Adding -json flag to output results to stdout in JSON format (#147)

* Adding -json flag to output results to stdout in JSON format

* Updating user guide README

* Fixing userguide MD format

* Removig trailing space

docs/user-guide.md

@@ -287,6 +287,19 @@ policyExclusions:
 The GKE Policy Automation tool produces cluster validation results to the stderr, local JSON file,
 file on a GCS bucket and Pub/Sub topic.
 
+### Console JSON output
+
+The validation results can be displayed in the console standard output in a JSON format using the
+```-json``` flag.
+
+Example of enabling JSON standard output in a command line:
+
+```sh
+  ./gke-policy check \
+  --project my-project --location europe-west2 --name my-cluster \
+  -json
+```
+
 ### Local JSON file
 
 The validation results can be stored in the local file in a JSON format.

internal/app/app.go

@@ -119,6 +119,12 @@ func (p *PolicyAutomationApp) LoadConfig(config *cfg.Config) (err error) {
 	if !p.config.SilentMode {
 		p.out = outputs.NewStdOutOutput()
 		p.collectors = []outputs.ValidationResultCollector{outputs.NewConsoleResultCollector(p.out)}
+
+		if p.config.JsonOutput {
+			p.out = outputs.NewSilentOutput()
+			p.collectors = []outputs.ValidationResultCollector{outputs.NewConsoleJsonResultCollector(outputs.NewStdOutOutput())}
+		}
+
 		p.clusterDumpCollectors = append(p.clusterDumpCollectors, outputs.NewOutputClusterDumpCollector(p.out))
 	}
 	if p.config.DumpFile != "" {
@@ -351,6 +357,7 @@ func newConfigFromFile(path string) (*cfg.Config, error) {
 func newConfigFromCli(cliConfig *CliConfig) *cfg.Config {
 	config := &cfg.Config{}
 	config.SilentMode = cliConfig.SilentMode
+	config.JsonOutput = cliConfig.JsonOutput
 	config.K8SApiConfig.Enabled = cliConfig.K8SCheck
 	config.CredentialsFile = cliConfig.CredentialsFile
 	config.DumpFile = cliConfig.DumpFile

internal/app/app_test.go

@@ -165,6 +165,7 @@ func TestLoadConfig(t *testing.T) {
 func TestNewConfigFromCli(t *testing.T) {
 	input := &CliConfig{
 		SilentMode:      true,
+		JsonOutput:      true,
 		CredentialsFile: "/path/to/creds.json",
 		ClusterName:     "testCluster",
 		ClusterLocation: "europe-central2",
@@ -177,6 +178,9 @@ func TestNewConfigFromCli(t *testing.T) {
 	if config.SilentMode != input.SilentMode {
 		t.Errorf("silentMode = %v; want %v", config.SilentMode, input.SilentMode)
 	}
+	if config.JsonOutput != input.JsonOutput {
+		t.Errorf("jsonOutput = %v; want %v", config.JsonOutput, input.JsonOutput)
+	}
 	if config.CredentialsFile != input.CredentialsFile {
 		t.Errorf("credentialsFile = %v; want %v", config.CredentialsFile, input.CredentialsFile)
 	}

internal/app/cli.go

@@ -22,6 +22,7 @@ import (
 type CliConfig struct {
 	ConfigFile          string
 	SilentMode          bool
+	JsonOutput          bool
 	K8SCheck            bool
 	CredentialsFile     string
 	DumpFile            string
@@ -267,6 +268,11 @@ func getOutputFlags(config *CliConfig) []cli.Flag {
 			Usage:       "Path to the file for storing results",
 			Destination: &config.OutputFile,
 		},
+		&cli.BoolFlag{
+			Name:        "json",
+			Usage:       "Outputs results to standard console in JSON format",
+			Destination: &config.JsonOutput,
+		},
 	}
 }
 

internal/config/config.go

@@ -39,6 +39,7 @@ type ValidateConfig func(config Config) error
 
 type Config struct {
 	SilentMode       bool                   `yaml:"silent"`
+	JsonOutput       bool                   `yaml:"jsonOutput"`
 	DumpFile         string                 `yaml:"dumpFile"`
 	CredentialsFile  string                 `yaml:"credentialsFile"`
 	Clusters         []ConfigCluster        `yaml:"clusters"`

internal/outputs/console_json_collector.go

@@ -0,0 +1,52 @@
+// Copyright 2022 Google LLC
+//
+// 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
+//
+//      https://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 outputs
+
+import (
+	"github.com/google/gke-policy-automation/internal/policy"
+)
+
+type consoleJsonResultCollector struct {
+	out          *Output
+	reportMapper ValidationReportMapper
+}
+
+func NewConsoleJsonResultCollector(output *Output) ValidationResultCollector {
+	return &consoleJsonResultCollector{
+		out:          output,
+		reportMapper: NewValidationReportMapper(),
+	}
+}
+
+func (p *consoleJsonResultCollector) RegisterResult(results []*policy.PolicyEvaluationResult) error {
+	p.reportMapper.AddResults(results)
+	return nil
+}
+
+func (p *consoleJsonResultCollector) Close() error {
+
+	jsonResult, err := p.reportMapper.GetJsonReport()
+
+	if err != nil {
+		return err
+	}
+
+	p.out.Printf(string(jsonResult))
+	return nil
+}
+
+func (p *consoleJsonResultCollector) Name() string {
+	return "console json"
+}

internal/outputs/console_json_collector_test.go

@@ -0,0 +1,51 @@
+// Copyright 2022 Google LLC
+//
+// 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
+//
+//      https://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 outputs
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/google/gke-policy-automation/internal/policy"
+)
+
+func TestConsoleJsonResultCollector(t *testing.T) {
+	var buff bytes.Buffer
+	var expectedJson = "json string"
+
+	out := &Output{w: &buff}
+	reportMapperMock := &validationReportMapperMock{
+		addResultsFn: func(results []*policy.PolicyEvaluationResult) {},
+		getJsonReportFn: func() ([]byte, error) {
+			return []byte(expectedJson), nil
+		},
+	}
+
+	collector := &consoleJsonResultCollector{out: out, reportMapper: reportMapperMock}
+	err := collector.RegisterResult([]*policy.PolicyEvaluationResult{{}})
+	if err != nil {
+		t.Fatalf("err on RegisterResult = %v; want nil", err)
+	}
+	err = collector.Close()
+	if err != nil {
+		t.Fatalf("err on Close = %v; want nil", err)
+	}
+	if len(buff.String()) <= 0 {
+		t.Errorf("nothing was written to the output buffer")
+	}
+	if buff.String() != expectedJson {
+		t.Errorf("expected \"%v\" but buffer was \"%v\"", expectedJson, buff.String())
+	}
+}