From 2754d20a2d82c3aa47e35f3015a575fa7cca9e3c Mon Sep 17 00:00:00 2001
From: Caleb Doxsey <cdoxsey@pomerium.com>
Date: Fri, 31 Jan 2025 18:31:47 -0700
Subject: [PATCH] config: handle SIGHUP (#5459)

---
 config/config_source.go      | 13 +++++++++++-
 config/config_source_test.go | 40 ++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/config/config_source.go b/config/config_source.go
index 194c82474..cca12f1a2 100644
--- a/config/config_source.go
+++ b/config/config_source.go
@@ -5,7 +5,9 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"os/signal"
 	"sync"
+	"syscall"
 
 	"github.com/google/uuid"
 	"github.com/rs/zerolog"
@@ -145,6 +147,16 @@ func NewFileOrEnvironmentSource(
 	ch := src.watcher.Bind()
 	go func() {
 		for range ch {
+			log.Ctx(ctx).Info().Msg("config: file updated, reconfiguring...")
+			src.check(ctx)
+		}
+	}()
+
+	sch := make(chan os.Signal, 1)
+	signal.Notify(sch, syscall.SIGHUP)
+	go func() {
+		for range sch {
+			log.Ctx(ctx).Info().Msg("config: received SIGHUP, reloading config")
 			src.check(ctx)
 		}
 	}()
@@ -156,7 +168,6 @@ func (src *FileOrEnvironmentSource) check(ctx context.Context) {
 	ctx = log.WithContext(ctx, func(c zerolog.Context) zerolog.Context {
 		return c.Str("config_change_id", uuid.New().String())
 	})
-	log.Ctx(ctx).Info().Msg("config: file updated, reconfiguring...")
 	src.mu.Lock()
 	cfg := src.config
 	options, err := newOptionsFromConfig(src.configFile)
diff --git a/config/config_source_test.go b/config/config_source_test.go
index 4ff6ce7f4..6ffacb3d9 100644
--- a/config/config_source_test.go
+++ b/config/config_source_test.go
@@ -5,14 +5,23 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
+	"syscall"
 	"testing"
 	"time"
 
+	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/pomerium/pomerium/internal/signal"
+	"github.com/pomerium/pomerium/internal/testutil"
 )
 
 func TestFileWatcherSource(t *testing.T) {
+	t.Parallel()
+
 	tmpdir := t.TempDir()
 
 	err := os.WriteFile(filepath.Join(tmpdir, "example.txt"), []byte{1}, 0o600)
@@ -104,6 +113,8 @@ func TestFileWatcherSource(t *testing.T) {
 }
 
 func TestFileOrEnvironmentSource(t *testing.T) {
+	t.Parallel()
+
 	tmpdir := t.TempDir()
 
 	err := os.WriteFile(filepath.Join(tmpdir, "example.txt"), []byte{1}, 0o600)
@@ -201,4 +212,33 @@ runtime_flags:
 
 	t.Run("Hot Reload Enabled", newTest(true))
 	t.Run("Hot Reload Disabled", newTest(false))
+
+	t.Run("SIGHUP", func(t *testing.T) {
+		t.Parallel()
+
+		ready := signal.New()
+		readyCh := ready.Bind()
+
+		ctx := testutil.GetContext(t, time.Minute)
+		ctx = log.Ctx(ctx).Hook(zerolog.HookFunc(func(_ *zerolog.Event, _ zerolog.Level, message string) {
+			if strings.Contains(message, "received SIGHUP") {
+				ready.Broadcast(ctx)
+			}
+		})).WithContext(ctx)
+		tmp := t.TempDir()
+
+		cfgFP := filepath.Join(tmp, "config.json")
+		require.NoError(t, os.WriteFile(cfgFP, []byte(`{}`), 0o600))
+
+		_, err := NewFileOrEnvironmentSource(ctx, cfgFP, "")
+		assert.NoError(t, err)
+
+		require.NoError(t, syscall.Kill(syscall.Getpid(), syscall.SIGHUP))
+
+		select {
+		case <-ctx.Done():
+			t.Error("expected to receive SIGHUP log message")
+		case <-readyCh:
+		}
+	})
 }