feat: trigger webhook on reload

Signed-off-by: Utibeabasi Umanah <utibeabasiumanah6@gmail.com>

internal/pkg/cmd/reloader.go

@@ -39,6 +39,7 @@ func NewReloaderCommand() *cobra.Command {
 	cmd.PersistentFlags().StringVar(&options.AutoSearchAnnotation, "auto-search-annotation", "reloader.stakater.com/search", "annotation to detect changes in configmaps or secrets tagged with special match annotation")
 	cmd.PersistentFlags().StringVar(&options.SearchMatchAnnotation, "search-match-annotation", "reloader.stakater.com/match", "annotation to mark secrets or configmaps to match the search")
 	cmd.PersistentFlags().StringVar(&options.LogFormat, "log-format", "", "Log format to use (empty string for text, or JSON")
+	cmd.PersistentFlags().StringVar(&options.WebhookUrl, "webhook-url", "", "webhook to trigger instead of performing a reload")
 	cmd.PersistentFlags().StringSlice("resources-to-ignore", []string{}, "list of resources to ignore (valid options 'configMaps' or 'secrets')")
 	cmd.PersistentFlags().StringSlice("namespaces-to-ignore", []string{}, "list of namespaces to ignore")
 	cmd.PersistentFlags().StringSlice("namespace-selector", []string{}, "list of key:value labels to filter on for namespaces")
@@ -156,6 +157,10 @@ func startReloader(cmd *cobra.Command, args []string) {
 		logrus.Warnf("resource-label-selector is set, will only detect changes on resources with these labels: %s.", resourceLabelSelector)
 	}
 
+	if options.WebhookUrl != "" {
+		logrus.Warnf("webhook-url is set, will only send webhook, no resources will be reloaded")
+	}
+
 	collectors := metrics.SetupPrometheusEndpoint()
 
 	var controllers []*controller.Controller

internal/pkg/handler/create.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"github.com/sirupsen/logrus"
 	"github.com/stakater/Reloader/internal/pkg/metrics"
+	"github.com/stakater/Reloader/internal/pkg/options"
 	"github.com/stakater/Reloader/internal/pkg/util"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/record"
@@ -21,6 +22,10 @@ func (r ResourceCreatedHandler) Handle() error {
 		logrus.Errorf("Resource creation handler received nil resource")
 	} else {
 		config, _ := r.GetConfig()
+		// Send webhook
+		if options.WebhookUrl != "" {
+			return sendUpgradeWebhook(config, options.WebhookUrl)
+		}
 		// process resource based on its type
 		return doRollingUpgrade(config, r.Collectors, r.Recorder)
 	}

internal/pkg/handler/update.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"github.com/sirupsen/logrus"
 	"github.com/stakater/Reloader/internal/pkg/metrics"
+	"github.com/stakater/Reloader/internal/pkg/options"
 	"github.com/stakater/Reloader/internal/pkg/util"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/client-go/tools/record"
@@ -23,6 +24,10 @@ func (r ResourceUpdatedHandler) Handle() error {
 	} else {
 		config, oldSHAData := r.GetConfig()
 		if config.SHAValue != oldSHAData {
+			// Send a webhook if update
+			if options.WebhookUrl != "" {
+				return sendUpgradeWebhook(config, options.WebhookUrl)
+			}
 			// process resource based on its type
 			return doRollingUpgrade(config, r.Collectors, r.Recorder)
 		}

internal/pkg/handler/upgrade.go

@@ -1,14 +1,17 @@
 package handler
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"os"
 	"regexp"
 	"strconv"
 	"strings"
 
+	"github.com/parnurzeal/gorequest"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/sirupsen/logrus"
 	alert "github.com/stakater/Reloader/internal/pkg/alerts"
@@ -94,6 +97,36 @@ func GetArgoRolloutRollingUpgradeFuncs() callbacks.RollingUpgradeFuncs {
 	}
 }
 
+func sendUpgradeWebhook(config util.Config, webhookUrl string) error {
+	message := fmt.Sprintf("Changes detected in '%s' of type '%s' in namespace '%s'", config.ResourceName, config.Type, config.Namespace)
+	message += fmt.Sprintf(", Sending webhook to '%s'", webhookUrl)
+	logrus.Infof(message)
+	body, errs := sendWebhook(webhookUrl)
+	if errs != nil {
+		// return the first error
+		return errs[0]
+	} else {
+		logrus.Info(body)
+	}
+
+	return nil
+}
+
+func sendWebhook(url string) (string, []error) {
+	request := gorequest.New()
+	resp, _, err := request.Post(url).Send(`{"webhook":"update successful"}`).End()
+	if err != nil {
+		// the reloader seems to retry automatically so no retry logic added
+		return "", err
+	}
+	var buffer bytes.Buffer
+	_, bufferErr := io.Copy(&buffer, resp.Body)
+	if bufferErr != nil {
+		logrus.Error(bufferErr)
+	}
+	return buffer.String(), nil
+}
+
 func doRollingUpgrade(config util.Config, collectors metrics.Collectors, recorder record.EventRecorder) error {
 	clients := kube.GetClients()
 

internal/pkg/options/flags.go

@@ -30,4 +30,6 @@ var (
 	SyncAfterRestart = false
 	// EnableHA adds support for running multiple replicas via leadership election
 	EnableHA = false
+	// Url to send a request to instead of triggering a reload
+	WebhookUrl = ""
 )