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go-lb

Go GitHub tag (latest SemVer) Go Dev GoDoc Go Report Card Coverage Status

go-lb provides a general load balancers library.

Features

The stocked algorithm are:

  • random
  • round-robin
  • weighted round-robin
  • consistent hash
  • weighted random
  • weighted versioning

Use Register(...)/Unregister(...) to add the balancer with your algorithm and use it with our New(algorithm, opts...).

History

  • v0.5.1

    • upgrade deps
  • v0.5.0

    • a tiny logger interface has been embedded. So

      • we removed the dep to hedzr/log and free you from it

      • you may still enable internal logging sentences in hedzr/lb by setting up a custom Logger

        import "github.com/hedzr/lb/pkg/logger" logger.SetLogger(yoursLogger)
    • all codes reviewed

  • v0.3.3

    • needs go modules 1.17 and higher
    • upgraded deps
    • remove unecessary deps
    • remove the nest go.mod since it cannot work any more
    • fix gin vuln report
  • v0.3.1, v0.3.0 : work for below go1.17

Usages

Simple

package main import ( "fmt"	lb "github.com/hedzr/lb" "github.com/hedzr/lb/lbapi" ) func main() { b := lb.New(lb.RoundRobin) b.Add(exP("172.16.0.7:3500"), exP("172.16.0.8:3500"), exP("172.16.0.9:3500")) sum := make(map[lbapi.Peer]int) for i := 0; i < 300; i++ { p, _ := b.Next(lbapi.DummyFactor) sum[p]++	} for k, v := range sum { fmt.Printf("%v: %v\n", k, v)	} } type exP string func (s exP) String() string { return string(s) }

About Weighted versioning

With the Weighted versioning algorithm, a set of version constraints and weights can be put as the basic rule. Such as:

  1. "<= 1.1.x", weight: 2,
  2. "^1.2.x", weight: 4,
  3. "^2.x", weight: 11,
  4. ^3.x", weight: 3,

the peers will be picked out by its version. And, all versioning peers will be picked with weights specified in constraints totally.

The partial codes:

var testConstraints = []lbapi.Constrainable{ version.NewConstrainablePeer("<= 1.1.x", 2), version.NewConstrainablePeer("^1.2.x", 4), version.NewConstrainablePeer("^2.x", 11), version.NewConstrainablePeer("^3.x", 3), } func TestVersionWRR2(t *testing.T) { lb := version.New(version.WithConstrainedPeers(testConstraints...)) sum := make(map[lbapi.Peer]int) hits := make(map[lbapi.Peer]map[lbapi.Constrainable]bool) factor := initFactors() for i := 0; i < 500; i++ { peer, c := lb.Next(factor) sum[peer]++ if ps, ok := hits[peer]; ok { if _, ok := ps[c]; !ok { ps[c] = true	}	} else { hits[peer] = make(map[lbapi.Constrainable]bool) hits[peer][c] = true	}	} // results total := 0 for _, v := range sum { total += v	} for peer, v := range sum { var keys []string var w int for c := range hits[peer] { if kk, ok := c.(fmt.Stringer); ok { keys = append(keys, kk.String())	} if ww, ok := c.(lbapi.Weighted); ok { w = ww.Weight()	}	} // ex := findC(peer) t.Logf("%v: %v/%0.2f%%/w:%v. [%v => weight: %v]", peer, v, (float32(v)/float32(total))*100.0, w, strings.Join(keys, ","), w)	} }

See the full codes at version/new_test.go,

For the full document of version constraints: Masterminds/semver .

API GW demo

Please check out the source codes:

And the command line to test its:

go run ./_examples/svc-small -port 8111 & go run ./_examples/svc-small -port 8112 & go run ./_examples/svc-small -port 8113 & go run ./_examples/gw-lb-aware/main.go 8111 8112 8113 & for ((i=0;i<5;i++)); do curl http://localhost:8103/ ; done

License

MIT