frostfs-s3-gw/api/resolver/resolver.go

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package resolver
import (
"context"
"fmt"
cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
"github.com/nspcc-dev/neofs-sdk-go/ns"
)
const (
NNSResolver = "nns"
DNSResolver = "dns"
)
// NeoFS represents virtual connection to the NeoFS network.
type NeoFS interface {
// SystemDNS reads system DNS network parameters of the NeoFS.
//
// It returns exactly on non-zero value. It returns any error encountered
// which prevented the parameter from being read.
SystemDNS(context.Context) (string, error)
}
type Config struct {
NeoFS NeoFS
RPCAddress string
}
type BucketResolver struct {
Name string
resolve func(context.Context, string) (*cid.ID, error)
next *BucketResolver
}
func (r *BucketResolver) SetResolveFunc(fn func(context.Context, string) (*cid.ID, error)) {
r.resolve = fn
}
func (r *BucketResolver) Resolve(ctx context.Context, name string) (*cid.ID, error) {
cnrID, err := r.resolve(ctx, name)
if err != nil {
if r.next != nil {
return r.next.Resolve(ctx, name)
}
return nil, err
}
return cnrID, err
}
func NewResolver(order []string, cfg *Config) (*BucketResolver, error) {
if len(order) == 0 {
return nil, fmt.Errorf("resolving order must not be empty")
}
bucketResolver, err := newResolver(order[len(order)-1], cfg, nil)
if err != nil {
return nil, err
}
for i := len(order) - 2; i >= 0; i-- {
resolverName := order[i]
next := bucketResolver
bucketResolver, err = newResolver(resolverName, cfg, next)
if err != nil {
return nil, err
}
}
return bucketResolver, nil
}
func newResolver(name string, cfg *Config, next *BucketResolver) (*BucketResolver, error) {
switch name {
case DNSResolver:
return NewDNSResolver(cfg.NeoFS, next)
case NNSResolver:
return NewNNSResolver(cfg.RPCAddress, next)
default:
return nil, fmt.Errorf("unknown resolver: %s", name)
}
}
func NewDNSResolver(neoFS NeoFS, next *BucketResolver) (*BucketResolver, error) {
if neoFS == nil {
return nil, fmt.Errorf("pool must not be nil for DNS resolver")
}
var dns ns.DNS
resolveFunc := func(ctx context.Context, name string) (*cid.ID, error) {
domain, err := neoFS.SystemDNS(ctx)
if err != nil {
return nil, fmt.Errorf("read system DNS parameter of the NeoFS: %w", err)
}
domain = name + "." + domain
cnrID, err := dns.ResolveContainerName(domain)
if err != nil {
return nil, fmt.Errorf("couldn't resolve container '%s' as '%s': %w", name, domain, err)
}
return &cnrID, nil
}
return &BucketResolver{
Name: DNSResolver,
resolve: resolveFunc,
next: next,
}, nil
}
func NewNNSResolver(address string, next *BucketResolver) (*BucketResolver, error) {
if address == "" {
return nil, fmt.Errorf("rpc address must not be empty for NNS resolver")
}
var nns ns.NNS
if err := nns.Dial(address); err != nil {
return nil, fmt.Errorf("dial %s: %w", address, err)
}
resolveFunc := func(_ context.Context, name string) (*cid.ID, error) {
cnrID, err := nns.ResolveContainerName(name)
if err != nil {
return nil, fmt.Errorf("couldn't resolve container '%s': %w", name, err)
}
return &cnrID, nil
}
return &BucketResolver{
Name: NNSResolver,
resolve: resolveFunc,
next: next,
}, nil
}