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|
package providerhealth
import (
"sort"
"sync"
"time"
)
const recentWindow = 100
type RouteKey struct {
ModelID string
ProviderID string
WireAPI string
}
type Observation struct {
StatusCode int
Latency time.Duration
Failed bool
ObservedAt time.Time
}
type Status struct {
ModelID string `json:"model_id"`
ProviderID string `json:"provider_id"`
WireAPI string `json:"wire_api"`
State string `json:"state"`
Attempts uint64 `json:"attempts"`
RecentSamples int `json:"recent_samples"`
AvailabilityPercent float64 `json:"availability_percent"`
HeaderLatencyEWMA int64 `json:"header_latency_ewma_ms"`
ConsecutiveFailures uint64 `json:"consecutive_failures"`
LastStatusCode int `json:"last_status_code,omitempty"`
LastObservedAt *time.Time `json:"last_observed_at,omitempty"`
LastHealthyAt *time.Time `json:"last_healthy_at,omitempty"`
CircuitOpenUntil *time.Time `json:"circuit_open_until,omitempty"`
}
type Options struct {
FailureThreshold uint64
OpenDuration time.Duration
Now func() time.Time
}
type Tracker struct {
states sync.Map
failureThreshold uint64
openDuration time.Duration
now func() time.Time
}
type routeState struct {
mu sync.RWMutex
attempts uint64
consecutiveFailures uint64
lastStatusCode int
lastObservedAt time.Time
lastHealthyAt time.Time
openUntil time.Time
headerLatencyEWMA float64
recent [recentWindow]bool
recentCount int
recentPosition int
recentHealthy int
}
func New(options Options) *Tracker {
if options.FailureThreshold == 0 {
options.FailureThreshold = 3
}
if options.OpenDuration <= 0 {
options.OpenDuration = 30 * time.Second
}
if options.Now == nil {
options.Now = time.Now
}
return &Tracker{failureThreshold: options.FailureThreshold, openDuration: options.OpenDuration, now: options.Now}
}
func (t *Tracker) Observe(key RouteKey, observation Observation) {
if t == nil || key.ProviderID == "" {
return
}
if observation.ObservedAt.IsZero() {
observation.ObservedAt = t.now()
}
value, _ := t.states.LoadOrStore(key, &routeState{})
state := value.(*routeState)
state.mu.Lock()
defer state.mu.Unlock()
state.attempts++
state.lastStatusCode = observation.StatusCode
state.lastObservedAt = observation.ObservedAt
if observation.Latency > 0 {
latency := float64(observation.Latency.Milliseconds())
if latency < 1 {
latency = 1
}
if state.headerLatencyEWMA == 0 {
state.headerLatencyEWMA = latency
} else {
state.headerLatencyEWMA = state.headerLatencyEWMA*0.8 + latency*0.2
}
}
state.addRecent(!observation.Failed)
if observation.Failed {
state.consecutiveFailures++
if state.consecutiveFailures >= t.failureThreshold {
state.openUntil = observation.ObservedAt.Add(t.openDuration)
}
return
}
state.consecutiveFailures = 0
state.openUntil = time.Time{}
state.lastHealthyAt = observation.ObservedAt
}
func (s *routeState) addRecent(healthy bool) {
if s.recentCount == recentWindow {
if s.recent[s.recentPosition] {
s.recentHealthy--
}
} else {
s.recentCount++
}
s.recent[s.recentPosition] = healthy
if healthy {
s.recentHealthy++
}
s.recentPosition = (s.recentPosition + 1) % recentWindow
}
func (t *Tracker) CircuitOpen(key RouteKey) bool {
if t == nil {
return false
}
value, ok := t.states.Load(key)
if !ok {
return false
}
state := value.(*routeState)
state.mu.RLock()
defer state.mu.RUnlock()
return state.openUntil.After(t.now())
}
func (t *Tracker) Snapshot() []Status {
if t == nil {
return []Status{}
}
now := t.now()
result := make([]Status, 0)
t.states.Range(func(rawKey, rawState any) bool {
key := rawKey.(RouteKey)
state := rawState.(*routeState)
state.mu.RLock()
item := statusFromState(key, state, now)
state.mu.RUnlock()
result = append(result, item)
return true
})
sort.Slice(result, func(i, j int) bool {
if result[i].ModelID != result[j].ModelID {
return result[i].ModelID < result[j].ModelID
}
return result[i].ProviderID < result[j].ProviderID
})
return result
}
func statusFromState(key RouteKey, state *routeState, now time.Time) Status {
item := Status{ModelID: key.ModelID, ProviderID: key.ProviderID, WireAPI: key.WireAPI,
Attempts: state.attempts, RecentSamples: state.recentCount, HeaderLatencyEWMA: int64(state.headerLatencyEWMA + 0.5),
ConsecutiveFailures: state.consecutiveFailures, LastStatusCode: state.lastStatusCode}
if state.recentCount > 0 {
item.AvailabilityPercent = float64(state.recentHealthy) / float64(state.recentCount) * 100
}
if !state.lastObservedAt.IsZero() {
value := state.lastObservedAt
item.LastObservedAt = &value
}
if !state.lastHealthyAt.IsZero() {
value := state.lastHealthyAt
item.LastHealthyAt = &value
}
if state.openUntil.After(now) {
value := state.openUntil
item.CircuitOpenUntil = &value
item.State = "open"
} else if state.attempts == 0 {
item.State = "unknown"
} else if state.consecutiveFailures > 0 || (state.recentCount >= 5 && item.AvailabilityPercent < 95) {
item.State = "degraded"
} else {
item.State = "healthy"
}
return item
}
|
