| // 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" |
| |
| "golang.org/x/net/trace" |
| ) |
| |
| 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 |
| |
| tr := trace.New("Sent."+name, method) |
| defer tr.Finish() |
| |
| 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. |
| tr.LazyPrintf("%s\n", err) |
| tr.SetError() |
| 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. |
| tr.LazyPrintf("%s\n", err) |
| tr.SetError() |
| return preferNonTimeout(err, prevErr) |
| case !backoff(retries, connOpts.connDeadline): |
| tr.LazyPrintf("%s\n", err) |
| tr.SetError() |
| return err |
| default: |
| ctx.VI(4).Infof("Retrying due to error: %s", err) |
| tr.LazyPrintf("%s\n", err) |
| tr.SetError() |
| } |
| 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 |
| } |