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Documentation
¶
Overview ¶
Package faststats contains helpers to calculate circuit statistics quickly (usually atomically).
Index ¶
- type AtomicBoolean
- type AtomicInt64
- func (a *AtomicInt64) Add(value int64) int64
- func (a *AtomicInt64) CompareAndSwap(expected int64, newVal int64) bool
- func (a *AtomicInt64) Duration() time.Duration
- func (a *AtomicInt64) Get() int64
- func (a *AtomicInt64) MarshalJSON() ([]byte, error)
- func (a *AtomicInt64) Set(value int64)
- func (a *AtomicInt64) String() string
- func (a *AtomicInt64) Swap(newValue int64) int64
- func (a *AtomicInt64) UnmarshalJSON(b []byte) error
- type RollingBuckets
- type RollingCounter
- func (r *RollingCounter) GetBuckets(now time.Time) []int64
- func (r *RollingCounter) Inc(now time.Time)
- func (r *RollingCounter) MarshalJSON() ([]byte, error)
- func (r *RollingCounter) Reset(now time.Time)
- func (r *RollingCounter) RollingSum() int64
- func (r *RollingCounter) RollingSumAt(now time.Time) int64
- func (r *RollingCounter) String() string
- func (r *RollingCounter) StringAt(now time.Time) string
- func (r *RollingCounter) TotalSum() int64
- func (r *RollingCounter) UnmarshalJSON(b []byte) error
- type RollingPercentile
- func (r *RollingPercentile) AddDuration(d time.Duration, now time.Time)
- func (r *RollingPercentile) Reset(now time.Time)
- func (r *RollingPercentile) Snapshot() SortedDurations
- func (r *RollingPercentile) SnapshotAt(now time.Time) SortedDurations
- func (r *RollingPercentile) SortedDurations(now time.Time) []time.Duration
- func (r *RollingPercentile) Var() expvar.Var
- type SortedDurations
- type TimedCheck
- func (c *TimedCheck) Check(now time.Time) bool
- func (c *TimedCheck) MarshalJSON() ([]byte, error)
- func (c *TimedCheck) SetEventCountToAllow(newCount int64)
- func (c *TimedCheck) SetSleepDuration(newDuration time.Duration)
- func (c *TimedCheck) SleepStart(now time.Time)
- func (c *TimedCheck) String() string
- func (c *TimedCheck) UnmarshalJSON(b []byte) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type AtomicBoolean ¶
type AtomicBoolean struct {
// contains filtered or unexported fields
}
AtomicBoolean is a helper struct to simulate atomic operations on a boolean
func (*AtomicBoolean) MarshalJSON ¶
func (a *AtomicBoolean) MarshalJSON() ([]byte, error)
MarshalJSON encodes this value in a thread safe way as a json bool
func (*AtomicBoolean) String ¶
func (a *AtomicBoolean) String() string
String returns "true" or "false"
func (*AtomicBoolean) UnmarshalJSON ¶
func (a *AtomicBoolean) UnmarshalJSON(b []byte) error
UnmarshalJSON decodes this value in a thread safe way as a json bool
type AtomicInt64 ¶
type AtomicInt64 struct {
// contains filtered or unexported fields
}
AtomicInt64 is a helper struct to simulate atomic operations on an int64 Note that I could have used `type AtomicInt642 int64`, but I did not want to make it easy to do + and - operations so easily without using atomic functions.
func (*AtomicInt64) Add ¶
func (a *AtomicInt64) Add(value int64) int64
Add a value to the current store
func (*AtomicInt64) CompareAndSwap ¶
func (a *AtomicInt64) CompareAndSwap(expected int64, newVal int64) bool
CompareAndSwap acts like a CompareAndSwap operation on the value
func (*AtomicInt64) Duration ¶
func (a *AtomicInt64) Duration() time.Duration
Duration returns the currently stored value as a time.Duration
func (*AtomicInt64) MarshalJSON ¶
func (a *AtomicInt64) MarshalJSON() ([]byte, error)
MarshalJSON encodes this value as an int in a thread safe way
func (*AtomicInt64) String ¶
func (a *AtomicInt64) String() string
String returns the integer as a string in a thread safe way
func (*AtomicInt64) Swap ¶
func (a *AtomicInt64) Swap(newValue int64) int64
Swap the current value with a new one
func (*AtomicInt64) UnmarshalJSON ¶
func (a *AtomicInt64) UnmarshalJSON(b []byte) error
UnmarshalJSON decodes this value as an int in a thread safe way
type RollingBuckets ¶
type RollingBuckets struct {
NumBuckets int
StartTime time.Time
BucketWidth time.Duration
LastAbsIndex AtomicInt64
}
RollingBuckets simulates a time rolling list of buckets of items. It is safe to use JSON to encode this object in a thread safe way.
This implementation cheats in order to not take a lock. It is correct, but only if the total size of the buckets (NumBuckets * BucketWidth) is less than any duration of how long Advance will take to execute. In anything but super small bucket sizes this should be fine. The common case, where (NumBuckets * BucketWidth >= 1sec) should always work.
func (*RollingBuckets) Advance ¶
func (r *RollingBuckets) Advance(now time.Time, clearBucket func(int)) int
Advance to now, clearing buckets as needed
func (*RollingBuckets) String ¶
func (r *RollingBuckets) String() string
type RollingCounter ¶
type RollingCounter struct {
// contains filtered or unexported fields
}
RollingCounter uses a slice of buckets to keep track of counts of an event over time with a sliding window
func NewRollingCounter ¶
NewRollingCounter initializes a rolling counter with a bucket width and # of buckets
func (*RollingCounter) GetBuckets ¶
func (r *RollingCounter) GetBuckets(now time.Time) []int64
GetBuckets returns a copy of the buckets in order backwards in time
func (*RollingCounter) Inc ¶
func (r *RollingCounter) Inc(now time.Time)
Inc adds a single event to the current bucket
func (*RollingCounter) MarshalJSON ¶
func (r *RollingCounter) MarshalJSON() ([]byte, error)
MarshalJSON JSON encodes a counter. It is thread safe.
func (*RollingCounter) Reset ¶
func (r *RollingCounter) Reset(now time.Time)
Reset the counter to all zero values.
func (*RollingCounter) RollingSum ¶
func (r *RollingCounter) RollingSum() int64
RollingSum returns the total number of events in the rolling time window (With time time.Now())
func (*RollingCounter) RollingSumAt ¶
func (r *RollingCounter) RollingSumAt(now time.Time) int64
RollingSumAt returns the total number of events in the rolling time window
func (*RollingCounter) StringAt ¶
func (r *RollingCounter) StringAt(now time.Time) string
StringAt converts the counter to a string at a given time.
func (*RollingCounter) TotalSum ¶
func (r *RollingCounter) TotalSum() int64
TotalSum returns the total number of events of all time
func (*RollingCounter) UnmarshalJSON ¶
func (r *RollingCounter) UnmarshalJSON(b []byte) error
UnmarshalJSON stores the previous JSON encoding. Note, this is *NOT* thread safe.
type RollingPercentile ¶
type RollingPercentile struct {
// contains filtered or unexported fields
}
RollingPercentile is a bucketed array of time.Duration that cycles over time
func NewRollingPercentile ¶
func NewRollingPercentile(bucketWidth time.Duration, numBuckets int, bucketSize int, now time.Time) RollingPercentile
NewRollingPercentile creates a new rolling percentile bucketer
func (*RollingPercentile) AddDuration ¶
func (r *RollingPercentile) AddDuration(d time.Duration, now time.Time)
AddDuration adds a duration to the rolling buckets
func (*RollingPercentile) Reset ¶
func (r *RollingPercentile) Reset(now time.Time)
Reset the counter to all zero values.
func (*RollingPercentile) Snapshot ¶
func (r *RollingPercentile) Snapshot() SortedDurations
Snapshot the current rolling buckets, allowing easy p99 calculations
func (*RollingPercentile) SnapshotAt ¶
func (r *RollingPercentile) SnapshotAt(now time.Time) SortedDurations
SnapshotAt is an optimization on Snapshot that takes the current time
func (*RollingPercentile) SortedDurations ¶
func (r *RollingPercentile) SortedDurations(now time.Time) []time.Duration
SortedDurations creates a raw []time.Duration in sorted order that is stored in these buckets
func (*RollingPercentile) Var ¶
func (r *RollingPercentile) Var() expvar.Var
Var allows exposing a rolling percentile snapshot on expvar
type SortedDurations ¶
SortedDurations is a sorted list of time.Duration that allows fast Percentile operations
func (SortedDurations) Max ¶
func (s SortedDurations) Max() time.Duration
Max returns the last (largest) item, or -1 if the list is empty
func (SortedDurations) Mean ¶
func (s SortedDurations) Mean() time.Duration
Mean (average) of the current list
func (SortedDurations) Min ¶
func (s SortedDurations) Min() time.Duration
Min returns the first (smallest) item, or -1 if the list is empty
func (SortedDurations) Percentile ¶
func (s SortedDurations) Percentile(p float64) time.Duration
Percentile returns a p [0.0 - 1.0] percentile of the list
func (SortedDurations) String ¶
func (s SortedDurations) String() string
func (SortedDurations) Var ¶
func (s SortedDurations) Var() expvar.Var
Var allows exposing the durations on expvar
type TimedCheck ¶
type TimedCheck struct {
TimeAfterFunc func(time.Duration, func()) *time.Timer
// contains filtered or unexported fields
}
TimedCheck lets X events happen every sleepDuration units of time. For optimizations, it uses TimeAfterFunc to reset an internal atomic boolean for when events are allowed. This timer could run a little bit behind real time since it depends on when the OS decides to trigger the timer.
func (*TimedCheck) Check ¶
func (c *TimedCheck) Check(now time.Time) bool
Check returns true if a check is allowed at this time
func (*TimedCheck) MarshalJSON ¶
func (c *TimedCheck) MarshalJSON() ([]byte, error)
MarshalJSON writes the object as JSON. It is thread safe.
func (*TimedCheck) SetEventCountToAllow ¶
func (c *TimedCheck) SetEventCountToAllow(newCount int64)
SetEventCountToAllow configures how many times Check() can return true before moving time to the next interval
func (*TimedCheck) SetSleepDuration ¶
func (c *TimedCheck) SetSleepDuration(newDuration time.Duration)
SetSleepDuration modifies how long time timed check will sleep. It will not change alredy sleeping checks, but will change during the next check.
func (*TimedCheck) SleepStart ¶
func (c *TimedCheck) SleepStart(now time.Time)
SleepStart resets the checker to trigger after now + sleepDuration
func (*TimedCheck) String ¶
func (c *TimedCheck) String() string
func (*TimedCheck) UnmarshalJSON ¶
func (c *TimedCheck) UnmarshalJSON(b []byte) error
UnmarshalJSON changes the object from JSON. It is *NOT* thread safe.
Source Files