Documentation
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Overview ¶
Package concurrent provides high-level synchronization tooling and thread-safe data structures.
Index ¶
Constants ¶
const DefaultConcurrency = 16
DefaultConcurrency is the default level of concurrency applied in the scoreboard constructor.
const DefaultCounterCheckInterval = 10 * time.Millisecond
DefaultCounterCheckInterval is the default check interval used by Await/AwaitCtx/Drain/Fill.
const DefaultReferenceCheckInterval = 10 * time.Millisecond
DefaultReferenceCheckInterval is the default check interval used by Await/AwaitCtx.
const DefaultScoreboardCheckInterval = 10 * time.Millisecond
DefaultScoreboardCheckInterval is the default check interval used by Await/AwaitCtx/Drain/Fill.
const Indefinitely = math.MaxInt64 * time.Nanosecond
Indefinitely is a constant that represents the longest allowable duration (approx. 290 years). It is used when an arbitrarily long timeout is needed.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type AtomicCounter ¶
type AtomicCounter interface {
fmt.Stringer
Get() int64
GetInt() int
Add(amount int64) int64
Inc() int64
Dec() int64
Set(amount int64)
CompareAndSwap(expected int64, replacement int64) bool
Fill(atLeast int64, timeout time.Duration, interval ...time.Duration) int64
Drain(atMost int64, timeout time.Duration, interval ...time.Duration) int64
Await(cond I64Condition, timeout time.Duration, interval ...time.Duration) int64
AwaitCtx(ctx context.Context, cond I64Condition, interval ...time.Duration) int64
}
AtomicCounter encapsulates an int64 value that may updated atomically.
func NewAtomicCounter ¶
func NewAtomicCounter(initial ...int64) AtomicCounter
NewAtomicCounter creates a new counter, optionally assigning its value to the given initial value (0 by default)
type AtomicReference ¶
type AtomicReference interface {
fmt.Stringer
Set(value interface{})
Get() interface{}
Await(cond RefCondition, timeout time.Duration, interval ...time.Duration) interface{}
AwaitCtx(ctx context.Context, cond RefCondition, interval ...time.Duration) interface{}
}
AtomicReference encapsulates a pointer that may updated atomically. Unlike its sync/atomic.Value counterpart, this implementation permits nil pointers.
func NewAtomicReference ¶
func NewAtomicReference(initial ...interface{}) AtomicReference
NewAtomicReference creates a new reference, optionally assigning its contents to the given initial referent (nil by default)
type Deadline ¶
type Deadline interface {
TryRun(f func()) bool
Elapsed() time.Duration
Expired() bool
Move(new time.Time)
Last() time.Time
Remaining() time.Duration
}
Deadline tracks the time a task was last run and conditionally runs a task if the deadline has lapsed.
Deadline is thread-safe.
func NewDeadline ¶
NewDeadline creates a new Deadline with the specified interval.
type I64Condition ¶
I64Condition is a predicate that checks whether the current (supplied) value meets some condition, returning true if the condition is met.
func I64Equal ¶
func I64Equal(target int64) I64Condition
I64Equal tests that the value equals a target value.
func I64GreaterThan ¶
func I64GreaterThan(target int64) I64Condition
I64GreaterThan tests that the value is greater than the given target value.
func I64GreaterThanOrEqual ¶
func I64GreaterThanOrEqual(target int64) I64Condition
I64GreaterThanOrEqual tests that the value is greater than or equal to the given target value.
func I64LessThan ¶
func I64LessThan(target int64) I64Condition
I64LessThan tests that the value is less than the given target value.
func I64LessThanOrEqual ¶
func I64LessThanOrEqual(target int64) I64Condition
I64LessThanOrEqual tests that the value is less than or equal to the given target value.
func I64Not ¶
func I64Not(cond I64Condition) I64Condition
I64Not produces a logical inverse of the given condition.
type RefCondition ¶
type RefCondition func(referent interface{}) bool
RefCondition is a predicate that checks whether the current (supplied) referent meets some condition, returning true if the condition is met.
func RefEqual ¶
func RefEqual(target interface{}) RefCondition
RefEqual tests that the encapsulated referent equals a target referent.
func RefNot ¶
func RefNot(cond RefCondition) RefCondition
RefNot produces a logical inverse of the given condition.
type Scoreboard ¶
type Scoreboard interface {
fmt.Stringer
Add(key string, amount int64) int64
Inc(key string) int64
Dec(key string) int64
Get(key string) int64
GetInt(key string) int
Set(key string, value int64)
Clear()
View() map[string]int64
Fill(key string, atLeast int64, timeout time.Duration, interval ...time.Duration) int64
Drain(key string, atMost int64, timeout time.Duration, interval ...time.Duration) int64
Await(key string, cond I64Condition, timeout time.Duration, interval ...time.Duration) int64
AwaitCtx(ctx context.Context, key string, cond I64Condition, interval ...time.Duration) int64
}
Scoreboard is a compactly represented map of atomic counters, where a counter takes up a map slot only if it is not equal to zero.
func NewScoreboard ¶
func NewScoreboard(concurrency ...int) Scoreboard
NewScoreboard creates a new scoreboard instance with an optionally specified concurrency level, controlling the number of internal shards. If unspecified, concurrency is set to DefaultConcurrency.
Each shard is individually locked. A greater number of shards allows for a greater degree of uncontended access, provided the keys are well-distributed. Shards are created up-front, meaning that scoreboards with more concurrency take up more space.
Source Files