Refactor Client Code, part 2 of several

clients/command/client.go

@@ -21,6 +21,7 @@ import (
 	"context"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 )
 
@@ -38,11 +39,11 @@ type CommandClient interface {
 
 type commandRestClient struct {
 	url      string
-	endpoint clients.Endpointer
+	endpoint interfaces.Endpointer
 }
 
 // NewCommandClient creates an instance of CommandClient
-func NewCommandClient(params types.EndpointParams, m clients.Endpointer) CommandClient {
+func NewCommandClient(params types.EndpointParams, m interfaces.Endpointer) CommandClient {
 	c := commandRestClient{endpoint: m}
 	c.init(params)
 	return &c

clients/coredata/event.go

@@ -27,6 +27,7 @@ import (
 	"strconv"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 	"github.com/edgexfoundry/go-mod-core-contracts/models"
 )
@@ -68,11 +69,11 @@ type EventClient interface {
 
 type eventRestClient struct {
 	url      string
-	endpoint clients.Endpointer
+	endpoint interfaces.Endpointer
 }
 
 // NewEventClient creates an instance of EventClient
-func NewEventClient(params types.EndpointParams, m clients.Endpointer) EventClient {
+func NewEventClient(params types.EndpointParams, m interfaces.Endpointer) EventClient {
 	e := eventRestClient{endpoint: m}
 	e.init(params)
 	return &e

clients/coredata/reading.go

@@ -24,6 +24,7 @@ import (
 	"strconv"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 	"github.com/edgexfoundry/go-mod-core-contracts/models"
 )
@@ -58,11 +59,11 @@ type ReadingClient interface {
 
 type readingRestClient struct {
 	url      string
-	endpoint clients.Endpointer
+	endpoint interfaces.Endpointer
 }
 
 // NewReadingClient creates an instance of a ReadingClient
-func NewReadingClient(params types.EndpointParams, m clients.Endpointer) ReadingClient {
+func NewReadingClient(params types.EndpointParams, m interfaces.Endpointer) ReadingClient {
 	r := readingRestClient{endpoint: m}
 	r.init(params)
 	return &r

clients/coredata/value_descriptor.go

@@ -21,6 +21,7 @@ import (
 	"strings"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 	"github.com/edgexfoundry/go-mod-core-contracts/models"
 )
@@ -56,10 +57,10 @@ type ValueDescriptorClient interface {
 
 type valueDescriptorRestClient struct {
 	url      string
-	endpoint clients.Endpointer
+	endpoint interfaces.Endpointer
 }
 
-func NewValueDescriptorClient(params types.EndpointParams, m clients.Endpointer) ValueDescriptorClient {
+func NewValueDescriptorClient(params types.EndpointParams, m interfaces.Endpointer) ValueDescriptorClient {
 	v := valueDescriptorRestClient{endpoint: m}
 	v.init(params)
 	return &v

clients/general/client.go

@@ -22,6 +22,7 @@ import (
 	"context"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 )
 
@@ -34,11 +35,11 @@ type GeneralClient interface {
 
 type generalRestClient struct {
 	url      string
-	endpoint clients.Endpointer
+	endpoint interfaces.Endpointer
 }
 
 // NewGeneralClient creates an instance of GeneralClient
-func NewGeneralClient(params types.EndpointParams, m clients.Endpointer) GeneralClient {
+func NewGeneralClient(params types.EndpointParams, m interfaces.Endpointer) GeneralClient {
 	gc := generalRestClient{endpoint: m}
 	gc.init(params)
 	return &gc

clients/endpointer.go → clients/interfaces/endpointer.go

@@ -12,16 +12,16 @@
  * the License.
  *******************************************************************************/
 
-package clients
+package interfaces
 
 import "github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 
-//Endpointer is the interface for types that need to implement or simulate integration
-//with a service discovery provider.
+// Endpointer is the interface for types that need to implement or simulate integration
+// with a service discovery provider.
 type Endpointer interface {
-	//Monitor is responsible for looking up information about the service endpoint corresponding
-	//to the params.ServiceKey property. The name "Monitor" implies that this lookup will be done
-	//at a regular interval. Information about the service from the discovery provider should be
-	//used to construct a URL which will then be pushed to the returned channel.
+	// Monitor is responsible for looking up information about the service endpoint corresponding
+	// to the params.ServiceKey property. The name "Monitor" implies that this lookup will be done
+	// at a regular interval. Information about the service from the discovery provider should be
+	// used to construct a URLClient which will then be pushed to the returned channel.
 	Monitor(params types.EndpointParams) chan string
 }

clients/interfaces/url.go

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright 2020 Dell Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ *******************************************************************************/
+
+package interfaces
+
+// URLClient is the interface for types that need to define some way to retrieve URLClient information about services.
+// This information can be anything that must be determined at runtime, whether it is unknown or simply not yet known.
+type URLClient interface {
+	// Prefix returns the URLClient base path (or root) of a service.
+	// This is the common root of all REST calls to the service,
+	// and is defined on a per service (rather than per endpoint) basis.
+	// Prefix returns the root URLClient for REST calls to the service if it was able to retrieve that URLClient;
+	// it returns an error otherwise.
+	Prefix() (string, error)
+}

clients/metadata/addressable.go

@@ -12,9 +12,7 @@
  * the License.
  *******************************************************************************/
 
-/*
- Package metadata provides clients used for integration with the core-metadata service.
-*/
+// metadata provides clients used for integration with the core-metadata service.
 package metadata
 
 import (
@@ -23,13 +21,13 @@ import (
 	"net/url"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/urlclient"
 	"github.com/edgexfoundry/go-mod-core-contracts/models"
 )
 
-/*
-AddressableClient defines the interface for interactions with the Addressable endpoint on the EdgeX Foundry core-metadata service.
-*/
+// AddressableClient defines the interface for interactions with the Addressable endpoint on core-metadata.
 type AddressableClient interface {
 	// Add creates a new Addressable and returns the ID of the new item if successful.
 	Add(addr *models.Addressable, ctx context.Context) (string, error)
@@ -44,35 +42,23 @@ type AddressableClient interface {
 }
 
 type addressableRestClient struct {
-	url      string
-	endpoint clients.Endpointer
+	urlClient interfaces.URLClient
 }
 
 // NewAddressableClient creates an instance of AddressableClient
-func NewAddressableClient(params types.EndpointParams, m clients.Endpointer) AddressableClient {
-	a := addressableRestClient{endpoint: m}
-	a.init(params)
+func NewAddressableClient(params types.EndpointParams, m interfaces.Endpointer) AddressableClient {
+	a := addressableRestClient{urlClient: urlclient.New(params, m)}
 	return &a
 }
 
-func (a *addressableRestClient) init(params types.EndpointParams) {
-	if params.UseRegistry {
-		go func(ch chan string) {
-			for {
-				select {
-				case url := <-ch:
-					a.url = url
-				}
-			}
-		}(a.endpoint.Monitor(params))
-	} else {
-		a.url = params.Url
+// Helper method to request and decode an addressable
+func (a *addressableRestClient) requestAddressable(urlSuffix string, ctx context.Context) (models.Addressable, error) {
+	urlPrefix, err := a.urlClient.Prefix()
+	if err != nil {
+		return models.Addressable{}, err
 	}
-}
 
-// Helper method to request and decode an addressable
-func (a *addressableRestClient) requestAddressable(url string, ctx context.Context) (models.Addressable, error) {
-	data, err := clients.GetRequest(url, ctx)
+	data, err := clients.GetRequest(urlPrefix+urlSuffix, ctx)
 	if err != nil {
 		return models.Addressable{}, err
 	}
@@ -83,21 +69,36 @@ func (a *addressableRestClient) requestAddressable(url string, ctx context.Conte
 }
 
 func (a *addressableRestClient) Add(addr *models.Addressable, ctx context.Context) (string, error) {
-	return clients.PostJsonRequest(a.url, addr, ctx)
+	serviceURL, err := a.urlClient.Prefix()
+	if err != nil {
+		return "", err
+	}
+
+	return clients.PostJsonRequest(serviceURL, addr, ctx)
 }
 
 func (a *addressableRestClient) Addressable(id string, ctx context.Context) (models.Addressable, error) {
-	return a.requestAddressable(a.url+"/"+id, ctx)
+	return a.requestAddressable("/"+id, ctx)
 }
 
 func (a *addressableRestClient) AddressableForName(name string, ctx context.Context) (models.Addressable, error) {
-	return a.requestAddressable(a.url+"/name/"+url.QueryEscape(name), ctx)
+	return a.requestAddressable("/name/"+url.QueryEscape(name), ctx)
 }
 
 func (a *addressableRestClient) Update(addr models.Addressable, ctx context.Context) error {
-	return clients.UpdateRequest(a.url, addr, ctx)
+	serviceURL, err := a.urlClient.Prefix()
+	if err != nil {
+		return err
+	}
+
+	return clients.UpdateRequest(serviceURL, addr, ctx)
 }
 
 func (a *addressableRestClient) Delete(id string, ctx context.Context) error {
-	return clients.DeleteRequest(a.url+"/id/"+id, ctx)
+	serviceURL, err := a.urlClient.Prefix()
+	if err != nil {
+		return err
+	}
+
+	return clients.DeleteRequest(serviceURL+"/id/"+id, ctx)
 }

clients/metadata/addressable_test.go

@@ -20,12 +20,12 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
-	"time"
+
+	"github.com/google/uuid"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
 	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
 	"github.com/edgexfoundry/go-mod-core-contracts/models"
-	"github.com/google/uuid"
 )
 
 func TestNewAddressableClientWithConsul(t *testing.T) {
@@ -44,15 +44,16 @@ func TestNewAddressableClientWithConsul(t *testing.T) {
 		t.Error("sc is not of expected type")
 	}
 
-	time.Sleep(25 * time.Millisecond)
-	if len(r.url) == 0 {
+	url, err := r.urlClient.Prefix()
+
+	if err != nil {
 		t.Error("url was not initialized")
-	} else if r.url != addressableURL {
-		t.Errorf("unexpected url value %s", r.url)
+	} else if url != addressableURL {
+		t.Errorf("unexpected url value %s", url)
 	}
 }
 
-// Test adding an addressable using the client
+// Test adding an addressable using the urlClient
 func TestAddAddressable(t *testing.T) {
 	addressable := models.Addressable{
 		Id:   uuid.New().String(),
@@ -98,7 +99,7 @@ func TestAddAddressable(t *testing.T) {
 	}
 }
 
-// Test get an addressable using the client
+// Test get an addressable using the urlClient
 func TestGetAddressable(t *testing.T) {
 	addressable := models.Addressable{
 		Id:   uuid.New().String(),
@@ -143,7 +144,7 @@ func TestGetAddressable(t *testing.T) {
 	}
 }
 
-// Test get an addressable using the client
+// Test get an addressable using the urlClient
 func TestGetAddressableForName(t *testing.T) {
 	addressable := models.Addressable{
 		Id:   uuid.New().String(),
@@ -188,7 +189,7 @@ func TestGetAddressableForName(t *testing.T) {
 	}
 }
 
-// Test updating an addressable using the client
+// Test updating an addressable using the urlClient
 func TestUpdateAddressable(t *testing.T) {
 	addressable := models.Addressable{
 		Id:   uuid.New().String(),
@@ -226,7 +227,7 @@ func TestUpdateAddressable(t *testing.T) {
 	}
 }
 
-// Test deleting an addressable using the client
+// Test deleting an addressable using the urlClient
 func TestDeleteAddressable(t *testing.T) {
 	addressable := models.Addressable{
 		Id:   uuid.New().String(),