Start cadence client worker upon worker role startup (cadence-workflo…

…w#1244)

Starts cadence client as part of worker role. Next diff will include plumbing to send signal to hosted workflow to do system activity.

.travis.yml

@@ -5,7 +5,7 @@ language: go
 directories:
     - $HOME/.glide/cache
 go:
-  - 1.11.x
+  - 1.11.1
 
 env:
   global:

client/clientfactory.go

@@ -21,6 +21,7 @@
 package client
 
 import (
+	"github.com/uber/cadence/client/frontend"
 	"github.com/uber/cadence/client/history"
 	"github.com/uber/cadence/client/matching"
 	"github.com/uber/cadence/common"
@@ -32,6 +33,7 @@ import (
 type Factory interface {
 	NewHistoryClient() (history.Client, error)
 	NewMatchingClient() (matching.Client, error)
+	NewFrontendClient() (frontend.Client, error)
 }
 
 type rpcClientFactory struct {
@@ -73,3 +75,14 @@ func (cf *rpcClientFactory) NewMatchingClient() (matching.Client, error) {
 	}
 	return client, nil
 }
+
+func (cf *rpcClientFactory) NewFrontendClient() (frontend.Client, error) {
+	client, err := frontend.NewClient(cf.df, cf.monitor)
+	if err != nil {
+		return nil, err
+	}
+	if cf.metricsClient != nil {
+		client = frontend.NewMetricClient(client, cf.metricsClient)
+	}
+	return client, nil
+}