From 4345e5d899f0630b3caf68dffaa46c8b02cccc04 Mon Sep 17 00:00:00 2001
From: Jan Dittberner <jandd@cacert.org>
Date: Sat, 3 Dec 2022 13:35:56 +0100
Subject: [PATCH] Implement graceful shutdown of client

Install handlers for SIGTERM and command line interrupt.
---
 cmd/signerclient/main.go  | 18 +++++++++++++++++-
 go.mod                    |  2 +-
 go.sum                    |  2 ++
 internal/client/client.go |  2 ++
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/cmd/signerclient/main.go b/cmd/signerclient/main.go
index 4358c56..169a56f 100644
--- a/cmd/signerclient/main.go
+++ b/cmd/signerclient/main.go
@@ -24,7 +24,9 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 
 	"github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v3"
@@ -150,7 +152,21 @@ func startClient(configFile string, logger *logrus.Logger) error {
 
 	logger.Info("setup complete, starting client operation")
 
-	if err = signerClient.Run(context.Background()); err != nil {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+
+	go func() {
+		<-c
+
+		logger.Info("received shutdown signal")
+
+		cancel()
+	}()
+
+	if err = signerClient.Run(ctx); err != nil {
 		return fmt.Errorf("error in client: %w", err)
 	}
 
diff --git a/go.mod b/go.mod
index 052ca2c..640f1a1 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module git.cacert.org/cacert-gosignerclient
 go 1.19
 
 require (
-	git.cacert.org/cacert-gosigner v0.0.0-20221203104439-bc81ab84cb4a
+	git.cacert.org/cacert-gosigner v0.0.0-20221203123337-46407b368528
 	github.com/balacode/go-delta v0.1.0
 	github.com/shamaton/msgpackgen v0.3.0
 	github.com/sirupsen/logrus v1.9.0
diff --git a/go.sum b/go.sum
index 6eabf0b..cf3ee8e 100644
--- a/go.sum
+++ b/go.sum
@@ -6,6 +6,8 @@ git.cacert.org/cacert-gosigner v0.0.0-20221202173159-afe7d23c9b6f h1:VcIwyogvdmY
 git.cacert.org/cacert-gosigner v0.0.0-20221202173159-afe7d23c9b6f/go.mod h1:OGIB5wLUhJiBhTzSXReOhGxuy7sT5VvyOyT8Ux8EGyw=
 git.cacert.org/cacert-gosigner v0.0.0-20221203104439-bc81ab84cb4a h1:yX3lhEoBQkUKu23xggAzAeYWuziCkRYktSjsAOfNGHY=
 git.cacert.org/cacert-gosigner v0.0.0-20221203104439-bc81ab84cb4a/go.mod h1:OGIB5wLUhJiBhTzSXReOhGxuy7sT5VvyOyT8Ux8EGyw=
+git.cacert.org/cacert-gosigner v0.0.0-20221203123337-46407b368528 h1:W1K/YiNp8ganr2GuOpoNC+ZcaVsG15tczpNuvAjHn+U=
+git.cacert.org/cacert-gosigner v0.0.0-20221203123337-46407b368528/go.mod h1:OGIB5wLUhJiBhTzSXReOhGxuy7sT5VvyOyT8Ux8EGyw=
 github.com/balacode/go-delta v0.1.0 h1:pwz4CMn06P2bIaIfAx3GSabMPwJp/Ww4if+7SgPYa3I=
 github.com/balacode/go-delta v0.1.0/go.mod h1:wLNrwTI3lHbPBvnLzqbHmA7HVVlm1u22XLvhbeA6t3o=
 github.com/balacode/zr v1.0.0/go.mod h1:pLeSAL3DhZ9L0JuiRkUtIX3mLOCtzBLnDhfmykbSmkE=
diff --git a/internal/client/client.go b/internal/client/client.go
index dabdd11..92e7d48 100644
--- a/internal/client/client.go
+++ b/internal/client/client.go
@@ -133,6 +133,8 @@ func (c *Client) Run(ctx context.Context) error {
 	}(c.framer)
 
 	go func() {
+		defer wg.Done()
+
 		clientProtocol := protocol.NewClient(c.handler, c.commands, c.in, c.out, c.logger)
 
 		err := clientProtocol.Handle(subCtx)