Golang proto.IsWrite函數代碼示例

// AddCmd adds a command for execution on this range. The command's
// affected keys are verified to be contained within the range and the
// range's leadership is confirmed. The command is then dispatched
// either along the read-only execution path or the read-write Raft
// command queue.
func (r *Range) AddCmd(ctx context.Context, call proto.Call) error {
	args := call.Args
	// TODO(tschottdorf) Some (internal) requests go here directly, so they
	// won't be traced.
	trace := tracer.FromCtx(ctx)
	// Differentiate between admin, read-only and read-write.
	var reply proto.Response
	var err error
	if proto.IsAdmin(args) {
		defer trace.Epoch("admin path")()
		reply, err = r.addAdminCmd(ctx, args)
	} else if proto.IsReadOnly(args) {
		defer trace.Epoch("read-only path")()
		reply, err = r.addReadOnlyCmd(ctx, args)
	} else if proto.IsWrite(args) {
		defer trace.Epoch("read-write path")()
		reply, err = r.addWriteCmd(ctx, args, nil)
	} else {
		panic(fmt.Sprintf("don't know how to handle command %T", args))
	}

	if reply != nil {
		gogoproto.Merge(call.Reply, reply)
	}

	if err != nil {
		replyHeader := call.Reply.Header()
		if replyHeader.Error != nil {
			panic("the world is on fire")
		}
		replyHeader.SetGoError(err)
	}

	return err
}

// applyRaftCommand applies a raft command from the replicated log to the
// underlying state machine (i.e. the engine).
// When certain critical operations fail, a replicaCorruptionError may be
// returned and must be handled by the caller.
func (r *Range) applyRaftCommand(ctx context.Context, index uint64, originNode proto.RaftNodeID, args proto.Request, reply proto.Response) error {
	if index <= 0 {
		log.Fatalc(ctx, "raft command index is <= 0")
	}

	// If we have an out of order index, there's corruption. No sense in trying
	// to update anything or run the command. Simply return a corruption error.
	if oldIndex := atomic.LoadUint64(&r.appliedIndex); oldIndex >= index {
		return newReplicaCorruptionError(util.Errorf("applied index moved backwards: %d >= %d", oldIndex, index))
	}

	// Call the helper, which returns a batch containing data written
	// during command execution and any associated error.
	ms := engine.MVCCStats{}
	batch, rErr := r.applyRaftCommandInBatch(ctx, index, originNode, args, reply, &ms)
	// ALWAYS set the reply header error to the error returned by the
	// helper. This is the definitive result of the execution. The
	// error must be set before saving to the response cache.
	// TODO(tschottdorf,tamird) For #1400, want to refactor executeCmd to not
	// touch the reply header's error field.
	reply.Header().SetGoError(rErr)
	defer batch.Close()

	// Advance the last applied index and commit the batch.
	if err := setAppliedIndex(batch, r.Desc().RaftID, index); err != nil {
		log.Fatalc(ctx, "setting applied index in a batch should never fail: %s", err)
	}
	if err := batch.Commit(); err != nil {
		rErr = newReplicaCorruptionError(util.Errorf("could not commit batch"), err, rErr)
	} else {
		// Update cached appliedIndex if we were able to set the applied index on disk.
		atomic.StoreUint64(&r.appliedIndex, index)
	}

	// On successful write commands, flush to event feed, and handle other
	// write-related triggers including splitting and config gossip updates.
	if rErr == nil && proto.IsWrite(args) {
		// Publish update to event feed.
		r.rm.EventFeed().updateRange(r, args.Method(), &ms)
		// If the commit succeeded, potentially add range to split queue.
		r.maybeAddToSplitQueue()
		// Maybe update gossip configs on a put.
		switch args.(type) {
		case *proto.PutRequest, *proto.DeleteRequest, *proto.DeleteRangeRequest:
			if key := args.Header().Key; key.Less(keys.SystemMax) {
				// We hold the lock already.
				r.maybeGossipConfigsLocked(func(configPrefix proto.Key) bool {
					return bytes.HasPrefix(key, configPrefix)
				})
			}
		}
	}

	return rErr
}

// applyRaftCommand applies a raft command from the replicated log to the
// underlying state machine (i.e. the engine).
// When certain critical operations fail, a replicaCorruptionError may be
// returned and must be handled by the caller.
func (r *Range) applyRaftCommand(ctx context.Context, index uint64, originNode proto.RaftNodeID, args proto.Request) (proto.Response, error) {
	if index <= 0 {
		log.Fatalc(ctx, "raft command index is <= 0")
	}

	// If we have an out of order index, there's corruption. No sense in trying
	// to update anything or run the command. Simply return a corruption error.
	if oldIndex := atomic.LoadUint64(&r.appliedIndex); oldIndex >= index {
		return nil, newReplicaCorruptionError(util.Errorf("applied index moved backwards: %d >= %d", oldIndex, index))
	}

	// Call the helper, which returns a batch containing data written
	// during command execution and any associated error.
	ms := engine.MVCCStats{}
	batch, reply, rErr := r.applyRaftCommandInBatch(ctx, index, originNode, args, &ms)
	defer batch.Close()

	// Advance the last applied index and commit the batch.
	if err := setAppliedIndex(batch, r.Desc().RaftID, index); err != nil {
		log.Fatalc(ctx, "setting applied index in a batch should never fail: %s", err)
	}
	if err := batch.Commit(); err != nil {
		rErr = newReplicaCorruptionError(util.Errorf("could not commit batch"), err, rErr)
	} else {
		// Update cached appliedIndex if we were able to set the applied index on disk.
		atomic.StoreUint64(&r.appliedIndex, index)
	}

	// On successful write commands, flush to event feed, and handle other
	// write-related triggers including splitting and config gossip updates.
	if rErr == nil && proto.IsWrite(args) {
		// Publish update to event feed.
		r.rm.EventFeed().updateRange(r, args.Method(), &ms)
		// If the commit succeeded, potentially add range to split queue.
		r.maybeAddToSplitQueue()
		// Maybe update gossip configs if the command is not part of a transaction.
		// If the command is part of an uncommitted transaction, we rely on the
		// periodic configGossipInterval loop since we will not see the update
		// until the transaction is committed.
		if key := args.Header().Key; key.Less(keys.SystemMax) && args.Header().Txn == nil {
			r.maybeGossipConfigs(func(configPrefix proto.Key) bool {
				return bytes.HasPrefix(key, configPrefix)
			})
		}
	}

	return reply, rErr
}

// AddCmd adds a command for execution on this range. The command's
// affected keys are verified to be contained within the range and the
// range's leadership is confirmed. The command is then dispatched
// either along the read-only execution path or the read-write Raft
// command queue.
func (r *Replica) AddCmd(ctx context.Context, args proto.Request) (proto.Response, error) {
	// TODO(tschottdorf) Some (internal) requests go here directly, so they
	// won't be traced.
	trace := tracer.FromCtx(ctx)
	// Differentiate between admin, read-only and read-write.
	var reply proto.Response
	var err error
	if proto.IsAdmin(args) {
		defer trace.Epoch("admin path")()
		reply, err = r.addAdminCmd(ctx, args)
	} else if proto.IsReadOnly(args) {
		defer trace.Epoch("read-only path")()
		reply, err = r.addReadOnlyCmd(ctx, args)
	} else if proto.IsWrite(args) {
		defer trace.Epoch("read-write path")()
		reply, err = r.addWriteCmd(ctx, args, nil)
	} else {
		panic(fmt.Sprintf("don't know how to handle command %T", args))
	}

	return reply, err
}

// verifyPermissions verifies that the requesting user (header.User)
// has permission to read/write (capabilities depend on method
// name). In the event that multiple permission configs apply to the
// key range implicated by the command, the lowest common denominator
// for permission. For example, if a scan crosses two permission
// configs, both configs must allow read permissions or the entire
// scan will fail.
func (ds *DistSender) verifyPermissions(args proto.Request) error {
	// The root user can always proceed.
	header := args.Header()
	if header.User == storage.UserRoot {
		return nil
	}
	// Check for admin methods.
	if proto.IsAdmin(args) {
		if header.User != storage.UserRoot {
			return util.Errorf("user %q cannot invoke admin command %s", header.User, args.Method())
		}
		return nil
	}
	// Get permissions map from gossip.
	configMap, err := ds.gossip.GetInfo(gossip.KeyConfigPermission)
	if err != nil {
		return util.Errorf("permissions not available via gossip")
	}
	if configMap == nil {
		return util.Errorf("perm configs not available; cannot execute %s", args.Method())
	}
	permMap := configMap.(storage.PrefixConfigMap)
	headerEnd := header.EndKey
	if len(headerEnd) == 0 {
		headerEnd = header.Key
	}
	// Visit PermConfig(s) which apply to the method's key range.
	//   - For each perm config which the range covers, verify read or writes
	//     are allowed as method requires.
	//   - Verify the permissions hierarchically; that is, if permissions aren't
	//     granted at the longest prefix, try next longest, then next, etc., up
	//     to and including the default prefix.
	//
	// TODO(spencer): it might make sense to visit prefixes from the
	//   shortest to longest instead for performance. Keep an eye on profiling
	//   for this code path as permission sets grow large.
	return permMap.VisitPrefixes(header.Key, headerEnd,
		func(start, end proto.Key, config interface{}) (bool, error) {
			hasPerm := false
			if err := permMap.VisitPrefixesHierarchically(start, func(start, end proto.Key, config interface{}) (bool, error) {
				perm := config.(*proto.PermConfig)
				if proto.IsRead(args) && !perm.CanRead(header.User) {
					return false, nil
				}
				if proto.IsWrite(args) && !perm.CanWrite(header.User) {
					return false, nil
				}
				// Return done = true, as permissions have been granted by this config.
				hasPerm = true
				return true, nil
			}); err != nil {
				return false, err
			}
			if !hasPerm {
				if len(header.EndKey) == 0 {
					return false, util.Errorf("user %q cannot invoke %s at %q", header.User, args.Method(), start)
				}
				return false, util.Errorf("user %q cannot invoke %s at %q-%q", header.User, args.Method(), start, end)
			}
			return false, nil
		})
}

// applyRaftCommand applies a raft command from the replicated log to the
// underlying state machine (i.e. the engine).
// When certain critical operations fail, a replicaCorruptionError may be
// returned and must be handled by the caller.
func (r *Range) applyRaftCommand(ctx context.Context, index uint64, originNode proto.RaftNodeID, args proto.Request, reply proto.Response) (rErr error) {
	if index <= 0 {
		log.Fatalc(ctx, "raft command index is <= 0")
	}

	committed := false
	// The very last thing we do before returning is move the applied index
	// forward, unless that has already happened as part of a successfully
	// committed batch.
	defer func() {
		if !committed {
			// We didn't commit the batch, but advance the last applied index nonetheless.
			if err := setAppliedIndex(r.rm.Engine(), r.Desc().RaftID, index); err != nil {
				rErr = newReplicaCorruptionError(
					util.Errorf("could not advance applied index"), err, rErr)
				return
			}
			atomic.StoreUint64(&r.appliedIndex, index)
		}
	}()

	if lease := r.getLease(); args.Method() != proto.InternalLeaderLease &&
		(!lease.OwnedBy(originNode) || !lease.Covers(args.Header().Timestamp)) {
		// Verify the leader lease is held, unless this command is trying to
		// obtain it. Any other Raft command has had the leader lease held
		// by the replica at proposal time, but this may no more be the case.
		// Corruption aside, the most likely reason is a leadership change (the
		// most recent leader assumes responsibility for all past timestamps as
		// well). In that case, it's not valid to go ahead with the execution:
		// Writes must be aware of the last time the mutated key was read, and
		// since reads are served locally by the lease holder without going
		// through Raft, a read which was not taken into account may have been
		// served. Hence, we must retry at the current leader.
		//
		// It's crucial that we don't update the response cache for the error
		// returned below since the request is going to be retried with the
		// same ClientCmdID and would get the distributed sender stuck in an
		// infinite loop, retrieving a stale NotLeaderError over and over
		// again, even when proposing at the correct replica.
		return r.newNotLeaderError(lease)
	}

	// Anything happening from now on needs to enter the response cache.
	defer func() {
		// TODO(tamird,tschottdorf): according to #1400 we intend to set the reply
		// header's error as late as possible and in a central location. Range
		// commands still write to the header directly, but once they don't this
		// could be the authoritative location that sets the reply error for any-
		// thing that makes it into Raft. Note that we must set this prior to
		// signaling cmd.done below, or the waiting RPC handler might proceed
		// before we've updated its reply.
		//
		// It is important that the error is set before the reply is saved into
		// the response cache.
		reply.Header().SetGoError(rErr)

		if proto.IsWrite(args) {
			// No matter the result, add result to the response cache if this
			// is a write method. This must be done as part of the execution of
			// raft commands so that every replica maintains the same responses
			// to continue request idempotence, even if leadership changes.
			if err := r.respCache.PutResponse(args.Header().CmdID, reply); err != nil {
				rErr = newReplicaCorruptionError(
					util.Errorf("could not put to response cache"), err, rErr)
				return
			}
		}
	}()

	header := args.Header()

	// Check the response cache to ensure idempotency.
	if proto.IsWrite(args) {
		if ok, err := r.respCache.GetResponse(header.CmdID, reply); ok && err == nil {
			if log.V(1) {
				log.Infoc(ctx, "found response cache entry for %+v", args.Header().CmdID)
			}
			return err
		} else if ok && err != nil {
			return newReplicaCorruptionError(
				util.Errorf("could not read from response cache"), err)
		}
	}

	// Create a new batch for the command to ensure all or nothing semantics.
	batch := r.rm.Engine().NewBatch()
	defer batch.Close()

	// Create a engine.MVCCStats instance.
	ms := engine.MVCCStats{}

	// Execute the command; the error will also be set in the reply header.
	// TODO(tschottdorf,tamird) For #1400, want to refactor executeCmd to not
	// touch the reply header's error field.
	intents, err := r.executeCmd(batch, &ms, args, reply)
	// If the execution of the command wasn't successful, stop here.
//.........這裏部分代碼省略.........

// applyRaftCommandInBatch executes the command in a batch engine and
// returns the batch containing the results. The caller is responsible
// for committing the batch, even on error.
func (r *Range) applyRaftCommandInBatch(ctx context.Context, index uint64, originNode proto.RaftNodeID,
	args proto.Request, ms *engine.MVCCStats) (engine.Engine, proto.Response, error) {
	// Create a new batch for the command to ensure all or nothing semantics.
	batch := r.rm.Engine().NewBatch()

	if lease := r.getLease(); args.Method() != proto.InternalLeaderLease &&
		(!lease.OwnedBy(originNode) || !lease.Covers(args.Header().Timestamp)) {
		// Verify the leader lease is held, unless this command is trying to
		// obtain it. Any other Raft command has had the leader lease held
		// by the replica at proposal time, but this may no longer be the case.
		// Corruption aside, the most likely reason is a leadership change (the
		// most recent leader assumes responsibility for all past timestamps as
		// well). In that case, it's not valid to go ahead with the execution:
		// Writes must be aware of the last time the mutated key was read, and
		// since reads are served locally by the lease holder without going
		// through Raft, a read which was not taken into account may have been
		// served. Hence, we must retry at the current leader.
		//
		// It's crucial that we don't update the response cache for the error
		// returned below since the request is going to be retried with the
		// same ClientCmdID and would get the distributed sender stuck in an
		// infinite loop, retrieving a stale NotLeaderError over and over
		// again, even when proposing at the correct replica.
		return batch, nil, r.newNotLeaderError(lease, originNode)
	}

	// Check the response cache to ensure idempotency.
	if proto.IsWrite(args) {
		if reply, err := r.respCache.GetResponse(batch, args.Header().CmdID); err != nil {
			// Any error encountered while fetching the response cache entry means corruption.
			return batch, reply, newReplicaCorruptionError(util.Errorf("could not read from response cache"), err)
		} else if reply != nil {
			if log.V(1) {
				log.Infoc(ctx, "found response cache entry for %+v", args.Header().CmdID)
			}
			// TODO(tamird): move this into the response cache itself
			defer func() { reply.Header().Error = nil }()
			// We successfully read from the response cache, so return whatever error
			// was present in the cached entry (if any).
			return batch, reply, reply.Header().GoError()
		}
	}

	// Execute the command.
	reply, intents, rErr := r.executeCmd(batch, ms, args)
	// Regardless of error, add result to the response cache if this is
	// a write method. This must be done as part of the execution of
	// raft commands so that every replica maintains the same responses
	// to continue request idempotence, even if leadership changes.
	if proto.IsWrite(args) {
		if rErr == nil {
			// If command was successful, flush the MVCC stats to the batch.
			if err := r.stats.MergeMVCCStats(batch, ms, args.Header().Timestamp.WallTime); err != nil {
				log.Fatalc(ctx, "setting mvcc stats in a batch should never fail: %s", err)
			}
		} else {
			// Otherwise, reset the batch to clear out partial execution and
			// prepare for the failed response cache entry.
			batch.Close()
			batch = r.rm.Engine().NewBatch()
		}
		// TODO(tamird): move this into the response cache itself
		if reply == nil {
			reply = args.CreateReply()
		}
		if reply.Header().Error != nil {
			panic("the world is on fire")
		}
		reply.Header().SetGoError(rErr)
		if err := r.respCache.PutResponse(batch, args.Header().CmdID, reply); err != nil {
			log.Fatalc(ctx, "putting a response cache entry in a batch should never fail: %s", err)
		}
		reply.Header().Error = nil
	}

	// If the execution of the command wasn't successful, stop here.
	if rErr != nil {
		return batch, reply, rErr
	}

	// On success and only on the replica on which this command originated,
	// resolve skipped intents asynchronously.
	if originNode == r.rm.RaftNodeID() {
		r.handleSkippedIntents(args, intents)
	}

	return batch, reply, nil
}

// TestVerifyPermissions verifies permissions are checked for single
// zones and across multiple zones. It also verifies that permissions
// are checked hierarchically.
func TestVerifyPermissions(t *testing.T) {
	defer leaktest.AfterTest(t)
	n := simulation.NewNetwork(1, "tcp", gossip.TestInterval)
	ds := NewDistSender(nil, n.Nodes[0].Gossip)
	config1 := &proto.PermConfig{
		Read:  []string{"read1", "readAll", "rw1", "rwAll"},
		Write: []string{"write1", "writeAll", "rw1", "rwAll"}}
	config2 := &proto.PermConfig{
		Read:  []string{"read2", "readAll", "rw2", "rwAll"},
		Write: []string{"write2", "writeAll", "rw2", "rwAll"}}
	configs := []*storage.PrefixConfig{
		{proto.KeyMin, nil, config1},
		{proto.Key("a"), nil, config2},
	}
	configMap, err := storage.NewPrefixConfigMap(configs)
	if err != nil {
		t.Fatalf("failed to make prefix config map, err: %s", err.Error())
	}
	if err := ds.gossip.AddInfo(gossip.KeyConfigPermission, configMap, time.Hour); err != nil {
		t.Fatal(err)
	}

	allRequestTypes := []proto.Request{
		&proto.GetRequest{},
		&proto.PutRequest{},
		&proto.ConditionalPutRequest{},
		&proto.IncrementRequest{},
		&proto.DeleteRequest{},
		&proto.DeleteRangeRequest{},
		&proto.ScanRequest{},
		&proto.EndTransactionRequest{},
		&proto.BatchRequest{},
		&proto.AdminSplitRequest{},
		&proto.AdminMergeRequest{},
		&proto.InternalHeartbeatTxnRequest{},
		&proto.InternalGCRequest{},
		&proto.InternalPushTxnRequest{},
		&proto.InternalRangeLookupRequest{},
		&proto.InternalResolveIntentRequest{},
		&proto.InternalResolveIntentRangeRequest{},
		&proto.InternalMergeRequest{},
		&proto.InternalTruncateLogRequest{},
		&proto.InternalLeaderLeaseRequest{},
		&proto.InternalBatchRequest{},
	}

	var readOnlyRequests []proto.Request
	var writeOnlyRequests []proto.Request
	var readWriteRequests []proto.Request

	for _, r := range allRequestTypes {
		if proto.IsRead(r) && !proto.IsWrite(r) {
			readOnlyRequests = append(readOnlyRequests, r)
		}
		if proto.IsWrite(r) && !proto.IsRead(r) {
			writeOnlyRequests = append(writeOnlyRequests, r)
		}
		if proto.IsRead(r) && proto.IsWrite(r) {
			readWriteRequests = append(readWriteRequests, r)
		}
	}

	testData := []struct {
		// Permission-based db methods from the storage package.
		requests         []proto.Request
		user             string
		startKey, endKey proto.Key
		hasPermission    bool
	}{
		// Test permissions within a single range
		{readOnlyRequests, "read1", proto.KeyMin, proto.KeyMin, true},
		{readOnlyRequests, "rw1", proto.KeyMin, proto.KeyMin, true},
		{readOnlyRequests, "write1", proto.KeyMin, proto.KeyMin, false},
		{readOnlyRequests, "random", proto.KeyMin, proto.KeyMin, false},
		{readWriteRequests, "rw1", proto.KeyMin, proto.KeyMin, true},
		{readWriteRequests, "read1", proto.KeyMin, proto.KeyMin, false},
		{readWriteRequests, "write1", proto.KeyMin, proto.KeyMin, false},
		{writeOnlyRequests, "write1", proto.KeyMin, proto.KeyMin, true},
		{writeOnlyRequests, "rw1", proto.KeyMin, proto.KeyMin, true},
		{writeOnlyRequests, "read1", proto.KeyMin, proto.KeyMin, false},
		{writeOnlyRequests, "random", proto.KeyMin, proto.KeyMin, false},
		// Test permissions hierarchically.
		{readOnlyRequests, "read1", proto.Key("a"), proto.Key("a1"), true},
		{readWriteRequests, "rw1", proto.Key("a"), proto.Key("a1"), true},
		{writeOnlyRequests, "write1", proto.Key("a"), proto.Key("a1"), true},
		// Test permissions across both ranges.
		{readOnlyRequests, "readAll", proto.KeyMin, proto.Key("b"), true},
		{readOnlyRequests, "read1", proto.KeyMin, proto.Key("b"), true},
		{readOnlyRequests, "read2", proto.KeyMin, proto.Key("b"), false},
		{readOnlyRequests, "random", proto.KeyMin, proto.Key("b"), false},
		{readWriteRequests, "rwAll", proto.KeyMin, proto.Key("b"), true},
		{readWriteRequests, "rw1", proto.KeyMin, proto.Key("b"), true},
		{readWriteRequests, "random", proto.KeyMin, proto.Key("b"), false},
		{writeOnlyRequests, "writeAll", proto.KeyMin, proto.Key("b"), true},
		{writeOnlyRequests, "write1", proto.KeyMin, proto.Key("b"), true},
		{writeOnlyRequests, "write2", proto.KeyMin, proto.Key("b"), false},
		{writeOnlyRequests, "random", proto.KeyMin, proto.Key("b"), false},
//.........這裏部分代碼省略.........