Move code to pkg

pkg/middlewares/chain/chain.go

@@ -0,0 +1,26 @@
+package chain
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/containous/alice"
+	"github.com/containous/traefik/pkg/config"
+	"github.com/containous/traefik/pkg/middlewares"
+)
+
+const (
+	typeName = "Chain"
+)
+
+type chainBuilder interface {
+	BuildChain(ctx context.Context, middlewares []string) *alice.Chain
+}
+
+// New creates a chain middleware
+func New(ctx context.Context, next http.Handler, config config.Chain, builder chainBuilder, name string) (http.Handler, error) {
+	middlewares.GetLogger(ctx, name, typeName).Debug("Creating middleware")
+
+	middlewareChain := builder.BuildChain(ctx, config.Middlewares)
+	return middlewareChain.Then(next)
+}