blob: 859d92f1298d46401908429bc234df6d5a9e765a [file] [log] [blame]
/*
* 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/google/uuid"
"github.com/opencord/voltha-go/common/log"
"google.golang.org/grpc"
)
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
}
//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() string {
return uuid.New().String()
}
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.NumOpenConnections() != 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].NumOpenConnections() > 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 requestFrame here since it holds the "context" of this communication
nf := &requestFrame{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 responseFrame here because it might be needed for return value intercept
sf := &responseFrame{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 *requestFrame) (*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 len(f.backend.openConns) == 0 {
err := fmt.Errorf("No open connections on backend '%s'", f.backend.name)
log.Error(err)
return f.backend, err
}
log.Debugf("Assigned backend %s", f.backend.name)
return f.backend, nil
}