Support read yaml contents of workload from stdin (#353)

docs/usage.md

@@ -149,6 +149,7 @@ Both the dashboard and audits can run against a local directory or YAML file
 rather than a cluster:
 ```bash
 polaris audit --audit-path ./deploy/
+cat pod.yaml | polaris audit --audit-path -
 ```
 
 #### Running with CI/CD

pkg/kube/resources.go

@@ -3,6 +3,7 @@ package kube
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -61,8 +62,14 @@ func CreateResourceProviderFromPath(directory string) (*ResourceProvider, error)
 		Controllers:   []GenericWorkload{},
 	}
 
-	addYaml := func(contents string) error {
-		return addResourceFromString(contents, &resources)
+	if directory == "-" {
+		fi, err := os.Stdin.Stat()
+		if err == nil && fi.Mode()&os.ModeNamedPipe == os.ModeNamedPipe {
+			if err := addResourcesFromReader(os.Stdin, &resources); err != nil {
+				return nil, err
+			}
+			return &resources, nil
+		}
 	}
 
 	visitFile := func(path string, f os.FileInfo, err error) error {
@@ -74,18 +81,7 @@ func CreateResourceProviderFromPath(directory string) (*ResourceProvider, error)
 			logrus.Errorf("Error reading file: %v", path)
 			return err
 		}
-		specs := regexp.MustCompile("[\r\n]-+[\r\n]").Split(string(contents), -1)
-		for _, spec := range specs {
-			if strings.TrimSpace(spec) == "" {
-				continue
-			}
-			err = addYaml(spec)
-			if err != nil {
-				logrus.Errorf("Error parsing YAML: (%v)", err)
-				return err
-			}
-		}
-		return nil
+		return addResourcesFromYaml(string(contents), &resources)
 	}
 
 	err := filepath.Walk(directory, visitFile)
@@ -234,6 +230,33 @@ func GetPodSpec(yaml map[string]interface{}) interface{} {
 	return nil
 }
 
+func addResourcesFromReader(reader io.Reader, resources *ResourceProvider) error {
+	contents, err := ioutil.ReadAll(reader)
+	if err != nil {
+		logrus.Errorf("Error reading from %v: %v", reader, err)
+		return err
+	}
+	if err := addResourcesFromYaml(string(contents), resources); err != nil {
+		return err
+	}
+	return nil
+}
+
+func addResourcesFromYaml(contents string, resources *ResourceProvider) error {
+	specs := regexp.MustCompile("[\r\n]-+[\r\n]").Split(string(contents), -1)
+	for _, spec := range specs {
+		if strings.TrimSpace(spec) == "" {
+			continue
+		}
+		err := addResourceFromString(spec, resources)
+		if err != nil {
+			logrus.Errorf("Error parsing YAML: (%v)", err)
+			return err
+		}
+	}
+	return nil
+}
+
 func addResourceFromString(contents string, resources *ResourceProvider) error {
 	contentBytes := []byte(contents)
 	decoder := k8sYaml.NewYAMLOrJSONDecoder(bytes.NewReader(contentBytes), 1000)

pkg/kube/resources_test.go

@@ -1,11 +1,14 @@
 package kube
 
 import (
+	"bytes"
+	"io/ioutil"
 	"testing"
 	"time"
 
 	"github.com/fairwindsops/polaris/test"
 	"github.com/stretchr/testify/assert"
+	corev1 "k8s.io/api/core/v1"
 )
 
 func TestGetResourcesFromPath(t *testing.T) {
@@ -57,6 +60,31 @@ func TestGetMultipleResourceFromBadFile(t *testing.T) {
 	assert.NotEqual(t, nil, err, "CreateResource From Path should fail with bad yaml")
 }
 
+func TestAddResourcesFromReader(t *testing.T) {
+	contents, err := ioutil.ReadFile("./test_files/test_2/multi.yaml")
+	assert.NoError(t, err)
+	reader := bytes.NewBuffer(contents)
+	resources := &ResourceProvider{
+		ServerVersion: "unknown",
+		SourceType:    "Path",
+		SourceName:    "-",
+		Nodes:         []corev1.Node{},
+		Namespaces:    []corev1.Namespace{},
+		Controllers:   []GenericWorkload{},
+	}
+	err = addResourcesFromReader(reader, resources)
+	assert.NoError(t, err)
+
+	assert.Equal(t, 0, len(resources.Nodes), "Should not have any nodes")
+
+	assert.Equal(t, 1, len(resources.Controllers), "Should have one controller")
+	assert.Equal(t, "dashboard", resources.Controllers[0].PodSpec.Containers[0].Name)
+
+	assert.Equal(t, 2, len(resources.Namespaces), "Should have a namespace")
+	assert.Equal(t, "polaris", resources.Namespaces[0].ObjectMeta.Name)
+	assert.Equal(t, "polaris-2", resources.Namespaces[1].ObjectMeta.Name)
+}
+
 func TestGetResourceFromAPI(t *testing.T) {
 	k8s, dynamicInterface := test.SetupTestAPI()
 	k8s = test.SetupAddControllers(k8s, "test")