custom-script-extension-linux/main/status.go

147 строки
4.0 KiB
Go

package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"time"
"github.com/go-kit/kit/log"
"github.com/pkg/errors"
)
type StatusReport []StatusItem
type StatusItem struct {
Version float64 `json:"version"`
TimestampUTC string `json:"timestampUTC"`
Status Status `json:"status"`
}
type Type string
const (
StatusTransitioning Type = "transitioning"
StatusError Type = "error"
StatusSuccess Type = "success"
)
type Status struct {
Operation string `json:"operation"`
Status Type `json:"status"`
FormattedMessage FormattedMessage `json:"formattedMessage"`
}
type FormattedMessage struct {
Lang string `json:"lang"`
Message string `json:"message"`
}
func NewStatus(t Type, operation, message string) StatusReport {
return []StatusItem{
{
Version: 1.0,
TimestampUTC: time.Now().UTC().Format(time.RFC3339),
Status: Status{
Operation: operation,
Status: t,
FormattedMessage: FormattedMessage{
Lang: "en",
Message: message},
},
},
}
}
func (r StatusReport) marshal() ([]byte, error) {
return json.MarshalIndent(r, "", "\t")
}
// Save persists the status message to the specified status folder using the
// sequence number. The operation consists of writing to a temporary file in the
// same folder and moving it to the final destination for atomicity.
func (r StatusReport) Save(statusFolder string, seqNum int) error {
fn := fmt.Sprintf("%d.status", seqNum)
path := filepath.Join(statusFolder, fn)
tmpFile, err := ioutil.TempFile(statusFolder, fn)
if err != nil {
return fmt.Errorf("status: failed to create temporary file: %v", err)
}
tmpFile.Close()
b, err := r.marshal()
if err != nil {
return fmt.Errorf("status: failed to marshal into json: %v", err)
}
if err := ioutil.WriteFile(tmpFile.Name(), b, 0644); err != nil {
return fmt.Errorf("status: failed to path=%s error=%v", tmpFile.Name(), err)
}
if err := os.Rename(tmpFile.Name(), path); err != nil {
return fmt.Errorf("status: failed to move to path=%s error=%v", path, err)
}
return nil
}
// reportStatus saves operation status to the status file for the extension
// handler with the optional given message, if the given cmd requires reporting
// status.
//
// If an error occurs reporting the status, it will be logged and returned.
func reportStatus(ctx *log.Context, hEnv HandlerEnvironment, seqNum int, t Type, c cmd, msg string) error {
if !c.shouldReportStatus {
ctx.Log("status", "not reported for operation (by design)")
return nil
}
s := NewStatus(t, c.name, statusMsg(c, t, msg))
if err := s.Save(hEnv.HandlerEnvironment.StatusFolder, seqNum); err != nil {
ctx.Log("event", "failed to save handler status", "error", err)
return errors.Wrap(err, "failed to save handler status")
}
return nil
}
// readStatus loads current status file in StatusReport
func readStatus(ctx *log.Context, hEnv HandlerEnvironment, seqNum int) (Type, error) {
fileName := fmt.Sprintf("%d.status", seqNum)
path := filepath.Join(hEnv.HandlerEnvironment.StatusFolder, fileName)
buffer, err := ioutil.ReadFile(path)
if err != nil {
return "", fmt.Errorf("Error reading status file %s: %v", path, err)
}
var statusReport StatusReport
if err := json.Unmarshal(buffer, &statusReport); err != nil {
return "", fmt.Errorf("error parsing json: %v", err)
}
if len(statusReport) != 1 {
return "", fmt.Errorf("wrong statusReport count. expected:1, got:%d", len(statusReport))
}
return statusReport[0].Status.Status, nil
}
// statusMsg creates the reported status message based on the provided operation
// type and the given message string.
//
// A message will be generated for empty string. For error status, pass the
// error message.
func statusMsg(c cmd, t Type, msg string) string {
s := c.name
switch t {
case StatusSuccess:
s += " succeeded"
case StatusTransitioning:
s += " in progress"
case StatusError:
s += " failed"
}
if msg != "" {
// append the original
s += ": " + msg
}
return s
}