For intelsdi-x#260 Add url checking and comment about invalid target

mgmt/rest/client/client.go

@@ -35,6 +35,8 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/asaskevich/govalidator"
+
 	"github.com/intelsdi-x/snap/mgmt/rest/rbody"
 )
 
@@ -91,7 +93,6 @@ func New(url, ver string, insecure bool) *Client {
 		},
 	}
 	c.prefix = url + "/" + ver
-	// TODO (danielscottt): assert that path is valid and target is available
 	return c
 }
 
@@ -111,14 +112,19 @@ func (c *Client) do(method, path string, ct contentType, body ...[]byte) (*rbody
 		rsp *http.Response
 		err error
 	)
+	// URL validation
+	validURL := govalidator.IsURL(c.prefix + path)
+	if !validURL {
+		return nil, errors.New("URL is not in the format of http(s)://<ip>:<port>")
+	}
 	switch method {
 	case "GET":
 		rsp, err = c.http.Get(c.prefix + path)
 		if err != nil {
 			if strings.Contains(err.Error(), "tls: oversized record") || strings.Contains(err.Error(), "malformed HTTP response") {
 				return nil, fmt.Errorf("error connecting to API URI: %s. Do you have an http/https mismatch?", c.URL)
 			}
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 	case "PUT":
 		var b *bytes.Reader
@@ -130,14 +136,14 @@ func (c *Client) do(method, path string, ct contentType, body ...[]byte) (*rbody
 		req, err := http.NewRequest("PUT", c.prefix+path, b)
 		req.Header.Add("Content-Type", ct.String())
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 		rsp, err = c.http.Do(req)
 		if err != nil {
 			if strings.Contains(err.Error(), "tls: oversized record") || strings.Contains(err.Error(), "malformed HTTP response") {
 				return nil, fmt.Errorf("error connecting to API URI: %s. Do you have an http/https mismatch?", c.URL)
 			}
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 	case "DELETE":
 		var b *bytes.Reader
@@ -149,14 +155,14 @@ func (c *Client) do(method, path string, ct contentType, body ...[]byte) (*rbody
 		req, err := http.NewRequest("DELETE", c.prefix+path, b)
 		req.Header.Add("Content-Type", "application/json")
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 		rsp, err = c.http.Do(req)
 		if err != nil {
 			if strings.Contains(err.Error(), "tls: oversized record") || strings.Contains(err.Error(), "malformed HTTP response") {
 				return nil, fmt.Errorf("error connecting to API URI: %s. Do you have an http/https mismatch?", c.URL)
 			}
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 	case "POST":
 		var b *bytes.Reader
@@ -170,7 +176,7 @@ func (c *Client) do(method, path string, ct contentType, body ...[]byte) (*rbody
 			if strings.Contains(err.Error(), "tls: oversized record") || strings.Contains(err.Error(), "malformed HTTP response") {
 				return nil, fmt.Errorf("error connecting to API URI: %s. Do you have an http/https mismatch?", c.URL)
 			}
-			return nil, err
+			return nil, fmt.Errorf("URL target is not available. %v", err)
 		}
 	}
 
@@ -237,7 +243,7 @@ func (c *Client) pluginUploadRequest(pluginPaths []string) (*rbody.APIResponse,
 
 	req, err := http.NewRequest("POST", c.prefix+"/plugins", pr)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("URL target is not available. %v", err)
 	}
 
 	req.Header.Add("Content-Type", writer.FormDataContentType())
@@ -249,7 +255,7 @@ func (c *Client) pluginUploadRequest(pluginPaths []string) (*rbody.APIResponse,
 		if strings.Contains(err.Error(), "tls: oversized record") || strings.Contains(err.Error(), "malformed HTTP response") {
 			return nil, fmt.Errorf("error connecting to API URI: %s. Do you have an http/https mismatch?", c.URL)
 		}
-		return nil, err
+		return nil, fmt.Errorf("URL target is not available. %v", err)
 	}
 	cErr := <-errChan
 	if cErr != nil {