Ensure Client is safe for concurrent use

Fixes #6287.

CHANGELOG.md

@@ -16,6 +16,7 @@
 - [#3773](https://github.com/influxdata/influxdb/issues/3773): Support empty tags for all WHERE equality operations.
 - [#6270](https://github.com/influxdata/influxdb/issues/6270): tsm1 query engine alloc reduction
 - [#6271](https://github.com/influxdata/influxdb/issues/6271): Fixed deadlock in tsm1 file store.
+- [#6287](https://github.com/influxdata/influxdb/issues/6287): Fix data race in Influx Client.
 
 ## v0.12.0 [2016-04-05]
 ### Release Notes

client/v2/client.go

@@ -90,7 +90,8 @@ type Client interface {
 	Close() error
 }
 
-// NewHTTPClient creates a client interface from the given config.
+// NewHTTPClient returns a new Client from the provided config.
+// Client is safe for concurrent use by multiple goroutines.
 func NewHTTPClient(conf HTTPConfig) (Client, error) {
 	if conf.UserAgent == "" {
 		conf.UserAgent = "InfluxDBClient"
@@ -114,7 +115,7 @@ func NewHTTPClient(conf HTTPConfig) (Client, error) {
 		tr.TLSClientConfig = conf.TLSConfig
 	}
 	return &client{
-		url:       u,
+		url:       *u,
 		username:  conf.Username,
 		password:  conf.Password,
 		useragent: conf.UserAgent,
@@ -210,8 +211,12 @@ func (uc *udpclient) Close() error {
 	return uc.conn.Close()
 }
 
+// client is safe for concurrent use as the fields are all read-only
+// once the client is instantiated.
 type client struct {
-	url        *url.URL
+	// N.B - if url.UserInfo is accessed in future modifications to the
+	// methods on client, you will need to syncronise access to url.
+	url        url.URL
 	username   string
 	password   string
 	useragent  string

client/v2/client_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http/httptest"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 )
@@ -138,6 +139,54 @@ func TestClient_Ping(t *testing.T) {
 	}
 }
 
+func TestClient_Concurrent_Use(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(`{}`))
+	}))
+	defer ts.Close()
+
+	config := HTTPConfig{Addr: ts.URL}
+	c, _ := NewHTTPClient(config)
+	defer c.Close()
+
+	var wg sync.WaitGroup
+	wg.Add(3)
+	n := 1000
+
+	go func() {
+		defer wg.Done()
+		bp, err := NewBatchPoints(BatchPointsConfig{})
+		if err != nil {
+			t.Errorf("got error %v", err)
+		}
+
+		for i := 0; i < n; i++ {
+			if err = c.Write(bp); err != nil {
+				t.Fatalf("got error %v", err)
+			}
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		var q Query
+		for i := 0; i < n; i++ {
+			if _, err := c.Query(q); err != nil {
+				t.Fatalf("got error %v", err)
+			}
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < n; i++ {
+			c.Ping(time.Second)
+		}
+	}()
+	wg.Wait()
+}
+
 func TestClient_Write(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		var data Response