "", "Base URL used to download schemas. Can also be specified with the environment variable KUBEVAL_SCHEMA_LOCATION")
 	cmd.Flags().StringVarP(&config.KubernetesVersion, "kubernetes-version", "v", "master", "Version of Kubernetes to validate against")
+	cmd.Flags().StringVarP(&config.OutputFormat, "output", "o", "", fmt.Sprintf("The format of the output of this script. Options are: %v", validOutputs()))
+
 	return cmd
 }

kubeval/output.go

@@ -12,19 +12,44 @@ import (
 // TODO (brendanryan) move these structs to `/log` once we have removed the potential
 // circular dependancy between this package and `/log`
 
-// OutputManager controls how results of the `kubeval` evaluation will be recorded
+// outputManager controls how results of the `kubeval` evaluation will be recorded
 // and reported to the end user.
-type OutputManager interface {
+// This interface is kept private to ensure all implementations are closed within
+// this package.
+type outputManager interface {
 	Put(r ValidationResult) error
 	Flush() error
 }
 
+const (
+	outputSTD  = "stdout"
+	outputJSON = "json"
+)
+
+func validOutputs() []string {
+	return []string{
+		outputSTD,
+		outputJSON,
+	}
+}
+
+func GetOutputManager(outFmt string) outputManager {
+	switch outFmt {
+	case outputSTD:
+		return newSTDOutputManager()
+	case outputJSON:
+		return newDefaultJSONOutputManager()
+	default:
+		return newSTDOutputManager()
+	}
+}
+
 // STDOutputManager reports `kubeval` results to stdout.
 type STDOutputManager struct {
 }
 
-// NewSTDOutputManager instantiates a new instance of STDOutputManager.
-func NewSTDOutputManager() *STDOutputManager {
+// newSTDOutputManager instantiates a new instance of STDOutputManager.
+func newSTDOutputManager() *STDOutputManager {
 	return &STDOutputManager{}
 }
 
@@ -98,7 +123,7 @@ func getStatus(r ValidationResult) status {
 	return statusValid
 }
 
-func (j *jsonOutputManager) put(r ValidationResult) error {
+func (j *jsonOutputManager) Put(r ValidationResult) error {
 	// stringify gojsonschema errors
 	// use a pre-allocated slice to ensure the json will have an
 	// empty array in the "zero" case
@@ -117,7 +142,7 @@ func (j *jsonOutputManager) put(r ValidationResult) error {
 	return nil
 }
 
-func (j *jsonOutputManager) flush() error {
+func (j *jsonOutputManager) Flush() error {
 	b, err := json.Marshal(j.data)
 	if err != nil {
 		return err

main.go

@@ -72,7 +72,7 @@ var RootCmd = &cobra.Command{
 				log.Error(err)
 				os.Exit(1)
 			}
-			success, err = logResults(results, success)
+			success, err = logResults(config.OutputFormat, results, success)
 			if err != nil {
 				log.Error(err)
 				os.Exit(1)
@@ -105,7 +105,7 @@ var RootCmd = &cobra.Command{
 					success = false
 					continue
 				}
-				success, err = logResults(results, success)
+				success, err = logResults(config.OutputFormat, results, success)
 				if err != nil {
 					log.Error(err)
 					os.Exit(1)
@@ -119,10 +119,9 @@ var RootCmd = &cobra.Command{
 	},
 }
 
-func logResults(results []kubeval.ValidationResult, success bool) (bool, error) {
-	//// fetch output logger based on enviroments params -- for now we only support
-	//// the stdout logger
-	out := kubeval.NewSTDOutputManager()
+func logResults(outFmt string, results []kubeval.ValidationResult, success bool) (bool, error) {
+	// fetch output logger based on enviroments params
+	out := kubeval.GetOutputManager(outFmt)
 
 	for _, result := range results {
 		if len(result.Errors) > 0 {
@@ -134,6 +133,11 @@ func logResults(results []kubeval.ValidationResult, success bool) (bool, error)
 		}
 	}
 
+	err := out.Flush()
+	if err != nil {
+		return false, err
+	}
+
 	return success, nil
 }