Merge pull request #5598 from PSUdaemon/client_ping

Add Ping() to v2 client.

client/v2/client.go

@@ -73,6 +73,9 @@ type BatchPointsConfig struct {
 
 // Client is a client interface for writing & querying the database
 type Client interface {
+	// Ping checks that status of cluster
+	Ping(timeout time.Duration) (time.Duration, string, error)
+
 	// Write takes a BatchPoints object and writes all Points to InfluxDB.
 	Write(bp BatchPoints) error
 
@@ -119,6 +122,50 @@ func NewHTTPClient(conf HTTPConfig) (Client, error) {
 	}, nil
 }
 
+// Ping will check to see if the server is up with an optional timeout on waiting for leader.
+// Ping returns how long the request took, the version of the server it connected to, and an error if one occurred.
+func (c *client) Ping(timeout time.Duration) (time.Duration, string, error) {
+	now := time.Now()
+	u := c.url
+	u.Path = "ping"
+
+	req, err := http.NewRequest("GET", u.String(), nil)
+	if err != nil {
+		return 0, "", err
+	}
+
+	req.Header.Set("User-Agent", c.useragent)
+
+	if c.username != "" {
+		req.SetBasicAuth(c.username, c.password)
+	}
+
+	if timeout > 0 {
+		params := req.URL.Query()
+		params.Set("wait_for_leader", fmt.Sprintf("%.0fs", timeout.Seconds()))
+		req.URL.RawQuery = params.Encode()
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return 0, "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return 0, "", err
+	}
+
+	if resp.StatusCode != http.StatusNoContent {
+		var err = fmt.Errorf(string(body))
+		return 0, "", err
+	}
+
+	version := resp.Header.Get("X-Influxdb-Version")
+	return time.Since(now), version, nil
+}
+
 // Close releases the client's resources.
 func (c *client) Close() error {
 	return nil
@@ -149,6 +196,12 @@ func NewUDPClient(conf UDPConfig) (Client, error) {
 	}, nil
 }
 
+// Ping will check to see if the server is up with an optional timeout on waiting for leader.
+// Ping returns how long the request took, the version of the server it connected to, and an error if one occurred.
+func (uc *udpclient) Ping(timeout time.Duration) (time.Duration, string, error) {
+	return 0, "", nil
+}
+
 // Close releases the udpclient's resources.
 func (uc *udpclient) Close() error {
 	return uc.conn.Close()

client/v2/client_test.go

@@ -24,6 +24,20 @@ func TestUDPClient_Query(t *testing.T) {
 	}
 }
 
+func TestUDPClient_Ping(t *testing.T) {
+	config := UDPConfig{Addr: "localhost:8089"}
+	c, err := NewUDPClient(config)
+	if err != nil {
+		t.Errorf("unexpected error.  expected %v, actual %v", nil, err)
+	}
+	defer c.Close()
+
+	rtt, version, err := c.Ping(0)
+	if rtt != 0 || version != "" || err != nil {
+		t.Errorf("unexpected error.  expected (%v, '%v', %v), actual (%v, '%v', %v)", 0, "", nil, rtt, version, err)
+	}
+}
+
 func TestUDPClient_Write(t *testing.T) {
 	config := UDPConfig{Addr: "localhost:8089"}
 	c, err := NewUDPClient(config)
@@ -106,6 +120,24 @@ func TestClient_BasicAuth(t *testing.T) {
 	}
 }
 
+func TestClient_Ping(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var data Response
+		w.WriteHeader(http.StatusNoContent)
+		_ = json.NewEncoder(w).Encode(data)
+	}))
+	defer ts.Close()
+
+	config := HTTPConfig{Addr: ts.URL}
+	c, _ := NewHTTPClient(config)
+	defer c.Close()
+
+	_, _, err := c.Ping(0)
+	if err != nil {
+		t.Errorf("unexpected error.  expected %v, actual %v", nil, err)
+	}
+}
+
 func TestClient_Write(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		var data Response

client/v2/example_test.go

@@ -55,6 +55,23 @@ func ExampleClient_uDP() {
 	c.Write(bp)
 }
 
+// Ping the cluster using the HTTP client
+func ExampleClient_Ping() {
+	// Make client
+	c, err := client.NewHTTPClient(client.HTTPConfig{
+		Addr: "http://localhost:8086",
+	})
+	if err != nil {
+		fmt.Println("Error creating InfluxDB Client: ", err.Error())
+	}
+	defer c.Close()
+
+	_, _, err = c.Ping(0)
+	if err != nil {
+		fmt.Println("Error pinging InfluxDB Cluster: ", err.Error())
+	}
+}
+
 // Write a point using the HTTP client
 func ExampleClient_write() {
 	// Make client