/
server.go
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/
server.go
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// Copyright 2021-2024 Zenauth Ltd.
// SPDX-License-Identifier: Apache-2.0
package server
import (
"context"
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/textproto"
"os"
"strconv"
"strings"
"time"
"github.com/cloudflare/certinel/fswatcher"
"github.com/gorilla/mux"
grpc_logging "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/logging"
grpc_validator "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/protovalidate"
grpc_recovery "github.com/grpc-ecosystem/go-grpc-middleware/v2/interceptors/recovery"
"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
reuseport "github.com/kavu/go_reuseport"
"github.com/sourcegraph/conc/pool"
"go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc"
"go.uber.org/zap"
"golang.org/x/net/http2"
"golang.org/x/net/http2/h2c"
"google.golang.org/grpc"
"google.golang.org/grpc/admin"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/credentials/local"
"google.golang.org/grpc/metadata"
svcv1 "github.com/cerbos/cerbos/api/genpb/cerbos/svc/v1"
"github.com/cerbos/cerbos/internal/audit"
"github.com/cerbos/cerbos/internal/telemetry"
"github.com/cerbos/cerbos/internal/validator"
// Import the default grpc encoding to ensure that it gets replaced by VT.
_ "google.golang.org/grpc/encoding/proto"
"google.golang.org/grpc/health"
healthpb "google.golang.org/grpc/health/grpc_health_v1"
"google.golang.org/grpc/keepalive"
"google.golang.org/grpc/reflection"
"google.golang.org/protobuf/encoding/protojson"
// Import to register the Badger audit log backend.
_ "github.com/cerbos/cerbos/internal/audit/local"
// Import to register the file audit log backend.
_ "github.com/cerbos/cerbos/internal/audit/file"
// Import to register the kafka audit log backend.
_ "github.com/cerbos/cerbos/internal/audit/kafka"
// Import to register the hub audit log backend.
_ "github.com/cerbos/cerbos/internal/audit/hub"
"github.com/cerbos/cerbos/internal/auxdata"
"github.com/cerbos/cerbos/internal/compile"
"github.com/cerbos/cerbos/internal/engine"
"github.com/cerbos/cerbos/internal/observability/metrics"
"github.com/cerbos/cerbos/internal/observability/tracing"
internalSchema "github.com/cerbos/cerbos/internal/schema"
"github.com/cerbos/cerbos/internal/storage"
// Import blob to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/blob"
"github.com/cerbos/cerbos/internal/storage/overlay"
// Import hub to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/hub"
// Import mysql to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/db/mysql"
// Import postgres to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/db/postgres"
// Import sqlite3 to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/db/sqlite3"
// Import sqlserver to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/db/sqlserver"
// Import disk to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/disk"
// Import git to register the storage driver.
_ "github.com/cerbos/cerbos/internal/storage/git"
"github.com/cerbos/cerbos/internal/svc"
"github.com/cerbos/cerbos/internal/util"
"github.com/cerbos/cerbos/schema"
)
const (
defaultTimeout = 30 * time.Second
metricsReportingInterval = 15 * time.Second
minGRPCConnectTimeout = 20 * time.Second
adminEndpoint = "/admin"
apiEndpoint = "/api"
healthEndpoint = "/_cerbos/health"
metricsEndpoint = "/_cerbos/metrics"
playgroundEndpoint = "/api/playground"
schemaEndpoint = "/schema/swagger.json"
)
var ErrInvalidStore = errors.New("store does not implement either SourceStore or BinaryStore interfaces")
func Start(ctx context.Context) error {
// get configuration
conf, err := GetConf()
if err != nil {
return fmt.Errorf("failed to load server configuration: %w", err)
}
// create audit log
auditLog, err := audit.NewLog(ctx)
if err != nil {
return fmt.Errorf("failed to create audit log: %w", err)
}
mdExtractor, err := audit.NewMetadataExtractor()
if err != nil {
return fmt.Errorf("failed to create metadata extractor: %w", err)
}
// create store
store, err := storage.New(ctx)
if err != nil {
return fmt.Errorf("failed to create store: %w", err)
}
// create schema manager
schemaMgr, err := internalSchema.New(ctx, store)
if err != nil {
return fmt.Errorf("failed to create schema manager: %w", err)
}
var policyLoader engine.PolicyLoader
switch st := store.(type) {
// Overlay needs to take precedence over BinaryStore in this type switch,
// as our overlay store implements BinaryStore also
case overlay.Overlay:
// create wrapped policy loader
pl, err := st.GetOverlayPolicyLoader(ctx, schemaMgr)
if err != nil {
return fmt.Errorf("failed to create overlay policy loader: %w", err)
}
policyLoader = pl
case storage.BinaryStore:
policyLoader = st
case storage.SourceStore:
// create compile manager
compileMgr, err := compile.NewManager(ctx, st, schemaMgr)
if err != nil {
return fmt.Errorf("failed to create compile manager: %w", err)
}
policyLoader = compileMgr
default:
return ErrInvalidStore
}
// create engine
eng, err := engine.New(ctx, engine.Components{
PolicyLoader: policyLoader,
SchemaMgr: schemaMgr,
AuditLog: auditLog,
MetadataExtractor: mdExtractor,
})
if err != nil {
return fmt.Errorf("failed to create engine: %w", err)
}
// initialize aux data
auxData, err := auxdata.New(ctx)
if err != nil {
return fmt.Errorf("failed to initialize auxData handler: %w", err)
}
s := NewServer(conf)
telemetry.Start(ctx, store)
defer telemetry.Stop()
return s.Start(ctx, Param{AuditLog: auditLog, AuxData: auxData, Engine: eng, Store: store})
}
type Param struct {
AuditLog audit.Log
AuxData *auxdata.AuxData
Engine *engine.Engine
Store storage.Store
}
type Server struct {
conf *Conf
cancelFunc context.CancelFunc
pool *pool.ContextPool
health *health.Server
tlsConfig *tls.Config
}
func NewServer(conf *Conf) *Server {
return &Server{
conf: conf,
health: health.NewServer(),
}
}
func (s *Server) Start(ctx context.Context, param Param) error {
ctx, cancelFunc := context.WithCancel(ctx)
s.pool = pool.New().WithContext(ctx).WithCancelOnError().WithFirstError()
s.cancelFunc = cancelFunc
defer s.cancelFunc()
log := zap.L().Named("server")
if err := s.initializeTLSConfig(log); err != nil {
log.Error("Failed to initialize TLS configuration", zap.Error(err))
}
// It would be nice to have a single port to serve both gRPC and HTTP. Unfortunately, cmux
// can't deal effectively with both gRPC and HTTP/2 when TLS is enabled (see https://github.com/soheilhy/cmux/issues/68).
// Another potential issue with single-port gRPC and HTTP/2 is when a proxy like Envoy is in front of the server it
// would have a connection pool per port and would end up sending HTTP/2 traffic to gRPC and vice-versa.
// This is why we have two dedicated ports for HTTP and gRPC traffic. However, if gRPC traffic is sent to the HTTP port, it
// will still be handled correctly.
grpcL, err := s.createListener(s.conf.GRPCListenAddr)
if err != nil {
log.Error("Failed to create gRPC listener", zap.Error(err))
return err
}
httpL, err := s.createListener(s.conf.HTTPListenAddr)
if err != nil {
log.Error("Failed to create HTTP listener", zap.Error(err))
return err
}
// start servers
grpcServer, err := s.startGRPCServer(grpcL, param)
if err != nil {
log.Error("Failed to start GRPC server", zap.Error(err))
return err
}
httpServer, err := s.startHTTPServer(ctx, httpL, grpcServer)
if err != nil {
log.Error("Failed to start HTTP server", zap.Error(err))
return err
}
s.pool.Go(func(ctx context.Context) error {
<-ctx.Done()
log.Info("Shutting down")
// mark this service as NOT_SERVING in the gRPC health check.
s.health.Shutdown()
log.Debug("Shutting down gRPC server")
grpcServer.GracefulStop()
log.Debug("Shutting down HTTP server")
shutdownCtx, cancelFunc := context.WithTimeout(context.Background(), defaultTimeout)
defer cancelFunc()
if err := httpServer.Shutdown(shutdownCtx); err != nil {
log.Error("Failed to cleanly shutdown HTTP server", zap.Error(err))
}
return nil
})
if err := s.pool.Wait(); err != nil {
log.Error("Stopping server due to error", zap.Error(err))
return err
}
log.Debug("Shutting down the audit log")
if err := param.AuditLog.Close(); err != nil {
log.Error("Failed to cleanly close audit log", zap.Error(err))
}
if closer, ok := param.Store.(io.Closer); ok {
log.Debug("Shutting down store")
if err := closer.Close(); err != nil {
log.Error("Store didn't shutdown correctly", zap.Error(err))
}
}
log.Info("Shutdown complete")
return nil
}
func (s *Server) initializeTLSConfig(log *zap.Logger) error {
if s.conf.TLS == nil || (s.conf.TLS.Cert == "" || s.conf.TLS.Key == "") {
return nil
}
conf := s.conf.TLS
certinel, err := fswatcher.New(conf.Cert, conf.Key)
if err != nil {
return fmt.Errorf("failed to load certificate and key: %w", err)
}
s.pool.Go(func(ctx context.Context) (outErr error) {
log.Info("Starting certificate watcher")
if err := certinel.Start(ctx); err != nil {
if !errors.Is(err, context.Canceled) {
log.Error("Stopping certificate watcher due to error", zap.Error(err))
return err
}
}
log.Info("Stopping certificate watcher")
return nil
})
s.tlsConfig = util.DefaultTLSConfig()
s.tlsConfig.GetCertificate = certinel.GetCertificate
if conf.CACert != "" {
if _, err := os.Stat(conf.CACert); err != nil {
//nolint:nilerr
return nil
}
certPool := x509.NewCertPool()
bs, err := os.ReadFile(conf.CACert)
if err != nil {
return fmt.Errorf("failed to load CA certificate: %w", err)
}
ok := certPool.AppendCertsFromPEM(bs)
if !ok {
return errors.New("failed to append certificates to the pool")
}
s.tlsConfig.ClientAuth = tls.VerifyClientCertIfGiven
s.tlsConfig.ClientCAs = certPool
}
return nil
}
func (s *Server) createListener(listenAddr string) (net.Listener, error) {
l, err := s.parseAndOpen(listenAddr)
if err != nil {
return nil, fmt.Errorf("failed to create listener at '%s': %w", listenAddr, err)
}
if s.tlsConfig != nil {
l = tls.NewListener(l, s.tlsConfig)
}
return l, nil
}
func (s *Server) startGRPCServer(l net.Listener, param Param) (*grpc.Server, error) {
log := zap.L().Named("grpc")
server, err := s.mkGRPCServer(log, param.AuditLog)
if err != nil {
return nil, fmt.Errorf("failed to create gRPC server: %w", err)
}
healthpb.RegisterHealthServer(server, s.health)
reflection.Register(server)
reqLimits := svc.RequestLimits{
MaxActionsPerResource: s.conf.RequestLimits.MaxActionsPerResource,
MaxResourcesPerRequest: s.conf.RequestLimits.MaxResourcesPerRequest,
}
cerbosSvc := svc.NewCerbosService(param.Engine, param.AuxData, reqLimits)
svcv1.RegisterCerbosServiceServer(server, cerbosSvc)
s.health.SetServingStatus(svcv1.CerbosService_ServiceDesc.ServiceName, healthpb.HealthCheckResponse_SERVING)
if s.conf.AdminAPI.Enabled {
log.Info("Starting admin service")
creds := s.conf.AdminAPI.AdminCredentials
adminUser, adminPasswdHash, err := creds.usernameAndPasswordHash()
if err != nil {
log.Error("Failed to get admin API credentials", zap.Error(err))
return nil, err
}
go checkForUnsafeAdminCredentials(log, adminPasswdHash)
svcv1.RegisterCerbosAdminServiceServer(server, svc.NewCerbosAdminService(param.Store, param.AuditLog, adminUser, adminPasswdHash))
s.health.SetServingStatus(svcv1.CerbosAdminService_ServiceDesc.ServiceName, healthpb.HealthCheckResponse_SERVING)
}
if s.conf.PlaygroundEnabled {
log.Info("Starting playground service")
svcv1.RegisterCerbosPlaygroundServiceServer(server, svc.NewCerbosPlaygroundService(reqLimits))
s.health.SetServingStatus(svcv1.CerbosPlaygroundService_ServiceDesc.ServiceName, healthpb.HealthCheckResponse_SERVING)
}
s.pool.Go(func(_ context.Context) error {
log.Info(fmt.Sprintf("Starting gRPC server at %s", s.conf.GRPCListenAddr))
cleanup, err := admin.Register(server)
if err != nil {
log.Error("Failed to register gRPC admin interfaces", zap.Error(err))
return err
}
defer cleanup()
if err := server.Serve(l); err != nil {
log.Error("gRPC server failed", zap.Error(err))
return err
}
log.Info("gRPC server stopped")
return nil
})
return server, nil
}
func checkForUnsafeAdminCredentials(log *zap.Logger, passwordHash []byte) {
unsafe, err := adminCredentialsAreUnsafe(passwordHash)
if err != nil {
log.Error("Failed to check admin API credentials", zap.Error(err))
} else if unsafe {
log.Warn("[INSECURE CONFIG] Admin API uses default credentials which are unsafe for production use. Please change the credentials by updating the configuration file.")
}
}
func (s *Server) mkGRPCServer(log *zap.Logger, auditLog audit.Log) (*grpc.Server, error) {
telemetryInt := telemetry.Intercept()
auditInterceptor, err := audit.NewUnaryInterceptor(auditLog, accessLogExclude)
if err != nil {
return nil, fmt.Errorf("failed to create audit unary interceptor: %w", err)
}
opts := []grpc.ServerOption{
grpc.ChainStreamInterceptor(
grpc_recovery.StreamServerInterceptor(),
telemetryInt.StreamServerInterceptor(),
grpc_validator.StreamServerInterceptor(validator.Validator),
grpc_logging.StreamServerInterceptor(RequestLogger(log, "Handled request")),
grpc_logging.StreamServerInterceptor(PayloadLogger(s.conf), grpc_logging.WithLogOnEvents(grpc_logging.PayloadReceived, grpc_logging.PayloadSent)),
),
grpc.ChainUnaryInterceptor(
grpc_recovery.UnaryServerInterceptor(),
telemetryInt.UnaryServerInterceptor(),
grpc_validator.UnaryServerInterceptor(validator.Validator),
RequestMetadataUnaryServerInterceptor,
auditInterceptor,
grpc_logging.UnaryServerInterceptor(RequestLogger(log, "Handled request")),
grpc_logging.UnaryServerInterceptor(PayloadLogger(s.conf), grpc_logging.WithLogOnEvents(grpc_logging.PayloadReceived, grpc_logging.PayloadSent)),
cerbosVersionUnaryServerInterceptor,
),
grpc.StatsHandler(otelgrpc.NewServerHandler()),
grpc.KeepaliveParams(keepalive.ServerParameters{MaxConnectionAge: s.conf.Advanced.GRPC.MaxConnectionAge}),
grpc.MaxConcurrentStreams(s.conf.Advanced.GRPC.MaxConcurrentStreams),
grpc.ConnectionTimeout(s.conf.Advanced.GRPC.ConnectionTimeout),
grpc.MaxRecvMsgSize(int(s.conf.Advanced.GRPC.MaxRecvMsgSizeBytes)),
grpc.UnknownServiceHandler(handleUnknownServices),
}
return grpc.NewServer(opts...), nil
}
func (s *Server) startHTTPServer(ctx context.Context, l net.Listener, grpcSrv *grpc.Server) (*http.Server, error) {
log := zap.S().Named("http")
grpcConn, err := s.mkGRPCConn()
if err != nil {
return nil, err
}
gwmux := runtime.NewServeMux(
runtime.WithForwardResponseOption(customHTTPResponseCode),
runtime.WithIncomingHeaderMatcher(incomingHeaderMatcher),
runtime.WithMarshalerOption("application/json+pretty", &runtime.JSONPb{
MarshalOptions: protojson.MarshalOptions{Indent: " "},
UnmarshalOptions: protojson.UnmarshalOptions{DiscardUnknown: false},
}),
runtime.WithMarshalerOption(runtime.MIMEWildcard, &runtime.JSONPb{
UnmarshalOptions: protojson.UnmarshalOptions{DiscardUnknown: false},
}),
runtime.WithMetadata(setPeerMetadata),
runtime.WithRoutingErrorHandler(handleRoutingError),
runtime.WithHealthEndpointAt(healthpb.NewHealthClient(grpcConn), healthEndpoint),
)
if err := svcv1.RegisterCerbosServiceHandler(ctx, gwmux, grpcConn); err != nil {
log.Errorw("Failed to register Cerbos HTTP service", "error", err)
return nil, fmt.Errorf("failed to register Cerbos HTTP service: %w", err)
}
if s.conf.AdminAPI.Enabled {
if err := svcv1.RegisterCerbosAdminServiceHandler(ctx, gwmux, grpcConn); err != nil {
log.Errorw("Failed to register Cerbos admin HTTP service", "error", err)
return nil, fmt.Errorf("failed to register Cerbos admin HTTP service: %w", err)
}
}
if s.conf.PlaygroundEnabled {
if err := svcv1.RegisterCerbosPlaygroundServiceHandler(ctx, gwmux, grpcConn); err != nil {
log.Errorw("Continuing without playground due to registration error", "error", err)
}
}
cerbosMux := mux.NewRouter()
// handle gRPC requests that come over http
cerbosMux.MatcherFunc(func(r *http.Request, _ *mux.RouteMatch) bool {
return r.ProtoMajor == 2 && strings.Contains(r.Header.Get("Content-Type"), "application/grpc")
}).Handler(tracing.HTTPHandler(grpcSrv, "grpc"))
cerbosMux.PathPrefix(adminEndpoint).Handler(tracing.HTTPHandler(prettyJSON(gwmux), adminEndpoint))
cerbosMux.PathPrefix(apiEndpoint).Handler(tracing.HTTPHandler(prettyJSON(gwmux), apiEndpoint))
cerbosMux.Path(healthEndpoint).Handler(prettyJSON(gwmux))
cerbosMux.Path(schemaEndpoint).HandlerFunc(schema.ServeSvcSwagger)
if s.conf.MetricsEnabled {
h, err := metrics.NewHandler()
if err != nil {
return nil, fmt.Errorf("failed to create Prometheus handler: %w", err)
}
cerbosMux.Path(metricsEndpoint).Handler(h)
}
if s.conf.APIExplorerEnabled {
cerbosMux.HandleFunc("/", schema.ServeUI)
}
httpHandler := withCORS(s.conf, cerbosMux)
h := &http.Server{
ErrorLog: zap.NewStdLog(zap.L().Named("http.error")),
Handler: h2c.NewHandler(httpHandler, &http2.Server{}),
ReadHeaderTimeout: s.conf.Advanced.HTTP.ReadHeaderTimeout,
ReadTimeout: s.conf.Advanced.HTTP.ReadTimeout,
WriteTimeout: s.conf.Advanced.HTTP.WriteTimeout,
IdleTimeout: s.conf.Advanced.HTTP.IdleTimeout,
}
s.pool.Go(func(_ context.Context) error {
log.Infof("Starting HTTP server at %s", s.conf.HTTPListenAddr)
err := h.Serve(l)
if err != nil && !errors.Is(err, http.ErrServerClosed) {
log.Errorw("HTTP server failed", "error", err)
return err
}
log.Info("HTTP server stopped")
return nil
})
return h, nil
}
func defaultGRPCDialOpts() []grpc.DialOption {
// see https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md
return []grpc.DialOption{
grpc.WithUserAgent("grpc-gateway"),
grpc.WithConnectParams(grpc.ConnectParams{MinConnectTimeout: minGRPCConnectTimeout}),
grpc.WithStatsHandler(otelgrpc.NewClientHandler()),
}
}
func (s *Server) mkGRPCConn() (*grpc.ClientConn, error) {
opts := defaultGRPCDialOpts()
if s.tlsConfig != nil {
tlsConf := s.tlsConfig.Clone()
tlsConf.InsecureSkipVerify = true // we are connecting as localhost which would differ from what the cert is issued for.
opts = append(opts, grpc.WithTransportCredentials(credentials.NewTLS(tlsConf)))
} else {
opts = append(opts, grpc.WithTransportCredentials(local.NewCredentials()))
}
grpcConn, err := util.EagerGRPCClient(s.conf.GRPCListenAddr, opts...)
if err != nil {
return nil, fmt.Errorf("failed to dial gRPC: %w", err)
}
return grpcConn, nil
}
// inspired by https://github.com/ghostunnel/ghostunnel/blob/6e58c75c8762fe371c1134e89dd55033a6d577a4/socket/net.go#L100
func (s *Server) parseAndOpen(listenAddr string) (net.Listener, error) {
network, addr, err := util.ParseListenAddress(listenAddr)
if err != nil {
return nil, err
}
//nolint:nestif
if network == "unix" {
if err := os.RemoveAll(addr); err != nil {
return nil, err
}
listener, err := net.Listen(network, addr)
if err != nil {
return nil, err
}
if s.conf.UDSFileMode != defaultUDSFileMode {
fileMode := toUDSFileMode(s.conf.UDSFileMode)
if err := os.Chmod(addr, fileMode); err != nil {
return nil, fmt.Errorf("failed to change file mode of %q to %O: %w", addr, fileMode, err)
}
}
//nolint:forcetypeassert
listener.(*net.UnixListener).SetUnlinkOnClose(true)
return listener, nil
}
return reuseport.NewReusablePortListener(network, addr)
}
//nolint:mnd
func toUDSFileMode(modeStr string) os.FileMode {
m, err := strconv.ParseInt(modeStr, 0, 32)
if err != nil || m <= 0 {
return 0o766
}
// Ignore everything but the last 9 bits which hold the user, group and world perms.
return os.FileMode(m & 0o777)
}
func incomingHeaderMatcher(key string) (string, bool) {
switch textproto.CanonicalMIMEHeaderKey(key) {
// The gateway sets its own user agent, so we need to alias it
case "User-Agent":
return "Grpcgateway-User-Agent", true
case
// The request sent by the gateway will have a different content length
"Content-Length",
// Reserved for aliasing the incoming User-Agent header
"Grpcgateway-User-Agent",
// Translated to X-Forwarded-Host by the gateway
"Host",
// Connection-specific headers must be removed when translating HTTP/1.x to HTTP/2 (https://httpwg.org/specs/rfc9113.html#ConnectionSpecific)
"Connection",
"Keep-Alive",
"Proxy-Connection",
"Transfer-Encoding",
"Upgrade":
return "", false
default:
return key, true
}
}
func setPeerMetadata(_ context.Context, req *http.Request) metadata.MD {
return metadata.Pairs(audit.HTTPRemoteAddrKey, req.RemoteAddr)
}