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package scale
import (
"fmt"
"time"
)
const DefaultBackoffBase = 15 * time.Second
const DefaultBackoffCap = 5 * time.Minute
type Backoff struct {
Ends int
Until time.Time
Reason string
}
func (o Options) backoffBase() time.Duration {
if o.BackoffBase <= 0 {
return DefaultBackoffBase
}
return o.BackoffBase
}
func (o Options) backoffCap() time.Duration {
if o.BackoffCap <= 0 {
return DefaultBackoffCap
}
return o.BackoffCap
}
func BackoffDelay(ends int, opts Options) time.Duration {
if ends <= 0 {
return 0
}
delay, ceiling := opts.backoffBase(), opts.backoffCap()
for i := 1; i < ends && delay < ceiling; i++ {
delay *= 2
}
if delay > ceiling {
return ceiling
}
return delay
}
func (b Backoff) Holds(now time.Time) bool {
return !b.Until.IsZero() && now.Before(b.Until)
}
func (st State) Declined(now time.Time, reason string, opts Options) State {
ends := st.Backoff.Ends + 1
st.Backoff = Backoff{Ends: ends, Until: now.Add(BackoffDelay(ends, opts)), Reason: reason}
return st
}
func (st State) Joined() State {
st.Backoff = Backoff{}
return st
}
func backingOff(st State, target int, now time.Time) Decision {
return Decision{
Action: None, Nodes: st.Nodes, Intent: true, BackoffUntil: st.Backoff.Until,
Reason: fmt.Sprintf("intent, and %d nodes are counted for a target of %d, and this cluster "+
"is backing off market provisions until %s (%s from now): %d market provision(s) in a "+
"row ended without a node (an RFP no bidder took, or a claim that failed or was lost), and "+
"asking again at once posts a new public RFP every pass -- %s", st.Nodes, target, st.Backoff.Until.UTC().Format(time.RFC3339),
st.Backoff.Until.Sub(now).Round(time.Second), st.Backoff.Ends, st.Backoff.Reason),
}
}
