Improvements and Kubernetes v1.22 support (#46)

* Make golangci.yml effective again

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* internal/utils: remove dead code

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* internal: fix found linter warnings

After making linter configuration effective, linter popped up new
issues. This commit addresses them in a minimal way.

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* Hide goreleaser.yml file

As usually it is hidden.

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* Update Go Kubernetes modules to v1.22.0

As part of #45

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* go.mod: update viper to latest version

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* go.mod: update nri-kubernetes to latest version

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* .github/workflows/push_pr.yml: fix link to Kubernetes releases

Previous link now redirects to new link and old link will be not
available by the end of this year.

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* deploy: make manifests compatible with Kubernetes v1.22+

As part of #45.

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* .github/workflows/push_pr.yml: test against Kubernetes v1.22.X

Closes #45

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* .golangci.yml: increase timeout

Closes #38

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* go.mod: force-update github.com/pkg/sftp to latest version

To fix snyk security scan. Upstream update is pending here:
spf13/afero#312

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* .github/workflows/push_pr.yml: drop support for Kubernetes v1.15

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

* .github/workflows/push_pr.yml: bump patch versions for Kubernetes

Signed-off-by: Mateusz Gozdek <mgozdek@microsoft.com>

.github/workflows/push_pr.yml

@@ -83,11 +83,11 @@ jobs:
   e2eTests:
     runs-on: ubuntu-20.04
     strategy:
-      max-parallel: 7 # len(k8sVersion) is a good number to have here
+      max-parallel: 8 # len(k8sVersion) is a good number to have here
       matrix:
-        # Latest patch version can be found in https://github.com/kubernetes/sig-release/blob/master/releases/patch-releases.md
+        # Latest patch version can be found in https://github.com/kubernetes/website/blob/main/content/en/releases/patch-releases.md
         # Some versions might not be available yet in https://storage.googleapis.com/kubernetes-release/release/v1.X.Y/bin/linux/amd64/kubelet
-        k8sVersion: [ "v1.15.12", "v1.16.15", "v1.17.17", "v1.18.18", "v1.19.10", "v1.20.6", "v1.21.0" ]
+        k8sVersion: [ "v1.16.15", "v1.17.17", "v1.18.20", "v1.19.14", "v1.20.10", "v1.21.4", "v1.22.0" ]
     env:
       DOCKER_BUILDKIT: '1' # Setting DOCKER_BUILDKIT=1 ensures TARGETOS and TARGETARCH are populated
     steps:

golangci.yml → .golangci.yml

@@ -1,3 +1,6 @@
+run:
+  timeout: 5m
+
 linters:
   enable:
     - govet

deploy/gcp.yaml.template

@@ -11,7 +11,7 @@ kind: Namespace
 metadata:
   name: test-ns
 ---
-apiVersion: rbac.authorization.k8s.io/v1beta1
+apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRole
 metadata:
   name: newrelic
@@ -27,7 +27,7 @@ rules:
       - "namespaces"
     verbs: ["get", "list"]
 ---
-apiVersion: rbac.authorization.k8s.io/v1beta1
+apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRoleBinding
 metadata:
   name: newrelic

deploy/minikube.yaml

@@ -11,7 +11,7 @@ kind: Namespace
 metadata:
   name: test-ns
 ---
-apiVersion: rbac.authorization.k8s.io/v1beta1
+apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRole
 metadata:
   name: newrelic
@@ -27,7 +27,7 @@ rules:
       - "namespaces"
     verbs: ["get", "list"]
 ---
-apiVersion: rbac.authorization.k8s.io/v1beta1
+apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRoleBinding
 metadata:
   name: newrelic

go.mod

@@ -3,13 +3,14 @@ module github.com/newrelic/nri-discovery-kubernetes
 go 1.13
 
 require (
-	github.com/imdario/mergo v0.3.8 // indirect
-	github.com/newrelic/nri-kubernetes/v2 v2.5.0
+	github.com/newrelic/nri-kubernetes/v2 v2.8.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/spf13/pflag v1.0.5
-	github.com/spf13/viper v1.7.1
+	github.com/spf13/viper v1.8.1
 	github.com/stretchr/testify v1.7.0
-	k8s.io/api v0.21.1
-	k8s.io/apimachinery v0.21.1
-	k8s.io/client-go v0.21.1
+	k8s.io/api v0.22.0
+	k8s.io/apimachinery v0.22.0
+	k8s.io/client-go v0.22.0
 )
+
+replace github.com/pkg/sftp => github.com/pkg/sftp v1.13.2

internal/config/config.go

@@ -8,23 +8,29 @@ import (
 )
 
 const (
+	// Host is a Kubelet host flag name.
+	Host = "host"
+
+	// DefaultHost is default address where discovery will look for Kubelet API.
+	DefaultHost = "localhost"
+
+	// DefaultPort is default port user for Kubelet API.
+	DefaultPort = 10255
+
 	namespaces = "namespaces"
 	port       = "port"
-	Host       = "host"
 	insecure   = "insecure"
 	timeout    = "timeout"
 	tls        = "tls"
 	envPrefix  = "NRIA"
-
-	DefaultHost = "localhost"
-	DefaultPort = 10255
 )
 
 var (
 	_ = flag.String(namespaces, "", "(optional, default '') Comma separated list of namespaces to discover pods on")
 	_ = flag.Bool(insecure, false, `(optional, default false, deprecated) Use insecure (non-ssl) connection.
 For backwards compatibility this flag takes precedence over 'tls')`)
 )
+
 var (
 	_ = flag.Int(timeout, 5000, "(optional, default 5000) timeout in ms")
 	_ = flag.Bool(tls, false, "(optional, default false) Use secure (tls) connection")
@@ -64,6 +70,7 @@ func (c *Config) IsAutoConfig() bool {
 	return !IsFlagPassed(Host) && !IsFlagPassed(port) && !IsFlagPassed(tls)
 }
 
+// NewConfig generates Config from flags.
 func NewConfig(version string) Config {
 	flag.Parse()
 

internal/discovery/consts.go

@@ -1,5 +1,6 @@
 package discovery
 
+// Property represents a discovery field.
 type Property = string
 
 const (

internal/discovery/discoverer.go

@@ -15,7 +15,9 @@ type Replacement struct {
 }
 
 type (
-	VariablesMap   map[string]interface{}
+	// VariablesMap is used to store discovery properties.
+	VariablesMap map[string]interface{}
+	// AnnotationsMap is used to discovered annotations.
 	AnnotationsMap = VariablesMap
 )
 

internal/discovery/discoverer_test.go

@@ -184,20 +184,20 @@ func fakeKubelet() kubernetes.Kubelet {
 		Items:    []corev1.Pod{pod1, pod2},
 	}
 
-	client := fakeHttpClient(podList)
+	client := fakeHTTPClient(podList)
 	k, _ := kubernetes.NewKubeletWithClient(client)
 	return k
 }
 
-func fakeHttpClient(pods corev1.PodList) http.HttpClient {
-	return &FakeHttpClient{pods: pods}
+func fakeHTTPClient(pods corev1.PodList) http.Client {
+	return &FakeHTTPClient{pods: pods}
 }
 
-type FakeHttpClient struct {
+type FakeHTTPClient struct {
 	pods corev1.PodList
 }
 
-func (k *FakeHttpClient) Get(path string) ([]byte, error) {
+func (k *FakeHTTPClient) Get(path string) ([]byte, error) {
 	return json.Marshal(k.pods)
 }
 

internal/http/client.go

@@ -13,7 +13,8 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-type HttpClient interface {
+// Client represents functionality of simple HTTP client.
+type Client interface {
 	Get(path string) ([]byte, error)
 }
 
@@ -30,7 +31,12 @@ func (c *httpClient) Get(path string) ([]byte, error) {
 		return nil, err
 	}
 
-	defer resp.Body.Close()
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			logrus.WithError(err).Warn("closing response body")
+		}
+	}()
+
 	buff, _ := ioutil.ReadAll(resp.Body)
 
 	if resp.StatusCode != http.StatusOK {
@@ -40,7 +46,8 @@ func (c *httpClient) Get(path string) ([]byte, error) {
 	return buff, nil
 }
 
-func NewClient(url url.URL, tr http.RoundTripper) HttpClient {
+// NewClient constructs new simple HTTP client with given base URL.
+func NewClient(url url.URL, tr http.RoundTripper) Client {
 	return &httpClient{
 		http: http.Client{
 			Transport: tr,
@@ -55,7 +62,7 @@ type kubeletClient struct {
 }
 
 // NewKubeletClient creates a new kubeletClient instance.
-func NewKubeletClient(nodeName string, timeout time.Duration) (HttpClient, error) {
+func NewKubeletClient(nodeName string, timeout time.Duration) (Client, error) {
 	logger := logrus.New()
 	logger.SetOutput(os.Stderr)
 
@@ -80,7 +87,12 @@ func (kc *kubeletClient) Get(path string) ([]byte, error) {
 		return nil, err
 	}
 
-	defer resp.Body.Close()
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			logrus.WithError(err).Warn("closing response body")
+		}
+	}()
+
 	buff, _ := ioutil.ReadAll(resp.Body)
 
 	if resp.StatusCode != http.StatusOK {

internal/kubernetes/kubelet.go

@@ -25,11 +25,15 @@ const (
 )
 
 type (
-	PortsMap       map[string]int32
-	LabelsMap      map[string]string
+	// PortsMap stores container ports indexed by name.
+	PortsMap map[string]int32
+	// LabelsMap stores Pod labels.
+	LabelsMap map[string]string
+	// AnnotationsMap stores Pod annotations.
 	AnnotationsMap map[string]string
 )
 
+// ContainerInfo represents discovery-specific format for found Pods via Kubelet API.
 type ContainerInfo struct {
 	Name           string
 	ID             string
@@ -46,12 +50,13 @@ type ContainerInfo struct {
 	Cluster        string
 }
 
+// Kubelet defines what functionality kubelet client provides.
 type Kubelet interface {
 	FindContainers(namespaces []string) ([]ContainerInfo, error)
 }
 
 type kubelet struct {
-	client      http.HttpClient
+	client      http.Client
 	NodeName    string
 	ClusterName string
 }
@@ -153,6 +158,7 @@ func getClusterName() string {
 	return clusterName
 }
 
+// NewKubelet validates and constructs Kubelet client.
 func NewKubelet(host string, port int, useTLS bool, autoConfig bool, timeout time.Duration) (Kubelet, error) {
 	restConfig, err := rest.InClusterConfig()
 	// not inside the cluster?
@@ -187,7 +193,7 @@ func NewKubelet(host string, port int, useTLS bool, autoConfig bool, timeout tim
 		kubeletHost = nodeName
 	}
 
-	hostUrl := makeUrl(kubeletHost, port, useTLS)
+	hostURL := makeURL(kubeletHost, port, useTLS)
 
 	// Allow kubelet to use self-signed serving certificate.
 	restConfig.Insecure = true
@@ -203,7 +209,7 @@ func NewKubelet(host string, port int, useTLS bool, autoConfig bool, timeout tim
 		return nil, fmt.Errorf("creating HTTP transport config from kubeconfig: %w", err)
 	}
 
-	httpClient := http.NewClient(hostUrl, tr)
+	httpClient := http.NewClient(hostURL, tr)
 
 	kubelet := &kubelet{
 		client:      httpClient,
@@ -214,22 +220,23 @@ func NewKubelet(host string, port int, useTLS bool, autoConfig bool, timeout tim
 	return kubelet, nil
 }
 
-func NewKubeletWithClient(httpClient http.HttpClient) (Kubelet, error) {
+// NewKubeletWithClient constructs Kubelet client with given HTTP client.
+func NewKubeletWithClient(httpClient http.Client) (Kubelet, error) {
 	k := &kubelet{
 		client: httpClient,
 	}
 
 	return k, nil
 }
 
-func makeUrl(host string, port int, useTLS bool) url.URL {
+func makeURL(host string, port int, useTLS bool) url.URL {
 	scheme := "http"
 	if useTLS {
 		scheme = "https"
 	}
-	kubeletUrl := url.URL{
+	kubeletURL := url.URL{
 		Scheme: scheme,
 		Host:   host + ":" + strconv.Itoa(port),
 	}
-	return kubeletUrl
+	return kubeletURL
 }

internal/utils/utils.go

@@ -4,6 +4,7 @@ import (
 	"os"
 )
 
+// Contains checks if given value is included in given slice.
 func Contains(set []string, str string) bool {
 	// a map may be faster
 	for _, s := range set {
@@ -14,17 +15,10 @@ func Contains(set []string, str string) bool {
 	return false
 }
 
+// HomeDir returns platform-specific path to user's home directory.
 func HomeDir() string {
 	if h := os.Getenv("HOME"); h != "" {
 		return h
 	}
 	return os.Getenv("USERPROFILE") // windows
 }
-
-func Hostname() string {
-	hostname, err := os.Hostname()
-	if err != nil {
-		return ""
-	}
-	return hostname
-}