Add POC of GitHub Webhook Delivery Forwarder (#682)

* Add POC of GitHub Webhook Delivery Forwarder

* multi-forwarder and ctrl-c existing and fix for non-woring http post

* Rename source files

* Extract signal handling into a dedicated source file

* Faster ctrl-c handling

* Enable automatic creation of repo hook on startup

* Add support for forwarding org hook deliveries

* Set hook secret on hook creation via envvar (HOOK_SECRET)

* Fix org hook support

* Fix HOOK_SECRET for consistency

* Refactor to prepare for custom log position provider

* Refactor to extract inmemory log position provider

* Add configmap-based log position provider

* Rename githubwebhookdeliveryforwarder to hookdeliveryforwarder

* Refactor to rename LogPositionProvider to Checkpointer and extract ConfigMap checkpointer into a dedicated pkg

* Refactor to extract logger initialization

* Add hookdeliveryforwarder README and bump go-github to unreleased ver

pkg/hookdeliveryforwarder/configmap/checkpointer.go

@@ -0,0 +1,100 @@
+package configmap
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	kerrors "k8s.io/apimachinery/pkg/api/errors"
+
+	"github.com/actions-runner-controller/actions-runner-controller/pkg/hookdeliveryforwarder"
+	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+type ConfigMapCheckpointer struct {
+	Name   string
+	NS     string
+	Client client.Client
+}
+
+type state struct {
+	DeliveredAt time.Time `json:"delivered_at"`
+	ID          int64     `json:"id"`
+}
+
+func (p *ConfigMapCheckpointer) GetOrCreate(hookID int64) (*hookdeliveryforwarder.State, error) {
+	var cm corev1.ConfigMap
+
+	if err := p.Client.Get(context.Background(), types.NamespacedName{Namespace: p.NS, Name: p.Name}, &cm); err != nil {
+		if !kerrors.IsNotFound(err) {
+			return nil, err
+		}
+
+		cm.Name = p.Name
+		cm.Namespace = p.NS
+
+		if err := p.Client.Create(context.Background(), &cm); err != nil {
+			return nil, err
+		}
+	}
+
+	idStr := fmt.Sprintf("hook_%d", hookID)
+
+	var unmarshalled state
+
+	data, ok := cm.Data[idStr]
+
+	if ok {
+		if err := json.Unmarshal([]byte(data), &unmarshalled); err != nil {
+			return nil, err
+		}
+	}
+
+	pos := &hookdeliveryforwarder.State{
+		DeliveredAt: unmarshalled.DeliveredAt,
+		ID:          unmarshalled.ID,
+	}
+
+	if pos.DeliveredAt.IsZero() {
+		pos.DeliveredAt = time.Now()
+	}
+
+	return pos, nil
+}
+
+func (p *ConfigMapCheckpointer) Update(hookID int64, pos *hookdeliveryforwarder.State) error {
+	var cm corev1.ConfigMap
+
+	if err := p.Client.Get(context.Background(), types.NamespacedName{Namespace: p.NS, Name: p.Name}, &cm); err != nil {
+		return err
+	}
+
+	var posData state
+
+	posData.DeliveredAt = pos.DeliveredAt
+	posData.ID = pos.ID
+
+	idStr := fmt.Sprintf("hook_%d", hookID)
+
+	data, err := json.Marshal(posData)
+	if err != nil {
+		return err
+	}
+
+	copy := cm.DeepCopy()
+
+	if copy.Data == nil {
+		copy.Data = map[string]string{}
+	}
+
+	copy.Data[idStr] = string(data)
+
+	if err := p.Client.Patch(context.Background(), copy, client.MergeFrom(&cm)); err != nil {
+		return err
+	}
+
+	return nil
+}