circuit

package
v1.0.6 Latest Latest
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 Go to latest Published: Jul 6, 2026 License: MIT Imports: 4 Imported by: 0

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Constants

View Source 
const (
	// NumBuckets is the number of buckets used for time-based sliding window.
	NumBuckets = 10
)

Variables

View Source 
var (
	// ErrCircuitOpen is returned when the circuit breaker is in the Open state.
	ErrCircuitOpen = errors.New("circuit breaker is open")
)

Functions

This section is empty.

Types

type Breaker 

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

Breaker implements a circuit breaker state machine with sliding windows.

func New 

func New(cfg Config) *Breaker

New returns a new Breaker with the provided configuration.

func (*Breaker) Execute 

func (b *Breaker) Execute(ctx context.Context, action func() error) error

Execute wraps an action with the circuit breaker logic.

func (*Breaker) Health added in v1.0.6 

func (b *Breaker) Health() <-chan StateEvent

Health returns a channel that emits state change events. The channel is created lazily on first access. The caller should use a select with default to handle non-blocking receive.

func (*Breaker) Reset added in v1.0.4 

func (b *Breaker) Reset()

Reset manually resets the circuit breaker to Closed state and clears the window.

func (*Breaker) State 

func (b *Breaker) State() State

State returns the current state of the breaker.

type Config 

type Config struct {
	// WindowType specifies the type of sliding window.
	WindowType WindowType

	// WindowSize is the size of the count-based sliding window.
	// Default is 100.
	WindowSize uint32

	// WindowDuration is the duration of the time-based sliding window.
	// Default is 60 seconds.
	WindowDuration time.Duration

	// FailureRateThreshold is the failure rate percentage (0.0 to 100.0).
	// If failures/total >= FailureRateThreshold/100, the circuit opens.
	// Default is 50.0.
	FailureRateThreshold float64

	// MinimumCalls is the minimum number of calls in the current window before the failure rate is calculated.
	// Default is 10.
	MinimumCalls uint64

	// ResetTimeout is the duration to wait in Open state before moving to Half-Open.
	// Default is 60 seconds.
	ResetTimeout time.Duration

	// HalfOpenMaxCalls is the number of calls allowed in Half-Open state.
	// Default is 10.
	HalfOpenMaxCalls uint64
}

Config defines the configuration for the circuit breaker.

type HealthState added in v1.0.6 

type HealthState int

State represents the health state of a resilience component. 

const (
	// StateHealthy represents a healthy state where requests are allowed.
	HealthStateHealthy HealthState = iota
	// StateDegraded represents a degraded but functional state.
	HealthStateDegraded
	// StateUnhealthy represents an unhealthy state (e.g., circuit open).
	HealthStateUnhealthy
)

type State 

type State int

State represents the health state of the circuit breaker. 

const (
	// StateClosed represents a healthy state where requests are allowed.
	StateClosed State = iota
	// StateOpen represents a failed state where requests are fast-failed.
	StateOpen
	// StateHalfOpen represents a state where a limited number of probes are allowed.
	StateHalfOpen
)

type StateEvent added in v1.0.6 

type StateEvent struct {
	Component string
	State     HealthState
	Timestamp time.Time
	Message   string
}

StateEvent represents a state change event emitted by resilience components.

type WindowType added in v1.0.4 

type WindowType int

WindowType specifies whether the window is count-based or time-based. 

const (
	// WindowCountBased uses the last N calls to calculate failure rate.
	WindowCountBased WindowType = iota
	// WindowTimeBased uses calls in the last N duration to calculate failure rate.
	WindowTimeBased
)

Source Files

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