Add example how to use kubeconform as a library

Readme.md

@@ -191,6 +191,13 @@ sys	0m1,069s
 
 ```
 
+### Using kubeconform as a Go Module
+
+**Warning**: This is a work-in-progress, the interface is not yet considered stable. Feedback is encouraged.
+
+Kubeconform contains a package that can be used as a library.
+An example of usage can be found in [examples/main.go](examples/main.go)
+
 ### Credits
 
  * @garethr for the [Kubeval](https://github.com/instrumenta/kubeval) and

cmd/kubeconform/main.go

@@ -74,25 +74,25 @@ func realMain() int {
 		IgnoreMissingSchemas: cfg.IgnoreMissingSchemas,
 	})
 
-	var resourcesChan <-chan resource.Resource
-	var errors <-chan error
 	validationResults := make(chan validator.Result)
-
 	ctx := context.Background()
 	successChan := processResults(ctx, o, validationResults, cfg.ExitOnError)
 
+	var resourcesChan <-chan resource.Resource
+	var errors <-chan error
 	if isStdin {
 		resourcesChan, errors = resource.FromStream(ctx, "stdin", os.Stdin)
 	} else {
 		resourcesChan, errors = resource.FromFiles(ctx, cfg.IgnoreFilenamePatterns, cfg.Files...)
 	}
 
+	// Process discovered resources across multiple workers
 	wg := sync.WaitGroup{}
 	for i := 0; i < cfg.NumberOfWorkers; i++ {
 		wg.Add(1)
 		go func(resources <-chan resource.Resource, validationResults chan<- validator.Result, v validator.Validator) {
 			for res := range resources {
-				validationResults <- v.Validate(res)
+				validationResults <- v.ValidateResource(res)
 			}
 			wg.Done()
 		}(resourcesChan, validationResults, v)
@@ -100,6 +100,7 @@ func realMain() int {
 
 	wg.Add(1)
 	go func() {
+		// Process errors while discovering resources
 		for err := range errors {
 			if err == nil {
 				continue
@@ -111,8 +112,14 @@ func realMain() int {
 					Err:      err.Err,
 					Status:   validator.Error,
 				}
-				ctx.Done()
+			} else {
+				validationResults <- validator.Result{
+					Resource: resource.Resource{},
+					Err:      err,
+					Status:   validator.Error,
+				}
 			}
+			ctx.Done()
 		}
 		wg.Done()
 	}()

examples/main.go

@@ -0,0 +1,26 @@
+package main
+
+// WARNING: API of Kubeconform is still under development and not yet
+// considered stable
+
+import (
+	"github.com/yannh/kubeconform/pkg/validator"
+	"log"
+	"os"
+)
+
+func main() {
+	filepath := "../fixtures/valid.yaml"
+	f, err := os.Open(filepath)
+	if err != nil {
+		log.Fatalf("failed opening %s: %s", filepath, err)
+	}
+
+	v := validator.New(nil, validator.Opts{Strict: true})
+	for i, res := range v.Validate(filepath, f) { // A file might contain multiple resources
+		// File starts with ---, the parser assumes a first empty resource
+		if res.Status != validator.Valid && res.Status != validator.Empty {
+			log.Fatalf("resource %d in file %s is not valid: %d, %s", i, filepath, res.Status, res.Err)
+		}
+	}
+}

pkg/config/config.go

@@ -88,10 +88,6 @@ func FromFlags(progName string, args []string) (Config, string, error) {
 	c.RejectKinds = splitCSV(rejectKindsCSV)
 	c.IgnoreFilenamePatterns = ignoreFilenamePatterns
 	c.SchemaLocations = schemaLocationsParam
-	if len(c.SchemaLocations) == 0 {
-		c.SchemaLocations = append(c.SchemaLocations, "https://kubernetesjsonschema.dev") // if not specified, default behaviour is to use kubernetesjson-schema.dev as registry
-	}
-
 	c.Files = flags.Args()
 
 	if c.Help {

pkg/config/config_test.go

@@ -52,7 +52,7 @@ func TestFromFlags(t *testing.T) {
 				KubernetesVersion: "1.18.0",
 				NumberOfWorkers:   4,
 				OutputFormat:      "text",
-				SchemaLocations:   []string{"https://kubernetesjsonschema.dev"},
+				SchemaLocations:   nil,
 				SkipKinds:         map[string]bool{},
 				RejectKinds:       map[string]bool{},
 			},
@@ -65,7 +65,7 @@ func TestFromFlags(t *testing.T) {
 				KubernetesVersion: "1.18.0",
 				NumberOfWorkers:   4,
 				OutputFormat:      "text",
-				SchemaLocations:   []string{"https://kubernetesjsonschema.dev"},
+				SchemaLocations:   nil,
 				SkipKinds:         map[string]bool{},
 				RejectKinds:       map[string]bool{},
 			},
@@ -77,7 +77,7 @@ func TestFromFlags(t *testing.T) {
 				KubernetesVersion: "1.18.0",
 				NumberOfWorkers:   4,
 				OutputFormat:      "text",
-				SchemaLocations:   []string{"https://kubernetesjsonschema.dev"},
+				SchemaLocations:   nil,
 				SkipKinds:         map[string]bool{"a": true, "b": true, "c": true},
 				RejectKinds:       map[string]bool{},
 			},
@@ -89,7 +89,7 @@ func TestFromFlags(t *testing.T) {
 				KubernetesVersion: "1.18.0",
 				NumberOfWorkers:   4,
 				OutputFormat:      "text",
-				SchemaLocations:   []string{"https://kubernetesjsonschema.dev"},
+				SchemaLocations:   nil,
 				SkipKinds:         map[string]bool{},
 				RejectKinds:       map[string]bool{},
 				Summary:           true,
@@ -116,10 +116,10 @@ func TestFromFlags(t *testing.T) {
 		},
 	}
 
-	for _, testCase := range testCases {
+	for i, testCase := range testCases {
 		cfg, _, _ := FromFlags("kubeconform", testCase.args)
 		if reflect.DeepEqual(cfg, testCase.conf) != true {
-			t.Errorf("failed parsing config - expected , got: \n%+v\n%+v", testCase.conf, cfg)
+			t.Errorf("test %d: failed parsing config - expected , got: \n%+v\n%+v", i, testCase.conf, cfg)
 		}
 	}
 }

pkg/validator/validator.go

@@ -1,10 +1,12 @@
 package validator
 
 import (
+	"context"
 	"fmt"
 	"github.com/yannh/kubeconform/pkg/cache"
 	"github.com/yannh/kubeconform/pkg/registry"
 	"github.com/yannh/kubeconform/pkg/resource"
+	"io"
 
 	"github.com/xeipuuv/gojsonschema"
 	"sigs.k8s.io/yaml"
@@ -29,7 +31,8 @@ type Result struct {
 }
 
 type Validator interface {
-	Validate(res resource.Resource) Result
+	ValidateResource(res resource.Resource) Result
+	Validate(filename string, r io.Reader) []Result
 }
 
 type Opts struct {
@@ -42,11 +45,20 @@ type Opts struct {
 }
 
 func New(schemaLocations []string, opts Opts) Validator {
+	// Default to kubernetesjsonschema.dev
+	if schemaLocations == nil || len(schemaLocations) == 0 {
+		schemaLocations = []string{"https://kubernetesjsonschema.dev"}
+	}
+
 	registries := []registry.Registry{}
 	for _, schemaLocation := range schemaLocations {
 		registries = append(registries, registry.New(schemaLocation, opts.Strict, opts.SkipTLS))
 	}
 
+	if opts.KubernetesVersion == "" {
+		opts.KubernetesVersion = "1.18.0"
+	}
+
 	if opts.SkipKinds == nil {
 		opts.SkipKinds = map[string]bool{}
 	}
@@ -69,7 +81,7 @@ type v struct {
 	regs           []registry.Registry
 }
 
-func (val *v) Validate(res resource.Resource) Result {
+func (val *v) ValidateResource(res resource.Resource) Result {
 	skip := func(signature resource.Signature) bool {
 		isSkipKind, ok := val.opts.SkipKinds[signature.Kind]
 		return ok && isSkipKind
@@ -151,6 +163,33 @@ func (val *v) Validate(res resource.Resource) Result {
 	return Result{Resource: res, Status: Invalid, Err: fmt.Errorf("%s", msg)}
 }
 
+func (val *v) ValidateWithContext(ctx context.Context, filename string, r io.Reader) []Result {
+	validationResults := []Result{}
+	resourcesChan, _ := resource.FromStream(ctx, filename, r)
+	for {
+		select {
+		case res, ok := <-resourcesChan:
+			validationResults = append(validationResults, val.ValidateResource(res))
+			if !ok {
+				resourcesChan = nil
+			}
+
+		case <-ctx.Done():
+			break
+		}
+
+		if resourcesChan == nil {
+			break
+		}
+	}
+
+	return validationResults
+}
+
+func (val *v) Validate(filename string, r io.Reader) []Result {
+	return val.ValidateWithContext(context.Background(), filename, r)
+}
+
 func downloadSchema(registries []registry.Registry, kind, version, k8sVersion string) (*gojsonschema.Schema, error) {
 	var err error
 	var schemaBytes []byte

pkg/validator/validator_test.go

@@ -149,7 +149,7 @@ lastName: bar
 			},
 			regs: nil,
 		}
-		if got := val.Validate(resource.Resource{Bytes: testCase.rawResource}); got.Status != testCase.expect {
+		if got := val.ValidateResource(resource.Resource{Bytes: testCase.rawResource}); got.Status != testCase.expect {
 			t.Errorf("%d - expected %d, got %d", i, testCase.expect, got.Status)
 		}
 	}