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|
package praefect
import (
"context"
"errors"
"fmt"
"sync"
"time"
"github.com/golang/protobuf/proto"
"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus/ctxlogrus"
"github.com/prometheus/client_golang/prometheus"
"github.com/sirupsen/logrus"
glerrors "gitlab.com/gitlab-org/gitaly/internal/errors"
"gitlab.com/gitlab-org/gitaly/internal/helper"
"gitlab.com/gitlab-org/gitaly/internal/metadata/featureflag"
"gitlab.com/gitlab-org/gitaly/internal/middleware/metadatahandler"
"gitlab.com/gitlab-org/gitaly/internal/praefect/commonerr"
"gitlab.com/gitlab-org/gitaly/internal/praefect/config"
"gitlab.com/gitlab-org/gitaly/internal/praefect/datastore"
"gitlab.com/gitlab-org/gitaly/internal/praefect/grpc-proxy/proxy"
"gitlab.com/gitlab-org/gitaly/internal/praefect/metrics"
"gitlab.com/gitlab-org/gitaly/internal/praefect/nodes"
"gitlab.com/gitlab-org/gitaly/internal/praefect/protoregistry"
"gitlab.com/gitlab-org/gitaly/internal/praefect/transactions"
"gitlab.com/gitlab-org/gitaly/internal/transaction/txinfo"
"gitlab.com/gitlab-org/gitaly/proto/go/gitalypb"
"gitlab.com/gitlab-org/labkit/correlation"
"golang.org/x/sync/errgroup"
grpc_metadata "google.golang.org/grpc/metadata"
)
// ErrRepositoryReadOnly is returned when the repository is in read-only mode. This happens
// if the primary does not have the latest changes.
var ErrRepositoryReadOnly = helper.ErrPreconditionFailedf("repository is in read-only mode")
type transactionsCondition func(context.Context) bool
func transactionsEnabled(context.Context) bool { return true }
func transactionsDisabled(context.Context) bool { return false }
func transactionsFlag(flag featureflag.FeatureFlag) transactionsCondition {
return func(ctx context.Context) bool {
return featureflag.IsEnabled(ctx, flag)
}
}
// transactionRPCs contains the list of repository-scoped mutating calls which may take part in
// transactions. An optional feature flag can be added to conditionally enable transactional
// behaviour. If none is given, it's always enabled.
var transactionRPCs = map[string]transactionsCondition{
"/gitaly.CleanupService/ApplyBfgObjectMapStream": transactionsEnabled,
"/gitaly.ConflictsService/ResolveConflicts": transactionsEnabled,
"/gitaly.ObjectPoolService/FetchIntoObjectPool": transactionsEnabled,
"/gitaly.OperationService/UserApplyPatch": transactionsEnabled,
"/gitaly.OperationService/UserCherryPick": transactionsEnabled,
"/gitaly.OperationService/UserCommitFiles": transactionsEnabled,
"/gitaly.OperationService/UserCreateBranch": transactionsEnabled,
"/gitaly.OperationService/UserCreateTag": transactionsEnabled,
"/gitaly.OperationService/UserDeleteBranch": transactionsEnabled,
"/gitaly.OperationService/UserDeleteTag": transactionsEnabled,
"/gitaly.OperationService/UserFFBranch": transactionsEnabled,
"/gitaly.OperationService/UserMergeBranch": transactionsEnabled,
"/gitaly.OperationService/UserMergeToRef": transactionsEnabled,
"/gitaly.OperationService/UserRebaseConfirmable": transactionsEnabled,
"/gitaly.OperationService/UserRevert": transactionsEnabled,
"/gitaly.OperationService/UserSquash": transactionsEnabled,
"/gitaly.OperationService/UserUpdateBranch": transactionsEnabled,
"/gitaly.OperationService/UserUpdateSubmodule": transactionsEnabled,
"/gitaly.RefService/DeleteRefs": transactionsEnabled,
"/gitaly.RemoteService/AddRemote": transactionsEnabled,
"/gitaly.RemoteService/FetchInternalRemote": transactionsEnabled,
"/gitaly.RemoteService/RemoveRemote": transactionsEnabled,
"/gitaly.RepositoryService/ApplyGitattributes": transactionsEnabled,
"/gitaly.RepositoryService/CloneFromPool": transactionsEnabled,
"/gitaly.RepositoryService/CloneFromPoolInternal": transactionsEnabled,
"/gitaly.RepositoryService/CreateFork": transactionsEnabled,
"/gitaly.RepositoryService/CreateRepository": transactionsEnabled,
"/gitaly.RepositoryService/CreateRepositoryFromBundle": transactionsEnabled,
"/gitaly.RepositoryService/CreateRepositoryFromSnapshot": transactionsEnabled,
"/gitaly.RepositoryService/CreateRepositoryFromURL": transactionsEnabled,
"/gitaly.RepositoryService/FetchRemote": transactionsEnabled,
"/gitaly.RepositoryService/FetchSourceBranch": transactionsEnabled,
"/gitaly.RepositoryService/ReplicateRepository": transactionsEnabled,
"/gitaly.RepositoryService/WriteRef": transactionsEnabled,
"/gitaly.SSHService/SSHReceivePack": transactionsEnabled,
"/gitaly.SmartHTTPService/PostReceivePack": transactionsEnabled,
"/gitaly.WikiService/WikiUpdatePage": transactionsEnabled,
"/gitaly.WikiService/WikiWritePage": transactionsEnabled,
"/gitaly.RepositoryService/SetConfig": transactionsFlag(featureflag.TxConfig),
"/gitaly.RepositoryService/DeleteConfig": transactionsFlag(featureflag.TxConfig),
// The following RPCs don't perform any reference updates and thus
// shouldn't use transactions.
"/gitaly.ObjectPoolService/CreateObjectPool": transactionsDisabled,
"/gitaly.ObjectPoolService/DeleteObjectPool": transactionsDisabled,
"/gitaly.ObjectPoolService/DisconnectGitAlternates": transactionsDisabled,
"/gitaly.ObjectPoolService/LinkRepositoryToObjectPool": transactionsDisabled,
"/gitaly.ObjectPoolService/ReduplicateRepository": transactionsDisabled,
"/gitaly.ObjectPoolService/UnlinkRepositoryFromObjectPool": transactionsDisabled,
"/gitaly.RefService/PackRefs": transactionsDisabled,
"/gitaly.RepositoryService/Cleanup": transactionsDisabled,
"/gitaly.RepositoryService/GarbageCollect": transactionsDisabled,
"/gitaly.RepositoryService/MidxRepack": transactionsDisabled,
"/gitaly.RepositoryService/OptimizeRepository": transactionsDisabled,
"/gitaly.RepositoryService/RemoveRepository": transactionsDisabled,
"/gitaly.RepositoryService/RenameRepository": transactionsDisabled,
"/gitaly.RepositoryService/RepackFull": transactionsDisabled,
"/gitaly.RepositoryService/RepackIncremental": transactionsDisabled,
"/gitaly.RepositoryService/RestoreCustomHooks": transactionsDisabled,
"/gitaly.RepositoryService/WriteCommitGraph": transactionsDisabled,
// These shouldn't ever use transactions for the sake of not creating
// cyclic dependencies.
"/gitaly.RefTransaction/StopTransaction": transactionsDisabled,
"/gitaly.RefTransaction/VoteTransaction": transactionsDisabled,
}
// forcePrimaryRoutingRPCs tracks RPCs which need to always get routed to the primary. This should
// really be a last-resort measure for a given RPC, so each RPC added must have a strong reason why
// it's being added.
var forcePrimaryRPCs = map[string]bool{
// GetObjectDirectorySize depends on a repository's on-disk state. It depends on when a
// repository was last packed and on git-pack-objects(1) producing deterministic results.
// Given that we can neither guarantee that replicas are always packed at the same time,
// nor that git-pack-objects(1) produces the same packs. We always report sizes for the
// primary node.
"/gitaly.RepositoryService/GetObjectDirectorySize": true,
// Same reasoning as for GetObjectDirectorySize.
"/gitaly.RepositoryService/RepositorySize": true,
}
func init() {
// Safety checks to verify that all registered RPCs are in `transactionRPCs`
for _, method := range protoregistry.GitalyProtoPreregistered.Methods() {
if method.Operation != protoregistry.OpMutator || method.Scope != protoregistry.ScopeRepository {
continue
}
if _, ok := transactionRPCs[method.FullMethodName()]; !ok {
panic(fmt.Sprintf("transactional RPCs miss repository-scoped mutator %q", method.FullMethodName()))
}
}
// Safety checks to verify that `transactionRPCs` has no unknown RPCs
for transactionalRPC := range transactionRPCs {
method, err := protoregistry.GitalyProtoPreregistered.LookupMethod(transactionalRPC)
if err != nil {
panic(fmt.Sprintf("transactional RPC not a registered method: %q", err))
}
if method.Operation != protoregistry.OpMutator {
panic(fmt.Sprintf("transactional RPC is not a mutator: %q", method.FullMethodName()))
}
if method.Scope != protoregistry.ScopeRepository {
panic(fmt.Sprintf("transactional RPC is not repository-scoped: %q", method.FullMethodName()))
}
}
}
func shouldUseTransaction(ctx context.Context, method string) bool {
if !featureflag.IsEnabled(ctx, featureflag.ReferenceTransactions) {
return false
}
condition, ok := transactionRPCs[method]
if !ok {
return false
}
return condition(ctx)
}
// getReplicationDetails determines the type of job and additional details based on the method name and incoming message
func getReplicationDetails(methodName string, m proto.Message) (datastore.ChangeType, datastore.Params, error) {
switch methodName {
case "/gitaly.RepositoryService/RemoveRepository":
return datastore.DeleteRepo, nil, nil
case "/gitaly.RepositoryService/CreateFork",
"/gitaly.RepositoryService/CreateRepository",
"/gitaly.RepositoryService/CreateRepositoryFromBundle",
"/gitaly.RepositoryService/CreateRepositoryFromSnapshot",
"/gitaly.RepositoryService/CreateRepositoryFromURL",
"/gitaly.RepositoryService/ReplicateRepository":
return datastore.CreateRepo, nil, nil
case "/gitaly.RepositoryService/RenameRepository":
req, ok := m.(*gitalypb.RenameRepositoryRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.RenameRepo, datastore.Params{"RelativePath": req.RelativePath}, nil
case "/gitaly.RepositoryService/GarbageCollect":
req, ok := m.(*gitalypb.GarbageCollectRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.GarbageCollect, datastore.Params{"CreateBitmap": req.GetCreateBitmap()}, nil
case "/gitaly.RepositoryService/RepackFull":
req, ok := m.(*gitalypb.RepackFullRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.RepackFull, datastore.Params{"CreateBitmap": req.GetCreateBitmap()}, nil
case "/gitaly.RepositoryService/RepackIncremental":
req, ok := m.(*gitalypb.RepackIncrementalRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.RepackIncremental, nil, nil
case "/gitaly.RepositoryService/Cleanup":
req, ok := m.(*gitalypb.CleanupRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.Cleanup, nil, nil
case "/gitaly.RefService/PackRefs":
req, ok := m.(*gitalypb.PackRefsRequest)
if !ok {
return "", nil, fmt.Errorf("protocol changed: for method %q expected message type '%T', got '%T'", methodName, req, m)
}
return datastore.PackRefs, nil, nil
default:
return datastore.UpdateRepo, nil, nil
}
}
// grpcCall is a wrapper to assemble a set of parameters that represents an gRPC call method.
type grpcCall struct {
fullMethodName string
methodInfo protoregistry.MethodInfo
msg proto.Message
targetRepo *gitalypb.Repository
}
// Coordinator takes care of directing client requests to the appropriate
// downstream server. The coordinator is thread safe; concurrent calls to
// register nodes are safe.
type Coordinator struct {
router Router
txMgr *transactions.Manager
queue datastore.ReplicationEventQueue
rs datastore.RepositoryStore
registry *protoregistry.Registry
conf config.Config
votersMetric *prometheus.HistogramVec
txReplicationCountMetric *prometheus.CounterVec
}
// NewCoordinator returns a new Coordinator that utilizes the provided logger
func NewCoordinator(
queue datastore.ReplicationEventQueue,
rs datastore.RepositoryStore,
router Router,
txMgr *transactions.Manager,
conf config.Config,
r *protoregistry.Registry,
) *Coordinator {
maxVoters := 1
for _, storage := range conf.VirtualStorages {
if len(storage.Nodes) > maxVoters {
maxVoters = len(storage.Nodes)
}
}
coordinator := &Coordinator{
queue: queue,
rs: rs,
registry: r,
router: router,
txMgr: txMgr,
conf: conf,
votersMetric: prometheus.NewHistogramVec(
prometheus.HistogramOpts{
Name: "gitaly_praefect_voters_per_transaction_total",
Help: "The number of voters a given transaction was created with",
Buckets: prometheus.LinearBuckets(1, 1, maxVoters),
},
[]string{"virtual_storage"},
),
txReplicationCountMetric: prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "gitaly_praefect_tx_replications_total",
Help: "The number of replication jobs scheduled for transactional RPCs",
},
[]string{"reason"},
),
}
return coordinator
}
func (c *Coordinator) Describe(descs chan<- *prometheus.Desc) {
prometheus.DescribeByCollect(c, descs)
}
func (c *Coordinator) Collect(metrics chan<- prometheus.Metric) {
c.votersMetric.Collect(metrics)
c.txReplicationCountMetric.Collect(metrics)
}
func (c *Coordinator) directRepositoryScopedMessage(ctx context.Context, call grpcCall) (*proxy.StreamParameters, error) {
ctxlogrus.AddFields(ctx, logrus.Fields{
"virtual_storage": call.targetRepo.StorageName,
"relative_path": call.targetRepo.RelativePath,
})
praefectServer, err := txinfo.PraefectFromConfig(c.conf)
if err != nil {
return nil, fmt.Errorf("repo scoped: could not create Praefect configuration: %w", err)
}
if ctx, err = praefectServer.Inject(ctx); err != nil {
return nil, fmt.Errorf("repo scoped: could not inject Praefect server: %w", err)
}
var ps *proxy.StreamParameters
switch call.methodInfo.Operation {
case protoregistry.OpAccessor:
ps, err = c.accessorStreamParameters(ctx, call)
case protoregistry.OpMutator:
ps, err = c.mutatorStreamParameters(ctx, call)
default:
err = fmt.Errorf("unknown operation type: %v", call.methodInfo.Operation)
}
if err != nil {
return nil, err
}
return ps, nil
}
func shouldRouteRepositoryAccessorToPrimary(ctx context.Context, call grpcCall) bool {
forcePrimary := forcePrimaryRPCs[call.fullMethodName]
// In case the call's metadata tells us to force-route to the primary, then we must abide
// and ignore what `forcePrimaryRPCs` says.
if md, ok := grpc_metadata.FromIncomingContext(ctx); ok {
header := md.Get(routeRepositoryAccessorPolicy)
if len(header) == 0 {
return forcePrimary
}
if header[0] == routeRepositoryAccessorPolicyPrimaryOnly {
return true
}
}
return forcePrimary
}
func (c *Coordinator) accessorStreamParameters(ctx context.Context, call grpcCall) (*proxy.StreamParameters, error) {
repoPath := call.targetRepo.GetRelativePath()
virtualStorage := call.targetRepo.StorageName
node, err := c.router.RouteRepositoryAccessor(
ctx, virtualStorage, repoPath, shouldRouteRepositoryAccessorToPrimary(ctx, call),
)
if err != nil {
if errors.As(err, new(commonerr.RepositoryNotFoundError)) {
return nil, helper.ErrNotFound(err)
}
return nil, fmt.Errorf("accessor call: route repository accessor: %w", err)
}
b, err := rewrittenRepositoryMessage(call.methodInfo, call.msg, node.Storage)
if err != nil {
return nil, fmt.Errorf("accessor call: rewrite storage: %w", err)
}
metrics.ReadDistribution.WithLabelValues(virtualStorage, node.Storage).Inc()
return proxy.NewStreamParameters(proxy.Destination{
Ctx: helper.IncomingToOutgoing(ctx),
Conn: node.Connection,
Msg: b,
}, nil, nil, nil), nil
}
func (c *Coordinator) registerTransaction(ctx context.Context, primary RouterNode, secondaries []RouterNode) (transactions.Transaction, transactions.CancelFunc, error) {
var voters []transactions.Voter
var threshold uint
// This voting-strategy is a majority-wins one: the primary always needs to agree
// with at least half of the secondaries.
secondaryLen := uint(len(secondaries))
// In order to ensure that no quorum can be reached without the primary, its number
// of votes needs to exceed the number of secondaries.
voters = append(voters, transactions.Voter{
Name: primary.Storage,
Votes: secondaryLen + 1,
})
threshold = secondaryLen + 1
for _, secondary := range secondaries {
voters = append(voters, transactions.Voter{
Name: secondary.Storage,
Votes: 1,
})
}
// If we only got a single secondary (or none), we don't increase the threshold so
// that it's allowed to disagree with the primary without blocking the transaction.
// Otherwise, we add `Math.ceil(len(secondaries) / 2.0)`, which means that at least
// half of the secondaries need to agree with the primary.
if len(secondaries) > 1 {
threshold += (secondaryLen + 1) / 2
}
return c.txMgr.RegisterTransaction(ctx, voters, threshold)
}
type nodeErrors struct {
sync.Mutex
errByNode map[string]error
}
func (c *Coordinator) mutatorStreamParameters(ctx context.Context, call grpcCall) (*proxy.StreamParameters, error) {
targetRepo := call.targetRepo
virtualStorage := call.targetRepo.StorageName
change, params, err := getReplicationDetails(call.fullMethodName, call.msg)
if err != nil {
return nil, fmt.Errorf("mutator call: replication details: %w", err)
}
var route RepositoryMutatorRoute
switch change {
case datastore.CreateRepo:
route, err = c.router.RouteRepositoryCreation(ctx, virtualStorage)
if err != nil {
return nil, fmt.Errorf("route repository creation: %w", err)
}
default:
route, err = c.router.RouteRepositoryMutator(ctx, virtualStorage, targetRepo.RelativePath)
if err != nil {
if errors.Is(err, ErrRepositoryReadOnly) {
return nil, err
}
return nil, fmt.Errorf("mutator call: route repository mutator: %w", err)
}
}
primaryMessage, err := rewrittenRepositoryMessage(call.methodInfo, call.msg, route.Primary.Storage)
if err != nil {
return nil, fmt.Errorf("mutator call: rewrite storage: %w", err)
}
var finalizers []func() error
primaryDest := proxy.Destination{
Ctx: helper.IncomingToOutgoing(ctx),
Conn: route.Primary.Connection,
Msg: primaryMessage,
}
var secondaryDests []proxy.Destination
if shouldUseTransaction(ctx, call.fullMethodName) {
c.votersMetric.WithLabelValues(virtualStorage).Observe(float64(1 + len(route.Secondaries)))
transaction, transactionCleanup, err := c.registerTransaction(ctx, route.Primary, route.Secondaries)
if err != nil {
return nil, fmt.Errorf("%w: %v %v", err, route.Primary, route.Secondaries)
}
finalizers = append(finalizers, transactionCleanup)
nodeErrors := &nodeErrors{
errByNode: make(map[string]error),
}
injectedCtx, err := txinfo.InjectTransaction(ctx, transaction.ID(), route.Primary.Storage, true)
if err != nil {
return nil, err
}
primaryDest.Ctx = helper.IncomingToOutgoing(injectedCtx)
primaryDest.ErrHandler = func(err error) error {
nodeErrors.Lock()
defer nodeErrors.Unlock()
nodeErrors.errByNode[route.Primary.Storage] = err
return err
}
for _, secondary := range route.Secondaries {
secondaryMsg, err := rewrittenRepositoryMessage(call.methodInfo, call.msg, secondary.Storage)
if err != nil {
return nil, err
}
injectedCtx, err := txinfo.InjectTransaction(ctx, transaction.ID(), secondary.Storage, false)
if err != nil {
return nil, err
}
secondaryDests = append(secondaryDests, proxy.Destination{
Ctx: helper.IncomingToOutgoing(injectedCtx),
Conn: secondary.Connection,
Msg: secondaryMsg,
ErrHandler: func(err error) error {
nodeErrors.Lock()
defer nodeErrors.Unlock()
nodeErrors.errByNode[secondary.Storage] = err
ctxlogrus.Extract(ctx).WithError(err).
Error("proxying to secondary failed")
// For now, any errors returned by secondaries are ignored.
// This is mostly so that we do not abort transactions which
// are ongoing and may succeed even with a subset of
// secondaries bailing out.
return nil
},
})
}
finalizers = append(finalizers,
c.createTransactionFinalizer(ctx, transaction, route, virtualStorage,
targetRepo, change, params, call.fullMethodName, nodeErrors),
)
} else {
finalizers = append(finalizers,
c.newRequestFinalizer(
ctx,
virtualStorage,
targetRepo,
route.Primary.Storage,
nil,
append(routerNodesToStorages(route.Secondaries), route.ReplicationTargets...),
change,
params,
call.fullMethodName,
))
}
reqFinalizer := func() error {
var firstErr error
for _, finalizer := range finalizers {
err := finalizer()
if err == nil {
continue
}
if firstErr == nil {
firstErr = err
continue
}
ctxlogrus.
Extract(ctx).
WithError(err).
Error("coordinator proxy stream finalizer failure")
}
return firstErr
}
return proxy.NewStreamParameters(primaryDest, secondaryDests, reqFinalizer, nil), nil
}
// StreamDirector determines which downstream servers receive requests
func (c *Coordinator) StreamDirector(ctx context.Context, fullMethodName string, peeker proxy.StreamPeeker) (*proxy.StreamParameters, error) {
// For phase 1, we need to route messages based on the storage location
// to the appropriate Gitaly node.
ctxlogrus.Extract(ctx).Debugf("Stream director received method %s", fullMethodName)
mi, err := c.registry.LookupMethod(fullMethodName)
if err != nil {
return nil, err
}
payload, err := peeker.Peek()
if err != nil {
return nil, err
}
m, err := protoMessage(mi, payload)
if err != nil {
return nil, err
}
if mi.Scope == protoregistry.ScopeRepository {
targetRepo, err := mi.TargetRepo(m)
if err != nil {
return nil, helper.ErrInvalidArgument(fmt.Errorf("repo scoped: %w", err))
}
if err := c.validateTargetRepo(targetRepo); err != nil {
return nil, helper.ErrInvalidArgument(fmt.Errorf("repo scoped: %w", err))
}
sp, err := c.directRepositoryScopedMessage(ctx, grpcCall{
fullMethodName: fullMethodName,
methodInfo: mi,
msg: m,
targetRepo: targetRepo,
})
if err != nil {
if errors.Is(err, nodes.ErrVirtualStorageNotExist) {
return nil, helper.ErrInvalidArgument(err)
}
return nil, err
}
return sp, nil
}
if mi.Scope == protoregistry.ScopeStorage {
return c.directStorageScopedMessage(ctx, mi, m)
}
return nil, helper.ErrInternalf("rpc with undefined scope %q", mi.Scope)
}
func (c *Coordinator) directStorageScopedMessage(ctx context.Context, mi protoregistry.MethodInfo, msg proto.Message) (*proxy.StreamParameters, error) {
virtualStorage, err := mi.Storage(msg)
if err != nil {
return nil, helper.ErrInvalidArgument(err)
}
if virtualStorage == "" {
return nil, helper.ErrInvalidArgumentf("storage scoped: target storage is invalid")
}
var ps *proxy.StreamParameters
switch mi.Operation {
case protoregistry.OpAccessor:
ps, err = c.accessorStorageStreamParameters(ctx, mi, msg, virtualStorage)
case protoregistry.OpMutator:
ps, err = c.mutatorStorageStreamParameters(ctx, mi, msg, virtualStorage)
default:
err = fmt.Errorf("storage scope: unknown operation type: %v", mi.Operation)
}
return ps, err
}
func (c *Coordinator) accessorStorageStreamParameters(ctx context.Context, mi protoregistry.MethodInfo, msg proto.Message, virtualStorage string) (*proxy.StreamParameters, error) {
node, err := c.router.RouteStorageAccessor(ctx, virtualStorage)
if err != nil {
if errors.Is(err, nodes.ErrVirtualStorageNotExist) {
return nil, helper.ErrInvalidArgument(err)
}
return nil, helper.ErrInternalf("accessor storage scoped: route storage accessor %q: %w", virtualStorage, err)
}
b, err := rewrittenStorageMessage(mi, msg, node.Storage)
if err != nil {
return nil, helper.ErrInvalidArgument(fmt.Errorf("accessor storage scoped: %w", err))
}
// As this is a read operation it could be routed to another storage (not only primary) if it meets constraints
// such as: it is healthy, it belongs to the same virtual storage bundle, etc.
// https://gitlab.com/gitlab-org/gitaly/-/issues/2972
primaryDest := proxy.Destination{
Ctx: ctx,
Conn: node.Connection,
Msg: b,
}
return proxy.NewStreamParameters(primaryDest, nil, func() error { return nil }, nil), nil
}
func (c *Coordinator) mutatorStorageStreamParameters(ctx context.Context, mi protoregistry.MethodInfo, msg proto.Message, virtualStorage string) (*proxy.StreamParameters, error) {
route, err := c.router.RouteStorageMutator(ctx, virtualStorage)
if err != nil {
if errors.Is(err, nodes.ErrVirtualStorageNotExist) {
return nil, helper.ErrInvalidArgument(err)
}
return nil, helper.ErrInternalf("mutator storage scoped: get shard %q: %w", virtualStorage, err)
}
b, err := rewrittenStorageMessage(mi, msg, route.Primary.Storage)
if err != nil {
return nil, helper.ErrInvalidArgument(fmt.Errorf("mutator storage scoped: %w", err))
}
primaryDest := proxy.Destination{
Ctx: ctx,
Conn: route.Primary.Connection,
Msg: b,
}
secondaryDests := make([]proxy.Destination, len(route.Secondaries))
for i, secondary := range route.Secondaries {
b, err := rewrittenStorageMessage(mi, msg, secondary.Storage)
if err != nil {
return nil, helper.ErrInvalidArgument(fmt.Errorf("mutator storage scoped: %w", err))
}
secondaryDests[i] = proxy.Destination{Ctx: ctx, Conn: secondary.Connection, Msg: b}
}
return proxy.NewStreamParameters(primaryDest, secondaryDests, func() error { return nil }, nil), nil
}
func rewrittenRepositoryMessage(mi protoregistry.MethodInfo, m proto.Message, storage string) ([]byte, error) {
targetRepo, err := mi.TargetRepo(m)
if err != nil {
return nil, helper.ErrInvalidArgument(err)
}
// rewrite storage name
targetRepo.StorageName = storage
additionalRepo, ok, err := mi.AdditionalRepo(m)
if err != nil {
return nil, helper.ErrInvalidArgument(err)
}
if ok {
additionalRepo.StorageName = storage
}
b, err := proxy.NewCodec().Marshal(m)
if err != nil {
return nil, err
}
return b, nil
}
func rewrittenStorageMessage(mi protoregistry.MethodInfo, m proto.Message, storage string) ([]byte, error) {
if err := mi.SetStorage(m, storage); err != nil {
return nil, helper.ErrInvalidArgument(err)
}
return proxy.NewCodec().Marshal(m)
}
func protoMessage(mi protoregistry.MethodInfo, frame []byte) (proto.Message, error) {
m, err := mi.UnmarshalRequestProto(frame)
if err != nil {
return nil, err
}
return m, nil
}
func (c *Coordinator) createTransactionFinalizer(
ctx context.Context,
transaction transactions.Transaction,
route RepositoryMutatorRoute,
virtualStorage string,
targetRepo *gitalypb.Repository,
change datastore.ChangeType,
params datastore.Params,
cause string,
nodeErrors *nodeErrors,
) func() error {
return func() error {
primaryDirtied, updated, outdated := getUpdatedAndOutdatedSecondaries(
ctx, route, transaction, nodeErrors, c.txReplicationCountMetric)
if !primaryDirtied {
// If the primary replica was not modified then we don't need to consider the secondaries
// outdated. Praefect requires the primary to be always part of the quorum, so no changes
// to secondaries would be made without primary being in agreement.
return nil
}
return c.newRequestFinalizer(
ctx, virtualStorage, targetRepo, route.Primary.Storage,
updated, outdated, change, params, cause)()
}
}
// getUpdatedAndOutdatedSecondaries returns all nodes which can be considered up-to-date or outdated
// after the given transaction. A node is considered outdated, if one of the following is true:
//
// - No subtransactions were created and the RPC was successful on the primary. This really is only
// a safeguard in case the RPC wasn't aware of transactions and thus failed to correctly assert
// its state matches across nodes. This is rather pessimistic, as it could also indicate that an
// RPC simply didn't change anything. If the RPC was a failure on the primary and there were no
// subtransactions, we assume no changes were done and that the nodes failed prior to voting.
//
// - The node failed to be part of the quorum. As a special case, if the primary fails the vote, all
// nodes need to get replication jobs.
//
// - The node has errored. As a special case, if the primary fails all nodes need to get replication
// jobs.
//
// Note that this function cannot and should not fail: if anything goes wrong, we need to create
// replication jobs to repair state.
func getUpdatedAndOutdatedSecondaries(
ctx context.Context,
route RepositoryMutatorRoute,
transaction transactions.Transaction,
nodeErrors *nodeErrors,
replicationCountMetric *prometheus.CounterVec,
) (primaryDirtied bool, updated []string, outdated []string) {
nodeErrors.Lock()
defer nodeErrors.Unlock()
primaryErr := nodeErrors.errByNode[route.Primary.Storage]
// If there were subtransactions, we only assume some changes were made if one of the subtransactions
// was committed.
//
// If there were no subtransactions, we assume changes were performed only if the primary successfully
// processed the RPC. This might be an RPC that is not correctly casting votes thus we replicate everywhere.
//
// If there were no subtransactions and the primary failed the RPC, we assume no changes have been made and
// the nodes simply failed before voting.
primaryDirtied = transaction.DidCommitAnySubtransaction() ||
(transaction.CountSubtransactions() == 0 && primaryErr == nil)
recordReplication := func(reason string, replicationCount int) {
// If the primary wasn't dirtied, then we never replicate any changes. While this is
// duplicates logic defined elsewhere, it's probably good enough given that we only
// talk about metrics here.
if primaryDirtied && replicationCount > 0 {
replicationCountMetric.WithLabelValues(reason).Add(float64(replicationCount))
}
}
// Replication targets were not added to the transaction, most likely because they are
// either not healthy or out of date. We thus need to make sure to create replication jobs
// for them.
outdated = append(outdated, route.ReplicationTargets...)
recordReplication("outdated", len(route.ReplicationTargets))
// If the primary errored, then we need to assume that it has modified on-disk state and
// thus need to replicate those changes to secondaries.
if primaryErr != nil {
ctxlogrus.Extract(ctx).WithError(primaryErr).Info("primary failed transaction")
outdated = append(outdated, routerNodesToStorages(route.Secondaries)...)
recordReplication("primary-failed", len(route.Secondaries))
return
}
// If no subtransaction happened, then the called RPC may not be aware of transactions or
// the nodes failed before casting any votes. If the primary failed the RPC, we assume
// no changes were done and the nodes hit an error prior to voting. If the primary processed
// the RPC successfully, we assume the RPC is not correctly voting and replicate everywhere.
if transaction.CountSubtransactions() == 0 {
ctxlogrus.Extract(ctx).Info("transaction did not create subtransactions")
outdated = append(outdated, routerNodesToStorages(route.Secondaries)...)
recordReplication("no-votes", len(route.Secondaries))
return
}
// If we cannot get the transaction state, then something's gone awfully wrong. We go the
// safe route and just replicate to all secondaries.
nodeStates, err := transaction.State()
if err != nil {
ctxlogrus.Extract(ctx).WithError(err).Error("could not get transaction state")
outdated = append(outdated, routerNodesToStorages(route.Secondaries)...)
recordReplication("missing-tx-state", len(route.Secondaries))
return
}
// If the primary node did not commit the transaction but there were some subtransactions committed,
// then we must assume that it dirtied on-disk state. This modified state may not be what we want,
// but it's what we got. So in order to ensure a consistent state, we need to replicate.
if state := nodeStates[route.Primary.Storage]; state != transactions.VoteCommitted {
if state == transactions.VoteFailed {
ctxlogrus.Extract(ctx).Error("transaction: primary failed vote")
}
outdated = append(outdated, routerNodesToStorages(route.Secondaries)...)
recordReplication("primary-not-committed", len(route.Secondaries))
return
}
// Now we finally got the potentially happy case: in case the secondary didn't run into an
// error and committed, it's considered up to date and thus does not need replication.
for _, secondary := range route.Secondaries {
if nodeErrors.errByNode[secondary.Storage] != nil {
outdated = append(outdated, secondary.Storage)
recordReplication("node-failed", 1)
continue
}
if nodeStates[secondary.Storage] != transactions.VoteCommitted {
outdated = append(outdated, secondary.Storage)
recordReplication("node-not-committed", 1)
continue
}
updated = append(updated, secondary.Storage)
}
return
}
func routerNodesToStorages(nodes []RouterNode) []string {
storages := make([]string, len(nodes))
for i, n := range nodes {
storages[i] = n.Storage
}
return storages
}
func (c *Coordinator) newRequestFinalizer(
ctx context.Context,
virtualStorage string,
targetRepo *gitalypb.Repository,
primary string,
updatedSecondaries []string,
outdatedSecondaries []string,
change datastore.ChangeType,
params datastore.Params,
cause string,
) func() error {
return func() error {
// Use a separate timeout for the database operations. If the request times out, the passed in context is
// canceled. We need to perform the database updates regardless whether the request was canceled or not as
// the primary replica could have been dirtied and secondaries become outdated. Otherwise we'd have no idea of
// the possible changes performed on the disk.
ctx, cancel := context.WithTimeout(helper.SuppressCancellation(ctx), 30*time.Second)
defer cancel()
log := ctxlogrus.Extract(ctx).WithFields(logrus.Fields{
"replication.cause": cause,
"replication.change": change,
"replication.primary": primary,
})
if len(updatedSecondaries) > 0 {
log = log.WithField("replication.updated", updatedSecondaries)
}
if len(outdatedSecondaries) > 0 {
log = log.WithField("replication.outdated", outdatedSecondaries)
}
log.Info("queueing replication jobs")
switch change {
case datastore.UpdateRepo:
// If this fails, the primary might have changes on it that are not recorded in the database. The secondaries will appear
// consistent with the primary but might serve different stale data. Follow-up mutator calls will solve this state although
// the primary will be a later generation in the mean while.
if err := c.rs.IncrementGeneration(ctx, virtualStorage, targetRepo.GetRelativePath(), primary, updatedSecondaries); err != nil {
return fmt.Errorf("increment generation: %w", err)
}
case datastore.RenameRepo:
// Renaming a repository is not idempotent on Gitaly's side. This combined with a failure here results in a problematic state,
// where the client receives an error but can't retry the call as the repository has already been moved on the primary.
// Ideally the rename RPC should copy the repository instead of moving so the client can retry if this failed.
if err := c.rs.RenameRepository(ctx, virtualStorage, targetRepo.GetRelativePath(), primary, params["RelativePath"].(string)); err != nil {
if !errors.Is(err, datastore.RepositoryNotExistsError{}) {
return fmt.Errorf("rename repository: %w", err)
}
ctxlogrus.Extract(ctx).WithError(err).Info("renamed repository does not have a store entry")
}
case datastore.DeleteRepo:
// If this fails, the repository was already deleted from the primary but we end up still having a record of it in the db.
// Ideally we would delete the record from the db first and schedule the repository for deletion later in order to avoid
// this problem. Client can reattempt this as deleting a repository is idempotent.
if err := c.rs.DeleteRepository(ctx, virtualStorage, targetRepo.GetRelativePath(), primary); err != nil {
if !errors.Is(err, datastore.RepositoryNotExistsError{}) {
return fmt.Errorf("delete repository: %w", err)
}
ctxlogrus.Extract(ctx).WithError(err).Info("deleted repository does not have a store entry")
}
case datastore.CreateRepo:
repositorySpecificPrimariesEnabled := c.conf.Failover.ElectionStrategy == config.ElectionStrategyPerRepository
variableReplicationFactorEnabled := repositorySpecificPrimariesEnabled &&
c.conf.DefaultReplicationFactors()[virtualStorage] > 0
if err := c.rs.CreateRepository(ctx,
virtualStorage,
targetRepo.GetRelativePath(),
primary,
updatedSecondaries,
outdatedSecondaries,
repositorySpecificPrimariesEnabled,
variableReplicationFactorEnabled,
); err != nil {
if !errors.Is(err, datastore.RepositoryExistsError{}) {
return fmt.Errorf("create repository: %w", err)
}
ctxlogrus.Extract(ctx).WithError(err).Info("create repository already has a store entry")
}
change = datastore.UpdateRepo
}
correlationID := correlation.ExtractFromContextOrGenerate(ctx)
g, ctx := errgroup.WithContext(ctx)
for _, secondary := range outdatedSecondaries {
event := datastore.ReplicationEvent{
Job: datastore.ReplicationJob{
Change: change,
RelativePath: targetRepo.GetRelativePath(),
VirtualStorage: virtualStorage,
SourceNodeStorage: primary,
TargetNodeStorage: secondary,
Params: params,
},
Meta: datastore.Params{metadatahandler.CorrelationIDKey: correlationID},
}
g.Go(func() error {
if _, err := c.queue.Enqueue(ctx, event); err != nil {
return fmt.Errorf("enqueue replication event: %w", err)
}
return nil
})
}
return g.Wait()
}
}
func (c *Coordinator) validateTargetRepo(repo *gitalypb.Repository) error {
if repo.GetStorageName() == "" || repo.GetRelativePath() == "" {
return glerrors.ErrInvalidRepository
}
if _, found := c.conf.StorageNames()[repo.StorageName]; !found {
// this needs to be nodes.ErrVirtualStorageNotExist error, but it will break
// existing API contract as praefect should be a transparent proxy of the gitaly
return glerrors.ErrInvalidRepository
}
return nil
}
|