From ec7a8ca61aa294afc7aeb1a2f0bc05221375394c Mon Sep 17 00:00:00 2001
From: surtur <wanderer@dotya.ml>
Date: Tue, 22 Aug 2023 20:56:32 +0200
Subject: [PATCH] go: run requests scheduler from main

* also, actually quit serving on shutdown timeout
---
 error.go |  9 +++++----
 run.go   | 60 +++++++++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 56 insertions(+), 13 deletions(-)

diff --git a/error.go b/error.go
index 8107477..3eadd06 100644
--- a/error.go
+++ b/error.go
@@ -6,8 +6,9 @@ package main
 import "errors"
 
 var (
-	errDBNotConfigured   = errors.New("Database connection string or database type were not set")
-	errUnsupportedDBType = errors.New("DBTYPE can only be one of postgres or sqlite3")
-	errDBConnFailed      = errors.New("Failed to open a connection to the database")
-	errImportFailed      = errors.New("Import of local breach data failed")
+	errDBNotConfigured     = errors.New("Database connection string or database type were not set")
+	errUnsupportedDBType   = errors.New("DBTYPE can only be one of postgres or sqlite3")
+	errDBConnFailed        = errors.New("Failed to open a connection to the database")
+	errImportFailed        = errors.New("Import of local breach data failed")
+	errHIBPSchedulerFailed = errors.New("HIBP requests scheduler failed")
 )
diff --git a/run.go b/run.go
index 59d6dd8..1a9309a 100644
--- a/run.go
+++ b/run.go
@@ -11,6 +11,7 @@ import (
 	"os"
 	"os/signal"
 	"strconv"
+	"sync"
 	"syscall"
 	"time"
 
@@ -25,6 +26,7 @@ import (
 	"git.dotya.ml/mirre-mt/pcmt/config"
 	"git.dotya.ml/mirre-mt/pcmt/ent"
 	moddb "git.dotya.ml/mirre-mt/pcmt/modules/db"
+	"git.dotya.ml/mirre-mt/pcmt/modules/hibp"
 	"git.dotya.ml/mirre-mt/pcmt/modules/localbreach"
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
 )
@@ -248,9 +250,9 @@ func run() error { //nolint:gocognit
 	// channel used to check whether the app had troubles starting up.
 	started := make(chan error, 1)
 
-	defer close(started)
+	go func() {
+		defer close(started)
 
-	go func(ok chan error) {
 		p := setting.Port()
 		h := setting.Host()
 
@@ -259,38 +261,60 @@ func run() error { //nolint:gocognit
 		if err := e.Start(address); err != nil && err != http.ErrServerClosed {
 			log.Error("troubles running the server, bailing...", "error", err)
 
-			ok <- err
+			started <- err
 
 			return
 		}
 
-		ok <- nil
-	}(started)
+		started <- nil
+	}()
 
 	quit := make(chan os.Signal, 1)
+	schedQuit := make(chan os.Signal, 1)
+	errCh := make(chan error, 1)
+	wg := &sync.WaitGroup{}
 
-	signal.Notify(quit, os.Interrupt)
-	signal.Notify(quit, syscall.SIGTERM)
-	signal.Notify(quit, syscall.SIGHUP)
+	handleSigs(schedQuit, quit)
+
+	go func() {
+		wg.Add(1)                                     // nolint:staticcheck
+		go hibp.RunReqScheduler(schedQuit, errCh, wg) // nolint:wsl
+	}()
 
 	// non-blocking channel receive.
 	select {
+	// monitor the server start-up chan.
 	case err := <-started:
 		if err != nil {
 			return err
 		}
 
+	case err := <-errCh:
+		defer func() {
+			signal.Stop(quit)
+
+			close(quit)
+			close(errCh)
+		}()
+
+		if err != nil {
+			return errHIBPSchedulerFailed
+		}
+
 	case <-quit:
+		// after the timeout the server forcefully quits.
 		shutdownTimeout := 10 * time.Second
 
+		log.Infof("Interrupt received, gracefully shutting down the server (timeout %s)", shutdownTimeout)
+
 		ctx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
 		defer func() {
-			log.Infof("Interrupt received, gracefully shutting down the server (timeout %s)", shutdownTimeout)
 			cancel()
 
 			signal.Stop(quit)
 
 			close(quit)
+			close(errCh)
 
 			log.Info("Bye!")
 		}()
@@ -299,11 +323,29 @@ func run() error { //nolint:gocognit
 			log.Error("There was an error shutting the server down")
 			return err
 		}
+
+		select {
+		case <-ctx.Done():
+			log.Error("Failed to stop the server in time, yolo")
+			return ctx.Err()
+
+		default:
+			wg.Wait()
+		}
 	}
 
 	return nil
 }
 
+// handleSigs configures given chans to be notified on os signals.
+func handleSigs(chans ...chan os.Signal) {
+	sigs := []os.Signal{os.Interrupt, syscall.SIGHUP, syscall.SIGTERM}
+
+	for _, ch := range chans {
+		signal.Notify(ch, sigs...)
+	}
+}
+
 func printHeader() {
 	slug := fmt.Sprintf(slug, version)