prometheus/retrieval/discovery/file_test.go
Julius Volz 20d0bf4d65 Fix flakey FileSD test.
When the test ends, all files matching the watcher's glob are removed
via defer. In that moment, the draining goroutine may still be running
and then detect no files matching the configured glob just before the
test exits.

This is now solved by waiting for the draining goroutine to finish
before leaving the test function and thus causing the deferred file
removal.
2016-01-11 16:48:12 +01:00

111 lines
2.6 KiB
Go

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
}