Allow log requests to specify a namespace filter

**What**
- Add `Namespace` field to the log request and response so that users
  can specify the namespace of the function.  This is required to
  support the new multi-namespace support. Using this, a user can
  deploy a function with the same name to multiple namespaces. E.g. to
  `dev` and `prod` namespaces. The namespace field is required so that
  the user can target the specific deployment of the function.  It is
  expected the that the empty namespace will be treated as "in the
  default namespace"

  Note that this does not actually implement any filtering logic, it
  only allows the log providers to accept and return the information.
  faas-provider and log-provider implementation will need to update
  and handle the new field accordingly.

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

logs/example/main.go

@@ -30,6 +30,7 @@ func (s staticLogRequestor) Query(ctx context.Context, r logs.Request) (<-chan l
 
 			resp <- logs.Message{
 				Name:      r.Name,
+				Namespace: r.Namespace,
 				Instance:  "fake",
 				Timestamp: time.Now(),
 				Text:      m,

logs/handler.go

@@ -107,6 +107,7 @@ func NewLogHandlerFunc(requestor Requester, timeout time.Duration) http.HandlerF
 func parseRequest(r *http.Request) (logRequest Request, err error) {
 	query := r.URL.Query()
 	logRequest.Name = getValue(query, "name")
+	logRequest.Namespace = getValue(query, "namespace")
 	logRequest.Instance = getValue(query, "instance")
 	tailStr := getValue(query, "tail")
 	if tailStr != "" {

logs/handler_test.go

@@ -19,7 +19,7 @@ func Test_logsHandlerDoesNotLeakGoroutinesWhenProviderClosesStream(t *testing.T)
 	defer goleak.VerifyNoLeaks(t)
 
 	msgs := []Message{
-		Message{Name: "funcFoo", Text: "msg 0"},
+		Message{Name: "funcFoo", Text: "msg 0", Namespace: "default"},
 		Message{Name: "funcFoo", Text: "msg 1"},
 	}
 
@@ -54,7 +54,7 @@ func Test_logsHandlerDoesNotLeakGoroutinesWhenClientClosesConnection(t *testing.
 	defer goleak.VerifyNoLeaks(t)
 
 	msgs := []Message{
-		Message{Name: "funcFoo", Text: "msg 0"},
+		Message{Name: "funcFoo", Text: "msg 0", Namespace: "default"},
 		Message{Name: "funcFoo", Text: "msg 1"},
 	}
 
@@ -103,12 +103,6 @@ func Test_GETRequestParsing(t *testing.T) {
 			err:             "",
 			expectedRequest: Request{Name: "foobar"},
 		},
-		{
-			name:            "name only query",
-			rawQueryStr:     "name=foobar",
-			err:             "",
-			expectedRequest: Request{Name: "foobar"},
-		},
 		{
 			name:            "multiple name values selects the last value",
 			rawQueryStr:     "name=foobar&name=theactual name",
@@ -117,13 +111,14 @@ func Test_GETRequestParsing(t *testing.T) {
 		},
 		{
 			name:        "valid request with every parameter",
-			rawQueryStr: "name=foobar&since=2019-02-16T09%3A10%3A06%2B00%3A00&tail=5&follow=true",
+			rawQueryStr: "name=foobar&since=2019-02-16T09%3A10%3A06%2B00%3A00&tail=5&follow=true&namespace=default",
 			err:         "",
 			expectedRequest: Request{
-				Name:   "foobar",
-				Since:  &sinceTime,
-				Tail:   5,
-				Follow: true,
+				Name:      "foobar",
+				Namespace: "default",
+				Since:     &sinceTime,
+				Tail:      5,
+				Follow:    true,
 			},
 		},
 	}

logs/logs.go

@@ -16,6 +16,9 @@ import (
 type Request struct {
 	// Name is the function name and is required
 	Name string `json:"name"`
+	// Namespace is the namespace the function is deployed to, how a namespace is defined
+	// is faas-provider specific
+	Namespace string `json:"namespace"`
 	// Instance is the optional container name, that allows you to request logs from a specific function instance
 	Instance string `json:"instance"`
 	// Since is the optional datetime value to start the logs from
@@ -29,13 +32,19 @@ type Request struct {
 // String implements that Stringer interface and prints the log Request in a consistent way that
 // allows you to safely compare if two requests have the same value.
 func (r Request) String() string {
-	return fmt.Sprintf("name:%s instance:%s since:%v tail:%d follow:%v", r.Name, r.Instance, r.Since, r.Tail, r.Follow)
+	return fmt.Sprintf(
+		"name:%s namespace: %s instance:%s since:%v tail:%d follow:%v",
+		r.Name, r.Namespace, r.Instance, r.Since, r.Tail, r.Follow,
+	)
 }
 
 // Message is a specific log message from a function container log stream
 type Message struct {
 	// Name is the function name
 	Name string `json:"name"`
+	// Namespace is the namespace the function is deployed to, how a namespace is defined
+	// is faas-provider specific
+	Namespace string `json:"namespace"`
 	// instance is the name/id of the specific function instance
 	Instance string `json:"instance"`
 	// Timestamp is the timestamp of when the log message was recorded
@@ -46,5 +55,8 @@ type Message struct {
 
 // String implements the Stringer interface and allows for nice and simple string formatting of a log Message.
 func (m Message) String() string {
-	return fmt.Sprintf("%s %s (%s) %s", m.Timestamp.String(), m.Name, m.Instance, m.Text)
+	return fmt.Sprintf(
+		"%s %s (%s %s) %s",
+		m.Timestamp.String(), m.Name, m.Namespace, m.Instance, m.Text,
+	)
 }