| /* |
| * Copyright 2019-present Open Networking Foundation |
| |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package afrouter |
| |
| import ( |
| "errors" |
| "fmt" |
| "github.com/opencord/voltha-go/common/log" |
| "google.golang.org/grpc" |
| "sync/atomic" |
| ) |
| |
| var clusters = make(map[string]*cluster) |
| |
| // cluster a collection of HA backends |
| type cluster struct { |
| name string |
| //backends map[string]*backend |
| backends []*backend |
| backendIDMap map[*backend]int |
| serialNoCounter uint64 |
| } |
| |
| //TODO: Move the backend type (active/active etc) to the cluster |
| // level. All backends should really be of the same type. |
| // Create a new backend cluster |
| func newBackendCluster(conf *BackendClusterConfig) (*cluster, error) { |
| var err error = nil |
| var rtrn_err = false |
| var be *backend |
| log.Debugf("Creating a backend cluster with %v", conf) |
| // Validate the configuration |
| if conf.Name == "" { |
| log.Error("A backend cluster must have a name") |
| rtrn_err = true |
| } |
| //bc := &cluster{name:conf.Name,backends:make(map[string]*backend)} |
| bc := &cluster{name: conf.Name, backendIDMap: make(map[*backend]int)} |
| clusters[bc.name] = bc |
| idx := 0 |
| for _, bec := range conf.Backends { |
| if bec.Name == "" { |
| log.Errorf("A backend must have a name in cluster %s\n", conf.Name) |
| rtrn_err = true |
| } |
| if be, err = newBackend(&bec, conf.Name); err != nil { |
| log.Errorf("Error creating backend %s", bec.Name) |
| rtrn_err = true |
| } |
| bc.backends = append(bc.backends, be) |
| bc.backendIDMap[bc.backends[idx]] = idx |
| idx++ |
| } |
| if rtrn_err { |
| return nil, errors.New("Error creating backend(s)") |
| } |
| return bc, nil |
| } |
| |
| func (c *cluster) getBackend(name string) *backend { |
| for _, v := range c.backends { |
| if v.name == name { |
| return v |
| } |
| } |
| return nil |
| } |
| |
| func (c *cluster) allocateSerialNumber() uint64 { |
| return atomic.AddUint64(&c.serialNoCounter, 1) - 1 |
| } |
| |
| func (c *cluster) nextBackend(be *backend, seq backendSequence) (*backend, error) { |
| switch seq { |
| case BackendSequenceRoundRobin: // Round robin |
| in := be |
| // If no backend is found having a connection |
| // then return nil. |
| if be == nil { |
| log.Debug("Previous backend is nil") |
| be = c.backends[0] |
| in = be |
| if be.openConns != 0 { |
| return be, nil |
| } |
| } |
| for { |
| log.Debugf("Requesting a new backend starting from %s", be.name) |
| cur := c.backendIDMap[be] |
| cur++ |
| if cur >= len(c.backends) { |
| cur = 0 |
| } |
| log.Debugf("Next backend is %d:%s", cur, c.backends[cur].name) |
| if c.backends[cur].openConns > 0 { |
| return c.backends[cur], nil |
| } |
| if c.backends[cur] == in { |
| err := fmt.Errorf("No backend with open connections found") |
| log.Debug(err) |
| return nil, err |
| } |
| be = c.backends[cur] |
| log.Debugf("Backend '%s' has no open connections, trying next", c.backends[cur].name) |
| } |
| default: // Invalid, default to round robin |
| log.Errorf("Invalid backend sequence %d. Defaulting to round robin", seq) |
| return c.nextBackend(be, BackendSequenceRoundRobin) |
| } |
| } |
| |
| func (c *cluster) handler(srv interface{}, serverStream grpc.ServerStream, r Router, methodInfo methodDetails, |
| mk string, mv string) error { |
| //func (c *cluster) handler(nbR * nbRequest) error { |
| |
| // The final backend cluster needs to be determined here. With non-affinity routed backends it could |
| // just be determined here and for affinity routed backends the first message must be received |
| // before the backend is determined. In order to keep things simple, the same approach is taken for |
| // now. |
| |
| // Get the backend to use. |
| // Allocate the nbFrame here since it holds the "context" of this communication |
| nf := &nbFrame{router: r, methodInfo: methodInfo, serialNo: c.allocateSerialNumber(), metaKey: mk, metaVal: mv} |
| log.Debugf("Nb frame allocate with method %s", nf.methodInfo.method) |
| |
| if be, err := c.assignBackend(serverStream, nf); err != nil { |
| // At this point, no backend streams have been initiated |
| // so just return the error. |
| return err |
| } else { |
| log.Debugf("Backend '%s' selected", be.name) |
| // Allocate a sbFrame here because it might be needed for return value intercept |
| sf := &sbFrame{router: r, backend: be, method: nf.methodInfo.method, metaKey: mk, metaVal: mv} |
| log.Debugf("Sb frame allocated with router %s", r.Name()) |
| return be.handler(srv, serverStream, nf, sf) |
| } |
| } |
| |
| func (c *cluster) assignBackend(src grpc.ServerStream, f *nbFrame) (*backend, error) { |
| // Receive the first message from the server. This calls the assigned codec in which |
| // Unmarshal gets executed. That will use the assigned router to select a backend |
| // and add it to the frame |
| if err := src.RecvMsg(f); err != nil { |
| return nil, err |
| } |
| // Check that the backend was routable and actually has connections open. |
| // If it doesn't then return a nil backend to indicate this |
| if f.backend == nil { |
| err := fmt.Errorf("Unable to route method '%s'", f.methodInfo.method) |
| log.Error(err) |
| return nil, err |
| } else if f.backend.openConns == 0 { |
| err := fmt.Errorf("No open connections on backend '%s'", f.backend.name) |
| log.Error(err) |
| return f.backend, err |
| } |
| return f.backend, nil |
| } |