utils

package
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 Go to latest Published: May 18, 2023 License: MIT Imports: 45 Imported by: 10

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package utils

StartStopOnce

stateDiagram-v2
    [*] --> Unstarted
    Unstarted --> Starting : StartOnce()
    Starting --> StartFailed
    Starting --> Started
    Started --> Stopping : StopOnce()
    Stopping --> Stopped
    Stopping --> StopFailed
    StartFailed --> [*]
    Stopped --> [*]
    StopFailed --> [*]

Documentation

Overview

Package utils is used for common functions and tools used across the codebase.

Index

Examples

Constants

View Source 
const (
	// FormatBytes encodes the output as bytes
	FormatBytes = "bytes"
	// FormatPreformatted encodes the output, assumed to be hex, as bytes.
	FormatPreformatted = "preformatted"
	// FormatUint256 encodes the output as bytes containing a uint256
	FormatUint256 = "uint256"
	// FormatInt256 encodes the output as bytes containing an int256
	FormatInt256 = "int256"
	// FormatBool encodes the output as bytes containing a bool
	FormatBool = "bool"
)
View Source 
const (
	KB = 1000
	MB = 1000 * KB
	GB = 1000 * MB
	TB = 1000 * GB
)

nolint

View Source 
const (
	// FastN is a shorter N parameter for testing
	FastN = 2
	// FastP is a shorter P parameter for testing
	FastP = 1
)
View Source 
const (
	// DefaultSecretSize is the entropy in bytes to generate a base64 string of 64 characters.
	DefaultSecretSize = 48
	// EVMWordByteLen the length of an EVM Word Byte
	EVMWordByteLen = 32
)
View Source 
const MinRequiredLen = 16
View Source 
const PasswordComplexityRequirements = `` /* 172-byte string literal not displayed */

PasswordComplexityRequirements defines the complexity requirements message Note that adding an entropy requirement wouldn't add much, since a 16 character password already has an entropy score of 75 even if it's all lowercase characters

Variables

View Source 
var (

	// MaxUint256 represents the largest number represented by an EVM word
	MaxUint256 = &big.Int{}
	// MaxInt256 represents the largest number represented by an EVM word using
	// signed encoding.
	MaxInt256 = &big.Int{}
	// MinInt256 represents the smallest number represented by an EVM word using
	// signed encoding.
	MinInt256 = &big.Int{}
)

"Constants" used by EVM words

View Source 
var (
	ErrPasswordWhitespace  = errors.New("leading/trailing whitespace detected in password")
	ErrEmptyPasswordInFile = errors.New("detected empty password in password file")
)
View Source 
var (
	ErrMsgHeader = fmt.Sprintf(`
Expected password complexity:
Must be at least %d characters long
Must not comprise:
	Leading or trailing whitespace
	A user's API email

Faults:
`, MinRequiredLen)
	ErrWhitespace = errors.New("password contains a leading or trailing whitespace")
)
View Source 
var (
	ErrAlreadyStopped      = errors.New("already stopped")
	ErrCannotStopUnstarted = errors.New("cannot stop unstarted service")
)
View Source 
var DefaultScryptParams = ScryptParams{N: keystore.StandardScryptN, P: keystore.StandardScryptP}

DefaultScryptParams is for use in production. It used geth's standard level of encryption and is relatively expensive to decode. Avoid using this in tests.

View Source 
var EmptyHash = common.Hash{}

EmptyHash is a hash of all zeroes, otherwise in Ethereum as 0x0000000000000000000000000000000000000000000000000000000000000000

View Source 
var FastScryptParams = ScryptParams{N: FastN, P: FastP}

FastScryptParams is for use in tests, where you don't want to wear out your CPU with expensive key derivations, do not use it in production, or your encrypted keys will be easy to brute-force!

View Source 
var LeadingWhitespace = regexp.MustCompile(`^\s+`)
View Source 
var TrailingWhitespace = regexp.MustCompile(`\s+$`)
View Source 
var ZeroAddress = common.Address{}

ZeroAddress is an address of all zeroes, otherwise in Ethereum as 0x0000000000000000000000000000000000000000

Functions

func ABIDecode 

func ABIDecode(abiStr string, data []byte) ([]interface{}, error)

ABIEncode is the equivalent of abi.decode. See a full set of examples https://github.com/ethereum/go-ethereum/blob/420b78659bef661a83c5c442121b13f13288c09f/accounts/abi/packing_test.go#L31

func ABIEncode 

func ABIEncode(abiStr string, values ...interface{}) ([]byte, error)

ABIEncode is the equivalent of abi.encode. See a full set of examples https://github.com/ethereum/go-ethereum/blob/420b78659bef661a83c5c442121b13f13288c09f/accounts/abi/packing_test.go#L31

func AddHexPrefix 

func AddHexPrefix(str string) string

AddHexPrefix adds the prefix (0x) to a given hex string.

func AllEqual 

func AllEqual[T comparable](elems ...T) bool

AllEqual returns true iff all the provided elements are equal to each other.

func BatchSplit 

func BatchSplit[T any](list []T, max int) (out [][]T, err error)

BatchSplit splits an slices into an slices of slicess with a maximum length

func BoxOutput 

func BoxOutput(errorMsgTemplate string, errorMsgValues ...interface{}) string

BoxOutput formats its arguments as fmt.Printf, and encloses them in a box of arrows pointing at their content, in order to better highlight it. See ExampleBoxOutput

func Bytes32FromString 

func Bytes32FromString(s string) [32]byte

Bytes32FromString returns a 32 byte array filled from the given string, which may be of any length.

func Bytes32ToSlice 

func Bytes32ToSlice(a [32]byte) (r []byte)

func Bytes4FromString 

func Bytes4FromString(s string) [4]byte

Bytes4FromString returns a 4 byte array filled from the given string, which may be of any length.

func CheckPasswordHash 

func CheckPasswordHash(password, hash string) bool

CheckPasswordHash wraps around bcrypt.CompareHashAndPassword for a friendlier API.

func CheckUint256 

func CheckUint256(n *big.Int) error

CheckUint256 returns an error if n is out of bounds for a uint256

func ConcatBytes 

func ConcatBytes(bufs ...[]byte) []byte

ConcatBytes appends a bunch of byte arrays into a single byte array

func ContextFromChan 

func ContextFromChan(chStop chan struct{}) (context.Context, context.CancelFunc)

ContextFromChan creates a context that finishes when the provided channel receives or is closed. Deprecated: Call StopChan.NewCtx directly.

func ContextFromChanWithTimeout added in v2.1.0 

func ContextFromChanWithTimeout(chStop chan struct{}, timeout time.Duration) (context.Context, context.CancelFunc)

ContextFromChanWithTimeout creates a context with a timeout that finishes when the provided channel receives or is closed. Deprecated: Call StopChan.CtxCancel directly

func DeleteUnstable 

func DeleteUnstable[T any](s []T, i int) []T

DeleteUnstable destructively removes slice element at index i It does no bounds checking and may re-order the slice

func DurationFromNow 

func DurationFromNow(t time.Time) time.Duration

DurationFromNow returns the amount of time since the Time field was last updated.

func EIP55CapitalizedAddress 

func EIP55CapitalizedAddress(possibleAddressString string) bool

EIP55CapitalizedAddress returns true iff possibleAddressString has the correct capitalization for an Ethereum address, per EIP 55

func EVMBytesToUint64 

func EVMBytesToUint64(buf []byte) uint64

EVMBytesToUint64 converts a bytebuffer to uint64

func EVMEncodeBytes 

func EVMEncodeBytes(input []byte) []byte

EVMEncodeBytes encodes arbitrary bytes as bytes expected by the EVM

func EVMTranscodeBool 

func EVMTranscodeBool(value gjson.Result) ([]byte, error)

EVMTranscodeBool converts a json input to an EVM bool

func EVMTranscodeInt256 

func EVMTranscodeInt256(value gjson.Result) ([]byte, error)

EVMTranscodeInt256 converts a json input to an EVM int256

func EVMTranscodeUint256 

func EVMTranscodeUint256(value gjson.Result) ([]byte, error)

EVMTranscodeUint256 converts a json input to an EVM uint256

func EVMWordBigInt 

func EVMWordBigInt(val *big.Int) ([]byte, error)

EVMWordBigInt returns a big.Int as an EVM word byte array, with support for a signed representation. Returns error on overflow.

func EVMWordSignedBigInt 

func EVMWordSignedBigInt(val *big.Int) ([]byte, error)

EVMWordSignedBigInt returns a big.Int as an EVM word byte array, with support for a signed representation. Returns error on overflow.

func EVMWordUint128 

func EVMWordUint128(val *big.Int) ([]byte, error)

EVMWordUint128 returns a uint128 as an EVM word byte array.

func EVMWordUint32 

func EVMWordUint32(val uint32) []byte

EVMWordUint32 returns a uint32 as an EVM word byte array.

func EVMWordUint64 

func EVMWordUint64(val uint64) []byte

EVMWordUint64 returns a uint64 as an EVM word byte array.

func EnsureClosed 

func EnsureClosed(c io.Closer) error

EnsureClosed closes the io.Closer, returning nil if it was already closed or not started yet

func EnsureDirAndMaxPerms 

func EnsureDirAndMaxPerms(path string, perms os.FileMode) error

EnsureDirAndMaxPerms ensures that the given path exists, that it's a directory, and that it has permissions that are no more permissive than the given ones.

- If the path does not exist, it is created - If the path exists, but is not a directory, an error is returned - If the path exists, and is a directory, but has the wrong perms, it is chmod'ed

func EnsureFileMaxPerms 

func EnsureFileMaxPerms(file *os.File, perms os.FileMode) error

EnsureFileMaxPerms ensures that the given file has permissions that are no more permissive than the given ones.

func EnsureFilepathMaxPerms 

func EnsureFilepathMaxPerms(filepath string, perms os.FileMode) (err error)

EnsureFilepathMaxPerms ensures that the file at the given filepath has permissions that are no more permissive than the given ones.

func FileExists 

func FileExists(name string) (bool, error)

FileExists returns true if a file at the passed string exists.

func FiniteTicker 

func FiniteTicker(period time.Duration, onTick func()) func()

FiniteTicker starts a goroutine to execute the given function periodically, until the returned function is called.

func FormatJSON 

func FormatJSON(v interface{}) ([]byte, error)

FormatJSON applies indent to format a JSON response.

func HasHexPrefix 

func HasHexPrefix(str string) bool

HasHexPrefix returns true if the string starts with 0x.

func HashPassword 

func HashPassword(password string) (string, error)

HashPassword wraps around bcrypt.GenerateFromPassword for a friendlier API.

func HexToBig 

func HexToBig(s string) *big.Int

HexToBig parses the given hex string or panics if it is invalid.

func HexToUint256 

func HexToUint256(s string) (*big.Int, error)

HexToUint256 returns the uint256 represented by s, or an error if it doesn't represent one.

func ISO8601UTC 

func ISO8601UTC(t time.Time) string

ISO8601UTC formats given time to ISO8601.

func IsEmpty 

func IsEmpty(bytes []byte) bool

IsEmpty returns true if bytes contains only zero values, or has len 0.

func IsEmptyAddress 

func IsEmptyAddress(addr common.Address) bool

IsEmptyAddress checks that the address is empty, synonymous with the zero account/address. No logs can come from this address, as there is no contract present there.

See https://stackoverflow.com/questions/48219716/what-is-address0-in-solidity for the more info on the zero address. 

func IsFileOwnedByChainlink(fileInfo os.FileInfo) (bool, error)

IsFileOwnedByChainlink attempts to read fileInfo to verify file owner

func IsQuoted 

func IsQuoted(input []byte) bool

IsQuoted checks if the first and last characters are either " or '.

func IsZero added in v2.1.0 

func IsZero[C comparable](val C) bool

func JustError 

func JustError(_ interface{}, err error) error

JustError takes a tuple and returns the last entry, the error.

func Keccak256 

func Keccak256(in []byte) ([]byte, error)

Keccak256 is a simplified interface for the legacy SHA3 implementation that Ethereum uses.

func Keccak256Fixed 

func Keccak256Fixed(in []byte) [32]byte

func LeftPadBitString 

func LeftPadBitString(input string, length int) string

func MinKey 

func MinKey[U any, T constraints.Ordered](elems []U, key func(U) T) T

MinKey returns the minimum value of the given element array with respect to the given key function. In the event U is not a compound type (e.g a struct) an identity function can be provided.

func MultiErrorList 

func MultiErrorList(err error) (int, error)

MultiErrorList returns an error which formats underlying errors as a list, or nil if err is nil.

func MustAbiType 

func MustAbiType(ts string, components []abi.ArgumentMarshaling) abi.Type

func MustHash 

func MustHash(in string) common.Hash

MustHash returns the keccak256 hash, or panics on failure.

func MustNewPeerID 

func MustNewPeerID() string

func MustUnmarshalToMap 

func MustUnmarshalToMap(input string) map[string]interface{}

MustUnmarshalToMap performs UnmarshalToMap, panics upon failure

func NewBytes32ID 

func NewBytes32ID() string

NewBytes32ID returns a randomly generated UUID that conforms to Ethereum bytes32.

func NewHash 

func NewHash() common.Hash

NewHash return random Keccak256

func NewRedialBackoff 

func NewRedialBackoff() backoff.Backoff

NewRedialBackoff is a standard backoff to use for redialling or reconnecting to unreachable network endpoints

func NewSecret 

func NewSecret(n int) string

NewSecret returns a new securely random sequence of n bytes of entropy. The result is a base64 encoded string.

Panics on failed attempts to read from system's PRNG.

func NormalizedJSON 

func NormalizedJSON(val []byte) (string, error)

NormalizedJSON returns a JSON representation of an object that has been normalized to produce a consistent output for hashing.

NOTE: If this string is unmarshalled again, there is no guarantee that the final representation will be consistent with the string produced by this function due to differences in JSON implementations and information loss. e.g: 

JSON does not have a requirement to respect object key ordering.

func PadByteToHash 

func PadByteToHash(b byte) common.Hash

PadByteToHash returns a hash with zeros padded on the left of the given byte.

func ParseEthereumAddress 

func ParseEthereumAddress(addressString string) (common.Address, error)

ParseEthereumAddress returns addressString as a go-ethereum Address, or an error if it's invalid, e.g. if EIP 55 capitalization check fails

func PasswordFromFile 

func PasswordFromFile(pwdFile string) (string, error)

func RandUint256 

func RandUint256() *big.Int

RandUint256 generates a random bigNum up to 2 ** 256 - 1

func RandomAddress 

func RandomAddress() common.Address

func RandomBytes32 

func RandomBytes32() (r [32]byte)

func RemoveHexPrefix 

func RemoveHexPrefix(str string) string

RemoveHexPrefix removes the prefix (0x) of a given hex string.

func RemoveQuotes 

func RemoveQuotes(input []byte) []byte

RemoveQuotes removes the first and last character if they are both either " or ', otherwise it is a noop.

func RetryWithBackoff 

func RetryWithBackoff(ctx context.Context, fn func() (retry bool))

RetryWithBackoff retries the sleeper and backs off if not Done

func Sha256 

func Sha256(in string) (string, error)

Sha256 returns a hexadecimal encoded string of a hashed input

func StringToHex 

func StringToHex(in string) string

StringToHex converts a standard string to a hex encoded string.

func ToDecimal 

func ToDecimal(input interface{}) (decimal.Decimal, error)

ToDecimal converts an input to a decimal

func TooPermissive 

func TooPermissive(fileMode, maxAllowedPerms os.FileMode) bool

TooPermissive checks if the file has more than the allowed permissions

func TryParseHex 

func TryParseHex(s string) (b []byte, err error)

TryParseHex parses the given hex string to bytes, it can return error if the hex string is invalid. Follows the semantic of ethereum's FromHex.

func Uint256ToBytes 

func Uint256ToBytes(x *big.Int) (uint256 []byte, err error)

Uint256ToBytes is x represented as the bytes of a uint256

func Uint256ToBytes32 

func Uint256ToBytes32(n *big.Int) []byte

Uint256ToBytes32 returns the bytes32 encoding of the big int provided

func UnmarshalToMap 

func UnmarshalToMap(input string) (map[string]interface{}, error)

UnmarshalToMap takes an input json string and returns a map[string]interface i.e. a raw object

func UnwrapError 

func UnwrapError(err error) []error

UnwrapError returns a list of underlying errors if passed error implements joinedError or return the err in a single-element list otherwise.

func ValidateCronSchedule 

func ValidateCronSchedule(schedule string) error

ValidateCronSchedule returns an error if the given schedule is invalid.

func VerifyPasswordComplexity 

func VerifyPasswordComplexity(password string, disallowedStrings ...string) (merr error)

func WaitGroupChan 

func WaitGroupChan(wg *sync.WaitGroup) <-chan struct{}

WaitGroupChan creates a channel that closes when the provided sync.WaitGroup is done.

func WithCloseChan 

func WithCloseChan(parentCtx context.Context, chStop chan struct{}) (context.Context, context.CancelFunc)

WithCloseChan wraps a context so that it is canceled if the passed in channel is closed. Deprecated: Call StopChan.Ctx directly

func WithJitter 

func WithJitter(d time.Duration) time.Duration

WithJitter adds +/- 10% to a duration

func WrapIfError 

func WrapIfError(err *error, msg string)

WrapIfError decorates an error with the given message. It is intended to be used with `defer` statements, like so: 

func SomeFunction() (err error) {
    defer WrapIfError(&err, "error in SomeFunction:")

    ...
}

func WriteFileWithMaxPerms 

func WriteFileWithMaxPerms(path string, data []byte, perms os.FileMode) (err error)

WriteFileWithMaxPerms writes `data` to `path` and ensures that the file has permissions that are no more permissive than the given ones.

Types

type BackoffSleeper 

type BackoffSleeper struct {
	backoff.Backoff
	// contains filtered or unexported fields
}

BackoffSleeper is a sleeper that backs off on subsequent attempts.

func NewBackoffSleeper 

func NewBackoffSleeper() *BackoffSleeper

NewBackoffSleeper returns a BackoffSleeper that is configured to sleep for 0 seconds initially, then backs off from 1 second minimum to 10 seconds maximum.

func (*BackoffSleeper) After 

func (bs *BackoffSleeper) After() time.Duration

After returns the duration for the next stop, and increments the backoff.

func (*BackoffSleeper) Duration 

func (bs *BackoffSleeper) Duration() time.Duration

Duration returns the current duration value.

func (*BackoffSleeper) Reset 

func (bs *BackoffSleeper) Reset()

Reset resets the backoff intervals.

func (*BackoffSleeper) Sleep 

func (bs *BackoffSleeper) Sleep()

Sleep waits for the given duration, incrementing the back off.

type BackoffTicker 

type BackoffTicker struct {
	C chan time.Time

	sync.Mutex
	// contains filtered or unexported fields
}

BackoffTicker sends ticks with periods that increase over time, over a configured range.

func NewBackoffTicker 

func NewBackoffTicker(min, max time.Duration) BackoffTicker

NewBackoffTicker returns a new BackoffTicker for the given range.

func (*BackoffTicker) Bounds 

func (t *BackoffTicker) Bounds() (time.Duration, time.Duration)

func (*BackoffTicker) Start 

func (t *BackoffTicker) Start() bool

Start - Starts the ticker Returns true if the ticker was not running yet

func (*BackoffTicker) Stop 

func (t *BackoffTicker) Stop() bool

Stop stops the ticker. A ticker can be restarted by calling Start on a stopped ticker. Returns true if the ticker was actually stopped at this invocation (was previously running)

func (*BackoffTicker) Ticks 

func (t *BackoffTicker) Ticks() <-chan time.Time

Ticks returns the underlying channel.

type Big 

type Big big.Int

Big stores large integers and can deserialize a variety of inputs.

func NewBig 

func NewBig(i *big.Int) *Big

NewBig constructs a Big from *big.Int.

func NewBigI 

func NewBigI(i int64) *Big

NewBigI constructs a Big from int64.

func (*Big) Add 

func (b *Big) Add(c *Big) *Big

Add returns the sum of b and c

func (*Big) Bytes 

func (b *Big) Bytes() []byte

Bytes returns the

func (*Big) Cmp 

func (b *Big) Cmp(c *Big) int

Cmp compares b and c as big.Ints.

func (*Big) Equal 

func (b *Big) Equal(c *Big) bool

Equal returns true if c is equal according to Cmp.

func (*Big) Hex 

func (b *Big) Hex() string

Bytes returns the absolute value of b as a big-endian byte slice.

func (*Big) Int64 

func (b *Big) Int64() int64

Int64 casts b as an int64 type

func (Big) MarshalJSON 

func (b Big) MarshalJSON() ([]byte, error)

MarshalJSON marshals this instance to base 10 number as string.

func (Big) MarshalText 

func (b Big) MarshalText() ([]byte, error)

MarshalText marshals this instance to base 10 number as string.

func (*Big) Mod 

func (b *Big) Mod(c *Big) *Big

Sub returns b % c

func (*Big) Scan 

func (b *Big) Scan(value interface{}) error

Scan reads the database value and returns an instance.

func (*Big) String 

func (b *Big) String() string

String returns the base 10 encoding of b.

func (*Big) Sub 

func (b *Big) Sub(c *Big) *Big

Sub returns the differencs between b and c

func (*Big) ToInt 

func (b *Big) ToInt() *big.Int

ToInt converts b to a big.Int.

func (*Big) UnmarshalJSON 

func (b *Big) UnmarshalJSON(input []byte) error

UnmarshalJSON implements encoding.JSONUnmarshaler.

func (*Big) UnmarshalText 

func (b *Big) UnmarshalText(input []byte) error

UnmarshalText implements encoding.TextUnmarshaler.

func (Big) Value 

func (b Big) Value() (driver.Value, error)

Value returns this instance serialized for database storage.

type BigFloat 

type BigFloat big.Float

BigFloat accepts both string and float JSON values.

func (BigFloat) MarshalJSON 

func (b BigFloat) MarshalJSON() ([]byte, error)

MarshalJSON implements the json.Marshaler interface.

func (*BigFloat) UnmarshalJSON 

func (b *BigFloat) UnmarshalJSON(buf []byte) error

UnmarshalJSON implements the json.Unmarshal interface.

func (*BigFloat) Value 

func (b *BigFloat) Value() *big.Float

Value returns the big.Float value.

type BoundedPriorityQueue 

type BoundedPriorityQueue[T any] struct {
	// contains filtered or unexported fields
}

BoundedPriorityQueue stores a series of BoundedQueues with associated priorities and capacities

func NewBoundedPriorityQueue 

func NewBoundedPriorityQueue[T any](capacities map[uint]int) *BoundedPriorityQueue[T]

NewBoundedPriorityQueue creates a new BoundedPriorityQueue

func (*BoundedPriorityQueue[T]) Add 

func (q *BoundedPriorityQueue[T]) Add(priority uint, x T)

Add pushes an item into a subque within a BoundedPriorityQueue

func (*BoundedPriorityQueue[T]) Empty 

func (q *BoundedPriorityQueue[T]) Empty() bool

Empty checks the BoundedPriorityQueue if all subqueues are empty

func (*BoundedPriorityQueue[T]) Take 

func (q *BoundedPriorityQueue[T]) Take() (t T)

Take takes from the BoundedPriorityQueue's subque

type BoundedQueue 

type BoundedQueue[T any] struct {
	// contains filtered or unexported fields
}

BoundedQueue is a FIFO queue that discards older items when it reaches its capacity.

func NewBoundedQueue 

func NewBoundedQueue[T any](capacity int) *BoundedQueue[T]

NewBoundedQueue creates a new BoundedQueue instance

func (*BoundedQueue[T]) Add 

func (q *BoundedQueue[T]) Add(x T)

Add appends items to a BoundedQueue

func (*BoundedQueue[T]) Empty 

func (q *BoundedQueue[T]) Empty() bool

Empty check is a BoundedQueue is empty

func (*BoundedQueue[T]) Full 

func (q *BoundedQueue[T]) Full() bool

Full checks if a BoundedQueue is over capacity.

func (*BoundedQueue[T]) Take 

func (q *BoundedQueue[T]) Take() (t T)

Take pulls the first item from the array and removes it

type CronTicker 

type CronTicker struct {
	*cron.Cron
	// contains filtered or unexported fields
}

CronTicker is like a time.Ticker but for a cron schedule.

func NewCronTicker 

func NewCronTicker(schedule string) (CronTicker, error)

NewCronTicker returns a new CrontTicker for the given schedule.

func (*CronTicker) Start 

func (t *CronTicker) Start() bool

Start - returns true if the CronTicker was actually started, false otherwise

func (*CronTicker) Stop 

func (t *CronTicker) Stop() bool

Stop - returns true if the CronTicker was actually stopped, false otherwise

func (*CronTicker) Ticks 

func (t *CronTicker) Ticks() <-chan time.Time

Ticks returns the underlying chanel.

type DeferableWriteCloser 

type DeferableWriteCloser struct {
	io.WriteCloser
	// contains filtered or unexported fields
}

DeferableWriteCloser is to be used in leiu of defer'ing Close on an io.WriteCloser (// For more background see https://www.joeshaw.org/dont-defer-close-on-writable-files/) Callers should *both* explicitly call Close and check for errors when done with the underlying writerclose *and* defer the Close() to handle returns before the explicit close

For example rather than 

import "os"
f, err := os.Create("./foo")
if err != nil { return err}
defer f.Close()
return f.Write([]bytes("hi"))

do 

import "os"
f, err := os.Create("./foo")
if err != nil {return nil}
wc := NewDeferableWriteCloser(f)
defer wc.Close()
err = wc.Write([]bytes("hi"))
if err != nil {return err}
return wc.Close()

func NewDeferableWriteCloser 

func NewDeferableWriteCloser(wc io.WriteCloser) *DeferableWriteCloser

NewDeferableWriteCloser creates a deferable writercloser. Callers should explicit call and defer Close. See DeferabelWriterCloser for details.

func (*DeferableWriteCloser) Close 

func (wc *DeferableWriteCloser) Close() error

Close closes the WriterCloser. The underlying Closer is Closed exactly once and resulting error is cached. Should be called explicitly AND defered Thread safe

type DependentAwaiter 

type DependentAwaiter interface {
	AwaitDependents() <-chan struct{}
	AddDependents(n int)
	DependentReady()
}

DependentAwaiter contains Dependent funcs

func NewDependentAwaiter 

func NewDependentAwaiter() DependentAwaiter

NewDependentAwaiter creates a new DependentAwaiter

type ErrorBuffer 

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

ErrorBuffer uses joinedErrors interface to join multiple errors into a single error. This is useful to track the most recent N errors in a service and flush them as a single error.

func (*ErrorBuffer) Append 

func (eb *ErrorBuffer) Append(incoming error)

func (*ErrorBuffer) Flush 

func (eb *ErrorBuffer) Flush() (err error)

func (*ErrorBuffer) SetCap 

func (eb *ErrorBuffer) SetCap(cap int)

type FileSize 

type FileSize uint64

FileSize repesents a file size in bytes.

func (FileSize) MarshalText 

func (s FileSize) MarshalText() ([]byte, error)

MarshalText encodes s as a human readable string.

func (FileSize) String 

func (s FileSize) String() string

func (*FileSize) UnmarshalText 

func (s *FileSize) UnmarshalText(bs []byte) error

UnmarshalText parses a file size from bs in to s.

type KeyedMutex 

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

KeyedMutex allows to lock based on particular values

func (*KeyedMutex) LockInt64 

func (m *KeyedMutex) LockInt64(key int64) func()

LockInt64 locks the value for read/write

type LazyLoad 

type LazyLoad[T any] struct {
	// contains filtered or unexported fields
}

func NewLazyLoad 

func NewLazyLoad[T any](f func() (T, error)) *LazyLoad[T]

func (*LazyLoad[T]) Get 

func (l *LazyLoad[T]) Get() (out T, err error)

func (*LazyLoad[T]) Reset 

func (l *LazyLoad[T]) Reset()

type Mailbox 

type Mailbox[T any] struct {
	// contains filtered or unexported fields
}

Mailbox contains a notify channel, a mutual exclusive lock, a queue of interfaces, and a queue capacity.

func NewHighCapacityMailbox 

func NewHighCapacityMailbox[T any]() *Mailbox[T]

NewHighCapacityMailbox create a new mailbox with a capacity that is better able to handle e.g. large log replays.

func NewMailbox 

func NewMailbox[T any](capacity uint64) *Mailbox[T]

NewMailbox creates a new mailbox instance. If name is non-empty, it must be unique and calling Start will launch prometheus metric monitor that periodically reports mailbox load until Close() is called.

func NewSingleMailbox 

func NewSingleMailbox[T any]() *Mailbox[T]

NewSingleMailbox returns a new Mailbox with capacity one.

func (*Mailbox[T]) Close 

func (m *Mailbox[T]) Close() error

func (*Mailbox[T]) Deliver 

func (m *Mailbox[T]) Deliver(x T) (wasOverCapacity bool)

Deliver appends to the queue and returns true if the queue was full, causing a message to be dropped.

func (*Mailbox[T]) Notify 

func (m *Mailbox[T]) Notify() <-chan struct{}

Notify returns the contents of the notify channel

func (*Mailbox[T]) Retrieve 

func (m *Mailbox[T]) Retrieve() (t T, ok bool)

Retrieve fetches one element from the queue.

func (*Mailbox[T]) RetrieveAll 

func (m *Mailbox[T]) RetrieveAll() []T

RetrieveAll fetches all elements from the queue.

func (*Mailbox[T]) RetrieveLatestAndClear 

func (m *Mailbox[T]) RetrieveLatestAndClear() (t T)

RetrieveLatestAndClear fetch the latest value (or nil), and clears the rest of the queue (if any).

type MailboxMonitor 

type MailboxMonitor struct {
	StartStopOnce
	// contains filtered or unexported fields
}

func NewMailboxMonitor 

func NewMailboxMonitor(appID string) *MailboxMonitor

func (*MailboxMonitor) Close 

func (m *MailboxMonitor) Close() error

func (*MailboxMonitor) HealthReport 

func (m *MailboxMonitor) HealthReport() map[string]error

func (*MailboxMonitor) Monitor 

func (m *MailboxMonitor) Monitor(mb mailbox, name ...string)

func (*MailboxMonitor) Name 

func (m *MailboxMonitor) Name() string

func (*MailboxMonitor) Start 

func (m *MailboxMonitor) Start(context.Context) error

type PausableTicker 

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

PausableTicker stores a ticker with a duration

func NewPausableTicker 

func NewPausableTicker(duration time.Duration) PausableTicker

NewPausableTicker creates a new PausableTicker

func (*PausableTicker) Destroy 

func (t *PausableTicker) Destroy()

Destroy pauses the PausibleTicker

func (*PausableTicker) Pause 

func (t *PausableTicker) Pause()

Pause pauses a PausableTicker

func (*PausableTicker) Resume 

func (t *PausableTicker) Resume()

Resume resumes a Ticker using a PausibleTicker's duration

func (*PausableTicker) Ticks 

func (t *PausableTicker) Ticks() <-chan time.Time

Ticks retrieves the ticks from a PausableTicker

type PlainHexBytes 

type PlainHexBytes []byte

PlainHexBytes marshals/unmarshals as a JSON string without a 0x prefix. The empty slice marshals as "".

func (PlainHexBytes) MarshalText 

func (b PlainHexBytes) MarshalText() ([]byte, error)

MarshalText implements encoding.TextMarshaler

func (PlainHexBytes) String 

func (b PlainHexBytes) String() string

func (*PlainHexBytes) UnmarshalJSON 

func (b *PlainHexBytes) UnmarshalJSON(input []byte) (err error)

UnmarshalJSON implements json.Unmarshaler.

func (*PlainHexBytes) UnmarshalText 

func (b *PlainHexBytes) UnmarshalText(input []byte) error

UnmarshalText implements encoding.TextUnmarshaler.

type ResettableTimer 

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

ResettableTimer stores a timer

func NewResettableTimer 

func NewResettableTimer() ResettableTimer

NewResettableTimer creates a new ResettableTimer

func (*ResettableTimer) Reset 

func (t *ResettableTimer) Reset(duration time.Duration)

Reset stops a ResettableTimer and resets it with a new duration

func (*ResettableTimer) Stop 

func (t *ResettableTimer) Stop()

Stop stops a ResettableTimer

func (*ResettableTimer) Ticks 

func (t *ResettableTimer) Ticks() <-chan time.Time

Ticks retrieves the ticks from a ResettableTimer

type ScryptConfigReader 

type ScryptConfigReader interface {
	InsecureFastScrypt() bool
}

ScryptConfigReader can check for an insecure, fast flag

type ScryptParams 

type ScryptParams struct{ N, P int }

ScryptParams represents two integers, N and P.

func GetScryptParams 

func GetScryptParams(config ScryptConfigReader) ScryptParams

GetScryptParams fetches ScryptParams from a ScryptConfigReader

type Sleeper 

type Sleeper interface {
	Reset()
	Sleep()
	After() time.Duration
	Duration() time.Duration
}

Sleeper interface is used for tasks that need to be done on some interval, excluding Cron, like reconnecting.

type SleeperTask 

type SleeperTask interface {
	Stop() error
	WakeUp()
	WakeUpIfStarted()
}

SleeperTask represents a task that waits in the background to process some work.

func NewSleeperTask 

func NewSleeperTask(worker Worker) SleeperTask

NewSleeperTask takes a worker and returns a SleeperTask.

SleeperTask is guaranteed to call Work on the worker at least once for every WakeUp call. If the Worker is busy when WakeUp is called, the Worker will be called again immediately after it is finished. For this reason you should take care to make sure that Worker is idempotent. WakeUp does not block.

type StartStopOnce 

type StartStopOnce struct {
	sync.RWMutex // lock is held during startup/shutdown, RLock is held while executing functions dependent on a particular state

	// SvcErrBuffer is an ErrorBuffer that let service owners track critical errors happening in the service.
	//
	// SvcErrBuffer.SetCap(int) Overrides buffer limit from defaultErrorBufferCap
	// SvcErrBuffer.Append(error) Appends an error to the buffer
	// SvcErrBuffer.Flush() error returns all tracked errors as a single joined error
	SvcErrBuffer ErrorBuffer
	// contains filtered or unexported fields
}

StartStopOnce contains a StartStopOnceState integer

func (*StartStopOnce) Healthy 

func (once *StartStopOnce) Healthy() error

Healthy returns ErrNotStarted if the state is not started. Override this per-service with more specific implementations.

func (*StartStopOnce) IfNotStopped 

func (once *StartStopOnce) IfNotStopped(f func()) (ok bool)

IfNotStopped runs the func and returns true if in any state other than Stopped

func (*StartStopOnce) IfStarted 

func (once *StartStopOnce) IfStarted(f func()) (ok bool)

IfStarted runs the func and returns true only if started, otherwise returns false

func (*StartStopOnce) Ready 

func (once *StartStopOnce) Ready() error

Ready returns ErrNotStarted if the state is not started.

func (*StartStopOnce) StartOnce 

func (once *StartStopOnce) StartOnce(name string, fn func() error) error

StartOnce sets the state to Started

func (*StartStopOnce) State 

func (once *StartStopOnce) State() StartStopOnceState

State retrieves the current state

func (*StartStopOnce) StopOnce 

func (once *StartStopOnce) StopOnce(name string, fn func() error) error

StopOnce sets the state to Stopped

type StartStopOnceState 

type StartStopOnceState int32

StartStopOnceState holds the state for StartStopOnce 

const (
	StartStopOnce_Unstarted StartStopOnceState = iota
	StartStopOnce_Started
	StartStopOnce_Starting
	StartStopOnce_StartFailed
	StartStopOnce_Stopping
	StartStopOnce_Stopped
	StartStopOnce_StopFailed
)

nolint

func (StartStopOnceState) String 

func (s StartStopOnceState) String() string

type StopChan added in v2.1.0 

type StopChan chan struct{}

A StopChan signals when some work should stop.

Example 
stopCh := make(StopChan)

work := func(context.Context) {}

a := func(ctx context.Context, done func()) {
	defer done()
	ctx, cancel := stopCh.Ctx(ctx)
	defer cancel()
	work(ctx)
}

b := func(ctx context.Context, done func()) {
	defer done()
	ctx, cancel := stopCh.CtxCancel(context.WithTimeout(ctx, time.Second))
	defer cancel()
	work(ctx)
}

c := func(ctx context.Context, done func()) {
	defer done()
	ctx, cancel := stopCh.CtxCancel(context.WithDeadline(ctx, time.Now().Add(5*time.Second)))
	defer cancel()
	work(ctx)
}

ctx, cancel := stopCh.NewCtx()
defer cancel()

var wg sync.WaitGroup
wg.Add(3)
go a(ctx, wg.Done)
go b(ctx, wg.Done)
go c(ctx, wg.Done)

time.AfterFunc(time.Second, func() { close(stopCh) })

wg.Wait()

Output:

func (StopChan) Ctx added in v2.1.0 

func (s StopChan) Ctx(ctx context.Context) (context.Context, context.CancelFunc)

Ctx cancels a context.Context when StopChan is closed.

func (StopChan) CtxCancel added in v2.1.0 

func (s StopChan) CtxCancel(ctx context.Context, cancel context.CancelFunc) (context.Context, context.CancelFunc)

CtxCancel cancels a context.Context when StopChan is closed. Returns ctx and cancel unmodified, for convenience.

func (StopChan) NewCtx added in v2.1.0 

func (s StopChan) NewCtx() (context.Context, context.CancelFunc)

NewCtx returns a background context.Context that is cancelled when StopChan is closed.

type StopRChan added in v2.2.0 

type StopRChan <-chan struct{}

A StopRChan signals when some work should stop. This version is receive-only.

func (StopRChan) Ctx added in v2.2.0 

func (s StopRChan) Ctx(ctx context.Context) (context.Context, context.CancelFunc)

Ctx cancels a context.Context when StopChan is closed.

func (StopRChan) CtxCancel added in v2.2.0 

func (s StopRChan) CtxCancel(ctx context.Context, cancel context.CancelFunc) (context.Context, context.CancelFunc)

CtxCancel cancels a context.Context when StopChan is closed. Returns ctx and cancel unmodified, for convenience.

func (StopRChan) NewCtx added in v2.2.0 

func (s StopRChan) NewCtx() (context.Context, context.CancelFunc)

NewCtx returns a background context.Context that is cancelled when StopChan is closed.

type TickerBase 

type TickerBase interface {
	Resume()
	Pause()
	Destroy()
	Ticks() <-chan time.Time
}

TickerBase is an interface for pausable tickers.

type Worker 

type Worker interface {
	Work()
	Name() string
}

Worker is a simple interface that represents some work to do repeatedly

func SleeperFuncTask 

func SleeperFuncTask(work func(), name string) Worker

SleeperFuncTask returns a Worker to execute the given work function.

Source Files

View all Source files

Directories

Path Synopsis
Package bigmath compensates for awkward big.Int API.
 Package bigmath compensates for awkward big.Int API.

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