common

package
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 Go to latest Published: Oct 12, 2020 License: Apache-2.0, Apache-2.0 Imports: 24 Imported by: 17

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Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrAlreadyStarted is returned when somebody tries to start an already
	// running service.
	ErrAlreadyStarted = errors.New("already started")
	// ErrAlreadyStopped is returned when somebody tries to stop an already
	// stopped service (without resetting it).
	ErrAlreadyStopped = errors.New("already stopped")
	// ErrNotStarted is returned when somebody tries to stop a not running
	// service.
	ErrNotStarted = errors.New("not started")
)

Functions

func ASCIITrim 

func ASCIITrim(s string) string

NOTE: Assumes that s is ASCII as per IsASCIIText(), otherwise panics.

func Connect 

func Connect(protoAddr string) (net.Conn, error)

Connect dials the given address and returns a net.Conn. The protoAddr argument should be prefixed with the protocol, eg. "tcp://127.0.0.1:8080" or "unix:///tmp/test.sock"

func EnsureDir 

func EnsureDir(dir string, mode os.FileMode) error

func Exit 

func Exit(s string)

func FileExists 

func FileExists(filePath string) bool

func Fingerprint 

func Fingerprint(slice []byte) []byte

Fingerprint returns the first 6 bytes of a byte slice. If the slice is less than 6 bytes, the fingerprint contains trailing zeroes.

func GetFreePort 

func GetFreePort() (int, error)

GetFreePort gets a free port from the operating system. Ripped from https://github.com/phayes/freeport. BSD-licensed.

func IntInSlice 

func IntInSlice(a int, list []int) bool

IntInSlice returns true if a is found in the list.

func IsASCIIText 

func IsASCIIText(s string) bool

Returns true if s is a non-empty printable non-tab ascii character.

func IsEmpty 

func IsEmpty(o interface{}) bool

Returns true if it has zero length.

func IsTypedNil 

func IsTypedNil(o interface{}) bool

Go lacks a simple and safe way to see if something is a typed nil. See:

func Kill 

func Kill() error

Kill the running process by sending itself SIGTERM.

func MaxInt 

func MaxInt(a, b int) int

func MaxInt64 

func MaxInt64(a, b int64) int64

func MinInt 

func MinInt(a, b int) int

func MinInt64 

func MinInt64(a, b int64) int64

func MustReadFile 

func MustReadFile(filePath string) []byte

func MustWriteFile 

func MustWriteFile(filePath string, contents []byte, mode os.FileMode)

func PrintAllGoroutines 

func PrintAllGoroutines()

func ProtocolAndAddress 

func ProtocolAndAddress(listenAddr string) (string, string)

ProtocolAndAddress splits an address into the protocol and address components. For instance, "tcp://127.0.0.1:8080" will be split into "tcp" and "127.0.0.1:8080". If the address has no protocol prefix, the default is "tcp".

func RandBool 

func RandBool() bool

func RandBytes 

func RandBytes(n int) []byte

func RandFloat32 

func RandFloat32() float32

func RandFloat64 

func RandFloat64() float64

func RandInt 

func RandInt() int

func RandInt16 

func RandInt16() int16

func RandInt31 

func RandInt31() int32

func RandInt31n 

func RandInt31n(n int32) int32

func RandInt32 

func RandInt32() int32

func RandInt63 

func RandInt63() int64

func RandInt63n 

func RandInt63n(n int64) int64

func RandInt64 

func RandInt64() int64

func RandIntn 

func RandIntn(n int) int

func RandPerm 

func RandPerm(n int) []int

func RandStr 

func RandStr(length int) string

func RandTime 

func RandTime() time.Time

func RandUint 

func RandUint() uint

func RandUint16 

func RandUint16() uint16

func RandUint32 

func RandUint32() uint32

func RandUint64 

func RandUint64() uint64

func ReadFile 

func ReadFile(filePath string) ([]byte, error)

func Routine 

func Routine(fn func()) <-chan struct{}

func Seed 

func Seed(seed int64)

func SplitAndTrim 

func SplitAndTrim(s, sep, cutset string) []string

SplitAndTrim slices s into all subslices separated by sep and returns a slice of the string s with all leading and trailing Unicode code points contained in cutset removed. If sep is empty, SplitAndTrim splits after each UTF-8 sequence. First part is equivalent to strings.SplitN with a count of -1.

func StringInSlice 

func StringInSlice(a string, list []string) bool

StringInSlice returns true if a is found the list.

func StringSliceEqual 

func StringSliceEqual(a, b []string) bool

StringSliceEqual checks if string slices a and b are equal

func TrapSignal 

func TrapSignal(logger logger, cb func())

TrapSignal catches the SIGTERM/SIGINT and executes cb function. After that it exits with code 0.

func WriteFile 

func WriteFile(filePath string, contents []byte, mode os.FileMode) error

func WriteFileAtomic 

func WriteFileAtomic(filename string, data []byte, perm os.FileMode) (err error)

WriteFileAtomic creates a temporary file with data and provided perm and swaps it atomically with filename if successful.

Types

type BaseService 

type BaseService struct {
	Logger log.Logger
	// contains filtered or unexported fields
}

Classical-inheritance-style service declarations. Services can be started, then stopped, then optionally restarted.

Users can override the OnStart/OnStop methods. In the absence of errors, these methods are guaranteed to be called at most once. If OnStart returns an error, service won't be marked as started, so the user can call Start again.

A call to Reset will panic, unless OnReset is overwritten, allowing OnStart/OnStop to be called again.

The caller must ensure that Start and Stop are not called concurrently.

It is ok to call Stop without calling Start first.

Typical usage: 

type FooService struct {
	BaseService
	// private fields
}

func NewFooService() *FooService {
	fs := &FooService{
		// init
	}
	fs.BaseService = *NewBaseService(log, "FooService", fs)
	return fs
}

func (fs *FooService) OnStart() error {
	fs.BaseService.OnStart() // Always call the overridden method.
	// initialize private fields
	// start subroutines, etc.
}

func (fs *FooService) OnStop() error {
	fs.BaseService.OnStop() // Always call the overridden method.
	// close/destroy private fields
	// stop subroutines, etc.
}

func NewBaseService 

func NewBaseService(logger log.Logger, name string, impl Service) *BaseService

NewBaseService creates a new BaseService.

func (*BaseService) IsRunning 

func (bs *BaseService) IsRunning() bool

IsRunning implements Service by returning true or false depending on the service's state.

func (*BaseService) OnReset 

func (bs *BaseService) OnReset() error

OnReset implements Service by panicking.

func (*BaseService) OnStart 

func (bs *BaseService) OnStart() error

OnStart implements Service by doing nothing. NOTE: Do not put anything in here, that way users don't need to call BaseService.OnStart()

func (*BaseService) OnStop 

func (bs *BaseService) OnStop()

OnStop implements Service by doing nothing. NOTE: Do not put anything in here, that way users don't need to call BaseService.OnStop()

func (*BaseService) Quit 

func (bs *BaseService) Quit() <-chan struct{}

Quit Implements Service by returning a quit channel.

func (*BaseService) Reset 

func (bs *BaseService) Reset() error

Reset implements Service by calling OnReset callback (if defined). An error will be returned if the service is running.

func (*BaseService) SetLogger 

func (bs *BaseService) SetLogger(l log.Logger)

SetLogger implements Service by setting a logger.

func (*BaseService) Start 

func (bs *BaseService) Start() error

Start implements Service by calling OnStart (if defined). An error will be returned if the service is already running or stopped. Not to start the stopped service, you need to call Reset.

func (*BaseService) Stop 

func (bs *BaseService) Stop() error

Stop implements Service by calling OnStop (if defined) and closing quit channel. An error will be returned if the service is already stopped.

func (*BaseService) String 

func (bs *BaseService) String() string

String implements Service by returning a string representation of the service.

func (*BaseService) Wait 

func (bs *BaseService) Wait()

Wait blocks until the service is stopped.

type BitArray 

type BitArray struct {
	Bits  int      `json:"bits"`  // NOTE: persisted via reflect, must be exported
	Elems []uint64 `json:"elems"` // NOTE: persisted via reflect, must be exported
	// contains filtered or unexported fields
}

BitArray is a thread-safe implementation of a bit array.

func NewBitArray 

func NewBitArray(bits int) *BitArray

NewBitArray returns a new bit array. It returns nil if the number of bits is zero.

func (*BitArray) And 

func (bA *BitArray) And(o *BitArray) *BitArray

And returns a bit array resulting from a bitwise AND of the two bit arrays. If the two bit-arrys have different lengths, this truncates the larger of the two bit-arrays from the right. Thus the size of the return value is the minimum of the two provided bit arrays.

func (*BitArray) Bytes 

func (bA *BitArray) Bytes() []byte

Bytes returns the byte representation of the bits within the bitarray.

func (*BitArray) Copy 

func (bA *BitArray) Copy() *BitArray

Copy returns a copy of the provided bit array.

func (*BitArray) GetIndex 

func (bA *BitArray) GetIndex(i int) bool

GetIndex returns the bit at index i within the bit array. The behavior is undefined if i >= bA.Bits

func (*BitArray) IsEmpty 

func (bA *BitArray) IsEmpty() bool

IsEmpty returns true iff all bits in the bit array are 0

func (*BitArray) IsFull 

func (bA *BitArray) IsFull() bool

IsFull returns true iff all bits in the bit array are 1.

func (*BitArray) MarshalJSON 

func (bA *BitArray) MarshalJSON() ([]byte, error)

MarshalJSON implements json.Marshaler interface by marshaling bit array using a custom format: a string of '-' or 'x' where 'x' denotes the 1 bit.

func (*BitArray) Not 

func (bA *BitArray) Not() *BitArray

Not returns a bit array resulting from a bitwise Not of the provided bit array.

func (*BitArray) Or 

func (bA *BitArray) Or(o *BitArray) *BitArray

Or returns a bit array resulting from a bitwise OR of the two bit arrays. If the two bit-arrys have different lengths, Or right-pads the smaller of the two bit-arrays with zeroes. Thus the size of the return value is the maximum of the two provided bit arrays.

func (*BitArray) PickRandom 

func (bA *BitArray) PickRandom() (int, bool)

PickRandom returns a random index for a set bit in the bit array. If there is no such value, it returns 0, false. It uses the global randomness in `random.go` to get this index.

func (*BitArray) SetIndex 

func (bA *BitArray) SetIndex(i int, v bool) bool

SetIndex sets the bit at index i within the bit array. The behavior is undefined if i >= bA.Bits

func (*BitArray) Size 

func (bA *BitArray) Size() int

Size returns the number of bits in the bitarray

func (*BitArray) String 

func (bA *BitArray) String() string

String returns a string representation of BitArray: BA{<bit-string>}, where <bit-string> is a sequence of 'x' (1) and '_' (0). The <bit-string> includes spaces and newlines to help people. For a simple sequence of 'x' and '_' characters with no spaces or newlines, see the MarshalJSON() method. Example: "BA{_x_}" or "nil-BitArray" for nil.

func (*BitArray) StringIndented 

func (bA *BitArray) StringIndented(indent string) string

StringIndented returns the same thing as String(), but applies the indent at every 10th bit, and twice at every 50th bit.

func (*BitArray) Sub 

func (bA *BitArray) Sub(o *BitArray) *BitArray

Sub subtracts the two bit-arrays bitwise, without carrying the bits. Note that carryless subtraction of a - b is (a and not b). The output is the same as bA, regardless of o's size. If bA is longer than o, o is right padded with zeroes

func (*BitArray) UnmarshalJSON 

func (bA *BitArray) UnmarshalJSON(bz []byte) error

UnmarshalJSON implements json.Unmarshaler interface by unmarshaling a custom JSON description.

func (*BitArray) Update 

func (bA *BitArray) Update(o *BitArray)

Update sets the bA's bits to be that of the other bit array. The copying begins from the begin of both bit arrays.

type CMap 

type CMap struct {
	// contains filtered or unexported fields
}

CMap is a goroutine-safe map

func NewCMap 

func NewCMap() *CMap

func (*CMap) Clear 

func (cm *CMap) Clear()

func (*CMap) Delete 

func (cm *CMap) Delete(key string)

func (*CMap) Get 

func (cm *CMap) Get(key string) interface{}

func (*CMap) Has 

func (cm *CMap) Has(key string) bool

func (*CMap) Keys 

func (cm *CMap) Keys() []string

func (*CMap) Set 

func (cm *CMap) Set(key string, value interface{})

func (*CMap) Size 

func (cm *CMap) Size() int

func (*CMap) Values 

func (cm *CMap) Values() []interface{}

type Error 

type Error interface {
	Error() string
	Stacktrace() Error
	Trace(offset int, format string, args ...interface{}) Error
	Data() interface{}
}

Usage with arbitrary error data:

```go 

// Error construction
type MyError struct{}
var err1 error = NewErrorWithData(MyError{}, "my message")
...
// Wrapping
var err2 error  = ErrorWrap(err1, "another message")
if (err1 != err2) { panic("should be the same")
...
// Error handling
switch err2.Data().(type){
	case MyError: ...
    default: ...
}

```

func ErrorWrap 

func ErrorWrap(cause interface{}, format string, args ...interface{}) Error

func NewError 

func NewError(format string, args ...interface{}) Error

New Error with formatted message. The Error's Data will be a FmtError type.

func NewErrorWithData 

func NewErrorWithData(data interface{}) Error

New Error with specified data.

type FmtError 

type FmtError struct {
	// contains filtered or unexported fields
}

FmtError is the data type for NewError() (e.g. NewError().Data().(FmtError)) Theoretically it could be used to switch on the format string.

```go 

// Error construction
var err1 error = NewError("invalid username %v", "BOB")
var err2 error = NewError("another kind of error")
...
// Error handling
switch err1.Data().(cmn.FmtError).Format() {
	case "invalid username %v": ...
	case "another kind of error": ...
    default: ...
}

```

func (FmtError) Error 

func (fe FmtError) Error() string

func (FmtError) Format 

func (fe FmtError) Format() string

func (FmtError) String 

func (fe FmtError) String() string

type KI64Pair 

type KI64Pair struct {
	Key   []byte
	Value int64
}

type KI64Pairs 

type KI64Pairs []KI64Pair

func (KI64Pairs) Len 

func (kvs KI64Pairs) Len() int

Sorting

func (KI64Pairs) Less 

func (kvs KI64Pairs) Less(i, j int) bool

func (KI64Pairs) Sort 

func (kvs KI64Pairs) Sort()

func (KI64Pairs) Swap 

func (kvs KI64Pairs) Swap(i, j int)

type KVPair 

type KVPair struct {
	Key   []byte
	Value []byte
}

type KVPairs 

type KVPairs []KVPair

func (KVPairs) Len 

func (kvs KVPairs) Len() int

Sorting

func (KVPairs) Less 

func (kvs KVPairs) Less(i, j int) bool

func (KVPairs) Sort 

func (kvs KVPairs) Sort()

func (KVPairs) Swap 

func (kvs KVPairs) Swap(i, j int)

type Rand 

type Rand struct {
	sync.Mutex
	// contains filtered or unexported fields
}

Rand is a prng, that is seeded with OS randomness. The OS randomness is obtained from crypto/rand, however none of the provided methods are suitable for cryptographic usage. They all utilize math/rand's prng internally.

All of the methods here are suitable for concurrent use. This is achieved by using a mutex lock on all of the provided methods.

func NewRand 

func NewRand() *Rand

func (*Rand) Bool 

func (r *Rand) Bool() bool

Bool returns a uniformly random boolean

func (*Rand) Bytes 

func (r *Rand) Bytes(n int) []byte

Bytes returns n random bytes generated from the internal prng.

func (*Rand) Float32 

func (r *Rand) Float32() float32

func (*Rand) Float64 

func (r *Rand) Float64() float64

func (*Rand) Int 

func (r *Rand) Int() int

func (*Rand) Int16 

func (r *Rand) Int16() int16

func (*Rand) Int31 

func (r *Rand) Int31() int32

func (*Rand) Int31n 

func (r *Rand) Int31n(n int32) int32

func (*Rand) Int32 

func (r *Rand) Int32() int32

func (*Rand) Int63 

func (r *Rand) Int63() int64

func (*Rand) Int63n 

func (r *Rand) Int63n(n int64) int64

func (*Rand) Int64 

func (r *Rand) Int64() int64

func (*Rand) Intn 

func (r *Rand) Intn(n int) int

Intn returns, as an int, a uniform pseudo-random number in the range [0, n). It panics if n <= 0.

func (*Rand) Perm 

func (r *Rand) Perm(n int) []int

Perm returns a pseudo-random permutation of n integers in [0, n).

func (*Rand) Seed 

func (r *Rand) Seed(seed int64)

func (*Rand) Str 

func (r *Rand) Str(length int) string

Str constructs a random alphanumeric string of given length.

func (*Rand) Time 

func (r *Rand) Time() time.Time

func (*Rand) Uint 

func (r *Rand) Uint() uint

func (*Rand) Uint16 

func (r *Rand) Uint16() uint16

func (*Rand) Uint32 

func (r *Rand) Uint32() uint32

func (*Rand) Uint64 

func (r *Rand) Uint64() uint64

type Service 

type Service interface {
	// Start the service.
	// If it's already started or stopped, will return an error.
	// If OnStart() returns an error, it's returned by Start()
	Start() error
	OnStart() error

	// Stop the service.
	// If it's already stopped, will return an error.
	// OnStop must never error.
	Stop() error
	OnStop()

	// Reset the service.
	// Panics by default - must be overwritten to enable reset.
	Reset() error
	OnReset() error

	// Return true if the service is running
	IsRunning() bool

	// Quit returns a channel, which is closed once service is stopped.
	Quit() <-chan struct{}

	// String representation of the service
	String() string

	// SetLogger sets a logger.
	SetLogger(log.Logger)
}

Service defines a service that can be started, stopped, and reset.

type Task 

type Task func(i int) (val interface{}, err error, abort bool)

val: the value returned after task execution. err: the error returned during task completion. abort: tells Parallel to return, whether or not all tasks have completed.

type TaskResult 

type TaskResult struct {
	Value interface{}
	Error error
}

type TaskResultCh 

type TaskResultCh <-chan TaskResult

type TaskResultSet 

type TaskResultSet struct {
	// contains filtered or unexported fields
}

func Parallel 

func Parallel(tasks ...Task) (trs *TaskResultSet, ok bool)

Run tasks in parallel, with ability to abort early. Returns ok=false iff any of the tasks returned abort=true. NOTE: Do not implement quit features here. Instead, provide convenient concurrent quit-like primitives, passed implicitly via Task closures. (e.g. it's not Parallel's concern how you quit/abort your tasks).

func (*TaskResultSet) Channels 

func (trs *TaskResultSet) Channels() []TaskResultCh

func (*TaskResultSet) FirstError 

func (trs *TaskResultSet) FirstError() error

Returns the firstmost (by task index) error as discovered by all previous Reap() calls.

func (*TaskResultSet) FirstValue 

func (trs *TaskResultSet) FirstValue() interface{}

Returns the firstmost (by task index) error as discovered by all previous Reap() calls.

func (*TaskResultSet) LatestResult 

func (trs *TaskResultSet) LatestResult(index int) (TaskResult, bool)

func (*TaskResultSet) Reap 

func (trs *TaskResultSet) Reap() *TaskResultSet

NOTE: Not concurrency safe. Writes results to trs.results without waiting for all tasks to complete.

func (*TaskResultSet) Wait 

func (trs *TaskResultSet) Wait() *TaskResultSet

NOTE: Not concurrency safe. Like Reap() but waits until all tasks have returned or panic'd.

type ThrottleTimer 

type ThrottleTimer struct {
	Name string
	Ch   chan struct{}
	// contains filtered or unexported fields
}

ThrottleTimer fires an event at most "dur" after each .Set() call. If a short burst of .Set() calls happens, ThrottleTimer fires once. If a long continuous burst of .Set() calls happens, ThrottleTimer fires at most once every "dur".

func NewThrottleTimer 

func NewThrottleTimer(name string, dur time.Duration) *ThrottleTimer

func (*ThrottleTimer) Set 

func (t *ThrottleTimer) Set()

func (*ThrottleTimer) Stop 

func (t *ThrottleTimer) Stop() bool

For ease of .Stop()'ing services before .Start()'ing them, we ignore .Stop()'s on nil ThrottleTimers

func (*ThrottleTimer) Unset 

func (t *ThrottleTimer) Unset()

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