Improve URL building in the logcli to strip trailing /. (#2000)

Fixes #1985.

Signed-off-by: Cyril Tovena <cyril.tovena@gmail.com>

pkg/logcli/client/client.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"net/http"
 	"net/url"
+	"path"
 	"strings"
 	"time"
 
@@ -119,7 +120,11 @@ func (c *Client) doQuery(path string, quiet bool) (*loghttp.QueryResponse, error
 }
 
 func (c *Client) doRequest(path string, quiet bool, out interface{}) error {
-	us := c.Address + path
+
+	us, err := buildURL(c.Address, path)
+	if err != nil {
+		return err
+	}
 	if !quiet {
 		log.Print(us)
 	}
@@ -175,7 +180,10 @@ func (c *Client) LiveTailQueryConn(queryStr string, delayFor int, limit int, fro
 }
 
 func (c *Client) wsConnect(path string, quiet bool) (*websocket.Conn, error) {
-	us := c.Address + path
+	us, err := buildURL(c.Address, path)
+	if err != nil {
+		return nil, err
+	}
 
 	tlsConfig, err := config.NewTLSConfig(&c.TLSConfig)
 	if err != nil {
@@ -213,3 +221,13 @@ func (c *Client) wsConnect(path string, quiet bool) (*websocket.Conn, error) {
 
 	return conn, nil
 }
+
+// buildURL concats a url `http://foo/bar` with a path `/buzz`.
+func buildURL(u, p string) (string, error) {
+	url, err := url.Parse(u)
+	if err != nil {
+		return "", err
+	}
+	url.Path = path.Join(url.Path, p)
+	return url.String(), nil
+}

pkg/logcli/client/client_test.go

@@ -0,0 +1,28 @@
+package client
+
+import "testing"
+
+func Test_buildURL(t *testing.T) {
+	tests := []struct {
+		name    string
+		u, p    string
+		want    string
+		wantErr bool
+	}{
+		{"err", "8://2", "/bar", "", true},
+		{"strip /", "http://localhost//", "//bar", "http://localhost/bar", false},
+		{"sub path", "https://localhost/loki/", "/bar/foo", "https://localhost/loki/bar/foo", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := buildURL(tt.u, tt.p)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("buildURL() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("buildURL() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}