#204: Added structure so that a RegistryClient can use different algo…

…rithms for retrieving a URL. (#211)

#206: Refactor usage of Context to make idiomatic.

#209: Remove Endpointer structure.

Signed-off-by: Brandon Forster <me@brandonforster.com>

README.md

@@ -1,35 +1,15 @@
 # go-mod-core-contracts
-This module contains the contract models used to describe data as it is passed via Request/Response between various EdgeX Foundry services. It also contains service clients for each service within the [edgex-go](https://github.com/edgexfoundry/edgex-go) repository. The definition of the various models and clients can be found in their respective top-level directories.
+This module contains the contract models used to describe data as it is passed via Request/Response between various
+EdgeX Foundry services. It also contains service clients for each service within the
+[edgex-go](https://github.com/edgexfoundry/edgex-go) repository. The definition of the various models and clients can
+be found in their respective top-level directories.
 
-The default encoding for the models is JSON, although in at least one case -- [DeviceProfile](https://github.com/edgexfoundry/go-mod-core-contracts/blob/master/models/deviceprofile.go) -- YAML encoding is also supported since a device profile is defined as a YAML document.
+The default encoding for the models is JSON, although in at least one case --
+[DeviceProfile](https://github.com/edgexfoundry/go-mod-core-contracts/blob/master/models/deviceprofile.go) --
+YAML encoding is also supported since a device profile is defined as a YAML document.
 
 ### Installation ###
 * Make sure you're using at least Go 1.11.1 and have modules enabled, i.e. have an initialized  go.mod file 
 * If your code is in your GOPATH then make sure ```GO111MODULE=on``` is set
 * Run ```go get github.com/edgexfoundry/go-mod-core-contracts```
     * This will add the go-mod-core-contracts to the go.mod file and download it into the module cache
-
-### How to Use ###
-In order to instantiate a service client, you would do the following:
-
-Let's say you want to utilize a client for the core-metadata service, the first thing you want to do is initialize an instance of [types.EndpointParams](https://github.com/edgexfoundry/go-mod-core-contracts/blob/master/clients/types/endpoint_params.go). This simple struct provides all the properties you need to address a given service endpoint. Population of the relevant properties might look like this:
-
-```
-params := types.EndpointParams{
-        ServiceKey:  internal.CoreMetaDataServiceKey,
-	Path:        clients.ApiDeviceRoute,
-	UseRegistry: useRegistry,
-	Url:         Configuration.Clients["Metadata"].Url() + clients.ApiDeviceRoute,
-	Interval:    Configuration.Service.ClientMonitor,
-}
-```
-From there you simply pass the EndpointParams into the initialization function for the client you wish to use. In the above case, we're trying to initialize a client for the Device endpoint of the core-metadata service.
-```
-mdc := metadata.NewDeviceClient(params, startup.Endpoint{RegistryClient: &registryClient})
-```
-_More information on the `RegistryClient` can be found [here](https://github.com/edgexfoundry/go-mod-registry). The `RegistryClient` is only used if the `useRegistry` flag provided to the `EndpointParams` is true._ 
-
-Once you have a reference to the client, you simply need to call its methods like so:
-`_, err := mdc.CheckForDevice(device, ctx)`
-
-Each client has a `Monitor` goroutine in it. If the registry is being used, the Monitor's job is to refresh the protocol, host and port of your service client at some configured interval. The default interval is 15 seconds.

clients/command/client.go

@@ -22,58 +22,58 @@ import (
 
 	"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"
 )
 
 // CommandClient interface defines interactions with the EdgeX Core Command microservice.
 type CommandClient interface {
 	// Get issues a GET command targeting the specified device, using the specified command id
-	Get(deviceId string, commandId string, ctx context.Context) (string, error)
+	Get(ctx context.Context, deviceId string, commandId string) (string, error)
 	// Put issues a PUT command targeting the specified device, using the specified command id
-	Put(deviceId string, commandId string, body string, ctx context.Context) (string, error)
+	Put(ctx context.Context, deviceId string, commandId string, body string) (string, error)
 	// GetDeviceCommandByNames issues a GET command targeting the specified device, using the specified device and command name
-	GetDeviceCommandByNames(deviceName string, commandName string, ctx context.Context) (string, error)
+	GetDeviceCommandByNames(ctx context.Context, deviceName string, commandName string) (string, error)
 	// PutDeviceCommandByNames issues a PUT command targeting the specified device, using the specified device and command names
-	PutDeviceCommandByNames(deviceName string, commandName string, body string, ctx context.Context) (string, error)
+	PutDeviceCommandByNames(ctx context.Context, deviceName string, commandName string, body string) (string, error)
 }
 
 type commandRestClient struct {
 	urlClient interfaces.URLClient
 }
 
 // NewCommandClient creates an instance of CommandClient
-func NewCommandClient(params types.EndpointParams, m interfaces.Endpointer) CommandClient {
-	return &commandRestClient{urlClient: urlclient.New(params, m)}
+func NewCommandClient(urlClient interfaces.URLClient) CommandClient {
+	return &commandRestClient{
+		urlClient: urlClient,
+	}
 }
 
-func (cc *commandRestClient) Get(deviceId string, commandId string, ctx context.Context) (string, error) {
-	return cc.getRequestJSONBody("/"+deviceId+"/command/"+commandId, ctx)
+func (cc *commandRestClient) Get(ctx context.Context, deviceId string, commandId string) (string, error) {
+	return cc.getRequestJSONBody(ctx, "/"+deviceId+"/command/"+commandId)
 }
 
-func (cc *commandRestClient) Put(deviceId string, commandId string, body string, ctx context.Context) (string, error) {
-	return clients.PutRequest("/"+deviceId+"/command/"+commandId, []byte(body), ctx, cc.urlClient)
+func (cc *commandRestClient) Put(ctx context.Context, deviceId string, commandId string, body string) (string, error) {
+	return clients.PutRequest(ctx, "/"+deviceId+"/command/"+commandId, []byte(body), cc.urlClient)
 }
 
 func (cc *commandRestClient) GetDeviceCommandByNames(
+	ctx context.Context,
 	deviceName string,
-	commandName string,
-	ctx context.Context) (string, error) {
+	commandName string) (string, error) {
 
-	return cc.getRequestJSONBody("/name/"+deviceName+"/command/"+commandName, ctx)
+	return cc.getRequestJSONBody(ctx, "/name/"+deviceName+"/command/"+commandName)
 }
 
 func (cc *commandRestClient) PutDeviceCommandByNames(
+	ctx context.Context,
 	deviceName string,
 	commandName string,
-	body string,
-	ctx context.Context) (string, error) {
+	body string) (string, error) {
 
-	return clients.PutRequest("/name/"+deviceName+"/command/"+commandName, []byte(body), ctx, cc.urlClient)
+	return clients.PutRequest(ctx, "/name/"+deviceName+"/command/"+commandName, []byte(body), cc.urlClient)
 }
 
-func (cc *commandRestClient) getRequestJSONBody(urlSuffix string, ctx context.Context) (string, error) {
-	body, err := clients.GetRequest(urlSuffix, ctx, cc.urlClient)
+func (cc *commandRestClient) getRequestJSONBody(ctx context.Context, urlSuffix string) (string, error) {
+	body, err := clients.GetRequest(ctx, urlSuffix, cc.urlClient)
 
 	return string(body), err
 }

clients/command/client_test.go

@@ -21,119 +21,73 @@ import (
 	"testing"
 
 	"github.com/edgexfoundry/go-mod-core-contracts/clients"
-	"github.com/edgexfoundry/go-mod-core-contracts/clients/types"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/interfaces"
+	"github.com/edgexfoundry/go-mod-core-contracts/clients/urlclient"
 )
 
 func TestGetDeviceCommandById(t *testing.T) {
-	ts := testHttpServer(t, http.MethodGet, clients.ApiDeviceRoute+"/device1/command/command1")
+	ts := testHTTPServer(t, http.MethodGet, clients.ApiDeviceRoute+"/device1/command/command1")
 
 	defer ts.Close()
 
-	url := ts.URL + clients.ApiDeviceRoute
+	cc := NewCommandClient(urlclient.NewLocalClient(interfaces.URLStream(ts.URL + clients.ApiDeviceRoute)))
 
-	params := types.EndpointParams{
-		ServiceKey:  clients.CoreCommandServiceKey,
-		Path:        clients.ApiDeviceRoute,
-		UseRegistry: false,
-		Url:         url,
-		Interval:    clients.ClientMonitorDefault,
-	}
-
-	cc := NewCommandClient(params, MockEndpoint{})
-
-	res, _ := cc.Get("device1", "command1", context.Background())
+	res, _ := cc.Get(context.Background(), "device1", "command1")
 
 	if res != "Ok" {
 		t.Errorf("expected response body \"Ok\", but received %s", res)
 	}
 }
 
 func TestPutDeviceCommandById(t *testing.T) {
-	ts := testHttpServer(t, http.MethodPut, clients.ApiDeviceRoute+"/device1/command/command1")
+	ts := testHTTPServer(t, http.MethodPut, clients.ApiDeviceRoute+"/device1/command/command1")
 
 	defer ts.Close()
 
-	url := ts.URL + clients.ApiDeviceRoute
-
-	params := types.EndpointParams{
-		ServiceKey:  clients.CoreCommandServiceKey,
-		Path:        clients.ApiDeviceRoute,
-		UseRegistry: false,
-		Url:         url,
-		Interval:    clients.ClientMonitorDefault,
-	}
-
-	cc := NewCommandClient(params, MockEndpoint{})
+	cc := NewCommandClient(urlclient.NewLocalClient(interfaces.URLStream(ts.URL + clients.ApiDeviceRoute)))
 
-	res, _ := cc.Put("device1", "command1", "body", context.Background())
+	res, _ := cc.Put(context.Background(), "device1", "command1", "body")
 
 	if res != "Ok" {
 		t.Errorf("expected response body \"Ok\", but received %s", res)
 	}
 }
 
 func TestGetDeviceByName(t *testing.T) {
-	ts := testHttpServer(t, http.MethodGet, clients.ApiDeviceRoute+"/name/device1/command/command1")
+	ts := testHTTPServer(t, http.MethodGet, clients.ApiDeviceRoute+"/name/device1/command/command1")
 
 	defer ts.Close()
 
-	url := ts.URL + clients.ApiDeviceRoute
-
-	params := types.EndpointParams{
-		ServiceKey:  clients.CoreCommandServiceKey,
-		Path:        clients.ApiDeviceRoute,
-		UseRegistry: false,
-		Url:         url,
-		Interval:    clients.ClientMonitorDefault,
-	}
-
-	cc := NewCommandClient(params, MockEndpoint{})
+	cc := NewCommandClient(urlclient.NewLocalClient(interfaces.URLStream(ts.URL + clients.ApiDeviceRoute)))
 
-	res, _ := cc.GetDeviceCommandByNames("device1", "command1", context.Background())
+	res, _ := cc.GetDeviceCommandByNames(context.Background(), "device1", "command1")
 
 	if res != "Ok" {
 		t.Errorf("expected response body \"Ok\", but received %s", res)
 	}
 }
 
 func TestPutDeviceCommandByNames(t *testing.T) {
-	ts := testHttpServer(t, http.MethodPut, clients.ApiDeviceRoute+"/name/device1/command/command1")
+	ts := testHTTPServer(t, http.MethodPut, clients.ApiDeviceRoute+"/name/device1/command/command1")
 
 	defer ts.Close()
 
-	url := ts.URL + clients.ApiDeviceRoute
-
-	params := types.EndpointParams{
-		ServiceKey:  clients.CoreCommandServiceKey,
-		Path:        clients.ApiDeviceRoute,
-		UseRegistry: false,
-		Url:         url,
-		Interval:    clients.ClientMonitorDefault,
-	}
-
-	cc := NewCommandClient(params, MockEndpoint{})
+	cc := NewCommandClient(urlclient.NewLocalClient(interfaces.URLStream(ts.URL + clients.ApiDeviceRoute)))
 
-	res, _ := cc.PutDeviceCommandByNames("device1", "command1", "body", context.Background())
+	res, _ := cc.PutDeviceCommandByNames(context.Background(), "device1", "command1", "body")
 
 	if res != "Ok" {
 		t.Errorf("expected response body \"Ok\", but received %s", res)
 	}
 }
 
-type MockEndpoint struct {
-}
-
-func (e MockEndpoint) Monitor(params types.EndpointParams) chan string {
-	return make(chan string, 1)
-}
-
-// testHttpServer instantiates a test HTTP Server to be used for conveniently verifying a client's invocation
-func testHttpServer(t *testing.T, matchingRequestMethod string, matchingRequestUri string) *httptest.Server {
+// testHTTPServer instantiates a test HTTP Server to be used for conveniently verifying a client's invocation
+func testHTTPServer(t *testing.T, matchingRequestMethod string, matchingRequestUri string) *httptest.Server {
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 
 		if r.Method == matchingRequestMethod && r.RequestURI == matchingRequestUri {
-			w.Write([]byte("Ok"))
+			_, _ = w.Write([]byte("Ok"))
 		} else {
 			t.Errorf("expected endpoint %s to be invoked by client, %s invoked", matchingRequestUri, r.RequestURI)
 		}

clients/context.go

@@ -20,7 +20,7 @@ import (
 
 // FromContext allows for the retrieval of the specified key's value from the supplied Context.
 // If the value is not found, an empty string is returned.
-func FromContext(key string, ctx context.Context) string {
+func FromContext(ctx context.Context, key string) string {
 	hdr, ok := ctx.Value(key).(string)
 	if !ok {
 		hdr = ""