feat: add metrics system, move webhook feature to dedicated module (#372)

pkg/modules/webhook/webhook.go

@@ -0,0 +1,126 @@
+package webhook
+
+import (
+	"fmt"
+	"regexp"
+	"time"
+
+	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	"github.com/gotenberg/gotenberg/v7/pkg/modules/api"
+	flag "github.com/spf13/pflag"
+	"go.uber.org/multierr"
+)
+
+func init() {
+	gotenberg.MustRegisterModule(Webhook{})
+}
+
+// Webhook is a module which provides a middleware for uploading output files
+// to any destinations in an asynchronous fashion.
+type Webhook struct {
+	allowList      *regexp.Regexp
+	denyList       *regexp.Regexp
+	errorAllowList *regexp.Regexp
+	errorDenyList  *regexp.Regexp
+	maxRetry       int
+	retryMinWait   time.Duration
+	retryMaxWait   time.Duration
+	disable        bool
+}
+
+// Descriptor returns an Webhook's module descriptor.
+func (Webhook) Descriptor() gotenberg.ModuleDescriptor {
+	return gotenberg.ModuleDescriptor{
+		ID: "webhook",
+		FlagSet: func() *flag.FlagSet {
+			fs := flag.NewFlagSet("webhook", flag.ExitOnError)
+			// Deprecated flags.
+			fs.String("api-webhook-allow-list", "", "Set the allowed URLs for the webhook feature using a regular expression")
+			fs.String("api-webhook-deny-list", "", "Set the denied URLs for the webhook feature using a regular expression")
+			fs.String("api-webhook-error-allow-list", "", "Set the allowed URLs in case of an error for the webhook feature using a regular expression")
+			fs.String("api-webhook-error-deny-list", "", "Set the denied URLs in case of an error for the webhook feature using a regular expression")
+			fs.Int("api-webhook-max-retry", 4, "Set the maximum number of retries for the webhook feature")
+			fs.Duration("api-webhook-retry-min-wait", time.Duration(1)*time.Second, "Set the minimum duration to wait before trying to call the webhook again")
+			fs.Duration("api-webhook-retry-max-wait", time.Duration(30)*time.Second, "Set the maximum duration to wait before trying to call the webhook again")
+			fs.Bool("api-disable-webhook", false, "Disable the webhook feature")
+
+			var err error
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-allow-list", "use webhook-allow-list instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-deny-list", "use webhook-deny-list instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-error-allow-list", "use webhook-error-allow-list instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-error-deny-list", "use webhook-error-deny-list instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-max-retry", "use webhook-max-retry instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-retry-min-wait", "use webhook-retry-min-wait instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-webhook-retry-max-wait", "use webhook-retry-max-wait instead"))
+			err = multierr.Append(err, fs.MarkDeprecated("api-disable-webhook", "use webhook-disable instead"))
+
+			if err != nil {
+				panic(fmt.Errorf("create deprecated flags for webhook module: %v", err))
+			}
+
+			// New flags.
+			fs.String("webhook-allow-list", "", "Set the allowed URLs for the webhook feature using a regular expression")
+			fs.String("webhook-deny-list", "", "Set the denied URLs for the webhook feature using a regular expression")
+			fs.String("webhook-error-allow-list", "", "Set the allowed URLs in case of an error for the webhook feature using a regular expression")
+			fs.String("webhook-error-deny-list", "", "Set the denied URLs in case of an error for the webhook feature using a regular expression")
+			fs.Int("webhook-max-retry", 4, "Set the maximum number of retries for the webhook feature")
+			fs.Duration("webhook-retry-min-wait", time.Duration(1)*time.Second, "Set the minimum duration to wait before trying to call the webhook again")
+			fs.Duration("webhook-retry-max-wait", time.Duration(30)*time.Second, "Set the maximum duration to wait before trying to call the webhook again")
+			fs.Bool("webhook-disable", false, "Disable the webhook feature")
+
+			return fs
+		}(),
+		New: func() gotenberg.Module { return new(Webhook) },
+	}
+}
+
+// Provision sets the module properties.
+func (w *Webhook) Provision(ctx *gotenberg.Context) error {
+	flags := ctx.ParsedFlags()
+	w.allowList = flags.MustDeprecatedRegexp("api-webhook-allow-list", "webhook-allow-list")
+	w.denyList = flags.MustDeprecatedRegexp("api-webhook-deny-list", "webhook-deny-list")
+	w.errorAllowList = flags.MustDeprecatedRegexp("api-webhook-error-allow-list", "webhook-error-allow-list")
+	w.errorDenyList = flags.MustDeprecatedRegexp("api-webhook-error-deny-list", "webhook-error-deny-list")
+	w.maxRetry = flags.MustDeprecatedInt("api-webhook-max-retry", "webhook-max-retry")
+	w.retryMinWait = flags.MustDeprecatedDuration("api-webhook-retry-min-wait", "webhook-retry-min-wait")
+	w.retryMaxWait = flags.MustDeprecatedDuration("api-webhook-retry-min-wait", "webhook-retry-max-wait")
+	w.disable = flags.MustDeprecatedBool("api-disable-webhook", "webhook-disable")
+
+	return nil
+}
+
+// Middlewares returns the middleware.
+func (w Webhook) Middlewares() ([]api.Middleware, error) {
+	if w.disable {
+		return nil, nil
+	}
+
+	return []api.Middleware{
+		webhookMiddleware(w),
+	}, nil
+}
+
+// AddGraceDuration increases the grace duration provided by the API for the
+// garbage collector.
+func (w Webhook) AddGraceDuration() time.Duration {
+	var duration time.Duration
+
+	if w.disable {
+		return duration
+	}
+
+	for i := 0; i < w.maxRetry; i++ {
+		// Yep... Golang does not allow int * time.Duration.
+		duration += w.retryMaxWait
+	}
+
+	return duration
+}
+
+// Interface guards.
+var (
+	_ gotenberg.Module                             = (*Webhook)(nil)
+	_ gotenberg.Provisioner                        = (*Webhook)(nil)
+	_ api.MiddlewareProvider                       = (*Webhook)(nil)
+	_ api.GarbageCollectorGraceDurationIncrementer = (*Webhook)(nil)
+)