/
server.go
206 lines (179 loc) · 5.02 KB
/
server.go
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package server
import (
"context"
"time"
grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
grpc_auth "github.com/grpc-ecosystem/go-grpc-middleware/auth"
grpc_zap "github.com/grpc-ecosystem/go-grpc-middleware/logging/zap"
grpc_ctxtags "github.com/grpc-ecosystem/go-grpc-middleware/tags"
api "github.com/tkhoa2711/proglog/api/v1"
"go.opencensus.io/plugin/ocgrpc"
"go.opencensus.io/stats/view"
"go.opencensus.io/trace"
"go.uber.org/zap"
"go.uber.org/zap/zapcore"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/status"
)
const (
// ACL policy related constants
objectWildcard = "*"
produceAction = "produce"
consumeAction = "consume"
)
type subjectContextKey struct{}
type Authorizer interface {
Authorize(subject, object, action string) error
}
type CommitLog interface {
Append(*api.Record) (uint64, error)
Read(uint64) (*api.Record, error)
}
type Config struct {
CommitLog CommitLog
Authorizer Authorizer
}
type grpcServer struct {
api.UnimplementedLogServer
*Config
}
// NewGRPCServer initializes a new gRPC server with the given config.
func NewGRPCServer(config *Config, opts ...grpc.ServerOption) (*grpc.Server, error) {
logger := zap.L().Named("server")
zapOpts := []grpc_zap.Option{
grpc_zap.WithDurationField(
func(dur time.Duration) zapcore.Field {
return zap.Int64("grpc.time_ns", dur.Nanoseconds())
},
),
}
trace.ApplyConfig(trace.Config{
// TODO: change to probability sampler when the traffic is high enough
DefaultSampler: trace.AlwaysSample(),
})
err := view.Register(ocgrpc.DefaultServerViews...)
if err != nil {
return nil, err
}
opts = append(opts,
grpc.StreamInterceptor(
grpc_middleware.ChainStreamServer(
grpc_ctxtags.StreamServerInterceptor(),
grpc_zap.StreamServerInterceptor(logger, zapOpts...),
grpc_auth.StreamServerInterceptor(authenticate),
),
),
grpc.UnaryInterceptor(
grpc_middleware.ChainUnaryServer(
grpc_ctxtags.UnaryServerInterceptor(),
grpc_zap.UnaryServerInterceptor(logger, zapOpts...),
grpc_auth.UnaryServerInterceptor(authenticate),
),
),
grpc.StatsHandler(&ocgrpc.ServerHandler{}),
)
grpcSrv := grpc.NewServer(opts...)
srv := &grpcServer{Config: config}
api.RegisterLogServer(grpcSrv, srv)
return grpcSrv, nil
}
func (s *grpcServer) Produce(ctx context.Context, req *api.ProduceRequest) (
*api.ProduceResponse, error,
) {
if err := s.Authorizer.Authorize(
subject(ctx),
objectWildcard,
produceAction,
); err != nil {
return nil, err
}
off, err := s.CommitLog.Append(req.Record)
if err != nil {
return nil, err
}
return &api.ProduceResponse{Offset: off}, nil
}
func (s *grpcServer) Consume(ctx context.Context, req *api.ConsumeRequest) (
*api.ConsumeResponse, error,
) {
if err := s.Authorizer.Authorize(
subject(ctx),
objectWildcard,
consumeAction,
); err != nil {
return nil, err
}
record, err := s.CommitLog.Read(req.Offset)
if err != nil {
return nil, err
}
return &api.ConsumeResponse{Record: record}, nil
}
// ProduceStream implements bidirectional streaming so the client can stream
// request data into the server and the server can tell the client whether each
// request succeeds or not.
func (s *grpcServer) ProduceStream(stream api.Log_ProduceStreamServer) error {
for {
req, err := stream.Recv()
if err != nil {
return err
}
res, err := s.Produce(stream.Context(), req)
if err != nil {
return err
}
if err = stream.Send(res); err != nil {
return err
}
}
}
// ConsumeStream implements server-side streaming RPC whereas the client tells
// the server where in the commit log to start reading records, and the server
// will continuously stream every record that follows. When it reaches the end
// of the log, the server will wait for new records to come in.
func (s *grpcServer) ConsumeStream(
req *api.ConsumeRequest,
stream api.Log_ConsumeStreamServer,
) error {
for {
select {
case <-stream.Context().Done():
return nil
default:
res, err := s.Consume(stream.Context(), req)
switch err.(type) {
case nil:
case api.ErrOffsetOutOfRange:
continue
default:
return err
}
if err = stream.Send(res); err != nil {
return err
}
req.Offset++
}
}
}
// authenticate is an interceptor that reads the subject out of client's cert and
// write it to the gRPC context.
func authenticate(ctx context.Context) (context.Context, error) {
peer, ok := peer.FromContext(ctx)
if !ok {
return ctx, status.New(codes.Unknown, "couldn't find peer info").Err()
}
if peer.AuthInfo == nil {
return ctx, status.New(codes.Unauthenticated, "no transport security being used").Err()
}
tlsInfo := peer.AuthInfo.(credentials.TLSInfo)
subject := tlsInfo.State.VerifiedChains[0][0].Subject.CommonName
ctx = context.WithValue(ctx, subjectContextKey{}, subject)
return ctx, nil
}
// subject retrieves the client cert's subject from the given context.
func subject(ctx context.Context) string {
return ctx.Value(subjectContextKey{}).(string)
}