Added validation for extra field

For validation purpose, we are `gojsonschema` library and json schema for kedge file,
JSON schema are located in `pkg/validation` directory

pkg/cmd/commands.go

@@ -24,12 +24,44 @@ import (
 	"os/exec"
 	"path/filepath"
 
-	"github.com/kedgeproject/kedge/pkg/spec"
-
 	"github.com/ghodss/yaml"
+	"github.com/kedgeproject/kedge/pkg/spec"
+	"github.com/kedgeproject/kedge/pkg/validation"
 	"github.com/pkg/errors"
+	"github.com/xeipuuv/gojsonschema"
 )
 
+// https://github.com/xeipuuv/gojsonschema#formats
+type ValidFormat struct{}
+
+// IsFormat always returns true and meets the
+// gojsonschema.FormatChecker interface
+func (f ValidFormat) IsFormat(input interface{}) bool {
+	return true
+}
+
+// Based on https://stackoverflow.com/questions/40737122/convert-yaml-to-json-without-struct-golang
+// We unmarshal yaml into a value of type interface{},
+// go through the result recursively, and convert each encountered
+// map[interface{}]interface{} to a map[string]interface{} value
+// required to marshall to JSON.
+// Reference: https://github.com/garethr/kubeval/blob/master/kubeval/utils.go#L8
+func convertToStringKeys(i interface{}) interface{} {
+	switch x := i.(type) {
+	case map[interface{}]interface{}:
+		m2 := map[string]interface{}{}
+		for k, v := range x {
+			m2[k.(string)] = convertToStringKeys(v)
+		}
+		return m2
+	case []interface{}:
+		for i, v := range x {
+			x[i] = convertToStringKeys(v)
+		}
+	}
+	return i
+}
+
 // GenerateArtifacts either writes to file or uses kubectl/oc to deploy.
 // TODO: Refactor into two separate functions (remove `generate bool`).
 func CreateArtifacts(paths []string, generate bool, args ...string) error {
@@ -53,7 +85,8 @@ func CreateArtifacts(paths []string, generate bool, args ...string) error {
 		if err != nil {
 			return errors.Wrap(err, "failed to replace variables")
 		}
-
+		// Validate input kedge file
+		validate(input.data)
 		ros, includeResources, err := spec.CoreOperations(kedgeData)
 		if err != nil {
 			return errors.Wrap(err, "unable to perform controller operations")
@@ -180,3 +213,43 @@ func findAbsPath(baseFilePath, path string) string {
 	}
 	return filepath.Join(filepath.Dir(baseFilePath), path)
 }
+
+// validate function will validate input kedgefile against JSON schema provided in pkg/validation
+func validate(p []byte) {
+	var speco interface{}
+	err := yaml.Unmarshal(p, &speco)
+	if err != nil {
+		fmt.Printf("Error with Unmarhsalling")
+	}
+	body := convertToStringKeys(speco)
+	s := body.(map[string]interface{})
+	loader := gojsonschema.NewGoLoader(body)
+	if s["controller"] == nil {
+		s["controller"] = "deployment"
+	}
+
+	var schema gojsonschema.JSONLoader
+	// Depend on type of controller, we are fetching jsonschema stored in pkg/validation
+	if s["controller"] == "deployment" {
+		schema = gojsonschema.NewStringLoader(validation.DeploymentspecmodJson)
+	}
+	if s["controller"] == "job" {
+		schema = gojsonschema.NewStringLoader(validation.JobspecmodJson)
+	}
+
+	// Without forcing these types the schema fails to load
+	//Reference: https://github.com/xeipuuv/gojsonschema#formats
+	gojsonschema.FormatCheckers.Add("int64", ValidFormat{})
+	gojsonschema.FormatCheckers.Add("byte", ValidFormat{})
+	gojsonschema.FormatCheckers.Add("int32", ValidFormat{})
+	gojsonschema.FormatCheckers.Add("int-or-string", ValidFormat{})
+	result, err := gojsonschema.Validate(schema, loader)
+	if !result.Valid() {
+		fmt.Printf("The kedgefile is not valid. see errors :\n")
+		for _, err := range result.Errors() {
+			fmt.Printf("- %s\n", err)
+			// os.Exit(-1)
+		}
+	}
+
+}