Add CreateContextWithOptions for lintcontext

Allows users to provide options for creating lint context.

Related Issue: #141

Signed-off-by: Arvind Iyengar <arvind.iyengar@rancher.com>

pkg/lintcontext/context.go

@@ -5,6 +5,7 @@ import (
 
 	"golang.stackrox.io/kube-linter/internal/stringutils"
 	"golang.stackrox.io/kube-linter/pkg/k8sutil"
+	"helm.sh/helm/v3/pkg/cli/values"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )
@@ -77,7 +78,8 @@ type lintContextImpl struct {
 	objects        []Object
 	invalidObjects []InvalidObject
 
-	customDecoder runtime.Decoder
+	customDecoder     runtime.Decoder
+	helmValuesOptions values.Options
 }
 
 // Objects returns the (valid) objects loaded from this LintContext.
@@ -106,3 +108,10 @@ func newCtx(options Options) *lintContextImpl {
 		customDecoder: options.CustomDecoder,
 	}
 }
+
+func newHelmCtx(options Options, helmValueOptions values.Options) *lintContextImpl {
+	return &lintContextImpl{
+		customDecoder:     options.CustomDecoder,
+		helmValuesOptions: helmValueOptions,
+	}
+}

pkg/lintcontext/create_contexts.go

@@ -10,6 +10,7 @@ import (
 	"github.com/pkg/errors"
 	"golang.stackrox.io/kube-linter/internal/set"
 	"helm.sh/helm/v3/pkg/chartutil"
+	"helm.sh/helm/v3/pkg/cli/values"
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
@@ -36,6 +37,7 @@ func CreateContexts(filesOrDirs ...string) ([]LintContext, error) {
 // CreateContextsWithOptions creates a context with additional Options
 func CreateContextsWithOptions(options Options, filesOrDirs ...string) ([]LintContext, error) {
 	contextsByDir := make(map[string]*lintContextImpl)
+	contextsByChartDir := make(map[string][]LintContext)
 	for _, fileOrDir := range filesOrDirs {
 		// Stdin
 		if fileOrDir == "-" {
@@ -59,14 +61,17 @@ func CreateContextsWithOptions(options Options, filesOrDirs ...string) ([]LintCo
 				return nil
 			}
 
+			if _, exists := contextsByChartDir[currentPath]; exists {
+				return nil
+			}
+
 			if !info.IsDir() {
 				if strings.HasSuffix(strings.ToLower(currentPath), ".tgz") {
-					ctx := newCtx(options)
-					if err := ctx.loadObjectsFromTgzHelmChart(currentPath); err != nil {
+					lintCtxs, err := CreateHelmContextsWithOptions(HelmOptions{Options: options, FromArchive: true}, currentPath)
+					if err != nil {
 						return err
 					}
-
-					contextsByDir[currentPath] = ctx
+					contextsByChartDir[currentPath] = lintCtxs
 					return nil
 				}
 
@@ -85,15 +90,11 @@ func CreateContextsWithOptions(options Options, filesOrDirs ...string) ([]LintCo
 				return nil
 			}
 			if isHelm, _ := chartutil.IsChartDir(currentPath); isHelm {
-				// Path has already been loaded, possibly through another argument. Skip.
-				if _, alreadyExists := contextsByDir[currentPath]; alreadyExists {
-					return nil
-				}
-				ctx := newCtx(options)
-				contextsByDir[currentPath] = ctx
-				if err := ctx.loadObjectsFromHelmChart(currentPath); err != nil {
+				lintCtxs, err := CreateHelmContextsWithOptions(HelmOptions{Options: options, FromDir: true}, currentPath)
+				if err != nil {
 					return err
 				}
+				contextsByChartDir[currentPath] = lintCtxs
 				return filepath.SkipDir
 			}
 			return nil
@@ -102,24 +103,56 @@ func CreateContextsWithOptions(options Options, filesOrDirs ...string) ([]LintCo
 			return nil, errors.Wrapf(err, "loading from path %q", fileOrDir)
 		}
 	}
-	dirs := make([]string, 0, len(contextsByDir))
+	dirs := make([]string, 0, len(contextsByDir)+len(contextsByChartDir))
 	for dir := range contextsByDir {
 		dirs = append(dirs, dir)
 	}
+	for dir := range contextsByChartDir {
+		dirs = append(dirs, dir)
+	}
 	sort.Strings(dirs)
 	var contexts []LintContext
 	for _, dir := range dirs {
+		if helmCtxs, ok := contextsByChartDir[dir]; ok {
+			contexts = append(contexts, helmCtxs...)
+			continue
+		}
 		contexts = append(contexts, contextsByDir[dir])
 	}
 	return contexts, nil
 }
 
-// CreateContextsFromHelmArchive creates a context from TGZ reader of Helm Chart.
+// CreateContextsFromHelmArchive creates a context from a tgz file based on a provided tgzReader
 func CreateContextsFromHelmArchive(fileName string, tgzReader io.Reader) ([]LintContext, error) {
-	ctx := newCtx(Options{})
-	if err := ctx.readObjectsFromTgzHelmChart(fileName, tgzReader); err != nil {
-		return nil, err
-	}
+	return CreateHelmContextsWithOptions(HelmOptions{FromReader: tgzReader}, fileName)
+}
+
+type HelmOptions struct {
+	Options
 
-	return []LintContext{ctx}, nil
+	// HelmValuesOptions provide options for additional values.yamls that can be provided to Helm on loading a chart
+	// These will be ignored for contexts that are not Helm-based
+	HelmValuesOptions []values.Options
+
+	// Whether to treat this as a Helm chart directory
+	FromDir bool
+	// Whether to treat this as a Helm chart archive (tgz).
+	FromArchive bool
+	// FromReader is used if isDir and isArchive are both false
+	FromReader io.Reader
+}
+
+func CreateHelmContextsWithOptions(options HelmOptions, chartDir string) ([]LintContext, error) {
+	if isHelm, _ := chartutil.IsChartDir(chartDir); !isHelm {
+		return nil, errors.New("cannot generate helm context from non-helm dir " + chartDir)
+	}
+	contextsByHelmValues := []LintContext{}
+	for _, helmValueOptions := range options.HelmValuesOptions {
+		ctx := newHelmCtx(options.Options, helmValueOptions)
+		if err := ctx.loadObjectsFromHelmChart(chartDir, options); err != nil {
+			return nil, err
+		}
+		contextsByHelmValues = append(contextsByHelmValues, ctx)
+	}
+	return contextsByHelmValues, nil
 }

pkg/lintcontext/parse_helm.go

@@ -0,0 +1,79 @@
+package lintcontext
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/pkg/errors"
+	"helm.sh/helm/v3/pkg/chart"
+	"helm.sh/helm/v3/pkg/chart/loader"
+	"helm.sh/helm/v3/pkg/chartutil"
+	"helm.sh/helm/v3/pkg/engine"
+)
+
+func (l *lintContextImpl) loadObjectsFromHelmChart(path string, options HelmOptions) error {
+	metadata := ObjectMetadata{FilePath: path}
+	renderedFiles, err := l.renderHelmChart(path, options)
+	if err != nil {
+		l.addInvalidObjects(InvalidObject{Metadata: metadata, LoadErr: err})
+		return nil
+	}
+	for path, contents := range renderedFiles {
+		// The first element of path will be the same as the last element of dir, because
+		// Helm duplicates it.
+		pathToTemplate := filepath.Join(filepath.Dir(path), path)
+		if err := l.loadObjectsFromReader(pathToTemplate, strings.NewReader(contents)); err != nil {
+			return errors.Wrapf(err, "loading objects from rendered helm chart %s/%s", path, pathToTemplate)
+		}
+	}
+	return nil
+}
+
+func (l *lintContextImpl) renderHelmChart(path string, options HelmOptions) (map[string]string, error) {
+	// Helm doesn't have great logging behaviour, and can spam stderr, so silence their logging.
+	// TODO: capture these logs.
+	log.SetOutput(nopWriter{})
+	defer log.SetOutput(os.Stderr)
+
+	var chrt *chart.Chart
+	var err error
+	if options.FromDir && options.FromArchive {
+		err = errors.New("cannot specify that helm chart is both a directory and an archive")
+	} else if options.FromArchive {
+		chrt, err = loader.LoadFile(path)
+	} else if options.FromDir {
+		chrt, err = loader.Load(path)
+	} else {
+		chrt, err = loader.LoadArchive(options.FromReader)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if err := chrt.Validate(); err != nil {
+		return nil, err
+	}
+	values, err := l.helmValuesOptions.MergeValues(nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "loading provided Helm value options")
+	}
+
+	return l.renderValues(chrt, values)
+}
+
+func (l *lintContextImpl) renderValues(chrt *chart.Chart, values map[string]interface{}) (map[string]string, error) {
+	valuesToRender, err := chartutil.ToRenderValues(chrt, values, chartutil.ReleaseOptions{Name: "test-release", Namespace: "default"}, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	e := engine.Engine{LintMode: true}
+	rendered, err := e.Render(chrt, valuesToRender)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to render")
+	}
+
+	return rendered, nil
+}