feat: add --lookup-resources flag for offline lookup in render/lint commands

cmd/nelm/chart_lint.go

@@ -175,6 +175,14 @@ func newChartLintCommand(ctx context.Context, afterAllCommandsBuiltFuncs map[*co
 			return fmt.Errorf("add flag: %w", err)
 		}
 
+		if err := cli.AddFlag(cmd, &cfg.LocalLookupResourcesPaths, "lookup-resources", nil, "Manifest files used as a cluster stub for the lookup template function in non-remote mode. Multi-document and kind:List supported", cli.AddFlagOptions{
+			GetEnvVarRegexesFunc: cli.GetFlagGlobalAndLocalMultiEnvVarRegexes,
+			Group:                mainFlagGroup,
+			Type:                 cli.FlagTypeFile,
+		}); err != nil {
+			return fmt.Errorf("add flag: %w", err)
+		}
+
 		if err := cli.AddFlag(cmd, &cfg.LocalKubeVersion, "kube-version", common.DefaultLocalKubeVersion, "Kubernetes version stub for non-remote mode", cli.AddFlagOptions{
 			Group: mainFlagGroup,
 		}); err != nil {

cmd/nelm/chart_render.go

@@ -157,6 +157,14 @@ func newChartRenderCommand(ctx context.Context, afterAllCommandsBuiltFuncs map[*
 			return fmt.Errorf("add flag: %w", err)
 		}
 
+		if err := cli.AddFlag(cmd, &cfg.LocalLookupResourcesPaths, "lookup-resources", nil, "Manifest files used as a cluster stub for the lookup template function in non-remote mode. Multi-document and kind:List supported", cli.AddFlagOptions{
+			GetEnvVarRegexesFunc: cli.GetFlagGlobalAndLocalMultiEnvVarRegexes,
+			Group:                mainFlagGroup,
+			Type:                 cli.FlagTypeFile,
+		}); err != nil {
+			return fmt.Errorf("add flag: %w", err)
+		}
+
 		if err := cli.AddFlag(cmd, &cfg.LocalKubeVersion, "kube-version", common.DefaultLocalKubeVersion, "Kubernetes version stub for non-remote mode", cli.AddFlagOptions{
 			Group: mainFlagGroup,
 		}); err != nil {

docs/reference.md

@@ -1891,6 +1891,10 @@ nelm chart lint [options...] [chart-dir]
 
   Kubernetes version stub for non\-remote mode\. Var: \$NELM\_CHART\_LINT\_KUBE\_VERSION
 
+- `--lookup-resources` (default: `[]`)
+
+  Manifest files used as a cluster stub for the lookup template function in non\-remote mode\. Multi\-document and kind:List supported\. Vars: \$NELM\_LOOKUP\_RESOURCES\_\*, \$NELM\_CHART\_LINT\_LOOKUP\_RESOURCES\_\*
+
 - `-n`, `--namespace` (default: `"stub-namespace"`)
 
   The release namespace\. Resources with no namespace will be deployed here\. Vars: \$NELM\_NAMESPACE, \$NELM\_CHART\_LINT\_NAMESPACE
@@ -2235,6 +2239,10 @@ nelm chart render [options...] [chart-dir]
 
   Kubernetes version stub for non\-remote mode\. Var: \$NELM\_CHART\_RENDER\_KUBE\_VERSION
 
+- `--lookup-resources` (default: `[]`)
+
+  Manifest files used as a cluster stub for the lookup template function in non\-remote mode\. Multi\-document and kind:List supported\. Vars: \$NELM\_LOOKUP\_RESOURCES\_\*, \$NELM\_CHART\_RENDER\_LOOKUP\_RESOURCES\_\*
+
 - `-n`, `--namespace` (default: `"stub-namespace"`)
 
   The release namespace\. Resources with no namespace will be deployed here\. Vars: \$NELM\_NAMESPACE, \$NELM\_CHART\_RENDER\_NAMESPACE

pkg/action/chart_lint.go

@@ -94,6 +94,12 @@ type ChartLintOptions struct {
 	// LocalKubeVersion specifies the Kubernetes version to use for linting when not connected to a cluster.
 	// Format: "major.minor.patch" (e.g., "1.28.0"). Defaults to DefaultLocalKubeVersion if not set.
 	LocalKubeVersion string
+	// LocalLookupResourcesPaths are paths to YAML or JSON manifest files whose resources the "lookup"
+	// template function resolves against in local mode (Remote=false), instead of a live cluster.
+	// Each file may hold multiple documents separated by "---" and/or a kind: List (or typed *List)
+	// wrapper whose items are expanded; a bare top-level JSON array is not supported. Duplicate
+	// resources are rejected. Not allowed together with Remote.
+	LocalLookupResourcesPaths []string
 	// NetworkParallelism limits the number of concurrent network-related operations (API calls, resource fetches).
 	// Defaults to DefaultNetworkParallelism if not set or <= 0.
 	NetworkParallelism int
@@ -151,6 +157,10 @@ func ChartLint(ctx context.Context, opts ChartLintOptions) error {
 		lo.Must0(os.Setenv("WERF_SECRET_KEY", opts.SecretKey))
 	}
 
+	if opts.Remote && len(opts.LocalLookupResourcesPaths) > 0 {
+		return fmt.Errorf("local lookup resources are not allowed together with remote mode")
+	}
+
 	if !opts.Remote {
 		opts.ReleaseStorageDriver = common.ReleaseStorageDriverMemory
 	}
@@ -266,6 +276,7 @@ func ChartLint(ctx context.Context, opts ChartLintOptions) error {
 		ExtraAPIVersions:           opts.ExtraAPIVersions,
 		HelmOptions:                helmOptions,
 		LocalKubeVersion:           opts.LocalKubeVersion,
+		LocalLookupResourcesPaths:  opts.LocalLookupResourcesPaths,
 		Remote:                     opts.Remote,
 		TemplatesAllowDNS:          opts.TemplatesAllowDNS,
 		TempDirPath:                opts.TempDirPath,

pkg/action/chart_render.go

@@ -91,6 +91,12 @@ type ChartRenderOptions struct {
 	// LocalKubeVersion specifies the Kubernetes version to use for template rendering when not connected to a cluster.
 	// Format: "major.minor.patch" (e.g., "1.28.0"). Defaults to DefaultLocalKubeVersion if not set.
 	LocalKubeVersion string
+	// LocalLookupResourcesPaths are paths to YAML or JSON manifest files whose resources the "lookup"
+	// template function resolves against in local mode (Remote=false), instead of a live cluster.
+	// Each file may hold multiple documents separated by "---" and/or a kind: List (or typed *List)
+	// wrapper whose items are expanded; a bare top-level JSON array is not supported. Duplicate
+	// resources are rejected. Not allowed together with Remote.
+	LocalLookupResourcesPaths []string
 	// NetworkParallelism limits the number of concurrent network-related operations (API calls, resource fetches).
 	// Defaults to DefaultNetworkParallelism if not set or <= 0.
 	NetworkParallelism int
@@ -158,6 +164,10 @@ func ChartRender(ctx context.Context, opts ChartRenderOptions) (*ChartRenderResu
 		lo.Must0(os.Setenv("WERF_SECRET_KEY", opts.SecretKey))
 	}
 
+	if opts.Remote && len(opts.LocalLookupResourcesPaths) > 0 {
+		return nil, fmt.Errorf("local lookup resources are not allowed together with remote mode")
+	}
+
 	if !opts.Remote {
 		opts.ReleaseStorageDriver = common.ReleaseStorageDriverMemory
 	}
@@ -269,6 +279,7 @@ func ChartRender(ctx context.Context, opts ChartRenderOptions) (*ChartRenderResu
 		ExtraAPIVersions:           opts.ExtraAPIVersions,
 		HelmOptions:                helmOptions,
 		LocalKubeVersion:           opts.LocalKubeVersion,
+		LocalLookupResourcesPaths:  opts.LocalLookupResourcesPaths,
 		Remote:                     opts.Remote,
 		TemplatesAllowDNS:          opts.TemplatesAllowDNS,
 		TempDirPath:                opts.TempDirPath,

pkg/chart/chart_render.go

@@ -14,7 +14,10 @@ import (
 
 	"github.com/goccy/go-yaml"
 	"github.com/samber/lo"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/discovery"
+	"k8s.io/client-go/kubernetes/scheme"
 
 	"github.com/werf/nelm/pkg/common"
 	"github.com/werf/nelm/pkg/featgate"
@@ -34,6 +37,7 @@ import (
 	"github.com/werf/nelm/pkg/helm/pkg/werf/helmopts"
 	"github.com/werf/nelm/pkg/kube"
 	"github.com/werf/nelm/pkg/log"
+	"github.com/werf/nelm/pkg/lookup"
 	"github.com/werf/nelm/pkg/resource/spec"
 	"github.com/werf/nelm/pkg/ts"
 )
@@ -42,20 +46,21 @@ type RenderChartOptions struct {
 	common.ChartRepoConnectionOptions
 	common.ValuesOptions
 
-	ChartProvenanceKeyring  string
-	ChartProvenanceStrategy string
-	ChartRepoNoUpdate       bool
-	ChartVersion            string
-	DenoBinaryPath          string
-	ExtraAPIVersions        []string
-	HelmOptions             helmopts.HelmOptions
-	IgnoreBundleJS          bool
-	LocalKubeVersion        string
-	NoStandaloneCRDs        bool
-	Remote                  bool
-	SubchartNotes           bool
-	TempDirPath             string
-	TemplatesAllowDNS       bool
+	ChartProvenanceKeyring    string
+	ChartProvenanceStrategy   string
+	ChartRepoNoUpdate         bool
+	ChartVersion              string
+	DenoBinaryPath            string
+	ExtraAPIVersions          []string
+	HelmOptions               helmopts.HelmOptions
+	IgnoreBundleJS            bool
+	LocalKubeVersion          string
+	LocalLookupResourcesPaths []string
+	NoStandaloneCRDs          bool
+	Remote                    bool
+	SubchartNotes             bool
+	TempDirPath               string
+	TemplatesAllowDNS         bool
 }
 
 type RenderChartResult struct {
@@ -195,7 +200,15 @@ func RenderChart(ctx context.Context, chartPath, releaseName, releaseNamespace s
 	if opts.Remote && clientFactory.KubeClient() != nil {
 		engine = lo.ToPtr(helmengine.New(clientFactory.KubeConfig().RestConfig))
 	} else {
-		engine = lo.ToPtr(helmengine.Engine{})
+		engine = &helmengine.Engine{}
+		if len(opts.LocalLookupResourcesPaths) > 0 {
+			localLookupResources, err := parseLocalLookupResources(opts.LocalLookupResourcesPaths)
+			if err != nil {
+				return nil, fmt.Errorf("parse local lookup resources: %w", err)
+			}
+
+			engine.SetClientProvider(lookup.NewLocalClientProvider(localLookupResources))
+		}
 	}
 
 	engine.EnableDNS = opts.TemplatesAllowDNS
@@ -272,6 +285,57 @@ func RenderChart(ctx context.Context, chartPath, releaseName, releaseNamespace s
 	}, nil
 }
 
+func parseLocalLookupResources(paths []string) ([]*unstructured.Unstructured, error) {
+	var resources []*unstructured.Unstructured
+
+	seen := make(map[string]bool)
+
+	for _, filePath := range paths {
+		content, err := os.ReadFile(filePath)
+		if err != nil {
+			return nil, fmt.Errorf("read file %q: %w", filePath, err)
+		}
+
+		for i, manifest := range releaseutil.SplitManifestsToSlice(string(content)) {
+			obj, _, err := scheme.Codecs.UniversalDecoder().Decode([]byte(manifest), nil, &unstructured.Unstructured{})
+			if err != nil {
+				return nil, fmt.Errorf("decode resource #%d for %q: %w", i+1, filePath, err)
+			}
+
+			unstruct := obj.(*unstructured.Unstructured)
+
+			if unstruct.IsList() {
+				item := 0
+
+				if err := unstruct.EachListItem(func(o runtime.Object) error {
+					res, err := collectLocalLookupResource(o.(*unstructured.Unstructured), seen)
+					if err != nil {
+						return err
+					}
+
+					item++
+					resources = append(resources, res)
+
+					return nil
+				}); err != nil {
+					return nil, fmt.Errorf("collect resource #%d for %q (item %d): %w", i+1, filePath, item, err)
+				}
+
+				continue
+			}
+
+			res, err := collectLocalLookupResource(unstruct, seen)
+			if err != nil {
+				return nil, fmt.Errorf("collect resource #%d for %q: %w", i+1, filePath, err)
+			}
+
+			resources = append(resources, res)
+		}
+	}
+
+	return resources, nil
+}
+
 func buildChartCapabilities(ctx context.Context, clientFactory kube.ClientFactorier, opts buildChartCapabilitiesOptions) (*chartutil.Capabilities, error) {
 	capabilities := &chartutil.Capabilities{
 		HelmVersion: chartutil.DefaultCapabilities.HelmVersion,
@@ -366,6 +430,23 @@ func buildContextFromJSONSets(jsonSets []string) (map[string]interface{}, error)
 	return context, nil
 }
 
+func collectLocalLookupResource(unstruct *unstructured.Unstructured, seen map[string]bool) (*unstructured.Unstructured, error) {
+	if unstruct.GetAPIVersion() == "" {
+		return nil, fmt.Errorf("apiVersion is missing")
+	}
+
+	gvk := unstruct.GroupVersionKind()
+	id := spec.IDWithVersion(unstruct.GetName(), unstruct.GetNamespace(), gvk.Group, gvk.Version, gvk.Kind)
+
+	if seen[id] {
+		return nil, fmt.Errorf("duplicate resource %s", spec.IDHuman(unstruct.GetName(), unstruct.GetNamespace(), gvk.Group, gvk.Kind))
+	}
+
+	seen[id] = true
+
+	return unstruct, nil
+}
+
 func isLocalChart(path string) bool {
 	return filepath.IsAbs(path) || filepath.HasPrefix(path, "..") || filepath.HasPrefix(path, ".")
 }