cli: add a --context flag for setting kube context. Fixes #3296 (#3734)

internal/cli/ci.go

@@ -46,6 +46,7 @@ While Tilt is running, you can view the UI at %s:%d
 	addStartServerFlags(cmd)
 	addDevServerFlags(cmd)
 	addTiltfileFlag(cmd, &c.fileName)
+	addKubeContextFlag(cmd)
 
 	cmd.Flags().BoolVar(&logActionsFlag, "logactions", false, "log all actions and state changes")
 	cmd.Flags().Lookup("logactions").Hidden = true

internal/cli/doctor.go

@@ -25,6 +25,7 @@ func (c *doctorCmd) register() *cobra.Command {
 		Use:   "doctor",
 		Short: "Print diagnostic information about the Tilt environment, for filing bug reports",
 	}
+	addKubeContextFlag(cmd)
 	return cmd
 }
 

internal/cli/down.go

@@ -52,6 +52,7 @@ In that case, see https://tilt.dev/user_config.html and/or comments in your Tilt
 	}
 
 	addTiltfileFlag(cmd, &c.fileName)
+	addKubeContextFlag(cmd)
 	cmd.Flags().BoolVar(&c.deleteNamespaces, "delete-namespaces", false, "delete namespaces defined in the Tiltfile (by default, don't)")
 
 	return cmd

internal/cli/flags.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"github.com/spf13/cobra"
 
+	"github.com/tilt-dev/tilt/internal/k8s"
 	"github.com/tilt-dev/tilt/internal/tiltfile"
 )
 
@@ -13,6 +14,10 @@ func addTiltfileFlag(cmd *cobra.Command, s *string) {
 	cmd.Flags().StringVarP(s, "file", "f", tiltfile.FileName, "Path to Tiltfile")
 }
 
+func addKubeContextFlag(cmd *cobra.Command) {
+	cmd.Flags().StringVar(&kubeContextOverride, "context", "", "Kubernetes context override. Equivalent to kubectl --context")
+}
+
 // For commands that talk to the web server.
 func addConnectServerFlags(cmd *cobra.Command) {
 	cmd.Flags().IntVar(&webPort, "port", DefaultWebPort, "Port for the Tilt HTTP server. Only necessary if you started Tilt with --port.")
@@ -29,3 +34,9 @@ func addDevServerFlags(cmd *cobra.Command) {
 	cmd.Flags().IntVar(&webDevPort, "webdev-port", DefaultWebDevPort, "Port for the Tilt Dev Webpack server. Only applies when using --web-mode=local")
 	cmd.Flags().Var(&webModeFlag, "web-mode", "Values: local, prod. Controls whether to use prod assets or a local dev server. (If flag not specified: if Tilt was built from source, it will use a local asset server; otherwise, prod assets.)")
 }
+
+var kubeContextOverride string
+
+func ProvideKubeContextOverride() k8s.KubeContextOverride {
+	return k8s.KubeContextOverride(kubeContextOverride)
+}

internal/cli/tiltfile_result.go

@@ -63,6 +63,7 @@ Run with -v | --verbose to print Tiltfile execution logs on stderr, regardless o
 	}
 
 	addTiltfileFlag(cmd, &c.fileName)
+	addKubeContextFlag(cmd)
 	cmd.Flags().BoolVarP(&c.builtinTimings, "builtin-timings", "b", false, "If true, print timing data for Tiltfile builtin calls instead of Tiltfile result JSON")
 	cmd.Flags().DurationVar(&c.durThreshold, "dur-threshold", 0, "Only compatible with Builtin Timings mode. Should be a Go duration string. If passed, only print information about builtin calls lasting this duration and longer.")
 

internal/cli/up.go

@@ -89,6 +89,7 @@ local resources--i.e. those using serve_cmd--are terminated when you exit Tilt.
 	addStartServerFlags(cmd)
 	addDevServerFlags(cmd)
 	addTiltfileFlag(cmd, &c.fileName)
+	addKubeContextFlag(cmd)
 	cmd.Flags().Lookup("logactions").Hidden = true
 	cmd.Flags().StringVar(&c.outputSnapshotOnExit, "output-snapshot-on-exit", "", "If specified, Tilt will dump a snapshot of its state to the specified path when it exits")
 

internal/cli/wire.go

@@ -60,7 +60,8 @@ var K8sWireSet = wire.NewSet(
 	k8s.ProvideContainerRuntime,
 	k8s.ProvideServerVersion,
 	k8s.ProvideK8sClient,
-	k8s.ProvideOwnerFetcher)
+	k8s.ProvideOwnerFetcher,
+	ProvideKubeContextOverride)
 
 var BaseWireSet = wire.NewSet(
 	K8sWireSet,

internal/engine/wire.go

@@ -123,6 +123,7 @@ func provideDockerComposeBuildAndDeployer(
 
 		// EnvNone ensures that we get an exploding k8s client.
 		wire.Value(k8s.Env(k8s.EnvNone)),
+		wire.Value(k8s.KubeContextOverride("")),
 		k8s.ProvideClientConfig,
 		k8s.ProvideConfigNamespace,
 		k8s.ProvideKubeContext,

internal/k8s/client.go

@@ -40,6 +40,7 @@ type PodID string
 type NodeID string
 type ServiceName string
 type KubeContext string
+type KubeContextOverride string
 
 // NOTE(nick): This isn't right. DefaultNamespace is a function of your kubectl context.
 const DefaultNamespace = Namespace("default")
@@ -474,11 +475,13 @@ func ProvideClientset(cfg RESTConfigOrError) ClientsetOrError {
 	return ClientsetOrError{Clientset: clientset, Error: err}
 }
 
-func ProvideClientConfig() clientcmd.ClientConfig {
+func ProvideClientConfig(contextOverride KubeContextOverride) clientcmd.ClientConfig {
 	rules := clientcmd.NewDefaultClientConfigLoadingRules()
 	rules.DefaultClientConfig = &clientcmd.DefaultClientConfig
 
-	overrides := &clientcmd.ConfigOverrides{}
+	overrides := &clientcmd.ConfigOverrides{
+		CurrentContext: string(contextOverride),
+	}
 	return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
 		rules,
 		overrides)

internal/k8s/env.go

@@ -46,14 +46,26 @@ func ProvideKubeContext(config *api.Config) (KubeContext, error) {
 	return KubeContext(config.CurrentContext), nil
 }
 
-func ProvideKubeConfig(clientLoader clientcmd.ClientConfig) (*api.Config, error) {
-	access := clientLoader.ConfigAccess()
-	config, err := access.GetStartingConfig()
+func ProvideKubeConfig(clientLoader clientcmd.ClientConfig, contextOverride KubeContextOverride) (*api.Config, error) {
+	config, err := clientLoader.RawConfig()
 	if err != nil {
 		return nil, errors.Wrap(err, "Loading Kubernetes current-context")
 	}
 
-	return config, nil
+	// NOTE(nick): The RawConfig() accessor doesn't handle overrides.
+	// The other accessors do. So we do what ClientConfig does internally, and
+	// apply the overrides ourselves.
+	if contextOverride != "" {
+		config.CurrentContext = string(contextOverride)
+
+		// If the user explicitly passed an override, validate it.
+		err := clientcmd.ConfirmUsable(config, string(contextOverride))
+		if err != nil {
+			return nil, errors.Wrap(err, "Overriding Kubernetes context")
+		}
+	}
+
+	return &config, nil
 }
 
 func ProvideClusterName(ctx context.Context, config *api.Config) ClusterName {