rework caching - less leak of goschema everywhere

main.go

@@ -26,7 +26,7 @@ type validationResult struct {
 
 // filter returns true if the file should be skipped
 // Returning an array, this Reader might container multiple resources
-func validateFile(f io.Reader, regs []registry.Registry, k8sVersion string, skip func(signature resource.Signature) bool) []validationResult {
+func validateFile(f io.Reader, regs []registry.Registry, k8sVersion string, c *cache.SchemaCache, skip func(signature resource.Signature) bool) []validationResult {
 	rawResource, err := ioutil.ReadAll(f)
 	if err != nil {
 		return []validationResult{{err: fmt.Errorf("failed reading file: %s", err)}}
@@ -42,15 +42,33 @@ func validateFile(f io.Reader, regs []registry.Registry, k8sVersion string, skip
 	}
 
 	var schema *gojsonschema.Schema
-	for _, reg := range regs {
-		downloadSchema := cache.WithCache(reg.DownloadSchema)
-		schema, err = downloadSchema(sig.Kind, sig.Version, k8sVersion)
-		if err == nil {
-			break
+	var schemaBytes []byte
+	var ok bool
+
+	cacheKey := cache.Key(sig.Kind, sig.Version, k8sVersion)
+	schema, ok = c.Get(cacheKey)
+	if !ok {
+		for _, reg := range regs {
+			schemaBytes, err = reg.DownloadSchema(sig.Kind, sig.Version, k8sVersion)
+			if err == nil {
+				schema, err = gojsonschema.NewSchema(gojsonschema.NewBytesLoader(schemaBytes))
+				if err != nil {
+					return []validationResult{{err: err, skipped: false}} // skip if no schema found
+				}
+				break
+			}
+
+			// If we get a 404, we keep trying, but we exit if we get a real failure
+			if er, retryable := err.(registry.Retryable); !(retryable && !er.IsRetryable()) {
+				return []validationResult{{err: fmt.Errorf("error while downloading schema for resource: %s", err)}}
+			}
 		}
 	}
-	if err != nil {
-		return []validationResult{{err: fmt.Errorf("error while downloading schema for resource: %s", err)}}
+
+	c.Set(cacheKey, schema)
+
+	if err != nil { // Not found
+		return []validationResult{{err: nil, skipped: true}} // skip if no schema found
 	}
 
 	if err = validator.Validate(rawResource, schema); err != nil {
@@ -134,6 +152,7 @@ func realMain() int {
 		close(fileBatches)
 	}()
 
+	c := cache.NewSchemaCache()
 	var wg sync.WaitGroup
 	for i := 0; i < nWorkers; i++ {
 		wg.Add(1)
@@ -148,7 +167,7 @@ func realMain() int {
 						continue
 					}
 
-					res := validateFile(f, registries, k8sVersion, filter)
+					res := validateFile(f, registries, k8sVersion, c, filter)
 					f.Close()
 
 					for _, resourceValidation := range res {

pkg/cache/main.go

@@ -3,40 +3,33 @@ package cache
 import (
 	"fmt"
 	"github.com/xeipuuv/gojsonschema"
-	"github.com/yannh/kubeconform/pkg/registry"
 	"sync"
 )
 
-var mu sync.Mutex
-var schemas map[string]*gojsonschema.Schema
-
-func init() {
-	schemas = map[string]*gojsonschema.Schema{}
+type SchemaCache struct {
+	sync.RWMutex
+	schemas map[string]*gojsonschema.Schema
 }
 
-func WithCache(downloadSchema func(string, string, string) (*gojsonschema.Schema, error)) func(string, string, string) (*gojsonschema.Schema, error) {
-	return func(resourceKind, resourceAPIVersion, k8sVersion string) (*gojsonschema.Schema, error) {
-		cacheKey := fmt.Sprintf("%s-%s-%s", resourceKind, resourceAPIVersion, k8sVersion)
-		mu.Lock()
-		cachedSchema, ok := schemas[cacheKey]
-		mu.Unlock()
-		if ok {
-			return cachedSchema, nil
-		}
-
-		schema, err := downloadSchema(resourceKind, resourceAPIVersion, k8sVersion)
-		if err != nil {
-			// will try to download the schema later, except if the error implements Retryable
-			// and returns false on IsRetryable
-			if er, retryable := err.(registry.Retryable); !(retryable && !er.IsRetryable()) {
-				return schema, err
-			}
-		}
-
-		mu.Lock()
-		schemas[cacheKey] = schema
-		mu.Unlock()
-
-		return schema, err
+func NewSchemaCache() *SchemaCache {
+	return &SchemaCache{
+		schemas: map[string]*gojsonschema.Schema{},
 	}
 }
+
+func Key(resourceKind, resourceAPIVersion, k8sVersion string) string {
+	return fmt.Sprintf("%s-%s-%s", resourceKind, resourceAPIVersion, k8sVersion)
+}
+
+func (c *SchemaCache) Get(key string) (*gojsonschema.Schema, bool) {
+	c.RLock()
+	defer c.RUnlock()
+	schema, ok :=  c.schemas[key]
+	return schema, ok
+}
+
+func (c *SchemaCache) Set(key string, schema *gojsonschema.Schema) {
+	c.Lock()
+	defer c.Unlock()
+	c.schemas[key] = schema
+}

pkg/registry/kubernetesjsonschema.go

@@ -2,7 +2,6 @@ package registry
 
 import (
 	"fmt"
-	"github.com/xeipuuv/gojsonschema"
 	"io/ioutil"
 	"net/http"
 	"strings"
@@ -53,7 +52,7 @@ func (r KubernetesRegistry) schemaURL(resourceKind, resourceAPIVersion, k8sVersi
 	return fmt.Sprintf("%s/%s-standalone%s/%s%s.json", r.baseURL, normalisedVersion, strictSuffix, strings.ToLower(resourceKind), kindSuffix)
 }
 
-func (r KubernetesRegistry) DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) (*gojsonschema.Schema, error) {
+func (r KubernetesRegistry) DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) ([]byte, error) {
 	url := r.schemaURL(resourceKind, resourceAPIVersion, k8sVersion)
 
 	resp, err := http.Get(url)
@@ -75,5 +74,5 @@ func (r KubernetesRegistry) DownloadSchema(resourceKind, resourceAPIVersion, k8s
 		return nil, fmt.Errorf("failed downloading schema at %s: %s", url, err)
 	}
 
-	return gojsonschema.NewSchema(gojsonschema.NewBytesLoader(body))
+	return body, nil
 }

pkg/registry/local.go

@@ -2,20 +2,18 @@ package registry
 
 import (
 	"fmt"
-	"github.com/xeipuuv/gojsonschema"
 	"io/ioutil"
 	"os"
 	"sigs.k8s.io/yaml"
-	"strings"
 )
 
 type LocalSchemas struct {
-	schemas map[string]*gojsonschema.Schema
+	schemas map[string]string
 }
 
 func NewLocalSchemas(schemaFiles []string) (*LocalSchemas, error) {
 	schemas := &LocalSchemas{
-		schemas: map[string]*gojsonschema.Schema{},
+		schemas: map[string]string{},
 	}
 
 	for _, schemaFile := range schemaFiles {
@@ -36,32 +34,29 @@ func NewLocalSchemas(schemaFiles []string) (*LocalSchemas, error) {
 				} `json:"Names"`
 			} `json:"Spec"`
 		}
-		err = yaml.Unmarshal(content, &parsedSchema)
+		err = yaml.Unmarshal(content, &parsedSchema) // Index Schemas by kind
 		if err != nil {
 			return nil, fmt.Errorf("failed parsing schema %s", schemaFile)
 		}
 
-		if strings.HasSuffix(schemaFile, ".yml") || strings.HasSuffix(schemaFile, ".yaml") {
-			asJSON, err := yaml.YAMLToJSON(content)
-			if err != nil {
-				return nil, fmt.Errorf("error converting manifest %s to JSON: %s", schemaFile, err)
-			}
-
-			schema, err := gojsonschema.NewSchema(gojsonschema.NewBytesLoader(asJSON))
-			if err != nil {
-				return nil, err
-			}
-			schemas.schemas[parsedSchema.Spec.Names.Kind] = schema
-		}
+		schemas.schemas[parsedSchema.Spec.Names.Kind] = schemaFile
 	}
 
 	return schemas, nil
 }
 
-func (r LocalSchemas) DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) (*gojsonschema.Schema, error) {
-	schema, ok := r.schemas[resourceKind]
+func (r LocalSchemas) DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) ([]byte, error) {
+	schemaFile, ok := r.schemas[resourceKind]
 	if !ok {
 		return nil, fmt.Errorf("no local schema for Kind %s", resourceKind)
 	}
-	return schema, nil
+
+	f, err := os.Open(schemaFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open schema %s", schemaFile)
+	}
+	defer f.Close()
+	content, err := ioutil.ReadAll(f)
+
+	return content, nil
 }

pkg/registry/registry.go

@@ -1,13 +1,11 @@
 package registry
 
-import "github.com/xeipuuv/gojsonschema"
-
 type Manifest struct {
 	Kind, Version string
 }
 
 type Registry interface {
-	DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) (*gojsonschema.Schema, error)
+	DownloadSchema(resourceKind, resourceAPIVersion, k8sVersion string) ([]byte, error)
 }
 
 type Retryable interface {