Extract blockers

This will make it easier to manipulate main in the future.

Signed-off-by: Jean-Philippe Evrard <open-source@a.spamming.party>

pkg/blockers/blockers.go

@@ -0,0 +1,102 @@
+package blockers
+
+import (
+	"context"
+	"fmt"
+	"github.com/kubereboot/kured/pkg/alerts"
+	log "github.com/sirupsen/logrus"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	"regexp"
+)
+
+// RebootBlocked checks that a single block Checker
+// will block the reboot or not.
+func RebootBlocked(blockers ...RebootBlocker) bool {
+	for _, blocker := range blockers {
+		if blocker.IsBlocked() {
+			return true
+		}
+	}
+	return false
+}
+
+// RebootBlocker interface should be implemented by types
+// to know if their instantiations should block a reboot
+type RebootBlocker interface {
+	IsBlocked() bool
+}
+
+// PrometheusBlockingChecker contains info for connecting
+// to prometheus, and can give info about whether a reboot should be blocked
+type PrometheusBlockingChecker struct {
+	// prometheusClient to make prometheus-go-client and api config available
+	// into the PrometheusBlockingChecker struct
+	PromClient *alerts.PromClient
+	// regexp used to get alerts
+	Filter *regexp.Regexp
+	// bool to indicate if only firing alerts should be considered
+	FiringOnly bool
+	// bool to indicate that we're only blocking on alerts which match the filter
+	FilterMatchOnly bool
+}
+
+// KubernetesBlockingChecker contains info for connecting
+// to k8s, and can give info about whether a reboot should be blocked
+type KubernetesBlockingChecker struct {
+	// client used to contact kubernetes API
+	Client   *kubernetes.Clientset
+	Nodename string
+	// lised used to filter pods (podSelector)
+	Filter []string
+}
+
+// IsBlocked for the prometheus will check if there are active alerts matching
+// the arguments given into promclient which would actively block the reboot.
+// As of today, no blocker information is shared as a return of the method,
+// and the information is simply logged.
+func (pb PrometheusBlockingChecker) IsBlocked() bool {
+	alertNames, err := pb.PromClient.ActiveAlerts(pb.Filter, pb.FiringOnly, pb.FilterMatchOnly)
+	if err != nil {
+		log.Warnf("Reboot blocked: prometheus query error: %v", err)
+		return true
+	}
+	count := len(alertNames)
+	if count > 10 {
+		alertNames = append(alertNames[:10], "...")
+	}
+	if count > 0 {
+		log.Warnf("Reboot blocked: %d active alerts: %v", count, alertNames)
+		return true
+	}
+	return false
+}
+
+// IsBlocked for the KubernetesBlockingChecker will check if a pod, for the node, is preventing
+// the reboot. It will warn in the logs about blocking, but does not return an error.
+func (kb KubernetesBlockingChecker) IsBlocked() bool {
+	fieldSelector := fmt.Sprintf("spec.nodeName=%s,status.phase!=Succeeded,status.phase!=Failed,status.phase!=Unknown", kb.Nodename)
+	for _, labelSelector := range kb.Filter {
+		podList, err := kb.Client.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{
+			LabelSelector: labelSelector,
+			FieldSelector: fieldSelector,
+			Limit:         10})
+		if err != nil {
+			log.Warnf("Reboot blocked: pod query error: %v", err)
+			return true
+		}
+
+		if len(podList.Items) > 0 {
+			podNames := make([]string, 0, len(podList.Items))
+			for _, pod := range podList.Items {
+				podNames = append(podNames, pod.Name)
+			}
+			if len(podList.Continue) > 0 {
+				podNames = append(podNames, "...")
+			}
+			log.Warnf("Reboot blocked: matching pods: %v", podNames)
+			return true
+		}
+	}
+	return false
+}

pkg/blockers/blockers_test.go

@@ -0,0 +1,67 @@
+package blockers
+
+import (
+	"github.com/kubereboot/kured/pkg/alerts"
+	papi "github.com/prometheus/client_golang/api"
+	"testing"
+)
+
+type BlockingChecker struct {
+	blocking bool
+}
+
+func (fbc BlockingChecker) IsBlocked() bool {
+	return fbc.blocking
+}
+
+func Test_rebootBlocked(t *testing.T) {
+	noCheckers := []RebootBlocker{}
+	nonblockingChecker := BlockingChecker{blocking: false}
+	blockingChecker := BlockingChecker{blocking: true}
+
+	// Instantiate a prometheusClient with a broken_url
+	promClient, _ := alerts.NewPromClient(papi.Config{Address: "broken_url"})
+	brokenPrometheusClient := PrometheusBlockingChecker{PromClient: promClient, Filter: nil, FiringOnly: false}
+
+	type args struct {
+		blockers []RebootBlocker
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "Do not block on no blocker defined",
+			args: args{blockers: noCheckers},
+			want: false,
+		},
+		{
+			name: "Ensure a blocker blocks",
+			args: args{blockers: []RebootBlocker{blockingChecker}},
+			want: true,
+		},
+		{
+			name: "Ensure a non-blocker doesn't block",
+			args: args{blockers: []RebootBlocker{nonblockingChecker}},
+			want: false,
+		},
+		{
+			name: "Ensure one blocker is enough to block",
+			args: args{blockers: []RebootBlocker{nonblockingChecker, blockingChecker}},
+			want: true,
+		},
+		{
+			name: "Do block on error contacting prometheus API",
+			args: args{blockers: []RebootBlocker{brokenPrometheusClient}},
+			want: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := RebootBlocked(tt.args.blockers...); got != tt.want {
+				t.Errorf("rebootBlocked() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}