Feat: Support KRM input

cmd/kubeconform/main.go

@@ -1,14 +1,17 @@
 package main
 
 import (
+	"bufio"
 	"context"
 	"fmt"
 	"log"
 	"os"
 	"runtime"
 	"runtime/pprof"
+	"strings"
 	"sync"
 
+	"github.com/GoogleContainerTools/kpt-functions-sdk/go/fn"
 	"github.com/yannh/kubeconform/pkg/config"
 	"github.com/yannh/kubeconform/pkg/output"
 	"github.com/yannh/kubeconform/pkg/resource"
@@ -46,6 +49,26 @@ func processResults(cancel context.CancelFunc, o output.Output, validationResult
 	return result
 }
 
+func parseStdin(stdin *os.File) *strings.Reader {
+	var content string
+
+	// Read all stdin lines.
+	scanner := bufio.NewScanner(stdin)
+	for scanner.Scan() {
+		content += fmt.Sprintln(scanner.Text())
+	}
+
+	// Check if the stdin input is ResourceList.
+	rl, err := fn.ParseResourceList([]byte(content))
+	// If it's ResourceList, use the items as the new content.
+	if err == nil {
+		content = rl.Items.String()
+	}
+
+	// Convert the content which is type "string" to a "Reader" again.
+	return strings.NewReader(content)
+}
+
 func realMain() int {
 	cfg, out, err := config.FromFlags(os.Args[0], os.Args[1:])
 	if out != "" {
@@ -121,7 +144,7 @@ func realMain() int {
 	var resourcesChan <-chan resource.Resource
 	var errors <-chan error
 	if useStdin {
-		resourcesChan, errors = resource.FromStream(ctx, "stdin", os.Stdin)
+		resourcesChan, errors = resource.FromStream(ctx, "stdin", parseStdin(os.Stdin))
 	} else {
 		resourcesChan, errors = resource.FromFiles(ctx, cfg.Files, cfg.IgnoreFilenamePatterns)
 	}

fixtures/krm.yaml

@@ -0,0 +1,17 @@
+apiVersion: config.kubernetes.io/v1
+kind: ResourceList
+metadata:
+  name: krm-function-input
+items:
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: foo
+  data:
+    val: foo
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: bar
+  data:
+    val: bar

go.mod

@@ -3,10 +3,40 @@ module github.com/yannh/kubeconform
 go 1.17
 
 require (
-	github.com/beevik/etree v1.1.0
+	github.com/GoogleContainerTools/kpt-functions-sdk/go/fn v0.0.0-20221109010843-1f7d0c07a381
+	github.com/xeipuuv/gojsonschema v1.2.0
+	sigs.k8s.io/yaml v1.3.0
+)
+
+require (
+	github.com/GoogleContainerTools/kpt-functions-sdk/go/api v0.0.0-20220720212527-133180134b93 // indirect
+	github.com/PuerkitoBio/purell v1.1.1 // indirect
+	github.com/PuerkitoBio/urlesc v0.0.0-20170810143723-de5bf2ad4578 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-errors/errors v1.0.1 // indirect
+	github.com/go-logr/logr v1.2.0 // indirect
+	github.com/go-openapi/jsonpointer v0.19.5 // indirect
+	github.com/go-openapi/jsonreference v0.19.6 // indirect
+	github.com/go-openapi/swag v0.21.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/gnostic v0.5.7-v3refs // indirect
+	github.com/josharian/intern v1.0.0 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/monochromegane/go-gitignore v0.0.0-20200626010858-205db1a8cc00 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.8.0 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 // indirect
-	github.com/xeipuuv/gojsonschema v1.2.0
+	github.com/xlab/treeprint v1.1.0 // indirect
+	golang.org/x/net v0.0.0-20220722155237-a158d28d115b // indirect
+	golang.org/x/text v0.3.7 // indirect
+	google.golang.org/protobuf v1.28.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	sigs.k8s.io/yaml v1.2.0
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+	k8s.io/apimachinery v0.24.0 // indirect
+	k8s.io/klog/v2 v2.60.1 // indirect
+	k8s.io/kube-openapi v0.0.0-20220401212409-b28bf2818661 // indirect
+	sigs.k8s.io/kustomize/kyaml v0.13.7-0.20220418212550-9d5491c2e20c // indirect
 )