LogDog Butler: Catch SIGTERM on Linux.

client/cmd/logdog_butler/main_posix.go

Index: client/cmd/logdog_butler/main_posix.go
diff --git a/client/cmd/logdog_butler/streamserver_posix.go b/client/cmd/logdog_butler/main_posix.go
similarity index 87%
rename from client/cmd/logdog_butler/streamserver_posix.go
rename to client/cmd/logdog_butler/main_posix.go
index eb2b2dba155d947d87d690f32db04a6db13320c7..44d76c7db86e520aadb33b6cfc8e3f6f00ff2a4a 100644
--- a/client/cmd/logdog_butler/streamserver_posix.go
+++ b/client/cmd/logdog_butler/main_posix.go
@@ -9,6 +9,8 @@ package main
 import (
 	"errors"
 	"fmt"
+	"os"
+	"syscall"
 
 	"github.com/luci/luci-go/client/internal/logdog/butler/streamserver"
 	"golang.org/x/net/context"
@@ -19,6 +21,13 @@ const (
 	exampleStreamServerURI = streamServerURI("unix:/var/run/butler.sock")
 )
 
+// interruptSignals is the set of signals to handle gracefully (e.g., flush,
+// shutdown).
+var interruptSignals = []os.Signal{
+	os.Interrupt,
+	syscall.SIGTERM,
+}
+
 type streamServerURI string
 
 func (u streamServerURI) Parse() (string, error) {