feat: custom resource links

README.md

@@ -647,6 +647,52 @@ 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.
@@ -966,6 +1012,7 @@ 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

@@ -18,19 +18,20 @@ 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 `json:"customResourceLinks" yaml:"customResourceLinks"`
 	manualRefreshRate   int
 	manualHeadless      *bool
 	manualLogoless      *bool
@@ -49,16 +50,17 @@ 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,
 	}
 }
 
@@ -108,6 +110,7 @@ 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/resource_links.go

@@ -0,0 +1,101 @@
+package dao
+
+import (
+	"fmt"
+	"github.com/derailed/k9s/internal/config"
+	"github.com/rs/zerolog/log"
+	"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"
+	"strings"
+)
+
+// extractPathFromObject extracts a json path from a given object.
+func extractPathFromObject(o runtime.Object, path string) ([]string, error) {
+	var err error
+	parser := jsonpath.New("accessor").AllowMissingKeys(true)
+	parser.EnableJSONOutput(true)
+	fullPath := fmt.Sprintf("{%s}", path)
+	if err := parser.Parse(fullPath); err != nil {
+		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
+	}
+
+	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
+}
+
+// SelectorsForLink builds label and field selectors from a given object based on a custom resource link.
+func SelectorsForLink(link *config.CustomResourceLink, o runtime.Object) (string, string, error) {
+	var labelSelector = labels.Everything()
+	var fieldSelector fields.Selector
+
+	for target, source := range link.LabelSelector {
+		values, err := extractPathFromObject(o, source)
+		switch {
+		case err != nil:
+			return "", "", err
+		case values == nil || len(values) != 1:
+			continue
+		}
+		log.Debug().Msgf("Extracted values for label selector %s: %+v.", target, values)
+
+		req, err := labels.NewRequirement(target, selection.Equals, values)
+		if err != nil {
+			return "", "", err
+		}
+		labelSelector = labelSelector.Add(*req)
+	}
+
+	for target, source := range link.FieldSelector {
+		values, err := extractPathFromObject(o, source)
+		switch {
+		case err != nil:
+			return "", "", err
+		case values == nil:
+			continue
+		}
+		log.Debug().Msgf("Extracted values for field selector %s: %+v.", target, values)
+
+		sel := fields.OneTermEqualSelector(target, strings.Join(values, ","))
+		if fieldSelector == nil {
+			fieldSelector = sel
+			continue
+		}
+		fieldSelector = fields.AndSelectors(
+			fieldSelector,
+			sel,
+		)
+	}
+	fsel := ""
+	if fieldSelector != nil {
+		fsel = fieldSelector.String()
+	}
+
+	return labelSelector.String(), fsel, nil
+}

internal/dao/resource_links_test.go

@@ -0,0 +1,76 @@
+package dao
+
+import (
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"testing"
+)
+
+type obj struct {
+	Value string `json:"value,omitempty"`
+	Child struct {
+		Nested string `json:"nested,omitempty"`
+	} `json:"child"`
+}
+
+func (o obj) GetObjectKind() schema.ObjectKind {
+	return nil
+}
+
+func (o obj) DeepCopyObject() runtime.Object {
+	return nil
+}
+
+func TestExtractPathFromObject(t *testing.T) {
+	tests := []struct {
+		name string
+		obj  runtime.Object
+		path string
+		want []string
+	}{
+		{
+			name: "empty path",
+			obj: &obj{
+				Value: "",
+				Child: struct {
+					Nested string `json:"nested,omitempty"`
+				}{},
+			},
+			path: ".nonexistent",
+			want: []string{},
+		},
+		{
+			name: "object with path",
+			obj: &obj{
+				Value: "foo",
+				Child: struct {
+					Nested string `json:"nested,omitempty"`
+				}{},
+			},
+			path: ".value",
+			want: []string{"foo"},
+		},
+		{
+			name: "nested with path",
+			obj: &obj{
+				Value: "foo",
+				Child: struct {
+					Nested string `json:"nested,omitempty"`
+				}{
+					Nested: "bar",
+				},
+			},
+			path: ".child.nested",
+			want: []string{"bar"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := extractPathFromObject(tt.obj, tt.path)
+			require.NoError(t, err)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}