fix ping path from docker labels, clarify docs about path (not url) for the destination

README.md

@@ -58,14 +58,14 @@ This is a dynamic provider and file change will be applied automatically.
 
 ### Docker
 
-Docker provider works with no extra configuration and by default redirects all requests like  `https://server/api/<container_name>/(.*)` to the internal IP of given container and the exposed port. Only active (running) containers will be detected.
+Docker provider works with no extra configuration and by default redirects all requests like  `https://server/api/<container_name>/(.*)` to the internal IP of the given container and the exposed port. Only active (running) containers will be detected.
 
 This default can be changed with labels:
 
 - `reproxy.server` - server (hostname) to match
 - `reproxy.route` - source route (location)
-- `reproxy.dest` - destination URL
-- `reproxy.ping` - ping url for the destination container
+- `reproxy.dest` - destination path. Note: this is not full url, but just the path which will be appended to container's ip:port  
+- `reproxy.ping` - ping path for the destination container.
 
 By default all containers with exposed port will be considered as routing destinations. There are 2 ways to restrict it:
 

app/discovery/discovery.go

@@ -137,6 +137,8 @@ func (s *Service) mergeLists() (res []URLMapper) {
 func (s *Service) extendRule(m URLMapper) URLMapper {
 
 	src := m.SrcMatch.String()
+
+	// TODO: Probably should be ok in practice but we better figure a nicer way to do it
 	if strings.Contains(m.Dst, "$1") || strings.Contains(src, "(") || !strings.HasSuffix(src, "/") {
 		return m
 	}

app/discovery/provider/docker.go

@@ -88,7 +88,7 @@ func (d *Docker) List() ([]discovery.URLMapper, error) {
 		srcRegex, err := regexp.Compile(srcURL)
 
 		if v, ok := c.Labels["reproxy.ping"]; ok {
-			pingURL = v
+			pingURL = fmt.Sprintf("http://%s:%d%s", c.IP, c.Port, v)
 		}
 
 		if err != nil {

app/discovery/provider/docker_test.go

@@ -22,7 +22,7 @@ func TestDocker_List(t *testing.T) {
 						{PrivatePort: 12345},
 					},
 					Labels: map[string]string{"reproxy.route": "^/api/123/(.*)", "reproxy.dest": "/blah/$1",
-						"reproxy.server": "example.com", "reproxy.ping": "http://localhost/ping"},
+						"reproxy.server": "example.com", "reproxy.ping": "/ping"},
 				},
 				{Names: []string{"c2"}, State: "running",
 					Networks: dc.NetworkList{
@@ -53,7 +53,7 @@ func TestDocker_List(t *testing.T) {
 	assert.Equal(t, "^/api/123/(.*)", res[0].SrcMatch.String())
 	assert.Equal(t, "http://127.0.0.2:12345/blah/$1", res[0].Dst)
 	assert.Equal(t, "example.com", res[0].Server)
-	assert.Equal(t, "http://localhost/ping", res[0].PingURL)
+	assert.Equal(t, "http://127.0.0.2:12345/ping", res[0].PingURL)
 
 	assert.Equal(t, "^/api/c2/(.*)", res[1].SrcMatch.String())
 	assert.Equal(t, "http://127.0.0.3:12346/$1", res[1].Dst)

docker-compose.yml

@@ -28,3 +28,11 @@ services:
     ports:
       - "9092"
     command: python3 -m http.server 9092
+
+  whoami:
+    image: 'containous/whoami'
+    container_name: whoami
+    labels:
+      reproxy.server: '*'
+      reproxy.route: '^/whoami/(.*)'
+      reproxy.dest: '/$$1'