frostfs-http-gw/connections/pool.go

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package connections
import (
"context"
"crypto/ecdsa"
"math"
"math/rand"
"sync"
"time"
"github.com/nspcc-dev/neofs-api-go/pkg/client"
"github.com/nspcc-dev/neofs-api-go/pkg/token"
"github.com/pkg/errors"
"google.golang.org/grpc"
)
type PoolBuilderOptions struct {
Key *ecdsa.PrivateKey
NodeConnectionTimeout time.Duration
NodeRequestTimeout time.Duration
ClientRebalanceInterval time.Duration
SessionExpirationEpoch uint64
weights []float64
connections []*grpc.ClientConn
}
type PoolBuilder struct {
addresses []string
weights []float64
}
func (pb *PoolBuilder) AddNode(address string, weight float64) *PoolBuilder {
pb.addresses = append(pb.addresses, address)
pb.weights = append(pb.weights, weight)
return pb
}
func (pb *PoolBuilder) Build(ctx context.Context, options *PoolBuilderOptions) (Pool, error) {
totalWeight := 0.0
for _, w := range pb.weights {
totalWeight += w
}
if math.Abs(totalWeight-1.0) >= 1e-4 {
return nil, errors.New("total weight must be equal to unity")
}
var cons = make([]*grpc.ClientConn, len(pb.addresses))
for i, address := range pb.addresses {
con, err := func() (*grpc.ClientConn, error) {
toctx, c := context.WithTimeout(ctx, options.NodeConnectionTimeout)
defer c()
return grpc.DialContext(toctx, address, grpc.WithInsecure(), grpc.WithBlock())
}()
if err != nil {
return nil, err
}
cons[i] = con
}
options.weights = pb.weights
options.connections = cons
return new(ctx, options)
}
type Pool interface {
ConnectionArtifacts() (client.Client, *token.SessionToken, error)
}
type clientPack struct {
client client.Client
sessionToken *token.SessionToken
healthy bool
}
type pool struct {
lock sync.RWMutex
sampler *Sampler
clientPacks []*clientPack
}
func new(ctx context.Context, options *PoolBuilderOptions) (Pool, error) {
clientPacks := make([]*clientPack, len(options.weights))
for i, con := range options.connections {
c, err := client.New(client.WithDefaultPrivateKey(options.Key), client.WithGRPCConnection(con))
if err != nil {
return nil, err
}
st, err := c.CreateSession(ctx, options.SessionExpirationEpoch)
if err != nil {
address := "unknown"
if epi, err := c.EndpointInfo(ctx); err == nil {
address = epi.NodeInfo().Address()
}
return nil, errors.Wrapf(err, "failed to create neofs session token for client %s", address)
}
clientPacks[i] = &clientPack{client: c, sessionToken: st, healthy: true}
}
source := rand.NewSource(time.Now().UnixNano())
sampler := NewSampler(options.weights, source)
pool := &pool{sampler: sampler, clientPacks: clientPacks}
go func() {
ticker := time.NewTimer(options.ClientRebalanceInterval)
for range ticker.C {
ok := true
for i, clientPack := range pool.clientPacks {
func() {
tctx, c := context.WithTimeout(ctx, options.NodeRequestTimeout)
defer c()
if _, err := clientPack.client.EndpointInfo(tctx); err != nil {
ok = false
}
pool.lock.Lock()
pool.clientPacks[i].healthy = ok
pool.lock.Unlock()
}()
}
ticker.Reset(options.ClientRebalanceInterval)
}
}()
return pool, nil
}
func (p *pool) ConnectionArtifacts() (client.Client, *token.SessionToken, error) {
p.lock.RLock()
defer p.lock.RUnlock()
if len(p.clientPacks) == 1 {
cp := p.clientPacks[0]
if cp.healthy {
return cp.client, cp.sessionToken, nil
}
return nil, nil, errors.New("no healthy client")
}
attempts := 3 * len(p.clientPacks)
for k := 0; k < attempts; k++ {
i := p.sampler.Next()
if cp := p.clientPacks[i]; cp.healthy {
return cp.client, cp.sessionToken, nil
}
}
return nil, nil, errors.New("no healthy client")
}