Add CatMaster API

This commit adds the Cat Master API.

Close olivere#1486

README.md

@@ -298,7 +298,7 @@ Here are a few tips on how to get used to Elastic:
 - [X] cat fielddata
 - [X] cat health
 - [X] cat indices
-- [ ] cat master
+- [x] cat master
 - [ ] cat nodeattrs
 - [ ] cat nodes
 - [ ] cat pending tasks

cat_master.go

@@ -0,0 +1,191 @@
+// 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"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+// CatMasterService shows information about the master node,
+// including the ID, bound IP address, and name.
+//
+// See https://www.elastic.co/guide/en/elasticsearch/reference/7.12/cat-master.html
+// for details.
+type CatMasterService struct {
+	client *Client
+
+	pretty     *bool       // pretty format the returned JSON response
+	human      *bool       // return human readable values for statistics
+	errorTrace *bool       // include the stack trace of returned errors
+	filterPath []string    // list of filters used to reduce the response
+	headers    http.Header // custom request-level HTTP headers
+
+	local         *bool
+	masterTimeout string
+	columns       []string
+	sort          []string // list of columns for sort order
+}
+
+// NewCatMasterService creates a new CatMasterService
+func NewCatMasterService(client *Client) *CatMasterService {
+	return &CatMasterService{
+		client: client,
+	}
+}
+
+// Pretty tells Elasticsearch whether to return a formatted JSON response.
+func (s *CatMasterService) Pretty(pretty bool) *CatMasterService {
+	s.pretty = &pretty
+	return s
+}
+
+// Human specifies whether human readable values should be returned in
+// the JSON response, e.g. "7.5mb".
+func (s *CatMasterService) Human(human bool) *CatMasterService {
+	s.human = &human
+	return s
+}
+
+// ErrorTrace specifies whether to include the stack trace of returned errors.
+func (s *CatMasterService) ErrorTrace(errorTrace bool) *CatMasterService {
+	s.errorTrace = &errorTrace
+	return s
+}
+
+// FilterPath specifies a list of filters used to reduce the response.
+func (s *CatMasterService) FilterPath(filterPath ...string) *CatMasterService {
+	s.filterPath = filterPath
+	return s
+}
+
+// Header adds a header to the request.
+func (s *CatMasterService) Header(name string, value string) *CatMasterService {
+	if s.headers == nil {
+		s.headers = http.Header{}
+	}
+	s.headers.Add(name, value)
+	return s
+}
+
+// Headers specifies the headers of the request.
+func (s *CatMasterService) Headers(headers http.Header) *CatMasterService {
+	s.headers = headers
+	return s
+}
+
+// Local indicates to return local information, i.e. do not retrieve
+// the state from master node (default: false).
+func (s *CatMasterService) Local(local bool) *CatMasterService {
+	s.local = &local
+	return s
+}
+
+// MasterTimeout is the explicit operation timeout for connection to master node.
+func (s *CatMasterService) MasterTimeout(masterTimeout string) *CatMasterService {
+	s.masterTimeout = masterTimeout
+	return s
+}
+
+// Columns to return in the response.
+// To get a list of all possible columns to return, run the following command
+// in your terminal:
+//
+// Example:
+//   curl 'http://localhost:9200/_cat/master?help'
+//
+// You can use Columns("*") to return all possible columns. That might take
+// a little longer than the default set of columns.
+func (s *CatMasterService) Columns(columns ...string) *CatMasterService {
+	s.columns = columns
+	return s
+}
+
+// Sort is a list of fields to sort by.
+func (s *CatMasterService) Sort(fields ...string) *CatMasterService {
+	s.sort = fields
+	return s
+}
+
+// buildURL builds the URL for the operation.
+func (s *CatMasterService) buildURL() (string, url.Values, error) {
+	// Build URL
+	path := "/_cat/master"
+
+	// Add query string parameters
+	params := url.Values{
+		"format": []string{"json"}, // always returns as JSON
+	}
+	if v := s.pretty; v != nil {
+		params.Set("pretty", fmt.Sprint(*v))
+	}
+	if v := s.human; v != nil {
+		params.Set("human", fmt.Sprint(*v))
+	}
+	if v := s.errorTrace; v != nil {
+		params.Set("error_trace", fmt.Sprint(*v))
+	}
+	if len(s.filterPath) > 0 {
+		params.Set("filter_path", strings.Join(s.filterPath, ","))
+	}
+	if v := s.local; v != nil {
+		params.Set("local", fmt.Sprint(*v))
+	}
+	if s.masterTimeout != "" {
+		params.Set("master_timeout", s.masterTimeout)
+	}
+	if len(s.sort) > 0 {
+		params.Set("s", strings.Join(s.sort, ","))
+	}
+	if len(s.columns) > 0 {
+		params.Set("h", strings.Join(s.columns, ","))
+	}
+	return path, params, nil
+}
+
+// Do executes the operation.
+func (s *CatMasterService) Do(ctx context.Context) (CatMasterResponse, error) {
+	// 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,
+		Headers: s.headers,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// Return operation response
+	var ret CatMasterResponse
+	if err := s.client.decoder.Decode(res.Body, &ret); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+// -- Result of a get request.
+
+// CatMasterResponse is the outcome of CatMasterService.Do.
+type CatMasterResponse []CatMasterResponseRow
+
+// CatMasterResponseRow is a single row in a CatMasterResponse.
+// Notice that not all of these fields might be filled; that depends
+// on the number of columns chose in the request (see CatMasterService.Columns).
+type CatMasterResponseRow struct {
+	ID   string `json:"id"`
+	Host string `json:"host"`
+	IP   string `json:"ip"`
+	Node string `json:"node"`
+}

cat_master_test.go

@@ -0,0 +1,29 @@
+// 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"
+	"testing"
+)
+
+func TestCatMaster(t *testing.T) {
+	client := setupTestClientAndCreateIndexAndAddDocs(t, SetDecoder(&strictDecoder{})) //, SetTraceLog(log.New(os.Stdout, "", 0)))
+
+	ctx := context.Background()
+	res, err := client.CatMaster().Columns("*").Do(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if res == nil {
+		t.Fatal("want response, have nil")
+	}
+	if len(res) == 0 {
+		t.Fatalf("want response, have: %v", res)
+	}
+	if have := res[0].IP; have == "" {
+		t.Fatalf("IP[0]: want != %q, have %q", "", have)
+	}
+}

client.go

@@ -1885,7 +1885,6 @@ func (c *Client) GetFieldMapping() *IndicesGetFieldMappingService {
 
 // -- cat APIs --
 
-// TODO cat master
 // TODO cat nodes
 // TODO cat pending tasks
 // TODO cat plugins
@@ -1894,6 +1893,11 @@ func (c *Client) GetFieldMapping() *IndicesGetFieldMappingService {
 // TODO cat shards
 // TODO cat segments
 
+// CatMaster returns information about the master node
+func (c *Client) CatMaster() *CatMasterService {
+	return NewCatMasterService(c)
+}
+
 // CatFielddata returns information about the amount of heap memory currently used by the field data cache.
 func (c *Client) CatFielddata() *CatFielddataService {
 	return NewCatFielddataService(c)