Restore Graceful Restarting & Socket Activation (#7274)

* Prevent deadlock in indexer initialisation during graceful restart

* Move from gracehttp to our own service to add graceful ssh

* Add timeout for start of indexers and make hammer time configurable

* Fix issue with re-initialization in indexer during tests

* move the code to detect use of closed to graceful

* Handle logs gracefully - add a pid suffix just before restart

* Move to using a cond and a holder for indexers

* use time.Since

* Add some comments and attribution

* update modules.txt

* Use zero to disable timeout

* Move RestartProcess to its own file

* Add cleanup routine

modules/indexer/issues/indexer_test.go

@@ -5,7 +5,6 @@
 package issues
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -17,11 +16,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func fatalTestError(fmtStr string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, fmtStr, args...)
-	os.Exit(1)
-}
-
 func TestMain(m *testing.M) {
 	models.MainTest(m, filepath.Join("..", "..", ".."))
 }
@@ -32,9 +26,7 @@ func TestBleveSearchIssues(t *testing.T) {
 	os.RemoveAll(setting.Indexer.IssueQueueDir)
 	os.RemoveAll(setting.Indexer.IssuePath)
 	setting.Indexer.IssueType = "bleve"
-	if err := InitIssueIndexer(true); err != nil {
-		fatalTestError("Error InitIssueIndexer: %v\n", err)
-	}
+	InitIssueIndexer(true)
 
 	time.Sleep(5 * time.Second)
 
@@ -59,9 +51,7 @@ func TestDBSearchIssues(t *testing.T) {
 	assert.NoError(t, models.PrepareTestDatabase())
 
 	setting.Indexer.IssueType = "db"
-	if err := InitIssueIndexer(true); err != nil {
-		fatalTestError("Error InitIssueIndexer: %v\n", err)
-	}
+	InitIssueIndexer(true)
 
 	ids, err := SearchIssuesByKeyword(1, "issue2")
 	assert.NoError(t, err)