initial commit

Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>

agent.go

@@ -0,0 +1,52 @@
+package element
+
+import (
+	"errors"
+	"time"
+
+	"github.com/hashicorp/memberlist"
+	"google.golang.org/grpc"
+)
+
+const (
+	defaultInterval      = time.Second * 10
+	nodeReconcileTimeout = defaultInterval * 3
+	nodeUpdateTimeout    = defaultInterval / 2
+)
+
+var (
+	ErrUnknownConnectionType = errors.New("unknown connection type")
+)
+
+// Agent represents the node agent
+type Agent struct {
+	config             *Config
+	members            *memberlist.Memberlist
+	peerUpdateChan     chan bool
+	nodeEventChan      chan *NodeEvent
+	grpcServer         *grpc.Server
+	registeredServices map[string]struct{}
+}
+
+// NewAgent returns a new node agent
+func NewAgent(cfg *Config) (*Agent, error) {
+	updateCh := make(chan bool)
+	nodeEventCh := make(chan *NodeEvent)
+	mc, err := setupMemberlistConfig(cfg, updateCh, nodeEventCh)
+	if err != nil {
+		return nil, err
+	}
+
+	ml, err := memberlist.Create(mc)
+	if err != nil {
+		return nil, err
+	}
+	grpcServer := grpc.NewServer()
+	return &Agent{
+		config:         cfg,
+		members:        ml,
+		peerUpdateChan: updateCh,
+		nodeEventChan:  nodeEventCh,
+		grpcServer:     grpcServer,
+	}, nil
+}