[#479] cmd/neofs-node: Add eigen trust block timer

Eigen trust block timer ticks to start new round of
eigen trust calculations. Every epoch this timer
recalculates duration and starts again.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

cmd/neofs-node/timers.go

@@ -0,0 +1,85 @@
+package main
+
+import (
+	"sync"
+
+	wrapNetmap "github.com/nspcc-dev/neofs-node/pkg/morph/client/netmap/wrapper"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/timer"
+)
+
+type (
+	// EigenTrustDuration is a structure that provides duration of one
+	// eigen trust iteration round in blocks for block timer.
+	EigenTrustDuration struct {
+		sync.Mutex
+
+		nm  *wrapNetmap.Wrapper
+		val uint32
+	}
+)
+
+// NewEigenTrustDuration returns instance of EigenTrustDuration.
+func NewEigenTrustDuration(nm *wrapNetmap.Wrapper) *EigenTrustDuration {
+	return &EigenTrustDuration{
+		nm: nm,
+	}
+}
+
+// Value returns number of blocks between two iterations of EigenTrust
+// calculation. This value is not changed between `Update` calls.
+func (e *EigenTrustDuration) Value() (uint32, error) {
+	e.Lock()
+	defer e.Unlock()
+
+	if e.val == 0 {
+		e.update()
+	}
+
+	return e.val, nil
+}
+
+// Update function recalculate duration of EigenTrust iteration based on
+// NeoFS epoch duration and amount of iteration rounds from global config.
+func (e *EigenTrustDuration) Update() {
+	e.Lock()
+	defer e.Unlock()
+
+	e.update()
+}
+
+func (e *EigenTrustDuration) update() {
+	iterationAmount, err := e.nm.EigenTrustIterations()
+	if err != nil {
+		return
+	}
+
+	epochDuration, err := e.nm.EpochDuration()
+	if err != nil {
+		return
+	}
+
+	e.val = uint32(epochDuration / iterationAmount)
+}
+
+func startBlockTimers(c *cfg) {
+	for i := range c.cfgMorph.blockTimers {
+		if err := c.cfgMorph.blockTimers[i].Reset(); err != nil {
+			fatalOnErr(err)
+		}
+	}
+}
+
+func tickBlockTimers(c *cfg) {
+	for i := range c.cfgMorph.blockTimers {
+		c.cfgMorph.blockTimers[i].Tick()
+	}
+}
+
+func newEigenTrustIterTimer(c *cfg, it *EigenTrustDuration, handler timer.BlockTickHandler) {
+	c.cfgMorph.eigenTrustTimer = timer.NewBlockTimer(
+		it.Value,
+		handler,
+	)
+
+	c.cfgMorph.blockTimers = append(c.cfgMorph.blockTimers, c.cfgMorph.eigenTrustTimer)
+}