lint: Enable goimports

goimports checks import lines, adding missing ones and removing
unreferenced ones:
https://godoc.org/golang.org/x/tools/cmd/goimports

It also requires named imports for packages whose
import paths don't match their package names:
- golang/go#28428
- https://go-review.googlesource.com/c/tools/+/145699/

Also standardized named imports of common Kubernetes packaages.

Part of #217

Signed-off-by: Andrew Seigner <siggy@buoyant.io>

.golangci.yml

@@ -7,6 +7,7 @@ linters:
   - deadcode
   - depguard
   - gofmt
+  - goimports
   - golint
   - gosimple
   - govet
@@ -22,7 +23,6 @@ linters:
   # - gochecknoinits
   # - goconst
   # - gocyclo
-  # - goimports
   # - gosec
   # - interfacer
   # - lll

cli/cmd/inject.go

@@ -11,10 +11,10 @@ import (
 	"github.com/linkerd/linkerd2/pkg/healthcheck"
 	"github.com/linkerd/linkerd2/pkg/k8s"
 	"github.com/spf13/cobra"
-	v1 "k8s.io/api/core/v1"
+	corev1 "k8s.io/api/core/v1"
 	k8sMeta "k8s.io/apimachinery/pkg/api/meta"
 	k8sResource "k8s.io/apimachinery/pkg/api/resource"
-	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"sigs.k8s.io/yaml"
 )
@@ -54,7 +54,7 @@ func runInjectCmd(inputs []io.Reader, errWriter, outWriter io.Writer, options *i
 
 // objMeta provides a generic struct to parse the names of Kubernetes objects
 type objMeta struct {
-	metaV1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
+	metav1.ObjectMeta `json:"metadata,omitempty" protobuf:"bytes,1,opt,name=metadata"`
 }
 
 func newInjectOptions() *injectOptions {
@@ -118,7 +118,7 @@ func uninjectAndInject(inputs []io.Reader, errWriter, outWriter io.Writer, optio
 /* Given a ObjectMeta, update ObjectMeta in place with the new labels and
  * annotations.
  */
-func injectObjectMeta(t *metaV1.ObjectMeta, k8sLabels map[string]string, options *injectOptions, report *injectReport) bool {
+func injectObjectMeta(t *metav1.ObjectMeta, k8sLabels map[string]string, options *injectOptions, report *injectReport) bool {
 	report.injectDisabled = injectDisabled(t)
 	if report.injectDisabled {
 		return false
@@ -145,7 +145,7 @@ func injectObjectMeta(t *metaV1.ObjectMeta, k8sLabels map[string]string, options
  * and init-container injected. If the pod is unsuitable for having them
  * injected, return false.
  */
-func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameOverride string, options *injectOptions, report *injectReport) bool {
+func injectPodSpec(t *corev1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameOverride string, options *injectOptions, report *injectReport) bool {
 	report.hostNetwork = t.HostNetwork
 	report.sidecar = healthcheck.HasExistingSidecars(t)
 	report.udp = checkUDPPorts(t)
@@ -196,19 +196,19 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 		IntVal: int32(options.proxyMetricsPort),
 	}
 
-	proxyProbe := v1.Probe{
-		Handler: v1.Handler{
-			HTTPGet: &v1.HTTPGetAction{
+	proxyProbe := corev1.Probe{
+		Handler: corev1.Handler{
+			HTTPGet: &corev1.HTTPGetAction{
 				Path: "/metrics",
 				Port: metricsPort,
 			},
 		},
 		InitialDelaySeconds: 10,
 	}
 
-	resources := v1.ResourceRequirements{
-		Requests: v1.ResourceList{},
-		Limits:   v1.ResourceList{},
+	resources := corev1.ResourceRequirements{
+		Requests: corev1.ResourceList{},
+		Limits:   corev1.ResourceList{},
 	}
 
 	if options.proxyCPURequest != "" {
@@ -231,15 +231,15 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 	if options.disableExternalProfiles {
 		profileSuffixes = "svc.cluster.local."
 	}
-	sidecar := v1.Container{
+	sidecar := corev1.Container{
 		Name:                     k8s.ProxyContainerName,
 		Image:                    options.taggedProxyImage(),
-		ImagePullPolicy:          v1.PullPolicy(options.imagePullPolicy),
-		TerminationMessagePolicy: v1.TerminationMessageFallbackToLogsOnError,
-		SecurityContext: &v1.SecurityContext{
+		ImagePullPolicy:          corev1.PullPolicy(options.imagePullPolicy),
+		TerminationMessagePolicy: corev1.TerminationMessageFallbackToLogsOnError,
+		SecurityContext: &corev1.SecurityContext{
 			RunAsUser: &options.proxyUID,
 		},
-		Ports: []v1.ContainerPort{
+		Ports: []corev1.ContainerPort{
 			{
 				Name:          "linkerd-proxy",
 				ContainerPort: int32(options.inboundPort),
@@ -250,7 +250,7 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 			},
 		},
 		Resources: resources,
-		Env: []v1.EnvVar{
+		Env: []corev1.EnvVar{
 			{Name: "LINKERD2_PROXY_LOG", Value: options.proxyLogLevel},
 			{
 				Name:  "LINKERD2_PROXY_CONTROL_URL",
@@ -263,7 +263,7 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 			{Name: "LINKERD2_PROXY_DESTINATION_PROFILE_SUFFIXES", Value: profileSuffixes},
 			{
 				Name:      PodNamespaceEnvVarName,
-				ValueFrom: &v1.EnvVarSource{FieldRef: &v1.ObjectFieldSelector{FieldPath: "metadata.namespace"}},
+				ValueFrom: &corev1.EnvVarSource{FieldRef: &corev1.ObjectFieldSelector{FieldPath: "metadata.namespace"}},
 			},
 			{Name: "LINKERD2_PROXY_INBOUND_ACCEPT_KEEPALIVE", Value: fmt.Sprintf("%dms", defaultKeepaliveMs)},
 			{Name: "LINKERD2_PROXY_OUTBOUND_CONNECT_KEEPALIVE", Value: fmt.Sprintf("%dms", defaultKeepaliveMs)},
@@ -282,7 +282,7 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 	for _, container := range t.Containers {
 		if capacity, ok := options.proxyOutboundCapacity[container.Image]; ok {
 			sidecar.Env = append(sidecar.Env,
-				v1.EnvVar{
+				corev1.EnvVar{
 					Name:  "LINKERD2_PROXY_OUTBOUND_ROUTER_CAPACITY",
 					Value: fmt.Sprintf("%d", capacity),
 				},
@@ -294,19 +294,19 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 	if options.enableTLS() {
 		yes := true
 
-		configMapVolume := v1.Volume{
+		configMapVolume := corev1.Volume{
 			Name: k8s.TLSTrustAnchorVolumeName,
-			VolumeSource: v1.VolumeSource{
-				ConfigMap: &v1.ConfigMapVolumeSource{
-					LocalObjectReference: v1.LocalObjectReference{Name: k8s.TLSTrustAnchorConfigMapName},
+			VolumeSource: corev1.VolumeSource{
+				ConfigMap: &corev1.ConfigMapVolumeSource{
+					LocalObjectReference: corev1.LocalObjectReference{Name: k8s.TLSTrustAnchorConfigMapName},
 					Optional:             &yes,
 				},
 			},
 		}
-		secretVolume := v1.Volume{
+		secretVolume := corev1.Volume{
 			Name: k8s.TLSSecretsVolumeName,
-			VolumeSource: v1.VolumeSource{
-				Secret: &v1.SecretVolumeSource{
+			VolumeSource: corev1.VolumeSource{
+				Secret: &corev1.SecretVolumeSource{
 					SecretName: identity.ToSecretName(),
 					Optional:   &yes,
 				},
@@ -316,7 +316,7 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 		base := "/var/linkerd-io"
 		configMapBase := base + "/trust-anchors"
 		secretBase := base + "/identity"
-		tlsEnvVars := []v1.EnvVar{
+		tlsEnvVars := []corev1.EnvVar{
 			{Name: "LINKERD2_PROXY_TLS_TRUST_ANCHORS", Value: configMapBase + "/" + k8s.TLSTrustAnchorFileName},
 			{Name: "LINKERD2_PROXY_TLS_CERT", Value: secretBase + "/" + k8s.TLSCertFileName},
 			{Name: "LINKERD2_PROXY_TLS_PRIVATE_KEY", Value: secretBase + "/" + k8s.TLSPrivateKeyFileName},
@@ -329,7 +329,7 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 		}
 
 		sidecar.Env = append(sidecar.Env, tlsEnvVars...)
-		sidecar.VolumeMounts = []v1.VolumeMount{
+		sidecar.VolumeMounts = []corev1.VolumeMount{
 			{Name: configMapVolume.Name, MountPath: configMapBase, ReadOnly: true},
 			{Name: secretVolume.Name, MountPath: secretBase, ReadOnly: true},
 		}
@@ -341,15 +341,15 @@ func injectPodSpec(t *v1.PodSpec, identity k8s.TLSIdentity, controlPlaneDNSNameO
 	if !options.noInitContainer {
 		nonRoot := false
 		runAsUser := int64(0)
-		initContainer := v1.Container{
+		initContainer := corev1.Container{
 			Name:                     k8s.InitContainerName,
 			Image:                    options.taggedProxyInitImage(),
-			ImagePullPolicy:          v1.PullPolicy(options.imagePullPolicy),
-			TerminationMessagePolicy: v1.TerminationMessageFallbackToLogsOnError,
+			ImagePullPolicy:          corev1.PullPolicy(options.imagePullPolicy),
+			TerminationMessagePolicy: corev1.TerminationMessageFallbackToLogsOnError,
 			Args:                     initArgs,
-			SecurityContext: &v1.SecurityContext{
-				Capabilities: &v1.Capabilities{
-					Add: []v1.Capability{v1.Capability("NET_ADMIN")},
+			SecurityContext: &corev1.SecurityContext{
+				Capabilities: &corev1.Capabilities{
+					Add: []corev1.Capability{corev1.Capability("NET_ADMIN")},
 				},
 				Privileged:   &f,
 				RunAsNonRoot: &nonRoot,
@@ -509,18 +509,18 @@ func (resourceTransformerInject) generateReport(injectReports []injectReport, ou
 	output.Write([]byte("\n"))
 }
 
-func checkUDPPorts(t *v1.PodSpec) bool {
+func checkUDPPorts(t *corev1.PodSpec) bool {
 	// Check for ports with `protocol: UDP`, which will not be routed by Linkerd
 	for _, container := range t.Containers {
 		for _, port := range container.Ports {
-			if port.Protocol == v1.ProtocolUDP {
+			if port.Protocol == corev1.ProtocolUDP {
 				return true
 			}
 		}
 	}
 	return false
 }
 
-func injectDisabled(t *metaV1.ObjectMeta) bool {
+func injectDisabled(t *metav1.ObjectMeta) bool {
 	return t.GetAnnotations()[k8s.ProxyInjectAnnotation] == k8s.ProxyInjectDisabled
 }

cli/cmd/inject_util.go

@@ -9,11 +9,11 @@ import (
 	"path/filepath"
 
 	"github.com/linkerd/linkerd2/pkg/k8s"
-	appsV1 "k8s.io/api/apps/v1"
-	batchV1 "k8s.io/api/batch/v1"
-	"k8s.io/api/core/v1"
+	appsv1 "k8s.io/api/apps/v1"
+	batchv1 "k8s.io/api/batch/v1"
+	corev1 "k8s.io/api/core/v1"
 	"k8s.io/api/extensions/v1beta1"
-	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	yamlDecoder "k8s.io/apimachinery/pkg/util/yaml"
 	"sigs.k8s.io/yaml"
@@ -37,9 +37,9 @@ type injectReport struct {
 type resourceConfig struct {
 	obj             interface{}
 	om              objMeta
-	meta            metaV1.TypeMeta
-	podSpec         *v1.PodSpec
-	objectMeta      *metaV1.ObjectMeta
+	meta            metav1.TypeMeta
+	podSpec         *corev1.PodSpec
+	objectMeta      *metav1.ObjectMeta
 	dnsNameOverride string
 	k8sLabels       map[string]string
 }
@@ -106,7 +106,7 @@ func ProcessYAML(in io.Reader, out io.Writer, report io.Writer, options *injectO
 }
 
 func processList(b []byte, options *injectOptions, rt resourceTransformer) ([]byte, []injectReport, error) {
-	var sourceList v1.List
+	var sourceList corev1.List
 	if err := yaml.Unmarshal(b, &sourceList); err != nil {
 		return nil, nil, err
 	}
@@ -194,7 +194,7 @@ func (conf *resourceConfig) parse(bytes []byte, options *injectOptions, rt resou
 		conf.objectMeta = &deployment.Spec.Template.ObjectMeta
 
 	case "ReplicationController":
-		var rc v1.ReplicationController
+		var rc corev1.ReplicationController
 		if err := yaml.Unmarshal(bytes, &rc); err != nil {
 			return nil, nil, err
 		}
@@ -216,7 +216,7 @@ func (conf *resourceConfig) parse(bytes []byte, options *injectOptions, rt resou
 		conf.objectMeta = &rs.Spec.Template.ObjectMeta
 
 	case "Job":
-		var job batchV1.Job
+		var job batchv1.Job
 		if err := yaml.Unmarshal(bytes, &job); err != nil {
 			return nil, nil, err
 		}
@@ -238,7 +238,7 @@ func (conf *resourceConfig) parse(bytes []byte, options *injectOptions, rt resou
 		conf.objectMeta = &ds.Spec.Template.ObjectMeta
 
 	case "StatefulSet":
-		var statefulset appsV1.StatefulSet
+		var statefulset appsv1.StatefulSet
 		if err := yaml.Unmarshal(bytes, &statefulset); err != nil {
 			return nil, nil, err
 		}
@@ -249,7 +249,7 @@ func (conf *resourceConfig) parse(bytes []byte, options *injectOptions, rt resou
 		conf.objectMeta = &statefulset.Spec.Template.ObjectMeta
 
 	case "Pod":
-		var pod v1.Pod
+		var pod corev1.Pod
 		if err := yaml.Unmarshal(bytes, &pod); err != nil {
 			return nil, nil, err
 		}

cli/cmd/logs.go

@@ -12,8 +12,8 @@ import (
 	"github.com/linkerd/linkerd2/pkg/k8s"
 	"github.com/spf13/cobra"
 	"github.com/wercker/stern/stern"
-	"k8s.io/api/core/v1"
-	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/client-go/kubernetes"
 )
@@ -105,7 +105,7 @@ func (o *logsOptions) toSternConfig(controlPlaneComponents, availableContainers
 	return config, nil
 }
 
-func getControlPlaneComponentsAndContainers(pods *v1.PodList) ([]string, []string) {
+func getControlPlaneComponentsAndContainers(pods *corev1.PodList) ([]string, []string) {
 	var controlPlaneComponents, containers []string
 	for _, pod := range pods.Items {
 		controlPlaneComponents = append(controlPlaneComponents, pod.Labels["linkerd.io/control-plane-component"])
@@ -127,7 +127,7 @@ func newLogCmdConfig(options *logsOptions, kubeconfigPath, kubeContext string) (
 		return nil, err
 	}
 
-	podList, err := clientset.CoreV1().Pods(controlPlaneNamespace).List(meta_v1.ListOptions{})
+	podList, err := clientset.CoreV1().Pods(controlPlaneNamespace).List(metav1.ListOptions{})
 	if err != nil {
 		return nil, err
 	}

cli/cmd/uninject.go

@@ -8,8 +8,8 @@ import (
 
 	"github.com/linkerd/linkerd2/pkg/k8s"
 	"github.com/spf13/cobra"
-	"k8s.io/api/core/v1"
-	metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"sigs.k8s.io/yaml"
 )
 
@@ -126,8 +126,8 @@ func (resourceTransformerUninjectSilent) generateReport(uninjectReports []inject
 
 // Given a PodSpec, update the PodSpec in place with the sidecar
 // and init-container uninjected
-func uninjectPodSpec(t *v1.PodSpec, report *injectReport) {
-	initContainers := []v1.Container{}
+func uninjectPodSpec(t *corev1.PodSpec, report *injectReport) {
+	initContainers := []corev1.Container{}
 	for _, container := range t.InitContainers {
 		if container.Name != k8s.InitContainerName {
 			initContainers = append(initContainers, container)
@@ -137,15 +137,15 @@ func uninjectPodSpec(t *v1.PodSpec, report *injectReport) {
 	}
 	t.InitContainers = initContainers
 
-	containers := []v1.Container{}
+	containers := []corev1.Container{}
 	for _, container := range t.Containers {
 		if container.Name != k8s.ProxyContainerName {
 			containers = append(containers, container)
 		}
 	}
 	t.Containers = containers
 
-	volumes := []v1.Volume{}
+	volumes := []corev1.Volume{}
 	for _, volume := range t.Volumes {
 		// TODO: move those strings to constants
 		if volume.Name != k8s.TLSTrustAnchorVolumeName && volume.Name != k8s.TLSSecretsVolumeName {
@@ -155,7 +155,7 @@ func uninjectPodSpec(t *v1.PodSpec, report *injectReport) {
 	t.Volumes = volumes
 }
 
-func uninjectObjectMeta(t *metaV1.ObjectMeta) {
+func uninjectObjectMeta(t *metav1.ObjectMeta) {
 	newAnnotations := make(map[string]string)
 	for key, val := range t.Annotations {
 		if key != k8s.CreatedByAnnotation && key != k8s.ProxyVersionAnnotation {