Add support for getting snapshots for a repository (#983)

The commit adds the Snapshot Get API specified in the [REST API spec](https://github.com/elastic/elasticsearch/blob/6.x/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json).

client.go

@@ -1830,6 +1830,11 @@ func (c *Client) SnapshotGetRepository(repositories ...string) *SnapshotGetRepos
 	return NewSnapshotGetRepositoryService(c).Repository(repositories...)
 }
 
+// SnapshotGet lists snapshot for a repository.
+func (c *Client) SnapshotGet(repository string) *SnapshotGetService {
+	return NewSnapshotGetService(c).Repository(repository)
+}
+
 // SnapshotVerifyRepository verifies a snapshot repository.
 func (c *Client) SnapshotVerifyRepository(repository string) *SnapshotVerifyRepositoryService {
 	return NewSnapshotVerifyRepositoryService(c).Repository(repository)

snapshot_create.go

@@ -9,7 +9,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/url"
-	"time"
 
 	"github.com/olivere/elastic/uritemplates"
 )
@@ -172,20 +171,5 @@ type SnapshotCreateResponse struct {
 	Accepted *bool `json:"accepted"`
 
 	// Snapshot is available when waitForCompletion is true.
-	Snapshot *struct {
-		Snapshot          string                 `json:"snapshot"`
-		UUID              string                 `json:"uuid"`
-		VersionID         int                    `json:"version_id"`
-		Version           string                 `json:"version"`
-		Indices           []string               `json:"indices"`
-		State             string                 `json:"state"`
-		Reason            string                 `json:"reason"`
-		StartTime         time.Time              `json:"start_time"`
-		StartTimeInMillis int64                  `json:"start_time_in_millis"`
-		EndTime           time.Time              `json:"end_time"`
-		EndTimeInMillis   int64                  `json:"end_time_in_millis"`
-		DurationInMillis  int64                  `json:"duration_in_millis"`
-		Failures          []SnapshotShardFailure `json:"failures"`
-		Shards            *ShardsInfo            `json:"shards"`
-	} `json:"snapshot"`
+	Snapshot *Snapshot `json:"snapshot"`
 }

snapshot_get.go

@@ -0,0 +1,165 @@
+// Copyright 2012-present Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/olivere/elastic/uritemplates"
+)
+
+// SnapshotGetService lists the snapshots on a repository
+// See https://www.elastic.co/guide/en/elasticsearch/reference/6.2/modules-snapshots.html
+// for details.
+type SnapshotGetService struct {
+	client            *Client
+	repository        string
+	snapshot          []string
+	masterTimeout     string
+	ignoreUnavailable bool
+	verbose           bool
+}
+
+// NewSnapshotGetService creates a new SnapshotGetService.
+func NewSnapshotGetService(client *Client) *SnapshotGetService {
+	return &SnapshotGetService{
+		client:   client,
+		snapshot: make([]string, 0),
+	}
+}
+
+// Repository is the repository name.
+func (s *SnapshotGetService) Repository(repository string) *SnapshotGetService {
+	s.repository = repository
+	return s
+}
+
+// Snapshot is the list of snapshot names. If not set, defaults to all snapshots.
+func (s *SnapshotGetService) Snapshot(snapshots ...string) *SnapshotGetService {
+	s.snapshot = append(s.snapshot, snapshots...)
+	return s
+}
+
+// MasterTimeout specifies an explicit operation timeout for connection to master node.
+func (s *SnapshotGetService) MasterTimeout(masterTimeout string) *SnapshotGetService {
+	s.masterTimeout = masterTimeout
+	return s
+}
+
+// IgnoreUnavailable specifies whether to ignore unavailable snapshots, defaults to false
+func (s *SnapshotGetService) IgnoreUnavailable(ignoreUnavailable bool) *SnapshotGetService {
+	s.ignoreUnavailable = ignoreUnavailable
+	return s
+}
+
+// Verbose specifies whether to show verbose snapshot info or only show the basic info found in the repository index blob
+func (s *SnapshotGetService) Verbose(verbose bool) *SnapshotGetService {
+	s.verbose = verbose
+	return s
+}
+
+// buildURL builds the URL for the operation.
+func (s *SnapshotGetService) buildURL() (string, url.Values, error) {
+	// Build URL
+	var err error
+	var path string
+	if len(s.snapshot) > 0 {
+		path, err = uritemplates.Expand("/_snapshot/{repository}/{snapshot}", map[string]string{
+			"repository": s.repository,
+			"snapshot":   strings.Join(s.snapshot, ","),
+		})
+	} else {
+		path, err = uritemplates.Expand("/_snapshot/{repository}/_all", map[string]string{
+			"repository": s.repository,
+		})
+	}
+	if err != nil {
+		return "", url.Values{}, err
+	}
+
+	// Add query string parameters
+	params := url.Values{}
+	if s.masterTimeout != "" {
+		params.Set("master_timeout", s.masterTimeout)
+	}
+	if s.ignoreUnavailable {
+		params.Set("ignore_unavailable", "true")
+	}
+	if s.verbose {
+		params.Set("verbose", "true")
+	}
+	return path, params, nil
+}
+
+// Validate checks if the operation is valid.
+func (s *SnapshotGetService) Validate() error {
+	var invalid []string
+	if s.repository == "" {
+		invalid = append(invalid, "Repository")
+	}
+	if len(invalid) > 0 {
+		return fmt.Errorf("missing required fields: %v", invalid)
+	}
+	return nil
+}
+
+// Do executes the operation.
+func (s *SnapshotGetService) Do(ctx context.Context) (*SnapshotGetResponse, error) {
+	// Check pre-conditions
+	if err := s.Validate(); err != nil {
+		return nil, err
+	}
+
+	// Get URL for request
+	path, params, err := s.buildURL()
+	if err != nil {
+		return nil, err
+	}
+
+	// Get HTTP response
+	res, err := s.client.PerformRequest(ctx, PerformRequestOptions{
+		Method: "GET",
+		Path:   path,
+		Params: params,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// Return operation response
+	ret := new(SnapshotGetResponse)
+	if err := json.Unmarshal(res.Body, ret); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+// SnapshotGetResponse is the response of SnapshotGetService.Do.
+type SnapshotGetResponse struct {
+	Snapshots []*Snapshot `json:"snapshots"`
+}
+
+// Snapshot contains all information about a single snapshot
+type Snapshot struct {
+	Snapshot          string                 `json:"snapshot"`
+	UUID              string                 `json:"uuid"`
+	VersionID         int                    `json:"version_id"`
+	Version           string                 `json:"version"`
+	Indices           []string               `json:"indices"`
+	State             string                 `json:"state"`
+	Reason            string                 `json:"reason"`
+	StartTime         time.Time              `json:"start_time"`
+	StartTimeInMillis int64                  `json:"start_time_in_millis"`
+	EndTime           time.Time              `json:"end_time"`
+	EndTimeInMillis   int64                  `json:"end_time_in_millis"`
+	DurationInMillis  int64                  `json:"duration_in_millis"`
+	Failures          []SnapshotShardFailure `json:"failures"`
+	Shards            *ShardsInfo            `json:"shards"`
+}

snapshot_get_test.go

@@ -0,0 +1,77 @@
+package elastic
+
+import (
+	"net/url"
+	"reflect"
+	"testing"
+)
+
+func TestSnapshotGetValidate(t *testing.T) {
+	var client *Client
+
+	err := NewSnapshotGetService(client).Validate()
+	got := err.Error()
+	expected := "missing required fields: [Repository]"
+	if got != expected {
+		t.Errorf("expected %q; got: %q", expected, got)
+	}
+}
+
+func TestSnapshotGetURL(t *testing.T) {
+	client := setupTestClient(t)
+
+	tests := []struct {
+		Repository        string
+		Snapshot          []string
+		MasterTimeout     string
+		IgnoreUnavailable bool
+		Verbose           bool
+		ExpectedPath      string
+		ExpectedParams    url.Values
+	}{
+		{
+			Repository:        "repo",
+			Snapshot:          []string{},
+			MasterTimeout:     "60s",
+			IgnoreUnavailable: true,
+			Verbose:           true,
+			ExpectedPath:      "/_snapshot/repo/_all",
+			ExpectedParams: url.Values{
+				"master_timeout":     []string{"60s"},
+				"ignore_unavailable": []string{"true"},
+				"verbose":            []string{"true"},
+			},
+		},
+		{
+			Repository:        "repo",
+			Snapshot:          []string{"snapA", "snapB"},
+			MasterTimeout:     "60s",
+			IgnoreUnavailable: true,
+			Verbose:           true,
+			ExpectedPath:      "/_snapshot/repo/snapA%2CsnapB",
+			ExpectedParams: url.Values{
+				"master_timeout":     []string{"60s"},
+				"ignore_unavailable": []string{"true"},
+				"verbose":            []string{"true"},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		path, params, err := client.SnapshotGet(test.Repository).
+			MasterTimeout(test.MasterTimeout).
+			Snapshot(test.Snapshot...).
+			IgnoreUnavailable(true).
+			Verbose(true).
+			buildURL()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if path != test.ExpectedPath {
+			t.Errorf("expected %q; got: %q", test.ExpectedPath, path)
+		}
+		if !reflect.DeepEqual(params, test.ExpectedParams) {
+			t.Errorf("expected %q; got: %q", test.ExpectedParams, params)
+		}
+	}
+}