Memory registry from #801 with additional tweaks (#951)

* PoC: memory registry using maps instead of slice madness

* Updated proto and handlers. Fixed tests across codebase.

* Implemented ttl pruning for memory registry

* Added extensive memory registry tests

* Squased a bunch of bugs

* Proto indent; memory.Registry.String() returns "memory"

* Write a test to prove memory registry TTLs are busted

Signed-off-by: Erik Hollensbe <github@hollensbe.org>

* Additional memory testing and fixups:

* DefaultTTL removed
* When TTL == 0, it is automatically removed from expiry conditions
* Additional improvements to new tests

Signed-off-by: Erik Hollensbe <github@hollensbe.org>

registry/memory/util.go

@@ -0,0 +1,87 @@
+package memory
+
+import (
+	"time"
+
+	"github.com/micro/go-micro/registry"
+)
+
+func serviceToRecord(s *registry.Service, ttl time.Duration) *record {
+	metadata := make(map[string]string)
+	for k, v := range s.Metadata {
+		metadata[k] = v
+	}
+
+	nodes := make(map[string]*node)
+	for _, n := range s.Nodes {
+		nodes[n.Id] = &node{
+			Node:     n,
+			TTL:      ttl,
+			LastSeen: time.Now(),
+		}
+	}
+
+	endpoints := make([]*registry.Endpoint, len(s.Endpoints))
+	for i, e := range s.Endpoints {
+		endpoints[i] = e
+	}
+
+	return &record{
+		Name:      s.Name,
+		Version:   s.Version,
+		Metadata:  metadata,
+		Nodes:     nodes,
+		Endpoints: endpoints,
+	}
+}
+
+func recordToService(r *record) *registry.Service {
+	metadata := make(map[string]string)
+	for k, v := range r.Metadata {
+		metadata[k] = v
+	}
+
+	endpoints := make([]*registry.Endpoint, len(r.Endpoints))
+	for i, e := range r.Endpoints {
+		request := new(registry.Value)
+		request = e.Request
+		response := new(registry.Value)
+		response = e.Response
+
+		metadata := make(map[string]string)
+		for k, v := range e.Metadata {
+			metadata[k] = v
+		}
+
+		endpoints[i] = &registry.Endpoint{
+			Name:     e.Name,
+			Request:  request,
+			Response: response,
+			Metadata: metadata,
+		}
+	}
+
+	nodes := make([]*registry.Node, len(r.Nodes))
+	i := 0
+	for _, n := range r.Nodes {
+		metadata := make(map[string]string)
+		for k, v := range n.Metadata {
+			metadata[k] = v
+		}
+
+		nodes[i] = &registry.Node{
+			Id:       n.Id,
+			Address:  n.Address,
+			Metadata: metadata,
+		}
+		i++
+	}
+
+	return &registry.Service{
+		Name:      r.Name,
+		Version:   r.Version,
+		Metadata:  metadata,
+		Endpoints: endpoints,
+		Nodes:     nodes,
+	}
+}