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// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package rpc
import (
"fmt"
"io"
"math/rand"
"net"
"sync"
"time"
"v.io/v23"
"v.io/v23/context"
"v.io/v23/flow"
"v.io/v23/i18n"
"v.io/v23/naming"
"v.io/v23/rpc"
"v.io/v23/security"
vtime "v.io/v23/vdlroot/time"
"v.io/v23/verror"
"v.io/v23/vom"
"v.io/v23/vtrace"
"v.io/x/ref/lib/apilog"
slib "v.io/x/ref/lib/security"
"v.io/x/ref/runtime/internal/flow/conn"
"v.io/x/ref/runtime/internal/flow/manager"
)
const pkgPath = "v.io/x/ref/runtime/internal/rpc"
func reg(id, msg string) verror.IDAction {
// Note: the error action is never used and is instead computed
// at a higher level. The errors here are purely for informational
// purposes.
return verror.Register(verror.ID(pkgPath+id), verror.NoRetry, msg)
}
var (
// These errors are intended to be used as arguments to higher
// level errors and hence {1}{2} is omitted from their format
// strings to avoid repeating these n-times in the final error
// message visible to the user.
errClientCloseAlreadyCalled = reg(".errCloseAlreadyCalled", "rpc.Client.Close has already been called")
errClientFinishAlreadyCalled = reg(".errFinishAlreadyCalled", "rpc.ClientCall.Finish has already been called")
errNonRootedName = reg(".errNonRootedName", "{3} does not appear to contain an address")
errInvalidEndpoint = reg(".errInvalidEndpoint", "failed to parse endpoint")
errRequestEncoding = reg(".errRequestEncoding", "failed to encode request {3}{:4}")
errArgEncoding = reg(".errArgEncoding", "failed to encode arg #{3}{:4:}")
errMismatchedResults = reg(".errMismatchedResults", "got {3} results, but want {4}")
errResultDecoding = reg(".errResultDecoding", "failed to decode result #{3}{:4}")
errResponseDecoding = reg(".errResponseDecoding", "failed to decode response{:3}")
errRemainingStreamResults = reg(".errRemaingStreamResults", "stream closed with remaining stream results")
errBlessingGrant = reg(".errBlessingGrant", "failed to grant blessing to server with blessings{:3}")
errBlessingAdd = reg(".errBlessingAdd", "failed to add blessing granted to server{:3}")
errPeerAuthorizeFailed = reg(".errPeerAuthorizedFailed", "failed to authorize flow with remote blessings{:3} {:4}")
)
func isTimeout(err error) bool {
return verror.ErrorID(err) == verror.ErrTimeout.ID
}
func preferNonTimeout(curr, prev error) error {
if prev != nil && isTimeout(curr) {
return prev
}
return curr
}
const (
dataFlow = 'd'
typeFlow = 't'
)
type clientFlowManagerOpt struct {
mgr flow.Manager
}
func (clientFlowManagerOpt) RPCClientOpt() {}
type client struct {
flowMgr flow.Manager
preferredProtocols []string
ctx *context.T
outstanding *outstandingStats
// stop is kept for backward compatibilty to implement Close().
// TODO(mattr): deprecate Close.
stop func()
// typeCache maintains a cache of type encoders and decoders.
typeCache *typeCache
wg sync.WaitGroup
mu sync.Mutex
closing bool
closed chan struct{}
}
var _ rpc.Client = (*client)(nil)
func NewClient(ctx *context.T, opts ...rpc.ClientOpt) rpc.Client {
ctx, cancel := context.WithCancel(ctx)
statsPrefix := fmt.Sprintf("rpc/client/outstanding/%p", ctx)
c := &client{
ctx: ctx,
typeCache: newTypeCache(),
stop: cancel,
closed: make(chan struct{}),
outstanding: newOutstandingStats(statsPrefix),
}
connIdleExpiry := time.Duration(0)
for _, opt := range opts {
switch v := opt.(type) {
case PreferredProtocols:
c.preferredProtocols = v
case clientFlowManagerOpt:
c.flowMgr = v.mgr
case IdleConnectionExpiry:
connIdleExpiry = time.Duration(v)
}
}
if c.flowMgr == nil {
c.flowMgr = manager.New(ctx, naming.NullRoutingID, nil, 0, connIdleExpiry, nil)
}
go func() {
<-ctx.Done()
c.mu.Lock()
c.closing = true
c.mu.Unlock()
<-c.flowMgr.Closed()
c.wg.Wait()
c.outstanding.close()
close(c.closed)
c.typeCache.close()
}()
return c
}
func (c *client) StartCall(ctx *context.T, name, method string, args []interface{}, opts ...rpc.CallOpt) (rpc.ClientCall, error) {
defer apilog.LogCallf(ctx, "name=%.10s...,method=%.10s...,args=,opts...=%v", name, method, opts)(ctx, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
if !ctx.Initialized() {
return nil, verror.ExplicitNew(verror.ErrBadArg, i18n.LangID("en-us"), "<rpc.Client>", "StartCall", "context not initialized")
}
connOpts := getConnectionOptions(ctx, opts)
return c.startCall(ctx, name, method, args, connOpts, opts)
}
func (c *client) Call(ctx *context.T, name, method string, inArgs, outArgs []interface{}, opts ...rpc.CallOpt) error {
defer apilog.LogCallf(ctx, "name=%.10s...,method=%.10s...,inArgs=,outArgs=,opts...=%v", name, method, opts)(ctx, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
connOpts := getConnectionOptions(ctx, opts)
var prevErr error
for retries := uint(0); ; retries++ {
call, err := c.startCall(ctx, name, method, inArgs, connOpts, opts)
if err != nil {
// See explanation in connectToName.
return preferNonTimeout(err, prevErr)
}
switch err := call.Finish(outArgs...); {
case err == nil:
return nil
case !shouldRetryBackoff(verror.Action(err), connOpts):
ctx.VI(4).Infof("Cannot retry after error: %s", err)
// See explanation in connectToName.
return preferNonTimeout(err, prevErr)
case !backoff(retries, connOpts.connDeadline):
return err
default:
ctx.VI(4).Infof("Retrying due to error: %s", err)
}
prevErr = err
}
}
func (c *client) startCall(ctx *context.T, name, method string, args []interface{}, connOpts *connectionOpts, opts []rpc.CallOpt) (rpc.ClientCall, error) {
ctx, _ = vtrace.WithNewSpan(ctx, fmt.Sprintf("<rpc.Client>%q.%s", name, method))
r, err := c.connectToName(ctx, name, method, args, connOpts, opts)
if err != nil {
return nil, err
}
removeStat := c.outstanding.start(method, r.flow.RemoteEndpoint())
fc, err := newFlowClient(ctx, removeStat, r.flow, r.typeEnc, r.typeDec)
if err != nil {
return nil, err
}
if verr := fc.start(r.suffix, method, args, opts); verr != nil {
return nil, verr
}
return fc, nil
}
func (c *client) PinConnection(ctx *context.T, name string, opts ...rpc.CallOpt) (flow.PinnedConn, error) {
ctx, cancel := context.WithCancel(ctx)
connOpts := getConnectionOptions(ctx, opts)
r, err := c.connectToName(ctx, name, "", nil, connOpts, opts)
if err != nil {
cancel()
return nil, err
}
pinned := &pinnedConn{
cancel: cancel,
done: ctx.Done(),
conn: r.flow.Conn(),
}
c.wg.Add(1)
go c.reconnectPinnedConn(ctx, pinned, name, connOpts, opts...)
return pinned, nil
}
type pinnedConn struct {
cancel context.CancelFunc
done <-chan struct{}
mu sync.Mutex
conn flow.ManagedConn
}
func (p *pinnedConn) Conn() flow.ManagedConn {
defer p.mu.Unlock()
p.mu.Lock()
return p.conn
}
func (p *pinnedConn) Unpin() {
p.cancel()
}
func (c *client) reconnectPinnedConn(ctx *context.T, p *pinnedConn, name string, connOpts *connectionOpts, opts ...rpc.CallOpt) {
defer c.wg.Done()
delay := reconnectDelay
for {
p.mu.Lock()
closed := p.conn.Closed()
p.mu.Unlock()
select {
case <-closed:
r, err := c.connectToName(ctx, name, "", nil, connOpts, opts)
if err != nil {
time.Sleep(delay)
delay = nextDelay(delay)
} else {
delay = reconnectDelay
p.mu.Lock()
p.conn = r.flow.Conn()
closed = p.conn.Closed()
p.mu.Unlock()
}
case <-p.done:
// Reaching here means that the ctx passed to PinConnection is cancelled,
// so the flow on the conn created in PinConnection is closed here.
return
}
}
}
type serverStatus struct {
index int
server, suffix string
flow flow.Flow
serverErr *verror.SubErr
typeEnc *vom.TypeEncoder
typeDec *vom.TypeDecoder
}
// connectToName attempts to connect to the provided name. It may retry connecting
// to the servers the name resolves to based on the type of error encountered.
// Once connOpts.connDeadline is reached, it will stop retrying.
func (c *client) connectToName(ctx *context.T, name, method string, args []interface{}, connOpts *connectionOpts, opts []rpc.CallOpt) (*serverStatus, error) {
span := vtrace.GetSpan(ctx)
var prevErr error
for retries := uint(0); ; retries++ {
r, action, requireResolve, err := c.tryConnectToName(ctx, name, method, args, connOpts, opts)
switch {
case err == nil:
return r, nil
case !shouldRetry(action, requireResolve, connOpts, opts):
span.Annotatef("Cannot retry after error: %s", err)
span.Finish()
// If the latest error is a timeout, prefer the
// retryable error from the previous iteration, both to
// be consistent with what we'd return if backoff were
// to return false, and to give a more helpful error to
// the client (since the current timeout error is likely
// just a result of the context timing out).
return nil, preferNonTimeout(err, prevErr)
case !backoff(retries, connOpts.connDeadline):
span.Annotatef("Retries exhausted")
span.Finish()
return nil, err
default:
span.Annotatef("Retrying due to error: %s", err)
ctx.VI(2).Infof("Retrying due to error: %s", err)
}
prevErr = err
}
}
// tryConnectToName makes a single attempt in connecting to a name. It may
// connect to multiple servers (all that serve "name"), but will return a
// serverStatus for at most one of them (the server running on the most
// preferred protocol and network amongst all the servers that were successfully
// connected to and authorized).
// If requireResolve is true on return, then we shouldn't bother retrying unless
// you can re-resolve.
//
// TODO(toddw): Remove action from out-args, the error should tell us the action.
func (c *client) tryConnectToName(ctx *context.T, name, method string, args []interface{}, connOpts *connectionOpts, opts []rpc.CallOpt) (*serverStatus, verror.ActionCode, bool, error) {
blessingPattern, name := security.SplitPatternName(name)
resolved, err := v23.GetNamespace(ctx).Resolve(ctx, name, getNamespaceOpts(opts)...)
switch {
case verror.ErrorID(err) == naming.ErrNoSuchName.ID:
return nil, verror.RetryRefetch, false, verror.New(verror.ErrNoServers, ctx, name, err)
case verror.ErrorID(err) == verror.ErrNoServers.ID:
return nil, verror.NoRetry, false, err // avoid unnecessary wrapping
case isTimeout(err):
return nil, verror.NoRetry, false, err // return timeout without wrapping
case err != nil:
return nil, verror.NoRetry, false, verror.New(verror.ErrNoServers, ctx, name, err)
case len(resolved.Servers) == 0:
// This should never happen.
return nil, verror.NoRetry, true, verror.New(verror.ErrInternal, ctx, name)
}
if resolved.Servers, err = filterAndOrderServers(resolved.Servers, c.preferredProtocols); err != nil {
return nil, verror.RetryRefetch, true, verror.New(verror.ErrNoServers, ctx, name, err)
}
// servers is now ordered by the priority heurestic implemented in
// filterAndOrderServers.
//
// Try to connect to all servers in parallel. Provide sufficient
// buffering for all of the connections to finish instantaneously. This
// is important because we want to process the responses in priority
// order; that order is indicated by the order of entries in servers.
// So, if two respones come in at the same 'instant', we prefer the
// first in the resolved.Servers)
//
// TODO(toddw): Refactor the parallel dials so that the policy can be changed,
// and so that the goroutines for each Call are tracked separately.
responses := make([]*serverStatus, len(resolved.Servers))
ch := make(chan *serverStatus, len(resolved.Servers))
authorizer := newServerAuthorizer(blessingPattern, opts...)
peerAuth := peerAuthorizer{authorizer, method, args}
for i, server := range resolved.Names() {
c.mu.Lock()
if c.closing {
c.mu.Unlock()
return nil, verror.NoRetry, false, verror.New(errClientCloseAlreadyCalled, ctx)
}
c.wg.Add(1)
c.mu.Unlock()
go c.tryConnectToServer(ctx, i, name, server, method, args, peerAuth, connOpts, ch)
}
for {
// Block for at least one new response from the server, or the timeout.
select {
case r := <-ch:
responses[r.index] = r
// Read as many more responses as we can without blocking.
LoopNonBlocking:
for {
select {
default:
break LoopNonBlocking
case r := <-ch:
responses[r.index] = r
}
}
case <-ctx.Done():
return c.failedTryConnectToName(ctx, name, method, responses, ch)
}
// Process new responses, in priority order.
numResponses := 0
for _, r := range responses {
if r != nil {
numResponses++
}
if r == nil || r.flow == nil {
continue
}
// We must ensure that all flows other than r.flow are closed.
go cleanupTryConnectToName(r, responses, ch)
return r, verror.NoRetry, false, nil
}
if numResponses == len(responses) {
return c.failedTryConnectToName(ctx, name, method, responses, ch)
}
}
}
// tryConnectToServer attempts to establish a Flow to a single "server"
// (which must be a rooted name), over which a method invocation request
// could be sent.
//
// The server at the remote end of the flow is authorized using the provided
// authorizer, both during creation of the VC underlying the flow and the
// flow itself.
// TODO(cnicolaou): implement real, configurable load balancing.
func (c *client) tryConnectToServer(
ctx *context.T,
index int,
name, server, method string,
args []interface{},
auth flow.PeerAuthorizer,
connOpts *connectionOpts,
ch chan<- *serverStatus) {
defer c.wg.Done()
status := &serverStatus{index: index, server: server}
var span vtrace.Span
ctx, span = vtrace.WithNewSpan(ctx, "<client>tryConnectToServer "+server)
defer func() {
ch <- status
span.Finish()
}()
suberr := func(err error) *verror.SubErr {
return &verror.SubErr{
Name: suberrName(server, name, method),
Err: err,
Options: verror.Print,
}
}
address, suffix := naming.SplitAddressName(server)
if len(address) == 0 {
status.serverErr = suberr(verror.New(errNonRootedName, ctx, server))
return
}
status.suffix = suffix
ep, err := naming.ParseEndpoint(address)
if err != nil {
status.serverErr = suberr(verror.New(errInvalidEndpoint, ctx))
return
}
var flw flow.Flow
if connOpts.useOnlyCached {
flw, err = c.flowMgr.DialCached(ctx, ep, auth, connOpts.channelTimeout)
if err != nil {
ctx.VI(2).Infof("rpc: failed to find cached Conn to %v: %v", server, err)
status.serverErr = suberr(err)
return
}
} else {
flw, err = c.flowMgr.Dial(ctx, ep, auth, connOpts.channelTimeout)
if err != nil {
ctx.VI(2).Infof("rpc: failed to create Flow with %v: %v", server, err)
status.serverErr = suberr(err)
return
}
}
if write := c.typeCache.writer(flw.Conn()); write != nil {
// Create the type flow with a root-cancellable context.
// This flow must outlive the flow we're currently creating.
// It lives as long as the connection to which it is bound.
tctx, tcancel := context.WithRootCancel(ctx)
tflow, err := c.flowMgr.DialSideChannel(tctx, flw.RemoteEndpoint(), typeFlowAuthorizer{}, 0)
if err != nil {
write(nil, tcancel)
} else if tflow.Conn() != flw.Conn() {
tflow.Close()
write(nil, tcancel)
} else if _, err = tflow.Write([]byte{typeFlow}); err != nil {
tflow.Close()
write(nil, tcancel)
} else {
write(tflow, tcancel)
}
}
status.typeEnc, status.typeDec, err = c.typeCache.get(ctx, flw.Conn())
if err != nil {
status.serverErr = suberr(newErrTypeFlowFailure(ctx, err))
flw.Close()
return
}
status.flow = flw
}
// cleanupTryConnectToName ensures we've waited for every response from the tryConnectToServer
// goroutines, and have closed the flow from each one except skip. This is a
// blocking function; it should be called in its own goroutine.
func cleanupTryConnectToName(skip *serverStatus, responses []*serverStatus, ch chan *serverStatus) {
numPending := 0
for _, r := range responses {
switch {
case r == nil:
// The response hasn't arrived yet.
numPending++
case r == skip || r.flow == nil:
// Either we should skip this flow, or we've closed the flow for this
// response already; nothing more to do.
default:
// We received the response, but haven't closed the flow yet.
//
// TODO(toddw): Currently we only notice cancellation when we read or
// write the flow. Decide how to handle this.
r.flow.Close()
}
}
// Now we just need to wait for the pending responses and close their flows.
for i := 0; i < numPending; i++ {
if r := <-ch; r.flow != nil {
r.flow.Close()
}
}
}
// failedTryConnectToName performs asynchronous cleanup for connectToName, and returns an
// appropriate error from the responses we've already received. All parallel
// calls in tryConnectToName failed or we timed out if we get here.
func (c *client) failedTryConnectToName(ctx *context.T, name, method string, responses []*serverStatus, ch chan *serverStatus) (*serverStatus, verror.ActionCode, bool, error) {
go cleanupTryConnectToName(nil, responses, ch)
v23.GetNamespace(ctx).FlushCacheEntry(ctx, name)
suberrs := []verror.SubErr{}
topLevelError := verror.ErrNoServers
topLevelAction := verror.RetryRefetch
onlyErrNetwork := true
for _, r := range responses {
if r != nil && r.serverErr != nil && r.serverErr.Err != nil {
switch verror.ErrorID(r.serverErr.Err) {
case verror.ErrNotTrusted.ID, errPeerAuthorizeFailed.ID:
topLevelError = verror.ErrNotTrusted
topLevelAction = verror.NoRetry
onlyErrNetwork = false
case verror.ErrTimeout.ID:
topLevelError = verror.ErrTimeout
onlyErrNetwork = false
default:
onlyErrNetwork = false
}
suberrs = append(suberrs, *r.serverErr)
}
}
if onlyErrNetwork {
// If we only encountered network errors, then report ErrBadProtocol.
topLevelError = verror.ErrBadProtocol
}
switch ctx.Err() {
case context.Canceled:
topLevelError = verror.ErrCanceled
topLevelAction = verror.NoRetry
case context.DeadlineExceeded:
topLevelError = verror.ErrTimeout
topLevelAction = verror.NoRetry
default:
}
// TODO(cnicolaou): we get system errors for things like dialing using
// the 'ws' protocol which can never succeed even if we retry the connection,
// hence we return RetryRefetch below except for the case where the servers
// are not trusted, in case there's no point in retrying at all.
// TODO(cnicolaou): implementing at-most-once rpc semantics in the future
// will require thinking through all of the cases where the RPC can
// be retried by the client whilst it's actually being executed on the
// server.
return nil, topLevelAction, false, verror.AddSubErrs(verror.New(topLevelError, ctx), ctx, suberrs...)
}
func (c *client) Close() {
c.stop()
<-c.Closed()
}
func (c *client) Closed() <-chan struct{} {
return c.closed
}
// flowClient implements the RPC client-side protocol for a single RPC, over a
// flow that's already connected to the server.
type flowClient struct {
ctx *context.T // context to annotate with call details
flow *conn.BufferingFlow // the underlying flow
dec *vom.Decoder // to decode responses and results from the server
enc *vom.Encoder // to encode requests and args to the server
response rpc.Response // each decoded response message is kept here
remoteBNames []string
secCall security.Call
sendClosedMu sync.Mutex
sendClosed bool // is the send side already closed? GUARDED_BY(sendClosedMu)
finished bool // has Finish() already been called?
removeStat func()
}
var _ rpc.ClientCall = (*flowClient)(nil)
var _ rpc.Stream = (*flowClient)(nil)
func newFlowClient(ctx *context.T, removeStat func(), flow flow.Flow, typeEnc *vom.TypeEncoder, typeDec *vom.TypeDecoder) (*flowClient, error) {
bf := conn.NewBufferingFlow(ctx, flow)
if _, err := bf.Write([]byte{dataFlow}); err != nil {
flow.Close()
removeStat()
return nil, err
}
fc := &flowClient{
ctx: ctx,
flow: bf,
dec: vom.NewDecoderWithTypeDecoder(bf, typeDec),
enc: vom.NewEncoderWithTypeEncoder(bf, typeEnc),
removeStat: removeStat,
}
return fc, nil
}
func (fc *flowClient) Conn() flow.ManagedConn {
return fc.flow.Conn()
}
// close determines the appropriate error to return, in particular,
// if a timeout or cancelation has occured then any error
// is turned into a timeout or cancelation as appropriate.
// Cancelation takes precedence over timeout. This is needed because
// a timeout can lead to any other number of errors due to the underlying
// network connection being shutdown abruptly.
func (fc *flowClient) close(err error) error {
fc.removeStat()
if err == nil {
return nil
}
subErr := verror.SubErr{Err: err, Options: verror.Print}
subErr.Name = "remote=" + fc.flow.RemoteEndpoint().String()
if cerr := fc.flow.Close(); cerr != nil && err == nil {
// TODO(mattr): The context is often already canceled here, in
// which case we'll get an error. Not clear what to do.
//return verror.New(verror.ErrInternal, fc.ctx, subErr)
}
switch verror.ErrorID(err) {
case verror.ErrCanceled.ID:
return err
case verror.ErrTimeout.ID:
// Canceled trumps timeout.
if fc.ctx.Err() == context.Canceled {
return verror.AddSubErrs(verror.New(verror.ErrCanceled, fc.ctx), fc.ctx, subErr)
}
return err
default:
switch fc.ctx.Err() {
case context.DeadlineExceeded:
timeout := verror.New(verror.ErrTimeout, fc.ctx)
err := verror.AddSubErrs(timeout, fc.ctx, subErr)
return err
case context.Canceled:
canceled := verror.New(verror.ErrCanceled, fc.ctx)
err := verror.AddSubErrs(canceled, fc.ctx, subErr)
return err
}
}
switch verror.ErrorID(err) {
case errRequestEncoding.ID, errArgEncoding.ID, errResponseDecoding.ID:
return verror.New(verror.ErrBadProtocol, fc.ctx, err)
}
return err
}
func (fc *flowClient) start(suffix, method string, args []interface{}, opts []rpc.CallOpt) error {
grantedB, err := fc.initSecurity(fc.ctx, method, suffix, opts)
if err != nil {
berr := verror.New(verror.ErrNotTrusted, fc.ctx, err)
return fc.close(berr)
}
deadline, _ := fc.ctx.Deadline()
req := rpc.Request{
Suffix: suffix,
Method: method,
NumPosArgs: uint64(len(args)),
Deadline: vtime.Deadline{Time: deadline},
GrantedBlessings: grantedB,
TraceRequest: vtrace.GetRequest(fc.ctx),
Language: string(i18n.GetLangID(fc.ctx)),
}
if err := fc.enc.Encode(req); err != nil {
berr := verror.New(verror.ErrBadProtocol, fc.ctx, verror.New(errRequestEncoding, fc.ctx, fmt.Sprintf("%#v", req), err))
return fc.close(berr)
}
for ix, arg := range args {
if err := fc.enc.Encode(arg); err != nil {
berr := verror.New(errArgEncoding, fc.ctx, ix, err)
return fc.close(berr)
}
}
return fc.flow.Flush()
}
func (fc *flowClient) initSecurity(ctx *context.T, method, suffix string, opts []rpc.CallOpt) (security.Blessings, error) {
// The "Method" and "Suffix" fields of the call are not populated
// as they are considered irrelevant for authorizing server blessings.
// (This makes the call used here consistent with
// peerAuthorizer.AuthorizePeer that is used during Conn creation)
callparams := &security.CallParams{
LocalPrincipal: v23.GetPrincipal(ctx),
LocalBlessings: fc.flow.LocalBlessings(),
RemoteBlessings: fc.flow.RemoteBlessings(),
LocalEndpoint: fc.flow.LocalEndpoint(),
RemoteEndpoint: fc.flow.RemoteEndpoint(),
LocalDischarges: fc.flow.LocalDischarges(),
RemoteDischarges: fc.flow.RemoteDischarges(),
}
call := security.NewCall(callparams)
var grantedB security.Blessings
for _, o := range opts {
switch v := o.(type) {
case rpc.Granter:
if b, err := v.Grant(ctx, call); err != nil {
return grantedB, verror.New(errBlessingGrant, fc.ctx, err)
} else if grantedB, err = security.UnionOfBlessings(grantedB, b); err != nil {
return grantedB, verror.New(errBlessingAdd, fc.ctx, err)
}
}
}
// TODO(suharshs): Its unfortunate that we compute these here and also in the
// peerAuthorizer struct. Find a way to only do this once.
fc.remoteBNames, _ = security.RemoteBlessingNames(ctx, call)
// Going forward though, we can provide the security.Call with Method and Suffix
callparams.Method = method
callparams.Suffix = suffix
fc.secCall = security.NewCall(callparams)
return grantedB, nil
}
func (fc *flowClient) Send(item interface{}) error {
defer apilog.LogCallf(nil, "item=")(nil, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
if fc.sendClosed {
return verror.New(verror.ErrAborted, fc.ctx)
}
// The empty request header indicates what follows is a streaming arg.
if err := fc.enc.Encode(rpc.Request{}); err != nil {
return fc.close(verror.New(errRequestEncoding, fc.ctx, rpc.Request{}, err))
}
if err := fc.enc.Encode(item); err != nil {
return fc.close(verror.New(errArgEncoding, fc.ctx, -1, err))
}
return fc.flow.Flush()
}
func (fc *flowClient) Recv(itemptr interface{}) error {
defer apilog.LogCallf(nil, "itemptr=")(nil, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
switch {
case fc.response.Error != nil:
return verror.New(verror.ErrBadProtocol, fc.ctx, fc.response.Error)
case fc.response.EndStreamResults:
return io.EOF
}
// Decode the response header and handle errors and EOF.
if err := fc.dec.Decode(&fc.response); err != nil {
id, verr := decodeNetError(fc.ctx, err)
berr := verror.New(id, fc.ctx, verror.New(errResponseDecoding, fc.ctx, verr))
return fc.close(berr)
}
if fc.response.Error != nil {
return fc.response.Error
}
if fc.response.EndStreamResults {
// Return EOF to indicate to the caller that there are no more stream
// results. Any error sent by the server is kept in fc.response.Error, and
// returned to the user in Finish.
return io.EOF
}
// Decode the streaming result.
if err := fc.dec.Decode(itemptr); err != nil {
id, verr := decodeNetError(fc.ctx, err)
berr := verror.New(id, fc.ctx, verror.New(errResponseDecoding, fc.ctx, verr))
// TODO(cnicolaou): should we be caching this?
fc.response.Error = berr
return fc.close(berr)
}
return nil
}
func (fc *flowClient) CloseSend() error {
defer apilog.LogCall(nil)(nil) // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
return fc.closeSend()
}
func (fc *flowClient) closeSend() error {
fc.sendClosedMu.Lock()
defer fc.sendClosedMu.Unlock()
if fc.sendClosed {
return nil
}
if err := fc.enc.Encode(rpc.Request{EndStreamArgs: true}); err != nil {
// TODO(caprita): Indiscriminately closing the flow below causes
// a race as described in:
// https://docs.google.com/a/google.com/document/d/1C0kxfYhuOcStdV7tnLZELZpUhfQCZj47B0JrzbE29h8/edit
//
// There should be a finer grained way to fix this (for example,
// encoding errors should probably still result in closing the
// flow); on the flip side, there may exist other instances
// where we are closing the flow but should not.
//
// For now, commenting out the line below removes the flakiness
// from our existing unit tests, but this needs to be revisited
// and fixed correctly.
//
// return fc.close(verror.ErrBadProtocolf("rpc: end stream args encoding failed: %v", err))
}
// We ignore the error on this flush for the same reason we ignore the error above.
fc.flow.Flush()
fc.sendClosed = true
return nil
}
// TODO(toddw): Should we require Finish to be called, even if send or recv
// return an error?
func (fc *flowClient) Finish(resultptrs ...interface{}) error {
defer apilog.LogCallf(nil, "resultptrs...=%v", resultptrs)(nil, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
defer vtrace.GetSpan(fc.ctx).Finish()
if fc.finished {
err := verror.New(errClientFinishAlreadyCalled, fc.ctx)
return fc.close(verror.New(verror.ErrBadState, fc.ctx, err))
}
fc.finished = true
// Call closeSend implicitly, if the user hasn't already called it. There are
// three cases:
// 1) Server is blocked on Recv waiting for the final request message.
// 2) Server has already finished processing, the final response message and
// out args are queued up on the client, and the flow is closed.
// 3) Between 1 and 2: the server isn't blocked on Recv, but the final
// response and args aren't queued up yet, and the flow isn't closed.
//
// We must call closeSend to handle case (1) and unblock the server; otherwise
// we'll deadlock with both client and server waiting for each other. We must
// ignore the error (if any) to handle case (2). In that case the flow is
// closed, meaning writes will fail and reads will succeed, and closeSend will
// always return an error. But this isn't a "real" error; the client should
// read the rest of the results and succeed.
_ = fc.closeSend()
// Decode the response header, if it hasn't already been decoded by Recv.
if fc.response.Error == nil && !fc.response.EndStreamResults {
if err := fc.dec.Decode(&fc.response); err != nil {
id, verr := decodeNetError(fc.ctx, err)
berr := verror.New(id, fc.ctx, verror.New(errResponseDecoding, fc.ctx, verr))
return fc.close(berr)
}
// The response header must indicate the streaming results have ended.
if fc.response.Error == nil && !fc.response.EndStreamResults {
berr := verror.New(errRemainingStreamResults, fc.ctx)
return fc.close(berr)
}
}
// Incorporate any VTrace info that was returned.
vtrace.GetStore(fc.ctx).Merge(fc.response.TraceResponse)
if fc.response.Error != nil {
id := verror.ErrorID(fc.response.Error)
if id == verror.ErrNoAccess.ID {
// In case the error was caused by a bad discharge, we do not want to get stuck
// with retrying again and again with this discharge. As there is no direct way
// to detect it, we conservatively flush all discharges we used from the cache.
// TODO(ataly,andreser): add verror.BadDischarge and handle it explicitly?
l := len(fc.flow.LocalDischarges())
dis := make([]security.Discharge, 0, l)
for _, d := range fc.flow.LocalDischarges() {
dis = append(dis, d)
}
fc.ctx.VI(3).Infof("Discarding %d discharges as RPC failed with %v", l, fc.response.Error)
v23.GetPrincipal(fc.ctx).BlessingStore().ClearDischarges(dis...)
}
if id == errBadNumInputArgs.ID || id == errBadInputArg.ID {
return fc.close(verror.New(verror.ErrBadProtocol, fc.ctx, fc.response.Error))
}
return fc.close(verror.Convert(verror.ErrInternal, fc.ctx, fc.response.Error))
}
if got, want := fc.response.NumPosResults, uint64(len(resultptrs)); got != want {
berr := verror.New(verror.ErrBadProtocol, fc.ctx, verror.New(errMismatchedResults, fc.ctx, got, want))
return fc.close(berr)
}
for ix, r := range resultptrs {
if err := fc.dec.Decode(r); err != nil {
id, verr := decodeNetError(fc.ctx, err)
berr := verror.New(id, fc.ctx, verror.New(errResultDecoding, fc.ctx, ix, verr))
return fc.close(berr)
}
}
fc.close(nil)
return nil
}
func (fc *flowClient) RemoteBlessings() ([]string, security.Blessings) {
defer apilog.LogCall(nil)(nil) // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
return fc.remoteBNames, fc.flow.RemoteBlessings()
}
func (fc *flowClient) Security() security.Call {
defer apilog.LogCall(nil)(nil) // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
return fc.secCall
}
type typeFlowAuthorizer struct{}
func (a typeFlowAuthorizer) AuthorizePeer(
ctx *context.T,
localEP, remoteEP naming.Endpoint,
remoteBlessings security.Blessings,
remoteDischarges map[string]security.Discharge) ([]string, []security.RejectedBlessing, error) {
return nil, nil, nil
}
func (a typeFlowAuthorizer) BlessingsForPeer(ctx *context.T, peerNames []string) (
security.Blessings, map[string]security.Discharge, error) {
return security.Blessings{}, nil, nil
}
type peerAuthorizer struct {
auth security.Authorizer
method string
args []interface{}
}
func (x peerAuthorizer) AuthorizePeer(
ctx *context.T,
localEP, remoteEP naming.Endpoint,
remoteBlessings security.Blessings,
remoteDischarges map[string]security.Discharge) ([]string, []security.RejectedBlessing, error) {
localPrincipal := v23.GetPrincipal(ctx)
// The "Method" and "Suffix" fields of the call are not populated
// as they are considered irrelevant for authorizing server blessings.
call := security.NewCall(&security.CallParams{
Timestamp: time.Now(),
LocalPrincipal: localPrincipal,
LocalEndpoint: localEP,
RemoteBlessings: remoteBlessings,
RemoteDischarges: remoteDischarges,
RemoteEndpoint: remoteEP,
})
if err := x.auth.Authorize(ctx, call); err != nil {
return nil, nil, verror.New(errPeerAuthorizeFailed, ctx, call.RemoteBlessings(), err)
}
peerNames, rejectedPeerNames := security.RemoteBlessingNames(ctx, call)
return peerNames, rejectedPeerNames, nil
}
func (x peerAuthorizer) BlessingsForPeer(ctx *context.T, peerNames []string) (
security.Blessings, map[string]security.Discharge, error) {
localPrincipal := v23.GetPrincipal(ctx)
clientB := localPrincipal.BlessingStore().ForPeer(peerNames...)
dis, _ := slib.PrepareDischarges(ctx, clientB, peerNames, x.method, x.args)
return clientB, dis, nil
}
func shouldRetryBackoff(action verror.ActionCode, connOpts *connectionOpts) bool {
switch {
case connOpts.noRetry:
return false
case action != verror.RetryBackoff:
return false
case time.Now().After(connOpts.connDeadline):
return false
}
return true
}
func shouldRetry(action verror.ActionCode, requireResolve bool, connOpts *connectionOpts, opts []rpc.CallOpt) bool {
switch {
case connOpts.noRetry:
return false
case connOpts.useOnlyCached:
// If we should only used cached connections, it doesn't make sense to retry
// looking in the cache.
return false
case action != verror.RetryConnection && action != verror.RetryRefetch:
return false
case time.Now().After(connOpts.connDeadline):
return false
case requireResolve && getNoNamespaceOpt(opts):
// If we're skipping resolution and there are no servers for
// this call retrying is not going to help, we can't come up
// with new servers if there is no resolution.
return false
}
return true
}
// A randomized exponential backoff. The randomness deters error convoys
// from forming. The first time you retry n should be 0, then 1 etc.
func backoff(n uint, deadline time.Time) bool {
// This is ((100 to 200) * 2^n) ms.
b := time.Duration((100+rand.Intn(100))<<n) * time.Millisecond
if b > maxBackoff {
b = maxBackoff
}
r := deadline.Sub(time.Now())
// We need to budget some time for the call to have a chance to complete
// lest we'll timeout before we actually do anything. If we just don't
// have enough time left, give up.
//
// The value should cover a sensible call duration (which includes name
// resolution and the actual server RPC) on most supported platforms;
// use https://vanadium.github.io/performance.html for inspiration.
const reserveTime = 100 * time.Millisecond
if r <= reserveTime {
return false
}
r -= reserveTime
if b > r {
b = r
}
time.Sleep(b)
return true
}
func suberrName(server, name, method string) string {
// In the case the client directly dialed an endpoint we want to avoid printing
// the endpoint twice.
if server == name {
return fmt.Sprintf("%s.%s", server, method)
}
return fmt.Sprintf("%s:%s.%s", server, name, method)
}
// decodeNetError tests for a net.Error from the lower stream code and
// translates it into an appropriate error to be returned by the higher level
// RPC api calls. It also tests for the net.Error being a stream.NetError
// and if so, uses the error it stores rather than the stream.NetError itself
// as its retrun value. This allows for the stack trace of the original
// error to be chained to that of any verror created with it as a first parameter.
func decodeNetError(ctx *context.T, err error) (verror.IDAction, error) {
if neterr, ok := err.(net.Error); ok {
if neterr.Timeout() || neterr.Temporary() {
// If a read is canceled in the lower levels we see
// a timeout error - see readLocked in vc/reader.go
if ctx.Err() == context.Canceled {
return verror.ErrCanceled, err
}
return verror.ErrTimeout, err
}
}
if id := verror.ErrorID(err); id != verror.ErrUnknown.ID {
return verror.IDAction{
ID: id,
Action: verror.Action(err),
}, err
}
return verror.ErrBadProtocol, err
}