Queue: Make WorkerPools and Queues flushable (#10001)

* Make WorkerPools and Queues flushable

Adds Flush methods to Queues and the WorkerPool
Further abstracts the WorkerPool
Adds a final step to Flush the queues in the defer from PrintCurrentTest
Fixes an issue with Settings inheritance in queues

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Change to for loop

* Add IsEmpty and begin just making the queues composed WorkerPools

* subsume workerpool into the queues and create a flushable interface

* Add manager command

* Move flushall to queue.Manager and add to testlogger

* As per @guillep2k

* as per @guillep2k

* Just make queues all implement flushable and clean up the wrapped queue flushes

* cope with no timeout

Co-authored-by: Lauris BH <lauris@nix.lv>

cmd/manager.go

@@ -0,0 +1,92 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"code.gitea.io/gitea/modules/private"
+
+	"github.com/urfave/cli"
+)
+
+var (
+	// CmdManager represents the manager command
+	CmdManager = cli.Command{
+		Name:        "manager",
+		Usage:       "Manage the running gitea process",
+		Description: "This is a command for managing the running gitea process",
+		Subcommands: []cli.Command{
+			subcmdShutdown,
+			subcmdRestart,
+			subcmdFlushQueues,
+		},
+	}
+	subcmdShutdown = cli.Command{
+		Name:   "shutdown",
+		Usage:  "Gracefully shutdown the running process",
+		Action: runShutdown,
+	}
+	subcmdRestart = cli.Command{
+		Name:   "restart",
+		Usage:  "Gracefully restart the running process - (not implemented for windows servers)",
+		Action: runRestart,
+	}
+	subcmdFlushQueues = cli.Command{
+		Name:   "flush-queues",
+		Usage:  "Flush queues in the running process",
+		Action: runFlushQueues,
+		Flags: []cli.Flag{
+			cli.DurationFlag{
+				Name:  "timeout",
+				Value: 60 * time.Second,
+				Usage: "Timeout for the flushing process",
+			},
+			cli.BoolFlag{
+				Name:  "non-blocking",
+				Usage: "Set to true to not wait for flush to complete before returning",
+			},
+		},
+	}
+)
+
+func runShutdown(c *cli.Context) error {
+	setup("manager", false)
+	statusCode, msg := private.Shutdown()
+	switch statusCode {
+	case http.StatusInternalServerError:
+		fail("InternalServerError", msg)
+	}
+
+	fmt.Fprintln(os.Stdout, msg)
+	return nil
+}
+
+func runRestart(c *cli.Context) error {
+	setup("manager", false)
+	statusCode, msg := private.Restart()
+	switch statusCode {
+	case http.StatusInternalServerError:
+		fail("InternalServerError", msg)
+	}
+
+	fmt.Fprintln(os.Stdout, msg)
+	return nil
+}
+
+func runFlushQueues(c *cli.Context) error {
+	setup("manager", false)
+	statusCode, msg := private.FlushQueues(c.Duration("timeout"), c.Bool("non-blocking"))
+	switch statusCode {
+	case http.StatusInternalServerError:
+		fail("InternalServerError", msg)
+	}
+
+	fmt.Fprintln(os.Stdout, msg)
+	return nil
+}