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Switch up the selector so it actually allows you to inform it how the node performed

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This commit is contained in:
Asim 2015-12-07 23:56:17 +00:00
parent 4e6b9347d9
commit 140febb081
4 changed files with 87 additions and 54 deletions
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45
client/node_selector.go
View File

@ -6,21 +6,40 @@ import (
"github.com/micro/go-micro/errors"
"github.com/micro/go-micro/registry"
"golang.org/x/net/context"
)
// NodeSelector is used to retrieve a node to which a request
// should be routed. It takes a list of services and selects
// a single node. If a node cannot be selected it should return
// an error. A list of services is provided as a service may
// have 1 or more versions.
type NodeSelector func(service []*registry.Service) (*registry.Node, error)
// NodeSelector is used to Retrieve a node to which a request
// should be routed. It takes context and Request and returns a
// single node. If a node cannot be selected it should return
// an error. Response is called to inform the selector of the
// response from a client call. Reset is called to zero out
// any state.
type NodeSelector interface {
Retrieve(context.Context, Request) (*registry.Node, error)
Response(*registry.Node, error)
Reset()
}
// Selector takes a Registry and returns a NodeSelector.
// Used by the client to initialise a selector.
type Selector func(registry.Registry) NodeSelector
func init() {
rand.Seed(time.Now().UnixNano())
}
// Built in random hashed node selector
func nodeSelector(service []*registry.Service) (*registry.Node, error) {
type nodeSelector struct {
r registry.Registry
}
func (n *nodeSelector) Retrieve(ctx context.Context, req Request) (*registry.Node, error) {
service, err := n.r.GetService(req.Service())
if err != nil {
return nil, errors.InternalServerError("go.micro.client", err.Error())
}
if len(service) == 0 {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
@ -32,6 +51,14 @@ func nodeSelector(service []*registry.Service) (*registry.Node, error) {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
n := i % len(service[j].Nodes)
return service[j].Nodes[n], nil
k := i % len(service[j].Nodes)
return service[j].Nodes[k], nil
}
func (n *nodeSelector) Response(node *registry.Node, err error) {
return
}
func (n *nodeSelector) Reset() {
return
}

6
client/options.go
View File

@ -14,7 +14,7 @@ type options struct {
registry registry.Registry
transport transport.Transport
wrappers []Wrapper
selector NodeSelector
selector Selector
}
// Broker to be used for pub/sub
@ -52,8 +52,8 @@ func Transport(t transport.Transport) Option {
}
}
// Selector is used to select a node to route a request to
func Selector(s NodeSelector) Option {
// Select is used to select a node to route a request to
func Select(s Selector) Option {
return func(o *options) {
o.selector = s
}

35
client/rpc_client.go
View File

@ -18,9 +18,11 @@ import (
type rpcClient struct {
once sync.Once
opts options
sel NodeSelector
}
func newRpcClient(opt ...Option) Client {
var sel NodeSelector
var once sync.Once
opts := options{
@ -39,17 +41,24 @@ func newRpcClient(opt ...Option) Client {
opts.transport = transport.DefaultTransport
}
if opts.registry == nil {
opts.registry = registry.DefaultRegistry
}
if opts.broker == nil {
opts.broker = broker.DefaultBroker
}
if opts.selector == nil {
opts.selector = nodeSelector
if opts.selector != nil {
sel = opts.selector(opts.registry)
} else {
sel = &nodeSelector{opts.registry}
}
rc := &rpcClient{
once: once,
opts: opts,
sel: sel,
}
c := Client(rc)
@ -145,12 +154,7 @@ func (r *rpcClient) CallRemote(ctx context.Context, address string, request Requ
// TODO: Call(..., opts *Options) error {
func (r *rpcClient) Call(ctx context.Context, request Request, response interface{}) error {
service, err := registry.GetService(request.Service())
if err != nil {
return errors.InternalServerError("go.micro.client", err.Error())
}
node, err := r.opts.selector(service)
node, err := r.sel.Retrieve(ctx, request)
if err != nil {
return err
}
@ -160,7 +164,9 @@ func (r *rpcClient) Call(ctx context.Context, request Request, response interfac
address = fmt.Sprintf("%s:%d", address, node.Port)
}
return r.call(ctx, address, request, response)
err = r.call(ctx, address, request, response)
r.sel.Response(node, err)
return err
}
func (r *rpcClient) StreamRemote(ctx context.Context, address string, request Request, responseChan interface{}) (Streamer, error) {
@ -168,12 +174,7 @@ func (r *rpcClient) StreamRemote(ctx context.Context, address string, request Re
}
func (r *rpcClient) Stream(ctx context.Context, request Request, responseChan interface{}) (Streamer, error) {
service, err := registry.GetService(request.Service())
if err != nil {
return nil, errors.InternalServerError("go.micro.client", err.Error())
}
node, err := r.opts.selector(service)
node, err := r.sel.Retrieve(ctx, request)
if err != nil {
return nil, err
}
@ -183,7 +184,9 @@ func (r *rpcClient) Stream(ctx context.Context, request Request, responseChan in
address = fmt.Sprintf("%s:%d", address, node.Port)
}
return r.stream(ctx, address, request, responseChan)
stream, err := r.stream(ctx, address, request, responseChan)
r.sel.Response(node, err)
return stream, err
}
func (r *rpcClient) Publish(ctx context.Context, p Publication) error {

55
examples/client/node_selector/node_selector.go
View File

@ -7,7 +7,6 @@ import (
"github.com/micro/go-micro/client"
"github.com/micro/go-micro/cmd"
c "github.com/micro/go-micro/context"
"github.com/micro/go-micro/errors"
example "github.com/micro/go-micro/examples/server/proto/example"
"github.com/micro/go-micro/registry"
@ -18,33 +17,43 @@ func init() {
rand.Seed(time.Now().Unix())
}
// A random node selector
func randomSelector(s []*registry.Service) (*registry.Node, error) {
if len(s) == 0 {
// Built in random hashed node selector
type nodeSelector struct {
r registry.Registry
}
func (n *nodeSelector) Retrieve(ctx context.Context, req client.Request) (*registry.Node, error) {
service, err := n.r.GetService(req.Service())
if err != nil {
return nil, errors.InternalServerError("go.micro.client", err.Error())
}
if len(service) == 0 {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
i := rand.Int()
j := i % len(s)
j := i % len(service)
if len(s[j].Nodes) == 0 {
if len(service[j].Nodes) == 0 {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
n := i % len(s[j].Nodes)
return s[j].Nodes[n], nil
k := i % len(service[j].Nodes)
return service[j].Nodes[k], nil
}
// Wraps the node selector so that it will log what node was selected
func wrapSelector(fn client.NodeSelector) client.NodeSelector {
return func(s []*registry.Service) (*registry.Node, error) {
n, err := fn(s)
if err != nil {
return nil, err
}
fmt.Printf("Selected node %v\n", n)
return n, nil
}
func (n *nodeSelector) Response(node *registry.Node, err error) {
return
}
func (n *nodeSelector) Reset() {
return
}
// Return a new random node selector
func RandomSelector(r registry.Registry) client.NodeSelector {
return &nodeSelector{r}
}
func call(i int) {
@ -53,16 +62,10 @@ func call(i int) {
Name: "John",
})
// create context with metadata
ctx := c.WithMetadata(context.Background(), map[string]string{
"X-User-Id": "john",
"X-From-Id": "script",
})
rsp := &example.Response{}
// Call service
if err := client.Call(ctx, req, rsp); err != nil {
if err := client.Call(context.Background(), req, rsp); err != nil {
fmt.Println("call err: ", err, rsp)
return
}
@ -74,7 +77,7 @@ func main() {
cmd.Init()
client.DefaultClient = client.NewClient(
client.Selector(wrapSelector(randomSelector)),
client.Select(RandomSelector),
)
fmt.Println("\n--- Call example ---\n")