package discovery import ( "fmt" "io" "os" "testing" "time" "github.com/prometheus/prometheus/config" ) func TestFileSD(t *testing.T) { defer os.Remove("fixtures/_test.yml") defer os.Remove("fixtures/_test.json") testFileSD(t, ".yml") testFileSD(t, ".json") } func testFileSD(t *testing.T, ext string) { // As interval refreshing is more of a fallback, we only want to test // whether file watches work as expected. var conf config.FileSDConfig conf.Names = []string{"fixtures/_*" + ext} conf.RefreshInterval = config.Duration(1 * time.Hour) var ( fsd = NewFileDiscovery(&conf) ch = make(chan *config.TargetGroup) done = make(chan struct{}) ) go fsd.Run(ch, done) select { case <-time.After(25 * time.Millisecond): // Expected. case tg := <-ch: t.Fatalf("Unexpected target group in file discovery: %s", tg) } newf, err := os.Create("fixtures/_test" + ext) if err != nil { t.Fatal(err) } defer newf.Close() f, err := os.Open("fixtures/target_groups" + ext) if err != nil { t.Fatal(err) } defer f.Close() _, err = io.Copy(newf, f) if err != nil { t.Fatal(err) } newf.Close() // The files contain two target groups which are read and sent in order. select { case <-time.After(15 * time.Second): t.Fatalf("Expected new target group but got none") case tg := <-ch: if _, ok := tg.Labels["foo"]; !ok { t.Fatalf("Label not parsed") } if tg.String() != fmt.Sprintf("fixtures/_test%s:0", ext) { t.Fatalf("Unexpected target group %s", tg) } } select { case <-time.After(15 * time.Second): t.Fatalf("Expected new target group but got none") case tg := <-ch: if tg.String() != fmt.Sprintf("fixtures/_test%s:1", ext) { t.Fatalf("Unexpected target group %s", tg) } } // Based on unknown circumstances, sometimes fsnotify will trigger more events in // some runs (which might be empty, chains of different operations etc.). // We have to drain those (as the target manager would) to avoid deadlocking and must // not try to make sense of it all... drained := make(chan struct{}) go func() { for tg := range ch { // Below we will change the file to a bad syntax. Previously extracted target // groups must not be deleted via sending an empty target group. if len(tg.Targets) == 0 { t.Errorf("Unexpected empty target group received: %s", tg) } } close(drained) }() newf, err = os.Create("fixtures/_test.new") if err != nil { t.Fatal(err) } defer os.Remove(newf.Name()) if _, err := newf.Write([]byte("]gibberish\n][")); err != nil { t.Fatal(err) } newf.Close() os.Rename(newf.Name(), "fixtures/_test"+ext) close(done) <-drained }