fix(#1359): add option to keep missing clusters in config (#2213)

Co-authored-by: Clément Loiselet <clement.loiselet@cbp-group.com>

README.md

@@ -357,6 +357,8 @@ K9s uses aliases to navigate most K8s resources.
     currentContext: minikube
     # Indicates the current kube cluster. Defaults to current context cluster
     currentCluster: minikube
+    # KeepMissingClusters will keep clusters in the config if they are missing from the current kubeconfig file. Default false
+    KeepMissingClusters: false
     # Persists per cluster preferences for favorite namespaces and view.
     clusters:
       coolio:

internal/config/config_test.go

@@ -297,6 +297,7 @@ var expectedConfig = `k9s:
     showTime: false
   currentContext: blee
   currentCluster: blee
+  keepMissingClusters: false
   clusters:
     blee:
       namespace:
@@ -397,6 +398,7 @@ var resetConfig = `k9s:
     showTime: false
   currentContext: blee
   currentCluster: blee
+  keepMissingClusters: false
   clusters:
     blee:
       namespace:

internal/config/k9s.go

@@ -25,6 +25,7 @@ type K9s struct {
 	Logger              *Logger             `yaml:"logger"`
 	CurrentContext      string              `yaml:"currentContext"`
 	CurrentCluster      string              `yaml:"currentCluster"`
+	KeepMissingClusters bool                `yaml:"keepMissingClusters"`
 	Clusters            map[string]*Cluster `yaml:"clusters,omitempty"`
 	Thresholds          Threshold           `yaml:"thresholds"`
 	ScreenDumpDir       string              `yaml:"screenDumpDir"`
@@ -206,9 +207,17 @@ func (k *K9s) validateClusters(c client.Connection, ks KubeSettings) {
 	}
 	for key, cluster := range k.Clusters {
 		cluster.Validate(c, ks)
+		// if the cluster is defined in the $KUBECONFIG file, keep it in the k9s config file
 		if _, ok := cc[key]; ok {
 			continue
 		}
+
+		// if we asked to keep the clusters in the config file
+		if k.KeepMissingClusters {
+			continue
+		}
+
+		// else remove it from the k9s config file
 		if k.CurrentCluster == key {
 			k.CurrentCluster = ""
 		}