PT-2189 - Fix cluster selection

src/go/pt-k8s-debug-collector/dumper/dumper.go

@@ -84,14 +84,17 @@ type exportJob struct {
 }
 
 // New return new Dumper object
-func New(location, namespace, kubeconfig, forwardport, resource string, skipPodSummary bool, concurrentExportWorkers int) (*Dumper, error) {
-	var config *rest.Config
-
+func New(location, namespace, kubeconfig, clusterName, forwardport, resource string, skipPodSummary bool, concurrentExportWorkers int) (*Dumper, error) {
 	safeLog := NewSafeLogger()
 
 	log.AddHook(&ErrorArchiveHook{safeLogger: safeLog})
 
-	config, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
+	_, resourceClusterName := parseResourceSpec(resource)
+	if clusterName == "" {
+		clusterName = resourceClusterName
+	}
+
+	config, err := buildRestConfig(kubeconfig, clusterName)
 	if err != nil {
 		return nil, fmt.Errorf("failed to build config from flags: %w", err)
 	}
@@ -181,6 +184,27 @@ func New(location, namespace, kubeconfig, forwardport, resource string, skipPodS
 	return d, err
 }
 
+func buildRestConfig(kubeconfig, clusterName string) (*rest.Config, error) {
+	if clusterName == "" {
+		return clientcmd.BuildConfigFromFlags("", kubeconfig)
+	}
+
+	loadingRules := &clientcmd.ClientConfigLoadingRules{ExplicitPath: kubeconfig}
+	overrides := &clientcmd.ConfigOverrides{CurrentContext: clusterName}
+	clientConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, overrides)
+
+	rawConfig, err := clientConfig.RawConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	if _, ok := rawConfig.Contexts[clusterName]; !ok {
+		return nil, fmt.Errorf("context %q not found in kubeconfig", clusterName)
+	}
+
+	return clientConfig.ClientConfig()
+}
+
 // DumpCluster create dump of a cluster in Dumper.location
 func (d *Dumper) DumpCluster() error {
 	var err error

src/go/pt-k8s-debug-collector/dumper/dumper_test.go

@@ -15,6 +15,7 @@ package dumper
 
 import (
 	"context"
+	"os"
 	"testing"
 
 	corev1 "k8s.io/api/core/v1"
@@ -186,6 +187,97 @@ func TestResourceTypeParsing(t *testing.T) {
 	}
 }
 
+func TestParseResourceSpec(t *testing.T) {
+	tests := []struct {
+		name            string
+		resource        string
+		wantResource    string
+		wantClusterName string
+	}{
+		{
+			name:            "plain resource",
+			resource:        "auto",
+			wantResource:    "auto",
+			wantClusterName: "",
+		},
+		{
+			name:            "resource with cluster suffix",
+			resource:        "auto/k3d-pgv2",
+			wantResource:    "auto",
+			wantClusterName: "k3d-pgv2",
+		},
+		{
+			name:            "resource is trimmed",
+			resource:        "  psmdb/k3d-psmdb  ",
+			wantResource:    "psmdb",
+			wantClusterName: "k3d-psmdb",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotResource, gotClusterName := parseResourceSpec(tt.resource)
+			if gotResource != tt.wantResource || gotClusterName != tt.wantClusterName {
+				t.Fatalf("parseResourceSpec(%q) = (%q, %q), want (%q, %q)", tt.resource, gotResource, gotClusterName, tt.wantResource, tt.wantClusterName)
+			}
+		})
+	}
+}
+
+func TestBuildRestConfigUsesSelectedContext(t *testing.T) {
+	tmpFile, err := os.CreateTemp("", "kubeconfig-*.yaml")
+	if err != nil {
+		t.Fatalf("create temp kubeconfig: %v", err)
+	}
+	defer os.Remove(tmpFile.Name())
+
+	kubeconfig := `
+apiVersion: v1
+kind: Config
+clusters:
+- cluster:
+    server: https://default.example
+  name: default-cluster
+- cluster:
+    server: https://pgv2.example
+  name: pgv2-cluster
+contexts:
+- context:
+    cluster: default-cluster
+    user: default-user
+  name: default
+- context:
+    cluster: pgv2-cluster
+    user: pgv2-user
+  name: k3d-pgv2
+current-context: default
+users:
+- name: default-user
+  user:
+    token: default-token
+- name: pgv2-user
+  user:
+    token: pgv2-token
+`
+
+	if _, err := tmpFile.WriteString(kubeconfig); err != nil {
+		t.Fatalf("write temp kubeconfig: %v", err)
+	}
+
+	if err := tmpFile.Close(); err != nil {
+		t.Fatalf("close temp kubeconfig: %v", err)
+	}
+
+	cfg, err := buildRestConfig(tmpFile.Name(), "k3d-pgv2")
+	if err != nil {
+		t.Fatalf("buildRestConfig returned error: %v", err)
+	}
+
+	if cfg.Host != "https://pgv2.example" {
+		t.Fatalf("buildRestConfig selected host %q, want %q", cfg.Host, "https://pgv2.example")
+	}
+}
+
 // Tests for individual_files.go
 
 func TestGetSummarySkipPodSummary(t *testing.T) {

src/go/pt-k8s-debug-collector/dumper/resources.go

@@ -100,6 +100,20 @@ func (d *Dumper) autoCustomResource() ([]string, error) {
 	return result, nil
 }
 
+func parseResourceSpec(resource string) (string, string) {
+	resource = strings.TrimSpace(resource)
+	if resource == "" {
+		return "", ""
+	}
+
+	resourceName, clusterName, found := strings.Cut(resource, "/")
+	if !found {
+		return resourceName, ""
+	}
+
+	return resourceName, clusterName
+}
+
 // TODO: rewrite to use map or switch
 func resourceType(s string) string {
 	if s == "auto" {

src/go/pt-k8s-debug-collector/main.go

@@ -69,10 +69,6 @@ func (c *cliOptions) AfterApply() error {
 		}
 	}
 
-	if len(c.ClusterName) > 0 {
-		c.Resource += "/" + c.ClusterName
-	}
-
 	ll, err := log.ParseLevel(c.LogLevel)
 	if err != nil {
 		return err
@@ -111,7 +107,7 @@ func main() {
 		log.Infof("loaded default kubeconfig: %s", path)
 	}
 
-	d, err := dumper.New("cluster-dump", opts.Namespace, opts.Kubeconfig, opts.ForwardPort, opts.Resource, opts.SkipPodSummary, opts.ConcurrentExportWorkers)
+	d, err := dumper.New("cluster-dump", opts.Namespace, opts.Kubeconfig, opts.ClusterName, opts.ForwardPort, opts.Resource, opts.SkipPodSummary, opts.ConcurrentExportWorkers)
 	if err != nil {
 		log.Error(err)
 		os.Exit(1)