Common and useful utils for the Go project development.
- Only rely on the Go standard package
- Functions or lightweight packages
- Non-business related general tools
- Calendar Chinese Lunar Calendar, Solar Calendar and cron time rules
- CoarseTime Current time truncated to the nearest second
- Errors Improved errors package.
- Graceful Shutdown or reboot current process gracefully.
- GoPool Goroutines' pool
- ResPool Resources' pool
- Various Various small functions
Chinese Lunar Calendar, Solar Calendar and cron time rules.
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import it
"github.com/henrylee2cn/goutil/calendar"
The current time truncated to the nearest second.
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import it
"github.com/henrylee2cn/goutil/coarsetime" -
CoarseTimeNow returns the current time truncated to the nearest second. This is a faster alternative to time.Now().
func CoarseTimeNow() time.Time
Errors is improved errors package.
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import it
"github.com/henrylee2cn/goutil/errors" -
New returns an error that formats as the given text.
func New(text string) error
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Errorf formats according to a format specifier and returns the string as a value that satisfies error.
func Errorf(format string, a ...interface{}) error
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Merge merges multi errors.
func Merge(errs ...error) error
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Append appends multiple errors to the error.
func Append(err error, errs ...error) error
Shutdown or reboot current process gracefully.
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import it
"github.com/henrylee2cn/goutil/graceful" -
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. 'preCloseFunc' is executed before closing process, but not guaranteed to be completed. 'postCloseFunc' is executed after process are closed, but not guaranteed to be completed.
func SetShutdown(timeout time.Duration, fn ...func() error)
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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)
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Reboot all the frame process gracefully. Notes: Windows system are not supported!
func Reboot(timeout ...time.Duration)
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SetExtractProcFiles sets extract proc files only for reboot. Notes: Windows system are not supported!
func SetExtractProcFiles(extractProcFiles []*os.File)
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Logger logger interface
Logger interface { Infof(format string, v ...interface{}) Errorf(format string, v ...interface{}) }
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SetLog resets logger
func SetLog(logger Logger)
GoPool is a Goroutines pool. It can control concurrent numbers, reuse goroutines.
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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. }
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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
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Go executes function via a gor C242 outine. If returns non-nil, the function cannot be executed because exceeded maxGoroutinesAmount limit.
func (gp *GoPool) Go(fn func()) error
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Stop starts GoPool. If calling 'Go' after calling 'Stop', will no longer reuse goroutine.
func (gp *GoPool) Stop()
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.
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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 }
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NewResPool creates ResPool.
func NewResPool(name string, newfunc func(context.Context) (Resource, error)) ResPool
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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 }
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Avatar links a Resource with a mutex, to be held during all calls into the Avatar.
type Avatar struct { // Has unexported fields. }
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Free releases self to the ResPool. If error is not nil, close it.
func (avatar *Avatar) Free(err error)
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ResPool returns ResPool to which it belongs.
func (avatar *Avatar) ResPool() ResPool
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ResPools stores ResPool.
type ResPools struct { // Has unexported fields. }
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NewResPools creates a new ResPools.
func NewResPools() *ResPools
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Clean delects and close all the ResPools.
func (c *ResPools) Clean()
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Del delects ResPool by name, and close the ResPool.
func (c *ResPools) Del(name string)
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Get gets ResPool by name.
func (c *ResPools) Get(name string) (ResPool, bool)
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GetAll gets all the ResPools.
func (c *ResPools) GetAll() []ResPool
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Set stores ResPool. If the same name exists, will close and cover it.
func (c *ResPools) Set(pool ResPool)
Various small functions.
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import it
"github.com/henrylee2cn/goutil/pool" -
BytesToString convert []byte type to string type.
func BytesToString(b []byte) string
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StringToBytes convert string type to []byte type. NOTE: panic if modify the member value of the []byte.
func StringToBytes(s string) []byte
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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
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RandomString 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 RandomString(n int) string
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CamelString converts the accepted string to a camel string (xx_yy to XxYy)
func CamelString(s string) string
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SnakeString converts the accepted string to a snake string (XxYy to xx_yy)
func SnakeString(s string) string
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ObjectName gets the type name of the object
func ObjectName(obj interface{}) string
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JsQueryEscape escapes the string in javascript standard so it can be safely placed inside a URL query.
func JsQueryEscape(s string) string
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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)
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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) // Delete deletes the value for a key. Delete(key interface{}) // 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) // Len returns the length of the map. // Note: // the count implemented using atomicMap may be inaccurate; // the count implemented using rwMap is accurate. Len() int }
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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
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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
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SelfPath gets compiled executable file absolute path.
func SelfPath() string
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SelfDir gets compiled executable file directory.
func SelfDir() string
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RelPath gets relative path.
func RelPath(targpath string) string
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SelfChdir switch the working path to my own path.
func SelfChdir()
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FileExists reports whether the named file or directory exists.
func FileExists(name string) bool
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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)
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GrepFile like command grep -E. For example: GrepFile(
^hello, "hello.txt").\nis striped while readfunc GrepFile(patten string, filename string) (lines []string, err error)
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WalkDirs traverses the directory, return to the relative path. You can specify the suffix.
func WalkDirs(targpath string, suffixes ...string) (dirlist []string)
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IsExportedOrBuiltinType is this type exported or a builtin?
func IsExportedOrBuiltinType(t reflect.Type) bool
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IsExportedName is this an exported - upper case - name?
func IsExportedName(name string) bool