🎉: init project

internal/invoke/resolve.go

@@ -0,0 +1,82 @@
+package invoke
+
+import (
+	"fmt"
+	"google.golang.org/grpc/resolver"
+	"strings"
+	"sync"
+)
+
+const (
+	scheme = "bifrost"
+)
+
+type CustomBuilder struct{}
+
+func (cb *CustomBuilder) Scheme() string {
+	return scheme
+}
+
+func (cb *CustomBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
+	cr := &customResolver{
+		cc:     cc,
+		target: target,
+	}
+
+	cr.ResolveNow(resolver.ResolveNowOptions{})
+
+	return cr, nil
+}
+
+type customResolver struct {
+	sync.Mutex
+	target resolver.Target
+	cc     resolver.ClientConn
+	ips    map[string]string
+}
+
+func (cr *customResolver) ResolveNow(o resolver.ResolveNowOptions) {
+	var (
+		addrs = make([]resolver.Address, 0)
+		hp    []string
+	)
+
+	cr.Lock()
+	defer cr.Unlock()
+
+	if hp = strings.Split(cr.target.URL.Host, ":"); len(hp) >= 2 {
+		if ip, ok := pool[hp[0]]; ok {
+			addr := fmt.Sprintf("%s:%s", ip, hp[1])
+			addrs = append(addrs, resolver.Address{Addr: addr})
+		}
+	}
+
+	_ = cr.cc.UpdateState(resolver.State{Addresses: addrs})
+}
+
+func (cr *customResolver) Close() {}
+
+var (
+	cb   = &CustomBuilder{}
+	pool = make(map[string]string)
+)
+
+func init() {
+	resolver.Register(cb)
+}
+
+type CustomDomain struct {
+	Domain string
+	IP     string
+}
+
+func NewCustomBuilder(cds ...CustomDomain) resolver.Builder {
+	locker.Lock()
+	defer locker.Unlock()
+
+	for _, cd := range cds {
+		pool[cd.Domain] = cd.IP
+	}
+
+	return cb
+}