Build in a way to detect the ES version so it can be used for version-specific things

goes.go

@@ -34,7 +34,7 @@ func (err *SearchError) Error() string {
 // This function is pretty useless for now but might be useful in a near future
 // if wee need more features like connection pooling or load balancing.
 func NewClient(host string, port string) *Client {
-	return &Client{host, port, http.DefaultClient}
+	return &Client{host, port, http.DefaultClient, ""}
 }
 
 // WithHTTPClient sets the http.Client to be used with the connection. Returns the original client.
@@ -43,6 +43,28 @@ func (c *Client) WithHTTPClient(cl *http.Client) *Client {
 	return c
 }
 
+// Version returns the detected version of the connected ES server
+func (c *Client) Version() (string, error) {
+	// Use cached version if it was already fetched
+	if c.version != "" {
+		return c.version, nil
+	}
+
+	// Get the version if it was not cached
+	r := Request{Method: "GET"}
+	res, err := c.Do(&r)
+	if err != nil {
+		return "", err
+	}
+	if version, ok := res.Raw["version"].(map[string]interface{}); ok {
+		if number, ok := version["number"].(string); ok {
+			c.version = number
+			return number, nil
+		}
+	}
+	return "", errors.New("No version returned by ElasticSearch Server")
+}
+
 // CreateIndex creates a new index represented by a name and a mapping
 func (c *Client) CreateIndex(name string, mapping interface{}) (*Response, error) {
 	r := Request{

goes_test.go

@@ -5,7 +5,6 @@
 package goes
 
 import (
-	"encoding/json"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -20,7 +19,6 @@ import (
 var (
 	ESHost = "localhost"
 	ESPort = "9200"
-	ESVersion = "0.0.0"
 )
 
 // Hook up gocheck into the gotest runner.
@@ -40,24 +38,11 @@ func (s *GoesTestSuite) SetUpTest(c *C) {
 	if p != "" {
 		ESPort = p
 	}
-	ESVersion = getESVersion(c, ESHost, ESPort)
-}
-
-func getESVersion(c *C, host, port string) string {
-	res, err := http.Get(fmt.Sprintf("http://%s:%s/", host, port))
-	c.Assert(err, Equals, nil)
-	defer res.Body.Close()
-	decoder := json.NewDecoder(res.Body)
-
-	var info map[string]interface{}
-	err = decoder.Decode(&info)
-	c.Assert(err, Equals, nil)
-	return info["version"].(map[string]interface{})["number"].(string)
 }
 
 func (s *GoesTestSuite) TestNewClient(c *C) {
 	conn := NewClient(ESHost, ESPort)
-	c.Assert(conn, DeepEquals, &Client{ESHost, ESPort, http.DefaultClient})
+	c.Assert(conn, DeepEquals, &Client{ESHost, ESPort, http.DefaultClient, ""})
 }
 
 func (s *GoesTestSuite) TestWithHTTPClient(c *C) {
@@ -70,7 +55,7 @@ func (s *GoesTestSuite) TestWithHTTPClient(c *C) {
 	}
 	conn := NewClient(ESHost, ESPort).WithHTTPClient(cl)
 
-	c.Assert(conn, DeepEquals, &Client{ESHost, ESPort, cl})
+	c.Assert(conn, DeepEquals, &Client{ESHost, ESPort, cl, ""})
 	c.Assert(conn.Client.Transport.(*http.Transport).DisableCompression, Equals, true)
 	c.Assert(conn.Client.Transport.(*http.Transport).ResponseHeaderTimeout, Equals, 1*time.Second)
 }
@@ -945,7 +930,7 @@ func (s *GoesTestSuite) TestScroll(c *C) {
 	c.Assert(err, IsNil)
 
 	var query map[string]interface{}
-	if ESVersion > "5" {
+	if version, _ := conn.Version(); version > "5" {
 		query = map[string]interface{}{
 			"query": map[string]interface{}{
 				"bool": map[string]interface{}{
@@ -1219,7 +1204,7 @@ func (s *GoesTestSuite) TestUpdate(c *C) {
 
 	// Now that we have an ordinary document indexed, try updating it
 	var query map[string]interface{}
-	if ESVersion > "5" {
+	if version, _ := conn.Version(); version > "5" {
 		query = map[string]interface{}{
 			"script": map[string]interface{}{
 				"inline": "ctx._source.counter += params.count",

structs.go

@@ -20,6 +20,9 @@ type Client struct {
 	// Client is the http client used to make requests, allowing settings things
 	// such as timeouts etc
 	Client *http.Client
+
+	// Detected version of ES
+	version string
 }
 
 // Response holds an elasticsearch response