Dial functions; import path changes for Go 1.11

This commit prepares the 6.2.0 release. It comes with the following
set of changes.

First, we fix the import path to work correctly with Go modules
introduced in Go 1.11. Notice that this change requires using
Go 1.10.4+ or later. If you're on an earlier version of Go, consider
updating or use `6.1.x` until you can.

Second, we add a set of `Dial` functions, i.e. `Dial`, `DialContext`,
and `DialWithConfig` to better align with the standard library in terms
of keeping a long-running TCP connection with a resource, in our case:
Elasticsearch.

In v6, the `Dial` functions will be kept as an alias to `NewClient`.
This might change in v7.

Also, the `DialContext` and `DialWithConfig` functions allow to pass a
context to be able to cancel connecting early. Notice that cancelation
can happen both due to the context being canceled, or because of a
configured timeout, e.g. via `SetHealthcheckTimeoutStartup`, whichever
timeout comes first (close #815).

Author: olivere

README.md

@@ -24,7 +24,7 @@ Here's the version matrix:
 
 Elasticsearch version | Elastic version  | Package URL | Remarks |
 ----------------------|------------------|-------------|---------|
-6.x                   | 6.0              | [`github.com/olivere/elastic`](https://github.com/olivere/elastic) ([source](https://github.com/olivere/elastic/tree/release-branch.v6) [doc](http://godoc.org/github.com/olivere/elastic)) | Use a dependency manager (see below).
+6.x                   | 6.0              | [`github.com/olivere/elastic/v6`](https://github.com/olivere/elastic) ([source](https://github.com/olivere/elastic/tree/release-branch.v6) [doc](http://godoc.org/github.com/olivere/elastic)) | Use a dependency manager (see below).
 5.x                   | 5.0              | [`gopkg.in/olivere/elastic.v5`](https://gopkg.in/olivere/elastic.v5) ([source](https://github.com/olivere/elastic/tree/release-branch.v5) [doc](http://godoc.org/gopkg.in/olivere/elastic.v5)) | Actively maintained.
 2.x                   | 3.0              | [`gopkg.in/olivere/elastic.v3`](https://gopkg.in/olivere/elastic.v3) ([source](https://github.com/olivere/elastic/tree/release-branch.v3) [doc](http://godoc.org/gopkg.in/olivere/elastic.v3)) | Deprecated. Please update.
 1.x                   | 2.0              | [`gopkg.in/olivere/elastic.v2`](https://gopkg.in/olivere/elastic.v2) ([source](https://github.com/olivere/elastic/tree/release-branch.v2) [doc](http://godoc.org/gopkg.in/olivere/elastic.v2)) | Deprecated. Please update.
@@ -39,15 +39,22 @@ To use the required version of Elastic in your application, it is strongly
 advised to use a tool like
 [dep](https://github.com/golang/dep)
 or
-[Glide](https://glide.sh/)
-to manage that dependency. Make sure to use a version such as `^6.0.0`.
+[Go modules](https://github.com/golang/go/wiki/Modules)
+to manage dependencies. Make sure to use a version such as `^6.0.0`.
 
-To use Elastic, simply import:
+To use Elastic with Go 1.10.2 or earlier, import:
 
 ```go
 import "github.com/olivere/elastic"
 ```
 
+If you're using Go 1.11 (or Go 1.10.3+) with modules support, make sure
+to import Elastic like this:
+
+```go
+import "github.com/olivere/elastic/v6"
+```
+
 ### Elastic 6.0
 
 Elastic 6.0 targets Elasticsearch 6.x which was [released on 14th November 2017](https://www.elastic.co/blog/elasticsearch-6-0-0-released).

aws/sign_v4_test.go

@@ -11,8 +11,9 @@ import (
 	"net/http/httptest"
 	"testing"
 
-	"github.com/olivere/elastic"
 	"github.com/smartystreets/go-aws-auth"
+
+	"github.com/olivere/elastic/v6"
 )
 
 func TestSigningClient(t *testing.T) {

bulk.go

@@ -11,7 +11,7 @@ import (
 	"fmt"
 	"net/url"
 
-	"github.com/olivere/elastic/uritemplates"
+	"github.com/olivere/elastic/v6/uritemplates"
 )
 
 // BulkService allows for batching bulk requests and sending them to

bulk_processor.go

@@ -574,7 +574,7 @@ func (w *bulkWorker) waitForActiveConnection(ready chan<- struct{}) {
 				return
 			}
 		case <-t.C:
-			client.healthcheck(time.Duration(3)*time.Second, true)
+			client.healthcheck(context.Background(), time.Duration(3)*time.Second, true)
 			if client.mustActiveConn() == nil {
 				// found an active connection
 				// exit and signal done to the WaitGroup

cat_aliases.go

@@ -10,7 +10,7 @@ import (
 	"net/url"
 	"strings"
 
-	"github.com/olivere/elastic/uritemplates"
+	"github.com/olivere/elastic/v6/uritemplates"
 )
 
 // CatAliasesService shows information about currently configured aliases

cat_allocation.go

@@ -10,7 +10,7 @@ import (
 	"net/url"
 	"strings"
 
-	"github.com/olivere/elastic/uritemplates"
+	"github.com/olivere/elastic/v6/uritemplates"
 )
 
 // CatAllocationService provides a snapshot of how many shards are allocated

cat_count.go

@@ -10,7 +10,7 @@ import (
 	"net/url"
 	"strings"
 
-	"github.com/olivere/elastic/uritemplates"
+	"github.com/olivere/elastic/v6/uritemplates"
 )
 
 // CatCountService provides quick access to the document count of the entire cluster,

cat_indices.go

@@ -10,7 +10,7 @@ import (
 	"net/url"
 	"strings"
 
-	"github.com/olivere/elastic/uritemplates"
+	"github.com/olivere/elastic/v6/uritemplates"
 )
 
 // CatIndicesService returns the list of indices plus some additional