README
¶
Go LoadBalancer 
Require Go 1.21+.
Install
$ go get -u github.com/xgfone/go-loadbalancer
Example
Mini API Gateway
package main
import (
"encoding/json"
"flag"
"net/http"
"github.com/xgfone/go-loadbalancer"
"github.com/xgfone/go-loadbalancer/balancer"
"github.com/xgfone/go-loadbalancer/forwarder"
"github.com/xgfone/go-loadbalancer/httpx"
)
var listenAddr = flag.String("listenaddr", ":80", "The address that api gateway listens on.")
func main() {
flag.Parse()
http.HandleFunc("/admin/route", registerRouteHandler)
_ = http.ListenAndServe(*listenAddr, nil)
}
func registerRouteHandler(w http.ResponseWriter, r *http.Request) {
if r.Method != http.MethodPost {
w.WriteHeader(http.StatusMethodNotAllowed)
return
}
var req struct {
// Route Matcher
Path string `json:"path" validate:"required"`
Method string `json:"method" validate:"required"`
// Upstream Endpoints
Upstream struct {
ForwardPolicy string `json:"forwardPolicy" default:"weight_random"`
Servers []struct {
Host string `json:"host" validate:"host"`
Port uint16 `json:"port" validate:"ranger(1,65535)"`
Weight int `json:"weight" default:"1" validate:"min(1)"`
} `json:"servers"`
} `json:"upstream"`
}
// Notice: here we don't validate whether the values are valid.
if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
http.Error(w, "invalid request route paramenter: "+err.Error(), 400)
return
}
// Build the upstream backend servers.
static := loadbalancer.NewStaticWithCap(len(req.Upstream.Servers))
for _, server := range req.Upstream.Servers {
c := httpx.Config{Host: server.Host, Port: server.Port, Weight: server.Weight}
static.Append(c.NewEndpoint())
}
// Build the loadbalancer forwarder.
balancer := balancer.Get(req.Upstream.ForwardPolicy) // not check it is nil
forwarder := forwarder.New(req.Method+"@"+req.Path, balancer, static)
// Register the route and forward the request to forwarder.
http.HandleFunc(req.Path, func(w http.ResponseWriter, r *http.Request) {
if r.Method != req.Method {
w.WriteHeader(http.StatusMethodNotAllowed)
} else {
// You can use forwarder.ForwardHTTP to control the request and response.
forwarder.ServeHTTP(w, r)
}
})
}
# Run the mini API-Gateway on the host 192.168.1.10
$ nohup go run main.go &
# Add the route
# Notice: remove the characters from // to the line end.
$ curl -XPOST http://127.0.0.1/admin/route -H 'Content-Type: application/json' -d '
{
"path": "/path",
"method": "GET",
"upstream": {
"forwardPolicy": "weight_round_robin",
"servers": [
{"host": "192.168.1.11", "port": 80, "weight": 10}, // 33.3% requests
{"host": "192.168.1.12", "port": 80, "weight": 20} // 66.7% requests
]
}
}'
# Access the backend servers by the mini API-Gateway:
# 2/6(33.3%) requests -> 192.168.1.11
# 4/6(66.7%) requests -> 192.168.1.12
$ curl http://192.168.1.10/path
192.168.1.11/backend/path
$ curl http://192.168.1.10/path
192.168.1.12/backend/path
$ curl http://192.168.1.10/path
192.168.1.12/backend/path
$ curl http://192.168.1.10/path
192.168.1.11/backend/path
$ curl http://192.168.1.10/path
192.168.1.12/backend/path
$ curl http://192.168.1.10/path
192.168.1.12/backend/path
Documentation
¶
Overview ¶
Package loadbalancer provides some common functions.
Index ¶
Constants ¶
This section is empty.
Variables ¶
View Source
var ErrNoAvailableEndpoints = errors.New("no available endpoints")
ErrNoAvailableEndpoints is used to represents no available endpoints.
View Source
var None = new(Static)
None represents a static without endpoints.
View Source
var SortEndpoints func(Endpoints) = sortEndpoints
SortEndpoints is used to sort a set of the endpoints.
For the default implementation, sort them by the id from small to big.
Functions ¶
Types ¶
type AtomicStatic ¶ added in v0.9.0
type AtomicStatic struct {
// contains filtered or unexported fields
}
AtomicStatic is a atomic static discovery.
func NewAtomicStatic ¶ added in v0.9.0
func NewAtomicStatic(static *Static) *AtomicStatic
NewAtomicStatic a new atomic static.
func (*AtomicStatic) Discover ¶ added in v0.9.0
func (s *AtomicStatic) Discover() *Static
Discover implements the interface Discovery.
func (*AtomicStatic) Set ¶ added in v0.9.0
func (s *AtomicStatic) Set(new *Static)
Set sets the static to new.
func (*AtomicStatic) Swap ¶ added in v0.9.0
func (s *AtomicStatic) Swap(new *Static) (old *Static)
Swap swap the old static with the new.
type Discovery ¶ added in v0.8.0
type Discovery interface {
Discover() *Static
}
Discovery is used to discover the endpoints.
type DiscoveryFunc ¶ added in v0.8.0
type DiscoveryFunc func() *Static
DiscoveryFunc is a discovery function.
func (DiscoveryFunc) Discover ¶ added in v0.8.0
func (f DiscoveryFunc) Discover() *Static
Discover implements the interface Discovery.
type Endpoint ¶
type Endpoint interface {
LoadBalancer
ID() string
}
Endpoint represents a backend endpoint.
type Endpoints ¶
type Endpoints []Endpoint
Endpoints represents a group of the endpoints.
func (Endpoints) Contains ¶
Contains reports whether the endpoints contains the endpoint indicated by the id.
type LoadBalancer ¶
LoadBalancer is a load balancer to serve the request.
type RetryError ¶ added in v0.7.0
RetryError represents a retry error.
func NewRetryError ¶ added in v0.7.0
func NewRetryError(retry bool, err error) RetryError
NewRetryError returns a new retry error, but returns nil instead if err is nil.
type Static ¶ added in v0.8.0
type Static struct{ Endpoints }
Static is used to wrap a set of endpoints.
func NewStaticWithCap ¶ added in v0.9.0
NewStaticWithCap returns a new static with the 0-len and n-cap endpoints.
Source Files
¶
Directories
¶
| Path | Synopsis |
|---|---|
|
Package balancer provides a balancer interface and builder, which is used to forward the request to one of the backend endpoints by the specific policy.
|
Package balancer provides a balancer interface and builder, which is used to forward the request to one of the backend endpoints by the specific policy. |
|
consistenthash
Package consistenthash provides a balancer based on the consistent hash.
|
Package consistenthash provides a balancer based on the consistent hash. |
|
leastconn
Package leastconn provides a balancer based on the least connections.
|
Package leastconn provides a balancer based on the least connections. |
|
random
Package random provides a balancer based on the random.
|
Package random provides a balancer based on the random. |
|
retry
Package retry provides a retry balancer, which will retry the rest endpoints when failing to forward the request.
|
Package retry provides a retry balancer, which will retry the rest endpoints when failing to forward the request. |
|
roundrobin
Package roundrobin provides a balancer based on the roundrobin.
|
Package roundrobin provides a balancer based on the roundrobin. |
|
sourceiphash
Package sourceiphash provides a balancer based on the source-ip hash.
|
Package sourceiphash provides a balancer based on the source-ip hash. |
|
Package endpoint provides some auxiliary functions about endpoint.
|
Package endpoint provides some auxiliary functions about endpoint. |
|
Package forwarder provides a loadbalance forwarder.
|
Package forwarder provides a loadbalance forwarder. |
|
Package httpx provides some functions about http.
|
Package httpx provides some functions about http. |
|
internal
|
|
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