minio/utils.go
Harshavardhana 0188cd0b84 utils: Take monitorShutdownSignal to take an exitFunc which would executed upon error. (#2378)
This hook approach allows program to keep running but being able to handle exiting
of the program in the dynamic way.

Fixes #2377
2016-08-06 23:53:10 -07:00

138 lines
4.0 KiB
Go

/*
* Minio Cloud Storage, (C) 2015 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"encoding/base64"
"encoding/xml"
"io"
"os"
"strings"
"syscall"
)
// xmlDecoder provide decoded value in xml.
func xmlDecoder(body io.Reader, v interface{}, size int64) error {
var lbody io.Reader
if size > 0 {
lbody = io.LimitReader(body, size)
} else {
lbody = body
}
d := xml.NewDecoder(lbody)
return d.Decode(v)
}
// checkValidMD5 - verify if valid md5, returns md5 in bytes.
func checkValidMD5(md5 string) ([]byte, error) {
return base64.StdEncoding.DecodeString(strings.TrimSpace(md5))
}
/// http://docs.aws.amazon.com/AmazonS3/latest/dev/UploadingObjects.html
const (
// maximum object size per PUT request is 5GiB
maxObjectSize = 1024 * 1024 * 1024 * 5
// minimum Part size for multipart upload is 5MB
minPartSize = 1024 * 1024 * 5
// maximum Part ID for multipart upload is 10000 (Acceptable values range from 1 to 10000 inclusive)
maxPartID = 10000
)
// isMaxObjectSize - verify if max object size
func isMaxObjectSize(size int64) bool {
return size > maxObjectSize
}
// Check if part size is more than or equal to minimum allowed size.
func isMinAllowedPartSize(size int64) bool {
return size >= minPartSize
}
// isMaxPartNumber - Check if part ID is greater than the maximum allowed ID.
func isMaxPartID(partID int) bool {
return partID > maxPartID
}
func contains(stringList []string, element string) bool {
for _, e := range stringList {
if e == element {
return true
}
}
return false
}
// shutdownSignal - is the channel that receives any boolean when
// we want broadcast the start of shutdown
var shutdownSignal chan bool
// shutdownCallbacks - is the list of function callbacks executed one by one
// when a shutdown starts. A callback returns 0 for success and 1 for failure.
// Failure is considered an emergency error that needs an immediate exit
var shutdownCallbacks []func() errCode
// shutdownObjectStorageCallbacks - contains the list of function callbacks that
// need to be invoked when a shutdown starts. These callbacks will be called before
// the general callback shutdowns
var shutdownObjectStorageCallbacks []func() errCode
// Register callback functions that need to be called when process terminates.
func registerShutdown(callback func() errCode) {
shutdownCallbacks = append(shutdownCallbacks, callback)
}
// Register object storagecallback functions that need to be called when process terminates.
func registerObjectStorageShutdown(callback func() errCode) {
shutdownObjectStorageCallbacks = append(shutdownObjectStorageCallbacks, callback)
}
// Represents a type of an exit func which will be invoked during shutdown signal.
type onExitFunc func(code int)
// Start to monitor shutdownSignal to execute shutdown callbacks
func monitorShutdownSignal(onExitFn onExitFunc) {
go func() {
// Monitor signals.
trapCh := signalTrap(os.Interrupt, syscall.SIGTERM)
for {
select {
case <-trapCh:
// Start a graceful shutdown call
shutdownSignal <- true
case <-shutdownSignal:
// Call all callbacks and exit for emergency
for _, callback := range shutdownCallbacks {
exitCode := callback()
if exitCode != exitSuccess {
onExitFn(int(exitCode))
}
}
// Call all object storage shutdown callbacks and exit for emergency
for _, callback := range shutdownObjectStorageCallbacks {
exitCode := callback()
if exitCode != exitSuccess {
onExitFn(int(exitCode))
}
}
onExitFn(int(exitSuccess))
}
}
}()
}