Add unit tests

This commit is contained in:
Mayuresh Gaitonde
2020-12-17 17:25:53 -08:00
parent 3702339f44
commit 6be4d69d02
705 changed files with 120529 additions and 150051 deletions

View File

@@ -21,14 +21,18 @@
package balancer
import (
"context"
"encoding/json"
"errors"
"net"
"strings"
"golang.org/x/net/context"
"google.golang.org/grpc/connectivity"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/internal"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/resolver"
"google.golang.org/grpc/serviceconfig"
)
var (
@@ -37,7 +41,10 @@ var (
)
// Register registers the balancer builder to the balancer map. b.Name
// (lowercased) will be used as the name registered with this builder.
// (lowercased) will be used as the name registered with this builder. If the
// Builder implements ConfigParser, ParseConfig will be called when new service
// configs are received by the resolver, and the result will be provided to the
// Balancer in UpdateClientConnState.
//
// NOTE: this function must only be called during initialization time (i.e. in
// an init() function), and is not thread-safe. If multiple Balancers are
@@ -46,8 +53,20 @@ func Register(b Builder) {
m[strings.ToLower(b.Name())] = b
}
// unregisterForTesting deletes the balancer with the given name from the
// balancer map.
//
// This function is not thread-safe.
func unregisterForTesting(name string) {
delete(m, name)
}
func init() {
internal.BalancerUnregister = unregisterForTesting
}
// Get returns the resolver builder registered with the given name.
// Note that the compare is done in a case-insenstive fashion.
// Note that the compare is done in a case-insensitive fashion.
// If no builder is register with the name, nil will be returned.
func Get(name string) Builder {
if b, ok := m[strings.ToLower(name)]; ok {
@@ -88,7 +107,24 @@ type SubConn interface {
}
// NewSubConnOptions contains options to create new SubConn.
type NewSubConnOptions struct{}
type NewSubConnOptions struct {
// CredsBundle is the credentials bundle that will be used in the created
// SubConn. If it's nil, the original creds from grpc DialOptions will be
// used.
CredsBundle credentials.Bundle
// HealthCheckEnabled indicates whether health check service should be
// enabled on this SubConn
HealthCheckEnabled bool
}
// State contains the balancer's state relevant to the gRPC ClientConn.
type State struct {
// State contains the connectivity state of the balancer, which is used to
// determine the state of the ClientConn.
ConnectivityState connectivity.State
// Picker is used to choose connections (SubConns) for RPCs.
Picker V2Picker
}
// ClientConn represents a gRPC ClientConn.
//
@@ -105,17 +141,28 @@ type ClientConn interface {
// The SubConn will be shutdown.
RemoveSubConn(SubConn)
// UpdateBalancerState is called by balancer to nofity gRPC that some internal
// UpdateBalancerState is called by balancer to notify gRPC that some internal
// state in balancer has changed.
//
// gRPC will update the connectivity state of the ClientConn, and will call pick
// on the new picker to pick new SubConn.
//
// Deprecated: use UpdateState instead
UpdateBalancerState(s connectivity.State, p Picker)
// UpdateState notifies gRPC that the balancer's internal state has
// changed.
//
// gRPC will update the connectivity state of the ClientConn, and will call pick
// on the new picker to pick new SubConns.
UpdateState(State)
// ResolveNow is called by balancer to notify gRPC to do a name resolving.
ResolveNow(resolver.ResolveNowOption)
ResolveNow(resolver.ResolveNowOptions)
// Target returns the dial target for this ClientConn.
//
// Deprecated: Use the Target field in the BuildOptions instead.
Target() string
}
@@ -125,12 +172,18 @@ type BuildOptions struct {
// use to dial to a remote load balancer server. The Balancer implementations
// can ignore this if it does not need to talk to another party securely.
DialCreds credentials.TransportCredentials
// CredsBundle is the credentials bundle that the Balancer can use.
CredsBundle credentials.Bundle
// Dialer is the custom dialer the Balancer implementation can use to dial
// to a remote load balancer server. The Balancer implementations
// can ignore this if it doesn't need to talk to remote balancer.
Dialer func(context.Context, string) (net.Conn, error)
// ChannelzParentID is the entity parent's channelz unique identification number.
ChannelzParentID int64
// Target contains the parsed address info of the dial target. It is the same resolver.Target as
// passed to the resolver.
// See the documentation for the resolver.Target type for details about what it contains.
Target resolver.Target
}
// Builder creates a balancer.
@@ -142,21 +195,39 @@ type Builder interface {
Name() string
}
// PickOptions contains addition information for the Pick operation.
type PickOptions struct {
// ConfigParser parses load balancer configs.
type ConfigParser interface {
// ParseConfig parses the JSON load balancer config provided into an
// internal form or returns an error if the config is invalid. For future
// compatibility reasons, unknown fields in the config should be ignored.
ParseConfig(LoadBalancingConfigJSON json.RawMessage) (serviceconfig.LoadBalancingConfig, error)
}
// PickInfo contains additional information for the Pick operation.
type PickInfo struct {
// FullMethodName is the method name that NewClientStream() is called
// with. The canonical format is /service/Method.
FullMethodName string
// Ctx is the RPC's context, and may contain relevant RPC-level information
// like the outgoing header metadata.
Ctx context.Context
}
// DoneInfo contains additional information for done.
type DoneInfo struct {
// Err is the rpc error the RPC finished with. It could be nil.
Err error
// Trailer contains the metadata from the RPC's trailer, if present.
Trailer metadata.MD
// BytesSent indicates if any bytes have been sent to the server.
BytesSent bool
// BytesReceived indicates if any byte has been received from the server.
BytesReceived bool
// ServerLoad is the load received from server. It's usually sent as part of
// trailing metadata.
//
// The only supported type now is *orca_v1.LoadReport.
ServerLoad interface{}
}
var (
@@ -165,7 +236,7 @@ var (
ErrNoSubConnAvailable = errors.New("no SubConn is available")
// ErrTransientFailure indicates all SubConns are in TransientFailure.
// WaitForReady RPCs will block, non-WaitForReady RPCs will fail.
ErrTransientFailure = errors.New("all SubConns are in TransientFailure")
ErrTransientFailure = TransientFailureError(errors.New("all SubConns are in TransientFailure"))
)
// Picker is used by gRPC to pick a SubConn to send an RPC.
@@ -173,6 +244,8 @@ var (
// internal state has changed.
//
// The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
//
// Deprecated: use V2Picker instead
type Picker interface {
// Pick returns the SubConn to be used to send the RPC.
// The returned SubConn must be one returned by NewSubConn().
@@ -186,22 +259,83 @@ type Picker interface {
//
// If a SubConn is returned:
// - If it is READY, gRPC will send the RPC on it;
// - If it is not ready, or becomes not ready after it's returned, gRPC will block
// until UpdateBalancerState() is called and will call pick on the new picker.
// - If it is not ready, or becomes not ready after it's returned, gRPC will
// block until UpdateBalancerState() is called and will call pick on the
// new picker. The done function returned from Pick(), if not nil, will be
// called with nil error, no bytes sent and no bytes received.
//
// If the returned error is not nil:
// - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState()
// - If the error is ErrTransientFailure:
// - If the error is ErrTransientFailure or implements IsTransientFailure()
// bool, returning true:
// - If the RPC is wait-for-ready, gRPC will block until UpdateBalancerState()
// is called to pick again;
// - Otherwise, RPC will fail with unavailable error.
// - Else (error is other non-nil error):
// - The RPC will fail with unavailable error.
// - The RPC will fail with the error's status code, or Unknown if it is
// not a status error.
//
// The returned done() function will be called once the rpc has finished, with the
// final status of that RPC.
// done may be nil if balancer doesn't care about the RPC status.
Pick(ctx context.Context, opts PickOptions) (conn SubConn, done func(DoneInfo), err error)
// The returned done() function will be called once the rpc has finished,
// with the final status of that RPC. If the SubConn returned is not a
// valid SubConn type, done may not be called. done may be nil if balancer
// doesn't care about the RPC status.
Pick(ctx context.Context, info PickInfo) (conn SubConn, done func(DoneInfo), err error)
}
// PickResult contains information related to a connection chosen for an RPC.
type PickResult struct {
// SubConn is the connection to use for this pick, if its state is Ready.
// If the state is not Ready, gRPC will block the RPC until a new Picker is
// provided by the balancer (using ClientConn.UpdateState). The SubConn
// must be one returned by ClientConn.NewSubConn.
SubConn SubConn
// Done is called when the RPC is completed. If the SubConn is not ready,
// this will be called with a nil parameter. If the SubConn is not a valid
// type, Done may not be called. May be nil if the balancer does not wish
// to be notified when the RPC completes.
Done func(DoneInfo)
}
type transientFailureError struct {
error
}
func (e *transientFailureError) IsTransientFailure() bool { return true }
// TransientFailureError wraps err in an error implementing
// IsTransientFailure() bool, returning true.
func TransientFailureError(err error) error {
return &transientFailureError{error: err}
}
// V2Picker is used by gRPC to pick a SubConn to send an RPC.
// Balancer is expected to generate a new picker from its snapshot every time its
// internal state has changed.
//
// The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
type V2Picker interface {
// Pick returns the connection to use for this RPC and related information.
//
// Pick should not block. If the balancer needs to do I/O or any blocking
// or time-consuming work to service this call, it should return
// ErrNoSubConnAvailable, and the Pick call will be repeated by gRPC when
// the Picker is updated (using ClientConn.UpdateState).
//
// If an error is returned:
//
// - If the error is ErrNoSubConnAvailable, gRPC will block until a new
// Picker is provided by the balancer (using ClientConn.UpdateState).
//
// - If the error implements IsTransientFailure() bool, returning true,
// wait for ready RPCs will wait, but non-wait for ready RPCs will be
// terminated with this error's Error() string and status code
// Unavailable.
//
// - Any other errors terminate all RPCs with the code and message
// provided. If the error is not a status error, it will be converted by
// gRPC to a status error with code Unknown.
Pick(info PickInfo) (PickResult, error)
}
// Balancer takes input from gRPC, manages SubConns, and collects and aggregates
@@ -219,26 +353,74 @@ type Balancer interface {
// that back to gRPC.
// Balancer should also generate and update Pickers when its internal state has
// been changed by the new state.
//
// Deprecated: if V2Balancer is implemented by the Balancer,
// UpdateSubConnState will be called instead.
HandleSubConnStateChange(sc SubConn, state connectivity.State)
// HandleResolvedAddrs is called by gRPC to send updated resolved addresses to
// balancers.
// Balancer can create new SubConn or remove SubConn with the addresses.
// An empty address slice and a non-nil error will be passed if the resolver returns
// non-nil error to gRPC.
//
// Deprecated: if V2Balancer is implemented by the Balancer,
// UpdateClientConnState will be called instead.
HandleResolvedAddrs([]resolver.Address, error)
// Close closes the balancer. The balancer is not required to call
// ClientConn.RemoveSubConn for its existing SubConns.
Close()
}
// SubConnState describes the state of a SubConn.
type SubConnState struct {
// ConnectivityState is the connectivity state of the SubConn.
ConnectivityState connectivity.State
// ConnectionError is set if the ConnectivityState is TransientFailure,
// describing the reason the SubConn failed. Otherwise, it is nil.
ConnectionError error
}
// ClientConnState describes the state of a ClientConn relevant to the
// balancer.
type ClientConnState struct {
ResolverState resolver.State
// The parsed load balancing configuration returned by the builder's
// ParseConfig method, if implemented.
BalancerConfig serviceconfig.LoadBalancingConfig
}
// ErrBadResolverState may be returned by UpdateClientConnState to indicate a
// problem with the provided name resolver data.
var ErrBadResolverState = errors.New("bad resolver state")
// V2Balancer is defined for documentation purposes. If a Balancer also
// implements V2Balancer, its UpdateClientConnState method will be called
// instead of HandleResolvedAddrs and its UpdateSubConnState will be called
// instead of HandleSubConnStateChange.
type V2Balancer interface {
// UpdateClientConnState is called by gRPC when the state of the ClientConn
// changes. If the error returned is ErrBadResolverState, the ClientConn
// will begin calling ResolveNow on the active name resolver with
// exponential backoff until a subsequent call to UpdateClientConnState
// returns a nil error. Any other errors are currently ignored.
UpdateClientConnState(ClientConnState) error
// ResolverError is called by gRPC when the name resolver reports an error.
ResolverError(error)
// UpdateSubConnState is called by gRPC when the state of a SubConn
// changes.
UpdateSubConnState(SubConn, SubConnState)
// Close closes the balancer. The balancer is not required to call
// ClientConn.RemoveSubConn for its existing SubConns.
Close()
}
// ConnectivityStateEvaluator takes the connectivity states of multiple SubConns
// and returns one aggregated connectivity state.
//
// It's not thread safe.
type ConnectivityStateEvaluator struct {
numReady uint64 // Number of addrConns in ready state.
numConnecting uint64 // Number of addrConns in connecting state.
numTransientFailure uint64 // Number of addrConns in transientFailure.
numReady uint64 // Number of addrConns in ready state.
numConnecting uint64 // Number of addrConns in connecting state.
}
// RecordTransition records state change happening in subConn and based on that
@@ -258,8 +440,6 @@ func (cse *ConnectivityStateEvaluator) RecordTransition(oldState, newState conne
cse.numReady += updateVal
case connectivity.Connecting:
cse.numConnecting += updateVal
case connectivity.TransientFailure:
cse.numTransientFailure += updateVal
}
}

View File

@@ -19,7 +19,9 @@
package base
import (
"golang.org/x/net/context"
"context"
"errors"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/connectivity"
"google.golang.org/grpc/grpclog"
@@ -27,54 +29,83 @@ import (
)
type baseBuilder struct {
name string
pickerBuilder PickerBuilder
name string
pickerBuilder PickerBuilder
v2PickerBuilder V2PickerBuilder
config Config
}
func (bb *baseBuilder) Build(cc balancer.ClientConn, opt balancer.BuildOptions) balancer.Balancer {
return &baseBalancer{
cc: cc,
pickerBuilder: bb.pickerBuilder,
bal := &baseBalancer{
cc: cc,
pickerBuilder: bb.pickerBuilder,
v2PickerBuilder: bb.v2PickerBuilder,
subConns: make(map[resolver.Address]balancer.SubConn),
scStates: make(map[balancer.SubConn]connectivity.State),
csEvltr: &connectivityStateEvaluator{},
// Initialize picker to a picker that always return
// ErrNoSubConnAvailable, because when state of a SubConn changes, we
// may call UpdateBalancerState with this picker.
picker: NewErrPicker(balancer.ErrNoSubConnAvailable),
csEvltr: &balancer.ConnectivityStateEvaluator{},
config: bb.config,
}
// Initialize picker to a picker that always returns
// ErrNoSubConnAvailable, because when state of a SubConn changes, we
// may call UpdateState with this picker.
if bb.pickerBuilder != nil {
bal.picker = NewErrPicker(balancer.ErrNoSubConnAvailable)
} else {
bal.v2Picker = NewErrPickerV2(balancer.ErrNoSubConnAvailable)
}
return bal
}
func (bb *baseBuilder) Name() string {
return bb.name
}
type baseBalancer struct {
cc balancer.ClientConn
pickerBuilder PickerBuilder
var _ balancer.V2Balancer = (*baseBalancer)(nil) // Assert that we implement V2Balancer
csEvltr *connectivityStateEvaluator
type baseBalancer struct {
cc balancer.ClientConn
pickerBuilder PickerBuilder
v2PickerBuilder V2PickerBuilder
csEvltr *balancer.ConnectivityStateEvaluator
state connectivity.State
subConns map[resolver.Address]balancer.SubConn
scStates map[balancer.SubConn]connectivity.State
picker balancer.Picker
v2Picker balancer.V2Picker
config Config
}
func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
if err != nil {
grpclog.Infof("base.baseBalancer: HandleResolvedAddrs called with error %v", err)
return
panic("not implemented")
}
func (b *baseBalancer) ResolverError(err error) {
switch b.state {
case connectivity.TransientFailure, connectivity.Idle, connectivity.Connecting:
if b.picker != nil {
b.picker = NewErrPicker(err)
} else {
b.v2Picker = NewErrPickerV2(err)
}
}
}
func (b *baseBalancer) UpdateClientConnState(s balancer.ClientConnState) error {
// TODO: handle s.ResolverState.Err (log if not nil) once implemented.
// TODO: handle s.ResolverState.ServiceConfig?
if grpclog.V(2) {
grpclog.Infoln("base.baseBalancer: got new ClientConn state: ", s)
}
grpclog.Infoln("base.baseBalancer: got new resolved addresses: ", addrs)
// addrsSet is the set converted from addrs, it's used for quick lookup of an address.
addrsSet := make(map[resolver.Address]struct{})
for _, a := range addrs {
for _, a := range s.ResolverState.Addresses {
addrsSet[a] = struct{}{}
if _, ok := b.subConns[a]; !ok {
// a is a new address (not existing in b.subConns).
sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{})
sc, err := b.cc.NewSubConn([]resolver.Address{a}, balancer.NewSubConnOptions{HealthCheckEnabled: b.config.HealthCheck})
if err != nil {
grpclog.Warningf("base.baseBalancer: failed to create new SubConn: %v", err)
continue
@@ -93,33 +124,67 @@ func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error)
// The entry will be deleted in HandleSubConnStateChange.
}
}
return nil
}
// regeneratePicker takes a snapshot of the balancer, and generates a picker
// from it. The picker is
// - errPicker with ErrTransientFailure if the balancer is in TransientFailure,
// - built by the pickerBuilder with all READY SubConns otherwise.
func (b *baseBalancer) regeneratePicker() {
func (b *baseBalancer) regeneratePicker(err error) {
if b.state == connectivity.TransientFailure {
b.picker = NewErrPicker(balancer.ErrTransientFailure)
if b.pickerBuilder != nil {
b.picker = NewErrPicker(balancer.ErrTransientFailure)
} else {
if err != nil {
b.v2Picker = NewErrPickerV2(balancer.TransientFailureError(err))
} else {
// This means the last subchannel transition was not to
// TransientFailure (otherwise err must be set), but the
// aggregate state of the balancer is TransientFailure, meaning
// there are no other addresses.
b.v2Picker = NewErrPickerV2(balancer.TransientFailureError(errors.New("resolver returned no addresses")))
}
}
return
}
readySCs := make(map[resolver.Address]balancer.SubConn)
if b.pickerBuilder != nil {
readySCs := make(map[resolver.Address]balancer.SubConn)
// Filter out all ready SCs from full subConn map.
for addr, sc := range b.subConns {
if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
readySCs[addr] = sc
// Filter out all ready SCs from full subConn map.
for addr, sc := range b.subConns {
if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
readySCs[addr] = sc
}
}
b.picker = b.pickerBuilder.Build(readySCs)
} else {
readySCs := make(map[balancer.SubConn]SubConnInfo)
// Filter out all ready SCs from full subConn map.
for addr, sc := range b.subConns {
if st, ok := b.scStates[sc]; ok && st == connectivity.Ready {
readySCs[sc] = SubConnInfo{Address: addr}
}
}
b.v2Picker = b.v2PickerBuilder.Build(PickerBuildInfo{ReadySCs: readySCs})
}
b.picker = b.pickerBuilder.Build(readySCs)
}
func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
panic("not implemented")
}
func (b *baseBalancer) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
s := state.ConnectivityState
if grpclog.V(2) {
grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
}
oldS, ok := b.scStates[sc]
if !ok {
grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
if grpclog.V(2) {
grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
}
return
}
b.scStates[sc] = s
@@ -133,7 +198,7 @@ func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectiv
}
oldAggrState := b.state
b.state = b.csEvltr.recordTransition(oldS, s)
b.state = b.csEvltr.RecordTransition(oldS, s)
// Regenerate picker when one of the following happens:
// - this sc became ready from not-ready
@@ -142,10 +207,14 @@ func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectiv
// - the aggregated state of balancer became non-TransientFailure from TransientFailure
if (s == connectivity.Ready) != (oldS == connectivity.Ready) ||
(b.state == connectivity.TransientFailure) != (oldAggrState == connectivity.TransientFailure) {
b.regeneratePicker()
b.regeneratePicker(state.ConnectionError)
}
b.cc.UpdateBalancerState(b.state, b.picker)
if b.picker != nil {
b.cc.UpdateBalancerState(b.state, b.picker)
} else {
b.cc.UpdateState(balancer.State{ConnectivityState: b.state, Picker: b.v2Picker})
}
}
// Close is a nop because base balancer doesn't have internal state to clean up,
@@ -162,47 +231,19 @@ type errPicker struct {
err error // Pick() always returns this err.
}
func (p *errPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
func (p *errPicker) Pick(context.Context, balancer.PickInfo) (balancer.SubConn, func(balancer.DoneInfo), error) {
return nil, nil, p.err
}
// connectivityStateEvaluator gets updated by addrConns when their
// states transition, based on which it evaluates the state of
// ClientConn.
type connectivityStateEvaluator struct {
numReady uint64 // Number of addrConns in ready state.
numConnecting uint64 // Number of addrConns in connecting state.
numTransientFailure uint64 // Number of addrConns in transientFailure.
// NewErrPickerV2 returns a V2Picker that always returns err on Pick().
func NewErrPickerV2(err error) balancer.V2Picker {
return &errPickerV2{err: err}
}
// recordTransition records state change happening in every subConn and based on
// that it evaluates what aggregated state should be.
// It can only transition between Ready, Connecting and TransientFailure. Other states,
// Idle and Shutdown are transitioned into by ClientConn; in the beginning of the connection
// before any subConn is created ClientConn is in idle state. In the end when ClientConn
// closes it is in Shutdown state.
//
// recordTransition should only be called synchronously from the same goroutine.
func (cse *connectivityStateEvaluator) recordTransition(oldState, newState connectivity.State) connectivity.State {
// Update counters.
for idx, state := range []connectivity.State{oldState, newState} {
updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
switch state {
case connectivity.Ready:
cse.numReady += updateVal
case connectivity.Connecting:
cse.numConnecting += updateVal
case connectivity.TransientFailure:
cse.numTransientFailure += updateVal
}
}
// Evaluate.
if cse.numReady > 0 {
return connectivity.Ready
}
if cse.numConnecting > 0 {
return connectivity.Connecting
}
return connectivity.TransientFailure
type errPickerV2 struct {
err error // Pick() always returns this err.
}
func (p *errPickerV2) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
return balancer.PickResult{}, p.err
}

View File

@@ -42,11 +42,52 @@ type PickerBuilder interface {
Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker
}
// V2PickerBuilder creates balancer.V2Picker.
type V2PickerBuilder interface {
// Build returns a picker that will be used by gRPC to pick a SubConn.
Build(info PickerBuildInfo) balancer.V2Picker
}
// PickerBuildInfo contains information needed by the picker builder to
// construct a picker.
type PickerBuildInfo struct {
// ReadySCs is a map from all ready SubConns to the Addresses used to
// create them.
ReadySCs map[balancer.SubConn]SubConnInfo
}
// SubConnInfo contains information about a SubConn created by the base
// balancer.
type SubConnInfo struct {
Address resolver.Address // the address used to create this SubConn
}
// NewBalancerBuilder returns a balancer builder. The balancers
// built by this builder will use the picker builder to build pickers.
func NewBalancerBuilder(name string, pb PickerBuilder) balancer.Builder {
return NewBalancerBuilderWithConfig(name, pb, Config{})
}
// Config contains the config info about the base balancer builder.
type Config struct {
// HealthCheck indicates whether health checking should be enabled for this specific balancer.
HealthCheck bool
}
// NewBalancerBuilderWithConfig returns a base balancer builder configured by the provided config.
func NewBalancerBuilderWithConfig(name string, pb PickerBuilder, config Config) balancer.Builder {
return &baseBuilder{
name: name,
pickerBuilder: pb,
config: config,
}
}
// NewBalancerBuilderV2 returns a base balancer builder configured by the provided config.
func NewBalancerBuilderV2(name string, pb V2PickerBuilder, config Config) balancer.Builder {
return &baseBuilder{
name: name,
v2PickerBuilder: pb,
config: config,
}
}

View File

@@ -24,11 +24,10 @@ package roundrobin
import (
"sync"
"golang.org/x/net/context"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/balancer/base"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/resolver"
"google.golang.org/grpc/internal/grpcrand"
)
// Name is the name of round_robin balancer.
@@ -36,7 +35,7 @@ const Name = "round_robin"
// newBuilder creates a new roundrobin balancer builder.
func newBuilder() balancer.Builder {
return base.NewBalancerBuilder(Name, &rrPickerBuilder{})
return base.NewBalancerBuilderV2(Name, &rrPickerBuilder{}, base.Config{HealthCheck: true})
}
func init() {
@@ -45,14 +44,21 @@ func init() {
type rrPickerBuilder struct{}
func (*rrPickerBuilder) Build(readySCs map[resolver.Address]balancer.SubConn) balancer.Picker {
grpclog.Infof("roundrobinPicker: newPicker called with readySCs: %v", readySCs)
func (*rrPickerBuilder) Build(info base.PickerBuildInfo) balancer.V2Picker {
grpclog.Infof("roundrobinPicker: newPicker called with info: %v", info)
if len(info.ReadySCs) == 0 {
return base.NewErrPickerV2(balancer.ErrNoSubConnAvailable)
}
var scs []balancer.SubConn
for _, sc := range readySCs {
for sc := range info.ReadySCs {
scs = append(scs, sc)
}
return &rrPicker{
subConns: scs,
// Start at a random index, as the same RR balancer rebuilds a new
// picker when SubConn states change, and we don't want to apply excess
// load to the first server in the list.
next: grpcrand.Intn(len(scs)),
}
}
@@ -66,14 +72,10 @@ type rrPicker struct {
next int
}
func (p *rrPicker) Pick(ctx context.Context, opts balancer.PickOptions) (balancer.SubConn, func(balancer.DoneInfo), error) {
if len(p.subConns) <= 0 {
return nil, nil, balancer.ErrNoSubConnAvailable
}
func (p *rrPicker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
p.mu.Lock()
sc := p.subConns[p.next]
p.next = (p.next + 1) % len(p.subConns)
p.mu.Unlock()
return sc, nil, nil
return balancer.PickResult{SubConn: sc}, nil
}