Add report utils for gke-diagnoser to support json output

cmd/gke-diagnoser/app/util/report.go

@@ -0,0 +1,70 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"encoding/json"
+)
+
+const (
+	// Passed is the constant value for the Result field of a passed check
+	Passed string = "PASSED"
+	// Failed is the constant value for the Result field of a failed check
+	Failed string = "FAILED"
+	// Skipped is the constant value for the Result field of a skipped check
+	Skipped string = "SKIPPED"
+)
+
+const (
+	//JSONOutput is the constant value for output type JSON
+	JSONOutput string = "json"
+)
+
+// Report represents the final output of the analyzer
+type Report struct {
+	Resources []*Resource `json:"resources"`
+}
+
+// Resource represents the a resource of the cluster and all the checks done on it
+type Resource struct {
+	Kind      string   `json:"kind"`
+	Namespace string   `json:"namespace"`
+	Name      string   `json:"name"`
+	Checks    []*Check `json:"checks"`
+}
+
+// Check represents the result of a check
+type Check struct {
+	Name    string `json:"name"`
+	Message string `json:"message"`
+	Result  string `json:"result"`
+}
+
+func JsonReport(report *Report) (string, error) {
+	jsonRaw, err := json.MarshalIndent(report, "", "  ")
+	if err != nil {
+		return "", err
+	}
+	return string(jsonRaw), nil
+}
+
+// SupportedOutputs returns a string list of output formats supported by this package
+func SupportedOutputs() []string {
+	return []string{
+		JSONOutput,
+	}
+}