Upgrade EaseMesh to 2.0 (#696)

* Upgrade EaseMesh to 2.0

* Add timeout in server pool

pkg/filters/proxy/loadbalance.go

@@ -27,29 +27,42 @@ import (
  "github.com/megaease/easegress/pkg/protocols/httpprot"
 )
 
+const (
+ // LoadBalancePolicyRoundRobin is the load balance policy of round robin.
+ LoadBalancePolicyRoundRobin = "roundRobin"
+ // LoadBalancePolicyRandom is the load balance policy of random.
+ LoadBalancePolicyRandom = "random"
+ // LoadBalancePolicyWeightedRandom is the load balance policy of weighted random.
+ LoadBalancePolicyWeightedRandom = "weightedRandom"
+ // LoadBalancePolicyIPHash is the load balance policy of IP hash.
+ LoadBalancePolicyIPHash = "ipHash"
+ // LoadBalancePolicyHeaderHash is the load balance policy of HTTP header hash.
+ LoadBalancePolicyHeaderHash = "headerHash"
+)
+
 // LoadBalancer is the interface of an HTTP load balancer.
 type LoadBalancer interface {
  ChooseServer(req *httpprot.Request) *Server
 }
 
 // LoadBalanceSpec is the spec to create a load balancer.
 type LoadBalanceSpec struct {
- Policy string `yaml:"policy" jsonschema:"enum=roundRobin,enum=random,enum=weightedRandom,enum=ipHash,enum=headerHash"`
+ Policy string `yaml:"policy" jsonschema:"omitempty,enum=,enum=roundRobin,enum=random,enum=weightedRandom,enum=ipHash,enum=headerHash"`
  HeaderHashKey string `yaml:"headerHashKey" jsonschema:"omitempty"`
 }
 
 // NewLoadBalancer creates a load balancer for servers according to spec.
 func NewLoadBalancer(spec *LoadBalanceSpec, servers []*Server) LoadBalancer {
  switch spec.Policy {
- case "roundRobin", "":
+ case LoadBalancePolicyRoundRobin, "":
  return newRoundRobinLoadBalancer(servers)
- case "random":
+ case LoadBalancePolicyRandom:
  return newRandomLoadBalancer(servers)
- case "weightedRandom":
+ case LoadBalancePolicyWeightedRandom:
  return newWeightedRandomLoadBalancer(servers)
- case "ipHash":
+ case LoadBalancePolicyIPHash:
  return newIPHashLoadBalancer(servers)
- case "headerHash":
+ case LoadBalancePolicyHeaderHash:
  return newHeaderHashLoadBalancer(servers, spec.HeaderHashKey)
  default:
  logger.Errorf("unsupported load balancing policy: %s", spec.Policy)