# Background Tasks

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

			// all remaining cases imply corrupt data/metadata
			driveState = madmin.DriveStateCorrupt
		}

		result.Before.Drives = append(result.Before.Drives, madmin.HealDriveInfo{
			UUID:     "",
			Endpoint: storageEndpoints[i].String(),
			State:    driveState,
		})
		result.After.Drives = append(result.After.Drives, madmin.HealDriveInfo{
			UUID:     "",
			Endpoint: storageEndpoints[i].String(),
			State:    driveState,

)

// loadLoggerWebhookMetrics - `MetricsLoaderFn` for logger webhook
// such as failed messages and total messages.
func loadLoggerWebhookMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	tgts := append(logger.SystemTargets(), logger.AuditTargets()...)
	for _, t := range tgts {
		labels := []string{nameL, t.String(), endpointL, t.Endpoint()}
		m.Set(webhookFailedMessages, float64(t.Stats().FailedMessages), labels...)

	if b.err != nil {
		return 0, b.err
	}
	n := b.Available()
	if n < utf8.UTFMax {
		if b.Flush(); b.err != nil {
			return 0, b.err
		}
		n = b.Available()
		if n < utf8.UTFMax {
			// Can only happen if buffer is silly small.
			return b.WriteString(string(r))
		}
	}
	size = utf8.EncodeRune(b.buf[b.n:], r)
	b.n += size
	return size, nil
}

// WriteString writes a string.

	}, // 9
	{
		ExpectedErr: nil,
		Metadata: map[string]string{
			MetaIV: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 31)...)), MetaAlgorithm: SealAlgorithm,
			MetaSealedKeyS3: base64.StdEncoding.EncodeToString(append([]byte{1}, make([]byte, 63)...)), MetaKeyID: "key-1",
			MetaDataEncryptionKey: base64.StdEncoding.EncodeToString(make([]byte, 48)),
		},

	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	acl := &accessControlPolicy{}
	acl.AccessControlList.Grants = append(acl.AccessControlList.Grants, grant{
		Grantee: grantee{
			XMLNS:  "http://www.w3.org/2001/XMLSchema-instance",
			XMLXSI: "CanonicalUser",
			Type:   "CanonicalUser",
		},
		Permission: "FULL_CONTROL",
	})

	var commandStack []*cobra.Command

	commandStack = append(commandStack, rootCmd)

	for len(commandStack) > 0 {
		n := len(commandStack) - 1
		curCmd := commandStack[n]
		commandStack = commandStack[:n]
		seenCommands[curCmd] = true
		for _, command := range curCmd.Commands() {
			if !seenCommands[command] {
				commandStack = append(commandStack, command)
			}
		}

)

func getJSONStructs(b []byte) ([]interface{}, error) {
	dec := jstream.NewDecoder(bytes.NewBuffer(b), 0).ObjectAsKVS().MaxDepth(100)
	var result []interface{}
	for parsedVal := range dec.Stream() {
		result = append(result, parsedVal.Value)
	}
	if err := dec.Err(); err != nil {
		return nil, err
	}
	return result, nil
}

func TestJsonpathEval(t *testing.T) {
	f, err := os.Open(filepath.Join("jsondata", "books.json"))

type MultiFlag []string

func (m *MultiFlag) String() string {
	if len(*m) == 0 {
		return ""
	}
	return fmt.Sprint(*m)
}

func (m *MultiFlag) Set(val string) error {
	(*m) = append(*m, val)
	return nil
}

func Usage() {
	fmt.Fprintf(os.Stderr, "usage: asm [options] file.s ...\n")
	fmt.Fprintf(os.Stderr, "Flags:\n")
	flag.PrintDefaults()
	os.Exit(2)
}

func Parse() {

	}
}

func printLog(ms diag.Messages, colorize bool) string {
	logOutput := make([]string, 0, len(ms))
	for _, m := range ms {
		logOutput = append(logOutput, render(m, colorize))
	}
	return strings.Join(logOutput, "\n")
}

func printJSON(ms diag.Messages) (string, error) {
	jsonOutput, err := json.MarshalIndent(ms, "", "\t")
	return string(jsonOutput), err
}