piotrkowalczuk/mnemosyne

package mnemosyned

import (
    "time"

    "github.com/piotrkowalczuk/mnemosyne/internal/cache"
    "github.com/piotrkowalczuk/mnemosyne/internal/cluster"
    "github.com/piotrkowalczuk/mnemosyne/internal/jump"
    "github.com/piotrkowalczuk/mnemosyne/internal/storage"
    "github.com/piotrkowalczuk/mnemosyne/mnemosynerpc"
    "go.uber.org/zap"
    "golang.org/x/net/context"
    "google.golang.org/grpc/codes"
    "google.golang.org/grpc/status"
)

type sessionManagerGet struct {
    spanner

    storage storage.Storage
    cache   *cache.Cache
    cluster *cluster.Cluster
    logger  *zap.Logger
}

func (smg *sessionManagerGet) Get(ctx context.Context, req *mnemosynerpc.GetRequest) (*mnemosynerpc.GetResponse, error) {
    span, ctx := smg.span(ctx, "session-manager.get")
    defer span.Finish()

    if req.AccessToken == "" {
        return nil, errMissingAccessToken
    }
    if node, ok := smg.cluster.GetOther(req.AccessToken); ok {
        if cluster.IsInternalRequest(ctx) {
            return nil, status.Errorf(codes.FailedPrecondition,
                "it should be final destination of get request (%s), but found another node for it: %s",
                req.GetAccessToken(),
                node.Addr,
            )
        }
        smg.logger.Debug("get request forwarded", zap.String("remote_addr", node.Addr), zap.String("access_token", req.AccessToken))
        return node.Client.Get(ctx, req)
    }
    var (
        ses *mnemosynerpc.Session
        err error
    )

    hs := jump.Sum64(req.AccessToken)
    entry, ok := smg.cache.Read(hs)
    if !ok || (!entry.Refresh && time.Since(entry.Exp) > smg.cache.TTL) {
        if ok {
            smg.cache.Refresh(hs)
        }
        ses, err = smg.storage.Get(ctx, req.AccessToken)
        if err != nil {
            if err == storage.ErrSessionNotFound && ok {
                smg.cache.Del(hs)
            }
            return nil, err
        }
        smg.cache.Put(hs, *ses)
    } else {
        ses = &entry.Ses
    }

    return &mnemosynerpc.GetResponse{
        Session: ses,
    }, nil
}