Add a DeferExitHandler function

Useful for running exit handlers in the same order as defer statements
This commit is contained in:
Georgi Dimitrov 2019-01-29 18:29:38 +00:00 committed by Richard Poirier
parent 7d8d63893b
commit 4ea4861398
2 changed files with 70 additions and 6 deletions

View File

@ -51,9 +51,9 @@ func Exit(code int) {
os.Exit(code)
}
// RegisterExitHandler adds a Logrus Exit handler, call logrus.Exit to invoke
// all handlers. The handlers will also be invoked when any Fatal log entry is
// made.
// RegisterExitHandler appends a Logrus Exit handler to the list of handlers,
// call logrus.Exit to invoke all handlers. The handlers will also be invoked when
// any Fatal log entry is made.
//
// This method is useful when a caller wishes to use logrus to log a fatal
// message but also needs to gracefully shutdown. An example usecase could be
@ -62,3 +62,15 @@ func Exit(code int) {
func RegisterExitHandler(handler func()) {
handlers = append(handlers, handler)
}
// DeferExitHandler prepends a Logrus Exit handler to the list of handlers,
// call logrus.Exit to invoke all handlers. The handlers will also be invoked when
// any Fatal log entry is made.
//
// This method is useful when a caller wishes to use logrus to log a fatal
// message but also needs to gracefully shutdown. An example usecase could be
// closing database connections, or sending a alert that the application is
// closing.
func DeferExitHandler(handler func()) {
handlers = append([]func(){handler}, handlers...)
}

View File

@ -14,9 +14,61 @@ import (
func TestRegister(t *testing.T) {
current := len(handlers)
RegisterExitHandler(func() {})
if len(handlers) != current+1 {
t.Fatalf("expected %d handlers, got %d", current+1, len(handlers))
var results []string
h1 := func() { results = append(results, "first") }
h2 := func() { results = append(results, "second") }
RegisterExitHandler(h1)
RegisterExitHandler(h2)
if len(handlers) != current+2 {
t.Fatalf("expected %d handlers, got %d", current+2, len(handlers))
}
runHandlers()
if len(results) != 2 {
t.Fatalf("expected 2 handlers to be run, ran %d", len(results))
}
if results[0] != "first" {
t.Fatal("expected handler h1 to be run first, but it wasn't")
}
if results[1] != "second" {
t.Fatal("expected handler h2 to be run second, but it wasn't")
}
}
func TestDefer(t *testing.T) {
current := len(handlers)
var results []string
h1 := func() { results = append(results, "first") }
h2 := func() { results = append(results, "second") }
DeferExitHandler(h1)
DeferExitHandler(h2)
if len(handlers) != current+2 {
t.Fatalf("expected %d handlers, got %d", current+2, len(handlers))
}
runHandlers()
if len(results) != 2 {
t.Fatalf("expected 2 handlers to be run, ran %d", len(results))
}
if results[0] != "second" {
t.Fatal("expected handler h2 to be run first, but it wasn't")
}
if results[1] != "first" {
t.Fatal("expected handler h1 to be run second, but it wasn't")
}
}