Add debug information to help understand failures finding schemas (#133)

* Add debug information to help understand failures finding schemas

* Add debug information to help understand failures finding schemas

Author: yannh

Readme.md

@@ -76,6 +76,8 @@ Usage: ./bin/kubeconform [OPTION]... [FILE OR FOLDER]...
         cache schemas downloaded via HTTP to this folder
   -cpu-prof string
         debug - log CPU profiling to file
+  -debug
+        print debug information
   -exit-on-error
         immediately stop execution when the first error is encountered
   -h    show help information

cmd/kubeconform/main.go

@@ -97,9 +97,10 @@ func realMain() int {
 		fmt.Fprintln(os.Stderr, err)
 		return 1
 	}
-
-	v, err := validator.New(cfg.SchemaLocations, validator.Opts{
+	var v validator.Validator
+	v, err = validator.New(cfg.SchemaLocations, validator.Opts{
 		Cache:                cfg.Cache,
+		Debug:                cfg.Debug,
 		SkipTLS:              cfg.SkipTLS,
 		SkipKinds:            cfg.SkipKinds,
 		RejectKinds:          cfg.RejectKinds,

pkg/config/config.go

@@ -10,6 +10,7 @@ import (
 type Config struct {
 	Cache                  string
 	CPUProfileFile         string
+	Debug                  bool
 	ExitOnError            bool
 	Files                  []string
 	SchemaLocations        []string
@@ -67,6 +68,7 @@ func FromFlags(progName string, args []string) (Config, string, error) {
 	flags.Var(&schemaLocationsParam, "schema-location", "override schemas location search path (can be specified multiple times)")
 	flags.StringVar(&skipKindsCSV, "skip", "", "comma-separated list of kinds to ignore")
 	flags.StringVar(&rejectKindsCSV, "reject", "", "comma-separated list of kinds to reject")
+	flags.BoolVar(&c.Debug, "debug", false, "print debug information")
 	flags.BoolVar(&c.ExitOnError, "exit-on-error", false, "immediately stop execution when the first error is encountered")
 	flags.BoolVar(&c.IgnoreMissingSchemas, "ignore-missing-schemas", false, "skip files with missing schemas instead of failing")
 	flags.Var(&ignoreFilenamePatterns, "ignore-filename-pattern", "regular expression specifying paths to ignore (can be specified multiple times)")

pkg/config/config_test.go

@@ -112,9 +112,10 @@ func TestFromFlags(t *testing.T) {
 		{
 			[]string{"-cache", "cache", "-ignore-missing-schemas", "-kubernetes-version", "1.16.0", "-n", "2", "-output", "json",
 				"-schema-location", "folder", "-schema-location", "anotherfolder", "-skip", "kinda,kindb", "-strict",
-				"-reject", "kindc,kindd", "-summary", "-verbose", "file1", "file2"},
+				"-reject", "kindc,kindd", "-summary", "-debug", "-verbose", "file1", "file2"},
 			Config{
 				Cache:                "cache",
+				Debug:                true,
 				Files:                []string{"file1", "file2"},
 				IgnoreMissingSchemas: true,
 				KubernetesVersion:    "1.16.0",

pkg/registry/http.go

@@ -2,8 +2,10 @@ package registry
 
 import (
 	"crypto/tls"
+	"errors"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"os"
 	"time"
@@ -21,9 +23,10 @@ type SchemaRegistry struct {
 	schemaPathTemplate string
 	cache              cache.Cache
 	strict             bool
+	debug              bool
 }
 
-func newHTTPRegistry(schemaPathTemplate string, cacheFolder string, strict bool, skipTLS bool) (*SchemaRegistry, error) {
+func newHTTPRegistry(schemaPathTemplate string, cacheFolder string, strict bool, skipTLS bool, debug bool) (*SchemaRegistry, error) {
 	reghttp := &http.Transport{
 		MaxIdleConns:       100,
 		IdleConnTimeout:    3 * time.Second,
@@ -53,6 +56,7 @@ func newHTTPRegistry(schemaPathTemplate string, cacheFolder string, strict bool,
 		schemaPathTemplate: schemaPathTemplate,
 		cache:              filecache,
 		strict:             strict,
+		debug:              debug,
 	}, nil
 }
 
@@ -71,21 +75,41 @@ func (r SchemaRegistry) DownloadSchema(resourceKind, resourceAPIVersion, k8sVers
 
 	resp, err := r.c.Get(url)
 	if err != nil {
-		return nil, fmt.Errorf("failed downloading schema at %s: %s", url, err)
+		msg := fmt.Sprintf("failed downloading schema at %s: %s", url, err)
+		if r.debug {
+			log.Println(msg)
+		}
+		return nil, errors.New(msg)
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode == http.StatusNotFound {
-		return nil, newNotFoundError(fmt.Errorf("no schema found"))
+		msg := fmt.Sprintf("could not find schema at %s", url)
+		if r.debug {
+			log.Print(msg)
+		}
+		return nil, newNotFoundError(errors.New(msg))
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("error while downloading schema at %s - received HTTP status %d", url, resp.StatusCode)
+		msg := fmt.Sprintf("error while downloading schema at %s - received HTTP status %d", url, resp.StatusCode)
+		if r.debug {
+			log.Print(msg)
+		}
+		return nil, fmt.Errorf(msg)
 	}
 
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
-		return nil, fmt.Errorf("failed downloading schema at %s: %s", url, err)
+		msg := fmt.Sprintf("failed parsing schema from %s: %s", url, err)
+		if r.debug {
+			log.Print(msg)
+		}
+		return nil, errors.New(msg)
+	}
+
+	if r.debug {
+		log.Printf("using schema found at %s", url)
 	}
 
 	if r.cache != nil {

pkg/registry/http_test.go

@@ -59,7 +59,7 @@ func TestDownloadSchema(t *testing.T) {
 			"v1",
 			"1.18.0",
 			nil,
-			fmt.Errorf("no schema found"),
+			fmt.Errorf("could not find schema at http://kubernetesjson.dev"),
 		},
 		{
 			"getting 503",

pkg/registry/local.go

@@ -1,21 +1,25 @@
 package registry
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 )
 
 type LocalRegistry struct {
 	pathTemplate string
 	strict       bool
+	debug        bool
 }
 
 // NewLocalSchemas creates a new "registry", that will serve schemas from files, given a list of schema filenames
-func newLocalRegistry(pathTemplate string, strict bool) (*LocalRegistry, error) {
+func newLocalRegistry(pathTemplate string, strict bool, debug bool) (*LocalRegistry, error) {
 	return &LocalRegistry{
 		pathTemplate,
 		strict,
+		debug,
 	}, nil
 }
 
@@ -28,16 +32,32 @@ func (r LocalRegistry) DownloadSchema(resourceKind, resourceAPIVersion, k8sVersi
 	f, err := os.Open(schemaFile)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return nil, newNotFoundError(fmt.Errorf("no schema found"))
+			msg := fmt.Sprintf("could not open file %s", schemaFile)
+			if r.debug {
+				log.Print(msg)
+			}
+			return nil, newNotFoundError(errors.New(msg))
 		}
-		return nil, fmt.Errorf("failed to open schema %s", schemaFile)
+
+		msg := fmt.Sprintf("failed to open schema at %s: %s", schemaFile, err)
+		if r.debug {
+			log.Print(msg)
+		}
+		return nil, errors.New(msg)
 	}
 
 	defer f.Close()
 	content, err := ioutil.ReadAll(f)
 	if err != nil {
+		msg := fmt.Sprintf("failed to read schema at %s: %s", schemaFile, err)
+		if r.debug {
+			log.Print(msg)
+		}
 		return nil, err
 	}
 
+	if r.debug {
+		log.Printf("using schema found at %s", schemaFile)
+	}
 	return content, nil
 }

pkg/registry/registry.go

@@ -81,7 +81,7 @@ func schemaPath(tpl, resourceKind, resourceAPIVersion, k8sVersion string, strict
 	return buf.String(), nil
 }
 
-func New(schemaLocation string, cache string, strict bool, skipTLS bool) (Registry, error) {
+func New(schemaLocation string, cache string, strict bool, skipTLS bool, debug bool) (Registry, error) {
 	if schemaLocation == "default" {
 		schemaLocation = "https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{ .NormalizedKubernetesVersion }}-standalone{{ .StrictSuffix }}/{{ .ResourceKind }}{{ .KindSuffix }}.json"
 	} else if !strings.HasSuffix(schemaLocation, "json") { // If we dont specify a full templated path, we assume the paths of our fork of kubernetes-json-schema
@@ -94,8 +94,8 @@ func New(schemaLocation string, cache string, strict bool, skipTLS bool) (Regist
 	}
 
 	if strings.HasPrefix(schemaLocation, "http") {
-		return newHTTPRegistry(schemaLocation, cache, strict, skipTLS)
+		return newHTTPRegistry(schemaLocation, cache, strict, skipTLS, debug)
 	}
 
-	return newLocalRegistry(schemaLocation, strict)
+	return newLocalRegistry(schemaLocation, strict, debug)
 }

pkg/validator/validator.go

@@ -43,6 +43,7 @@ type Validator interface {
 // Opts contains a set of options for the validator.
 type Opts struct {
 	Cache                string              // Cache schemas downloaded via HTTP to this folder
+	Debug                bool                // Debug infos will be print here
 	SkipTLS              bool                // skip TLS validation when downloading from an HTTP Schema Registry
 	SkipKinds            map[string]struct{} // List of resource Kinds to ignore
 	RejectKinds          map[string]struct{} // List of resource Kinds to reject
@@ -61,7 +62,7 @@ func New(schemaLocations []string, opts Opts) (Validator, error) {
 
 	registries := []registry.Registry{}
 	for _, schemaLocation := range schemaLocations {
-		reg, err := registry.New(schemaLocation, opts.Cache, opts.Strict, opts.SkipTLS)
+		reg, err := registry.New(schemaLocation, opts.Cache, opts.Strict, opts.SkipTLS, opts.Debug)
 		if err != nil {
 			return nil, err
 		}
@@ -249,11 +250,3 @@ func downloadSchema(registries []registry.Registry, kind, version, k8sVersion st
 
 	return nil, nil // No schema found - we don't consider it an error, resource will be skipped
 }
-
-// From kubeval - let's see if absolutely necessary
-// func init () {
-// 	gojsonschema.FormatCheckers.Add("int64", ValidFormat{})
-// 	gojsonschema.FormatCheckers.Add("byte", ValidFormat{})
-// 	gojsonschema.FormatCheckers.Add("int32", ValidFormat{})
-// 	gojsonschema.FormatCheckers.Add("int-or-string", ValidFormat{})
-// }