Add kubernetes prober

prober/kubernetes.go

@@ -0,0 +1,84 @@
+package prober
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/bmatcuk/doublestar/v2"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/ribbybibby/ssl_exporter/config"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/clientcmd"
+
+	// Support oidc in kube config files
+	_ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
+)
+
+var (
+	ErrKubeBadTarget = fmt.Errorf("Target secret must be provided in the form: <namespace>/<name>")
+)
+
+func ProbeKubernetes(ctx context.Context, target string, module config.Module, registry *prometheus.Registry) error {
+	client, err := newKubeClient(module.Kubernetes.Kubeconfig)
+	if err != nil {
+		return err
+	}
+
+	return probeKubernetes(ctx, target, module, registry, client)
+}
+
+func probeKubernetes(ctx context.Context, target string, module config.Module, registry *prometheus.Registry, client kubernetes.Interface) error {
+	parts := strings.Split(target, "/")
+	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
+		return ErrKubeBadTarget
+	}
+
+	ns := parts[0]
+	name := parts[1]
+
+	var tlsSecrets []v1.Secret
+	secrets, err := client.CoreV1().Secrets("").List(ctx, metav1.ListOptions{})
+	if err != nil {
+		return err
+	}
+	for _, secret := range secrets.Items {
+		if secret.Type == "kubernetes.io/tls" {
+			nMatch, err := doublestar.Match(ns, secret.Namespace)
+			if err != nil {
+				return err
+			}
+			sMatch, err := doublestar.Match(name, secret.Name)
+			if err != nil {
+				return err
+			}
+			if nMatch && sMatch {
+				tlsSecrets = append(tlsSecrets, secret)
+			}
+		}
+	}
+
+	return collectKubernetesSecretMetrics(tlsSecrets, registry)
+}
+
+// newKubeClient returns a Kubernetes client (clientset) from the supplied
+// kubeconfig path, the KUBECONFIG environment variable, the default config file
+// location ($HOME/.kube/config) or from the in-cluster service account environment.
+func newKubeClient(path string) (*kubernetes.Clientset, error) {
+	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
+	if path != "" {
+		loadingRules.ExplicitPath = path
+	}
+	kubeConfig := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(
+		loadingRules,
+		&clientcmd.ConfigOverrides{},
+	)
+	config, err := kubeConfig.ClientConfig()
+	if err != nil {
+		return nil, err
+	}
+
+	return kubernetes.NewForConfig(config)
+}