feat: custom resource links

README.md

@@ -636,6 +636,52 @@ views:
 
 ---
 
+## Custom Resource Links
+
+You can change the behaviour of an `<ENTER>` keypress on resources defined by yourself. K9S will prepare selectors using your configuration and show you a browser with selected resources.
+The configuration of custom resource links leverages GVR (Group/Version/Resource) to configure the associated links. If no GVR is found for a view the default rendering will take over (ie what we have now).
+
+There are two types of selectors: `fieldSelector` and `labelSelector`. Both of them are optional and can be used together.
+The `fieldSelector` is used to filter resources by a fields, and the `labelSelector` is used to filter resources by a labels.
+The value of the `fieldSelector` and `labelSelector` is a JSONPath expression executed on the selected resource.
+
+For example, you can define a custom resource link for ExternalSecrets - `<ENTER>` keypress on ExternalSecrets will show your browser with target secret.
+
+```yaml
+k9s:
+  customResourceLinks:
+    external-secrets.io/v1beta1/externalsecrets:
+      target: v1/secrets
+      fieldSelector:
+        # key defines target field to filter
+        # value defines source field to filter (JSONPath executed on selected resource)
+        metadata.name: .spec.target.name
+```
+
+Or if you're using `cluster.k8s.io` resources, you can define a custom resource link to show pods on the machine:
+
+```yaml
+k9s:
+  customResourceLinks:
+    cluster.k8s.io/v1alpha1/machines:
+      target: v1/pods
+      fieldSelector:
+        spec.nodeName: .metadata.name
+```
+
+If you're running your own k8s operator which is spawning jobs for you, you can select pods from your custom resources:
+
+```yaml
+k9s:
+  customResourceLinks:
+    any.io/v1/customresources:
+      target: v1/pods
+      labelSelector:
+        batch.kubernetes.io/job-name: .metadata.name
+```
+
+---
+
 ## Plugins
 
 K9s allows you to extend your command line and tooling by defining your very own cluster commands via plugins. K9s will look at `$XDG_CONFIG_HOME/k9s/plugins.yaml` to locate all available plugins.
@@ -951,6 +997,7 @@ k9s:
     memory:
       critical: 90
       warn: 70
+  customResourceLinks: {}
 ```
 
 ```yaml

internal/config/json/schemas/k9s.json

@@ -125,6 +125,21 @@
               }
             }
           }
+        },
+        "customResourceLinks":{
+          "type": "object",
+          "additionalProperties": {
+              "type": "object",
+              "properties": {
+                "target": {"type": "string"},
+                "labelSelector": {
+                  "type": "object",
+                  "additionalItems": {
+                    "type": "string"
+                  }
+                }
+              }
+          }
         }
       }
     }

internal/config/k9s.go

@@ -15,19 +15,20 @@ import (
 
 // K9s tracks K9s configuration options.
 type K9s struct {
-	LiveViewAutoRefresh bool       `json:"liveViewAutoRefresh" yaml:"liveViewAutoRefresh"`
-	ScreenDumpDir       string     `json:"screenDumpDir" yaml:"screenDumpDir,omitempty"`
-	RefreshRate         int        `json:"refreshRate" yaml:"refreshRate"`
-	MaxConnRetry        int        `json:"maxConnRetry" yaml:"maxConnRetry"`
-	ReadOnly            bool       `json:"readOnly" yaml:"readOnly"`
-	NoExitOnCtrlC       bool       `json:"noExitOnCtrlC" yaml:"noExitOnCtrlC"`
-	UI                  UI         `json:"ui" yaml:"ui"`
-	SkipLatestRevCheck  bool       `json:"skipLatestRevCheck" yaml:"skipLatestRevCheck"`
-	DisablePodCounting  bool       `json:"disablePodCounting" yaml:"disablePodCounting"`
-	ShellPod            ShellPod   `json:"shellPod" yaml:"shellPod"`
-	ImageScans          ImageScans `json:"imageScans" yaml:"imageScans"`
-	Logger              Logger     `json:"logger" yaml:"logger"`
-	Thresholds          Threshold  `json:"thresholds" yaml:"thresholds"`
+	LiveViewAutoRefresh bool                `json:"liveViewAutoRefresh" yaml:"liveViewAutoRefresh"`
+	ScreenDumpDir       string              `json:"screenDumpDir" yaml:"screenDumpDir,omitempty"`
+	RefreshRate         int                 `json:"refreshRate" yaml:"refreshRate"`
+	MaxConnRetry        int                 `json:"maxConnRetry" yaml:"maxConnRetry"`
+	ReadOnly            bool                `json:"readOnly" yaml:"readOnly"`
+	NoExitOnCtrlC       bool                `json:"noExitOnCtrlC" yaml:"noExitOnCtrlC"`
+	UI                  UI                  `json:"ui" yaml:"ui"`
+	SkipLatestRevCheck  bool                `json:"skipLatestRevCheck" yaml:"skipLatestRevCheck"`
+	DisablePodCounting  bool                `json:"disablePodCounting" yaml:"disablePodCounting"`
+	ShellPod            ShellPod            `json:"shellPod" yaml:"shellPod"`
+	ImageScans          ImageScans          `json:"imageScans" yaml:"imageScans"`
+	Logger              Logger              `json:"logger" yaml:"logger"`
+	Thresholds          Threshold           `json:"thresholds" yaml:"thresholds"`
+	CustomResourceLinks CustomResourceLinks `yaml:"customResourceLinks,omitempty"`
 	manualRefreshRate   int
 	manualHeadless      *bool
 	manualLogoless      *bool
@@ -46,16 +47,17 @@ type K9s struct {
 // NewK9s create a new K9s configuration.
 func NewK9s(conn client.Connection, ks data.KubeSettings) *K9s {
 	return &K9s{
-		RefreshRate:   defaultRefreshRate,
-		MaxConnRetry:  defaultMaxConnRetry,
-		ScreenDumpDir: AppDumpsDir,
-		Logger:        NewLogger(),
-		Thresholds:    NewThreshold(),
-		ShellPod:      NewShellPod(),
-		ImageScans:    NewImageScans(),
-		dir:           data.NewDir(AppContextsDir),
-		conn:          conn,
-		ks:            ks,
+		RefreshRate:         defaultRefreshRate,
+		MaxConnRetry:        defaultMaxConnRetry,
+		ScreenDumpDir:       AppDumpsDir,
+		Logger:              NewLogger(),
+		Thresholds:          NewThreshold(),
+		ShellPod:            NewShellPod(),
+		ImageScans:          NewImageScans(),
+		CustomResourceLinks: NewCustomResourceLinks(),
+		dir:                 data.NewDir(AppContextsDir),
+		conn:                conn,
+		ks:                  ks,
 	}
 }
 
@@ -102,6 +104,7 @@ func (k *K9s) Merge(k1 *K9s) {
 	if k1.Thresholds != nil {
 		k.Thresholds = k1.Thresholds
 	}
+	k.CustomResourceLinks = k1.CustomResourceLinks
 }
 
 // AppScreenDumpDir fetch screen dumps dir.

internal/config/resource_link.go

@@ -0,0 +1,17 @@
+package config
+
+type CustomResourceLinks map[string]*CustomResourceLink
+
+func NewCustomResourceLinks() CustomResourceLinks {
+	return CustomResourceLinks{}
+}
+
+// CustomResourceLink tracks K9s CustomResourceLink configuration.
+type CustomResourceLink struct {
+	// Target represents the target GVR to open when activating a custom resource link.
+	Target string `yaml:"target"`
+	// LabelSelector defines keys (=target label) and values (=json path) to extract from the current resource.
+	LabelSelector map[string]string `yaml:"labelSelector,omitempty"`
+	// FieldSelector defines keys (=target field) and values (=json path) to extract from the current resource.
+	FieldSelector map[string]string `yaml:"fieldSelector,omitempty"`
+}

internal/dao/table.go

@@ -48,6 +48,8 @@ func (t *Table) Get(ctx context.Context, path string) (runtime.Object, error) {
 // List all Resources in a given namespace.
 func (t *Table) List(ctx context.Context, ns string) ([]runtime.Object, error) {
 	labelSel, _ := ctx.Value(internal.KeyLabels).(string)
+	fieldSel, _ := ctx.Value(internal.KeyFields).(string)
+
 	a := fmt.Sprintf(gvFmt, metav1.SchemeGroupVersion.Version, metav1.GroupName)
 	_, codec := t.codec()
 
@@ -59,7 +61,7 @@ func (t *Table) List(ctx context.Context, ns string) ([]runtime.Object, error) {
 		SetHeader("Accept", a).
 		Namespace(ns).
 		Resource(t.gvr.R()).
-		VersionedParams(&metav1.ListOptions{LabelSelector: labelSel}, codec).
+		VersionedParams(&metav1.ListOptions{LabelSelector: labelSel, FieldSelector: fieldSel}, codec).
 		Do(ctx).Get()
 	if err != nil {
 		return nil, err

internal/view/browser.go

@@ -6,6 +6,13 @@ package view
 import (
 	"context"
 	"fmt"
+	"github.com/derailed/k9s/internal/view/cmd"
+	"k8s.io/apimachinery/pkg/fields"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/selection"
+	"k8s.io/client-go/util/jsonpath"
+	"reflect"
 	"sort"
 	"strconv"
 	"strings"
@@ -79,6 +86,11 @@ func (b *Browser) Init(ctx context.Context) error {
 		return err
 	}
 
+	if target, found := b.App().Config.K9s.CustomResourceLinks[b.GVR().String()]; found {
+		log.Info().Msgf("Enabling custom resource link from %s to %s", b.GVR().String(), target.Target)
+		b.enterFn = b.showLinkedCustomResources
+	}
+
 	b.setNamespace(ns)
 	row, _ := b.GetSelection()
 	if row == 0 && b.GetRowCount() > 0 {
@@ -601,3 +613,129 @@ func (b *Browser) resourceDelete(selections []string, msg string) {
 	}
 	dialog.ShowDelete(b.app.Styles.Dialog(), b.app.Content.Pages, msg, okFn, func() {})
 }
+
+func (b *Browser) showLinkedCustomResources(app *App, tabular ui.Tabular, gvr client.GVR, path string) {
+	gvrValue := gvr.String()
+
+	o, err := app.factory.Get(gvrValue, path, true, labels.Everything())
+	if err != nil {
+		app.Flash().Err(err)
+		return
+	}
+
+	resourceLink, ok := app.Config.K9s.CustomResourceLinks[gvrValue]
+
+	if !ok {
+		b.app.Flash().Errf("Custom resource link for resource %s not found", gvrValue)
+		return
+	}
+
+	extractFromObject := func(sourceField string) ([]string, error) {
+		parser := jsonpath.New("labelSelector").AllowMissingKeys(true)
+		parser.EnableJSONOutput(true)
+		fullPath := fmt.Sprintf("{%s}", sourceField)
+		if err := parser.Parse(fullPath); err != nil {
+			app.Flash().Err(err)
+			return nil, err
+		}
+		log.Debug().Msgf("Prepared JSONPath %s.", fullPath)
+
+		var results [][]reflect.Value
+		if unstructured, ok := o.(runtime.Unstructured); ok {
+			results, err = parser.FindResults(unstructured.UnstructuredContent())
+		} else {
+			results, err = parser.FindResults(reflect.ValueOf(o).Elem().Interface())
+		}
+
+		if err != nil {
+			return nil, err
+		}
+
+		log.Debug().Msgf("Results extracted %s.", results)
+
+		if len(results) != 1 {
+			return nil, nil
+		}
+
+		if err != nil {
+			return nil, nil
+		}
+		var values = make([]string, 0)
+		for arrIx := range results {
+			for valIx := range results[arrIx] {
+				values = append(values, fmt.Sprint(results[arrIx][valIx].Interface()))
+			}
+		}
+		return values, nil
+	}
+
+	labelSelector := labels.Everything()
+	for targetLabel, sourceField := range resourceLink.LabelSelector {
+		values, err := extractFromObject(sourceField)
+		if err != nil {
+			app.Flash().Err(err)
+			return
+		}
+		if values == nil {
+			continue
+		}
+		if len(values) != 1 {
+			continue
+		}
+		log.Debug().Msgf("Extracted values for label selector %s: %+v.", targetLabel, values)
+
+		req, err := labels.NewRequirement(targetLabel, selection.Equals, values)
+		if err != nil {
+			app.Flash().Err(err)
+			return
+		}
+		labelSelector = labelSelector.Add(*req)
+	}
+	log.Debug().Msgf("Generated labelSelector: %s", labelSelector.String())
+
+	var fieldSelector fields.Selector
+	for targetField, sourceField := range resourceLink.FieldSelector {
+		values, err := extractFromObject(sourceField)
+		if err != nil {
+			app.Flash().Err(err)
+			return
+		}
+		if values == nil {
+			continue
+		}
+		log.Debug().Msgf("Extracted values for field selector %s: %+v.", targetField, values)
+
+		sel := fields.OneTermEqualSelector(targetField, strings.Join(values, ","))
+		if fieldSelector == nil {
+			fieldSelector = sel
+			continue
+		}
+		fieldSelector = fields.AndSelectors(
+			fieldSelector,
+			sel,
+		)
+	}
+	if fieldSelector != nil {
+		log.Debug().Msgf("Generated fieldSelector: %s", fieldSelector.String())
+	}
+
+	// new browser for linked resource
+	browser := NewBrowser(client.NewGVR(resourceLink.Target))
+	browser.SetLabelFilter(cmd.ToLabels(labelSelector.String()))
+	browser.SetContextFn(func(ctx context.Context) context.Context {
+		ctx = context.WithValue(ctx, internal.KeyPath, path)
+		lSel := labelSelector.String()
+		if lSel != labels.Everything().String() {
+			ctx = context.WithValue(ctx, internal.KeyLabels, lSel)
+		}
+
+		if fieldSelector != nil {
+			ctx = context.WithValue(ctx, internal.KeyFields, fieldSelector.String())
+		}
+		return ctx
+	})
+
+	if err := app.inject(browser, false); err != nil {
+		app.Flash().Err(err)
+	}
+}