From 44ff19e779aaa93329849e132d929e72eca34b41 Mon Sep 17 00:00:00 2001
From: Matthieu 'JP' DERASSE <github@derasse.fr>
Date: Mon, 9 Jan 2023 19:44:29 +0000
Subject: [PATCH] feat(server): Handle creation of a webserver

---
 commonctx/README.md    |  2 ++
 commonctx/logger.go    | 17 ++++++++++
 middleware/README.md   |  2 ++
 server/server.go       |  4 +--
 webserver/webserver.go | 72 ++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 commonctx/README.md
 create mode 100644 commonctx/logger.go
 create mode 100644 middleware/README.md
 create mode 100644 webserver/webserver.go

diff --git a/commonctx/README.md b/commonctx/README.md
new file mode 100644
index 0000000..6b44b2a
--- /dev/null
+++ b/commonctx/README.md
@@ -0,0 +1,2 @@
+# Common Context
+Contain code that will make work with context easier
\ No newline at end of file
diff --git a/commonctx/logger.go b/commonctx/logger.go
new file mode 100644
index 0000000..1454671
--- /dev/null
+++ b/commonctx/logger.go
@@ -0,0 +1,17 @@
+package commonctx
+
+import (
+	"context"
+
+	"github.com/sirupsen/logrus"
+)
+
+const LoggerKey = "mainLogger"
+
+func AddMainLogger(ctx context.Context, logger *logrus.Logger) context.Context {
+	return context.WithValue(ctx, LoggerKey, logger)
+}
+
+func GetLogger(ctx context.Context) *logrus.Logger {
+	return ctx.Value(LoggerKey).(*logrus.Logger)
+}
diff --git a/middleware/README.md b/middleware/README.md
new file mode 100644
index 0000000..9e66e5f
--- /dev/null
+++ b/middleware/README.md
@@ -0,0 +1,2 @@
+# Middleware Common
+Contain http middlewares that are helpful in the creation of a new webserver
\ No newline at end of file
diff --git a/server/server.go b/server/server.go
index dd0c497..e008353 100644
--- a/server/server.go
+++ b/server/server.go
@@ -25,11 +25,11 @@ func GetListenAddressFromEnvOrFlags() (string, error) {
 	pHost := flag.String("host", host, "Host address to listen to")
 	pPort := flag.String("port", port, "Port to listen to")
 
-	if govalidator.IsHost(*pHost) {
+	if !govalidator.IsHost(*pHost) {
 		return "", fmt.Errorf("provided 'host' is invalid")
 	}
 
-	if govalidator.IsPort(*pPort) {
+	if !govalidator.IsPort(*pPort) {
 		return "", fmt.Errorf("provided 'port' is invalid")
 	}
 
diff --git a/webserver/webserver.go b/webserver/webserver.go
new file mode 100644
index 0000000..c689ad6
--- /dev/null
+++ b/webserver/webserver.go
@@ -0,0 +1,72 @@
+package webserver
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"git.dev.m-and-m.ovh/mderasse/gocommon/commonctx"
+)
+
+const defaultTimeout = 90 * time.Second
+const defaultShutdownTimeout = 10 * time.Second
+
+type cleanupFunc func() error
+
+type ExecuteServerParams struct {
+	Cleanup         cleanupFunc
+	ShutdownTimeout *time.Duration
+}
+
+func ExecuteServer(ctx context.Context, srv *http.Server, params *ExecuteServerParams) error {
+
+	log := commonctx.GetLogger(ctx)
+
+	if srv == nil {
+		return fmt.Errorf("missing http.server params")
+	}
+
+	if srv.ReadTimeout == 0 {
+		srv.ReadTimeout = defaultTimeout
+	}
+
+	if srv.WriteTimeout == 0 {
+		srv.WriteTimeout = defaultTimeout
+	}
+
+	log.Infof("launching webserver on %s", srv.Addr)
+
+	go func() {
+		if err := srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
+			log.WithError(err).Fatalf("HTTP server error: %v", err)
+		}
+		log.Info("Stopped serving new connections.")
+	}()
+
+	sigChan := make(chan os.Signal, 1)
+	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
+	<-sigChan
+
+	shutdownCtx, shutdownRelease := context.WithTimeout(ctx, defaultShutdownTimeout)
+	defer shutdownRelease()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		log.WithError(err).Warnf("HTTP shutdown error: %v", err)
+	}
+
+	if params.Cleanup != nil {
+		if err := params.Cleanup(); err != nil {
+			log.WithError(err).Warnf("Impossible to cleanup correctly after shutdown. error : %v", err)
+			return nil
+		}
+	}
+
+	log.Info("Graceful shutdown complete.")
+
+	return nil
+}