goutil

Common and useful utils for the Go project development.

1. Inclusion criteria

Only rely on the Go standard package
Functions or lightweight packages
Non-business related general tools

2. Contents

BitSet A bit set
Calendar Chinese Lunar Calendar, Solar Calendar and cron time rules
CoarseTime Current time truncated to the nearest 100ms
Errors Improved errors package.
Graceful Shutdown or reboot current process gracefully.
GoPool Goroutines' pool
ResPool Resources' pool
Workshop Working workshop
Various Various small functions

3. UtilsAPI

BitSet

A bit set.

import it
```
"github.com/henrylee2cn/goutil/bitset"
```
New creates a bit set object.
```
func New(init ...byte) *BitSet
```
NewFromHex creates a bit set object from hex string.
```
func NewFromHex(s string) (*BitSet, error)
```
Not returns ^b.
```
func (b *BitSet) Not() *BitSet
```
And returns all the "AND" bit sets.
Notes:
If the bitSets are empty, returns b.
```
func (b *BitSet) And(bitSets ...*BitSet) *BitSet
```
Or returns all the "OR" bit sets.
Notes:
If the bitSets are empty, returns b.
```
func (b *BitSet) Or(bitSet ...*BitSet) *BitSet
```
Xor returns all the "XOR" bit sets.
Notes:
If the bitSets are empty, returns b.
```
func (b *BitSet) Xor(bitSet ...*BitSet) *BitSet
```
AndNot returns all the "&^" bit sets.
Notes:
If the bitSets are empty, returns b.
```
func (b *BitSet) AndNot(bitSet ...*BitSet) *BitSet
```
Set sets the bit bool value on the specified offset, and returns the value of before setting.
Notes:
0 means the 1st bit, -1 means the bottom 1th bit, -2 means the bottom 2th bit and so on;
If offset>=len(b.set), automatically grow the bit set;
If the bit offset is out of the left range, returns error.
```
func (b *BitSet) Set(offset int, value bool) (bool, error)
```
Get gets the bit bool value on the specified offset.
Notes:
0 means the 1st bit, -1 means the bottom 1th bit, -2 means the bottom 2th bit and so on;
If offset>=len(b.set), returns false.
```
func (b *BitSet) Get(offset int) bool
```
Range calls f sequentially for each bit present in the bit set.
If f returns false, range stops the iteration.
```
func (b *BitSet) Range(f func(offset int, truth bool) bool) 
```
Count counts the amount of bit set to 1 within the specified range of the bit set.
Notes:
0 means the 1st bit, -1 means the bottom 1th bit, -2 means the bottom 2th bit and so on.
```
func (b *BitSet) Count(start, end int) int
```
Clear clears the bit set.
```
func (b *BitSet) Clear()
```
Size returns the bits size.
```
func (b *BitSet) Size() int
```
Bytes returns the bit set copy bytes.
```
func (b *BitSet) Bytes() []byte
```
Binary returns the bit set by binary type.
Notes:
Paramter sep is the separator between chars.
```
func (b *BitSet) Binary(sep string) string
```
String returns the bit set by hex type.
```
func (b *BitSet) String() string
```
Sub returns the bit subset within the specified range of the bit set.
Notes:
0 means the 1st bit, -1 means the bottom 1th bit, -2 means the bottom 2th bit and so on.
```
func (b *BitSet) Sub(start, end int) *BitSet
```

Calendar

Chinese Lunar Calendar, Solar Calendar and cron time rules.

import it

"github.com/henrylee2cn/goutil/calendar"

Calendar details

CoarseTime

The current time truncated to the nearest second.

import it

"github.com/henrylee2cn/goutil/coarsetime"

FloorTimeNow returns the current time from the range (now-100ms,now]. This is a faster alternative to time.Now().
```
func FloorTimeNow() time.Time
```
CeilingTimeNow returns the current time from the range [now,now+100ms). This is a faster alternative to time.Now().
```
func CeilingTimeNow() time.Time
```

Errors

Errors is improved errors package.

import it
```
"github.com/henrylee2cn/goutil/errors"
```
New returns an error that formats as the given text.
```
func New(text string) error
```
Errorf formats according to a format specifier and returns the string as a value that satisfies error.
```
func Errorf(format string, a ...interface{}) error
```
Merge merges multi errors.
```
func Merge(errs ...error) error
```

Append appends multiple errors to the error.

func Append(err error, errs ...error) error

Graceful

Shutdown or reboot current process gracefully.

import it

"github.com/henrylee2cn/goutil/graceful"

GraceSignal open graceful shutdown or reboot signal.
```
func GraceSignal()
```
SetShutdown sets the function which is called after the process shutdown, and the time-out period for the process shutdown. If 0<=timeout<5s, automatically use 'MinShutdownTimeout'(5s). If timeout<0, indefinite period. 'firstSweepFunc' is first executed. 'beforeExitingFunc' is executed before process exiting.
```
func SetShutdown(timeout time.Duration, firstSweepFunc, beforeExitingFunc func() error)
```
Shutdown closes all the frame process gracefully. Parameter timeout is used to reset time-out period for the process shutdown.
```
func Shutdown(timeout ...time.Duration)
```
Reboot all the frame process gracefully.
Notes:
Windows system are not supported!
```
func Reboot(timeout ...time.Duration)
```
AddInherited adds the files and envs to be inherited by the new process.
Notes:
Only for reboot!
Windows system are not supported!
```
func AddInherited(procFiles []*os.File, envs []*Env)
```

Logger logger interface

Logger interface {
    Infof(format string, v ...interface{})
    Errorf(format string, v ...interface{})
}

SetLog resets logger
```
func SetLog(logger Logger)
```

GoPool

GoPool is a Goroutines pool. It can control concurrent numbers, reuse goroutines.

import it
```
"github.com/henrylee2cn/goutil/pool"
```
GoPool executes concurrently incoming function via a pool of goroutines in FILO order, i.e. the most recently stopped goroutine will execute the next incoming function. Such a scheme keeps CPU caches hot (in theory).
```
type GoPool struct {
    // Has unexported fields.
}
```
NewGoPool creates a new *GoPool. If maxGoroutinesAmount<=0, will use default value. If maxGoroutineIdleDuration<=0, will use default value.
```
func NewGoPool(maxGoroutinesAmount int, maxGoroutineIdleDuration time.Duration) *GoPool
```
Go executes the function via a goroutine. If returns non-nil, the function cannot be executed because exceeded maxGoroutinesAmount limit.
```
func (gp *GoPool) Go(fn func()) error
```
TryGo tries to execute the function via goroutine. If there are no concurrent resources, execute it synchronously.
```
func (gp *GoPool) TryGo(fn func())
```
Stop starts GoPool. If calling 'Go' after calling 'Stop', will no longer reuse goroutine.
```
func (gp *GoPool) Stop()
```

ResPool

ResPool is a high availability/high concurrent resource pool, which automatically manages the number of resources. So it is similar to database/sql's db pool.

import it
```
"github.com/henrylee2cn/goutil/pool"
```

ResPool is a pool of zero or more underlying avatar(resource). It's safe for concurrent use by multiple goroutines. ResPool creates and frees resource automatically; it also maintains a free pool of idle avatar(resource).

type ResPool interface {
    // Name returns the name.
    Name() string
    // Get returns a object in Resource type.
    Get() (Resource, error)
    // GetContext returns a object in Resource type.
    // Support context cancellation.
    GetContext(context.Context) (Resource, error)
    // Put gives a resource back to the ResPool.
    // If error is not nil, close the avatar.
    Put(Resource, error)
    // Callback callbacks your handle function, returns the error of getting resource or handling.
    // Support recover panic.
    Callback(func(Resource) error) error
    // Callback callbacks your handle function, returns the error of getting resource or handling.
    // Support recover panic and context cancellation.
    CallbackContext(context.Context, func(Resource) error) error
    // SetMaxLifetime sets the maximum amount of time a resource may be reused.
    //
    // Expired resource may be closed lazily before reuse.
    //
    // If d <= 0, resource are reused forever.
    SetMaxLifetime(d time.Duration)
    // SetMaxIdle sets the maximum number of resources in the idle
    // resource pool.
    //
    // If SetMaxIdle is greater than 0 but less than the new MaxIdle
    // then the new MaxIdle will be reduced to match the SetMaxIdle limit
    //
    // If n <= 0, no idle resources are retained.
    SetMaxIdle(n int)
    // SetMaxOpen sets the maximum number of open resources.
    //
    // If MaxIdle is greater than 0 and the new MaxOpen is less than
    // MaxIdle, then MaxIdle will be reduced to match the new
    // MaxOpen limit
    //
    // If n <= 0, then there is no limit on the number of open resources.
    // The default is 0 (unlimited).
    SetMaxOpen(n int)
    // Close closes the ResPool, releasing any open resources.
    //
    // It is rare to close a ResPool, as the ResPool handle is meant to be
    // long-lived and shared between many goroutines.
    Close() error
    // Stats returns resource statistics.
    Stats() ResPoolStats
}

NewResPool creates ResPool.

func NewResPool(name string, newfunc func(context.Context) (Resource, error)) ResPool

Resource is a resource that can be stored in the ResPool.

type Resource interface {
    // SetAvatar stores the contact with resPool
    // Do not call it yourself, it is only called by (*ResPool).get, and will only be called once
    SetAvatar(*Avatar)
    // GetAvatar gets the contact with resPool
    // Do not call it yourself, it is only called by (*ResPool).Put
    GetAvatar() *Avatar
    // Close closes the original source
    // No need to call it yourself, it is only called by (*Avatar).close
    Close() error
}

Avatar links a Resource with a mutex, to be held during all calls into the Avatar.
```
type Avatar struct {
    // Has unexported fields.
}
```
Free releases self to the ResPool. If error is not nil, close it.
```
func (avatar *Avatar) Free(err error)
```
ResPool returns ResPool to which it belongs.
```
func (avatar *Avatar) ResPool() ResPool
```

ResPools stores ResPool.

type ResPools struct {
    // Has unexported fields.
}

NewResPools creates a new ResPools.
```
func NewResPools() *ResPools
```
Clean delects and close all the ResPools.
```
func (c *ResPools) Clean()
```
Del delects ResPool by name, and close the ResPool.
```
func (c *ResPools) Del(name string)
```

Get gets ResPool by name.

func (c *ResPools) Get(name string) (ResPool, bool)

GetAll gets all the ResPools.
```
func (c *ResPools) GetAll() []ResPool
```
Set stores ResPool. If the same name exists, will close and cover it.
```
func (c *ResPools) Set(pool ResPool)
```

Workshop

Working workshop

import it
```
"github.com/henrylee2cn/goutil/pool"
```

Type definition

type (
    // Worker woker interface
    // Note: Worker can not be implemented using empty structures(struct{})!
    Worker interface {
        Health() bool
        Close() error
    }
    // Workshop working workshop
    Workshop struct {
        // Has unexported fields.
    }
)

NewWorkshop creates a new workshop.
If maxQuota<=0, will use default value.
If maxIdleDuration<=0, will use default value.
Notes:
Worker can not be implemented using empty structures(struct{})!
```
func NewWorkshop(maxQuota int, maxIdleDuration time.Duration, newWorkerFunc func() (Worker, error)) *Workshop
```
Close wait for all the work to be completed and close the workshop.
```
func (w *Workshop) Close()
```

Callback assigns a healthy worker to execute the function.

func (w *Workshop) Callback(fn func(Worker) error) error

Fire marks the worker to reduce a job.
If the worker does not belong to the workshop, close the worker.
```
func (w *Workshop) Fire(worker Worker)
```
Hire hires a healthy worker and marks the worker to add a job.
```
func (w *Workshop) Hire() (Worker, error)
```

Stats returns the current workshop stats.

func (w *Workshop) Stats() *WorkshopStats

Various

Various small functions.

import it
```
"github.com/henrylee2cn/goutil"
```
BytesToString convert []byte type to string type.
```
func BytesToString(b []byte) string
```
StringToBytes convert string type to []byte type. NOTE: panic if modify the member value of the []byte.
```
func StringToBytes(s string) []byte
```
NewRandom creates a new padded Encoding defined by the given alphabet string.
```
func NewRandom(alphabet string) *Random
```
RandomBytes returns securely generated random bytes. It will panic if the system's secure random number generator fails to function correctly.
```
func RandomBytes(n int) []byte
```
URLRandomString returns a URL-safe, base64 encoded securely generated
random string. It will panic if the system's secure random number generator
fails to function correctly.
The length n must be an integer multiple of 4, otherwise the last character will be padded with =.
```
func URLRandomString(n int) string
```
CamelString converts the accepted string to a camel string (xx_yy to XxYy)
```
func CamelString(s string) string
```
SnakeString converts the accepted string to a snake string (XxYy to xx_yy)
```
func SnakeString(s string) string
```
ObjectName gets the type name of the object
```
func ObjectName(obj interface{}) string
```
JsQueryEscape escapes the string in javascript standard so it can be safely placed inside a URL query.
```
func JsQueryEscape(s string) string
```
JsQueryUnescape does the inverse transformation of JsQueryEscape, converting %AB into the byte 0xAB and '+' into ' ' (space). It returns an error if any % is not followed by two hexadecimal digits.
```
func JsQueryUnescape(s string) (string, error)
```

Map is a concurrent map with loads, stores, and deletes. It is safe for multiple goroutines to call a Map's methods concurrently.

type Map interface {
    // Load returns the value stored in the map for a key, or nil if no
    // value is present.
    // The ok result indicates whether value was found in the map.
    Load(key interface{}) (value interface{}, ok bool)
    // Store sets the value for a key.
    Store(key, value interface{})
    // LoadOrStore returns the existing value for the key if present.
    // Otherwise, it stores and returns the given value.
    // The loaded result is true if the value was loaded, false if stored.
    LoadOrStore(key, value interface{}) (actual interface{}, loaded bool)
    // Range calls f sequentially for each key and value present in the map.
    // If f returns false, range stops the iteration.
    Range(f func(key, value interface{}) bool)
    // Random returns a pair kv randomly.
    // If exist=false, no kv data is exist.
    Random() (key, value interface{}, exist bool)
    // Delete deletes the value for a key.
    Delete(key interface{})
    // Clear clears all current data in the map.
    Clear()
    // Len returns the length of the map.
    Len() int
}

RwMap creates a new concurrent safe map with sync.RWMutex. The normal Map is high-performance mapping under low concurrency conditions.
```
func RwMap(capacity ...int) Map
```
AtomicMap creates a concurrent map with amortized-constant-time loads, stores, and deletes. It is safe for multiple goroutines to call a atomicMap's methods concurrently. From go v1.9 sync.Map.
```
func AtomicMap() Map
```
SelfPath gets compiled executable file absolute path.
```
func SelfPath() string
```
SelfDir gets compiled executable file directory.
```
func SelfDir() string
```
RelPath gets relative path.
```
func RelPath(targpath string) string
```
SelfChdir switch the working path to my own path.
```
func SelfChdir()
```
FileExists reports whether the named file or directory exists.
```
func FileExists(name string) bool
```

SearchFile Search a file in paths. This is often used in search config file in /etc ~/

func SearchFile(filename string, paths ...string) (fullpath string, err error)

GrepFile like command grep -E. For example: GrepFile(^hello, "hello.txt"). \n is striped while read
```
func GrepFile(patten string, filename string) (lines []string, err error)
```
WalkDirs traverses the directory, return to the relative path. You can specify the suffix.
```
func WalkDirs(targpath string, suffixes ...string) (dirlist []string)
```
IsExportedOrBuiltinType is this type exported or a builtin?
```
func IsExportedOrBuiltinType(t reflect.Type) bool
```
IsExportedName is this an exported - upper case - name?
```
func IsExportedName(name string) bool
```
PanicTrace trace panic stack info.
```
func PanicTrace(kb int) []byte
```

ExtranetIP get external IP addr.

func ExtranetIP() (ip string, err error)

IntranetIP get internal IP addr.
```
func IntranetIP() (string, error)
```
Md5 returns the MD5 checksum string of the data.
```
func Md5(b []byte) string
```
AESEncrypt encrypts a piece of data. The cipherkey argument should be the AES key, either 16, 24, or 32 bytes to select AES-128, AES-192, or AES-256.
```
func AESEncrypt(cipherkey, src []byte) []byte
```
AESDecrypt decrypts a piece of data. The cipherkey argument should be the AES key, either 16, 24, or 32 bytes to select AES-128, AES-192, or AES-256.
```
func AESDecrypt(cipherkey, ciphertext []byte) ([]byte, error)
```
WritePidFile writes the current PID to the specified file.
```
func WritePidFile(pidFile ...string)
```

SetToStrings sets a element to the string set.

func SetToStrings(set []string, a string) []string

RemoveFromStrings removes a element from the string set.

func RemoveFromStrings(set []string, a string) []string

RemoveAllFromStrings removes all the a element from the string set.
```
func RemoveAllFromStrings(set []string, a string) []string
```
SetToInts sets a element to the int set.
```
func SetToInts(set []int, a int) []int
```
RemoveFromInts removes a element from the int set.
```
func RemoveFromInts(set []int, a int) []int
```
RemoveAllFromInts removes all the a element from the int set.
```
func RemoveAllFromInts(set []int, a int) []int
```

SetToInt32s sets a element to the int32 set.

func SetToInt32s(set []int32, a int32) []int32

RemoveFromInt32s removes a element from the int32 set.

func RemoveFromInt32s(set []int32, a int32) []int32

RemoveAllFromInt32s removes all the a element from the int32 set.
```
func RemoveAllFromInt32s(set []int32, a int32) []int32
```

SetToInt64s sets a element to the int64 set.

func SetToInt64s(set []int64, a int64) []int64

RemoveFromInt64s removes a element from the int64 set.

func RemoveFromInt64s(set []int64, a int64) []int64

RemoveAllFromInt64s removes all the a element from the int64 set.
```
func RemoveAllFromInt64s(set []int64, a int64) []int64
```

SetToInterfaces sets a element to the interface{} set.

func SetToInterfaces(set []interface{}, a interface{}) []interface{}

RemoveFromInterfaces removes a element from the interface{} set.

func RemoveFromInterfaces(set []interface{}, a interface{}) []interface{}

RemoveAllFromInterfaces removes all the a element from the interface{} set.

func RemoveAllFromInterfaces(set []interface{}, a interface{}) []interface{}

farkaskid/goutil

goutil

1. Inclusion criteria

2. Contents

3. UtilsAPI

BitSet

Calendar

CoarseTime

Errors

Graceful

GoPool

ResPool

Workshop

Various