enhanced default cluster selection, add 'cluster switch', overhaul json header setting (#47)

pkg/cfg/cluster.go

@@ -0,0 +1,126 @@
+/*
+Copyright © 2026 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+package cfg
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"os"
+
+	"github.com/elastic/elastic-transport-go/v8/elastictransport"
+	"github.com/elastic/go-elasticsearch/v9"
+	"gopkg.in/yaml.v3"
+)
+
+// used in general config struct
+type Cluster struct {
+	Uri, User, Pass string
+	client          *elasticsearch.TypedClient
+	Default         bool
+}
+
+// used just for writing back to the config file
+type ClusterConfig struct {
+	Uri, User, Pass string
+	Default         bool
+}
+
+// to write the config, we avoid all other config settings
+type WriteConfig struct {
+	Clusters map[string]*ClusterConfig
+}
+
+func (cluster *Cluster) ES() *elasticsearch.TypedClient {
+	if cluster.client == nil {
+		fmt.Println("no current cluster, use 'esctl cluster switch <name>' to set one")
+		os.Exit(1)
+	}
+
+	return cluster.client
+}
+
+func (cluster *Cluster) SetClient(client *elasticsearch.TypedClient) {
+	cluster.client = client
+}
+
+// set Default=true for the given cluster in the config (if exists)
+func (conf *Config) SwitchCluster(name string) error {
+	_, exists := conf.Clusters[name]
+	if !exists {
+		return errors.New("no cluster with that name configured")
+	}
+
+	cfg := WriteConfig{Clusters: map[string]*ClusterConfig{}}
+
+	for clustername, cluster := range conf.Clusters {
+		cfg.Clusters[clustername] = &ClusterConfig{
+			Uri:     cluster.Uri,
+			User:    cluster.User,
+			Pass:    cluster.Pass,
+			Default: false,
+		}
+
+		if clustername == name {
+			cfg.Clusters[clustername].Default = true
+		}
+	}
+
+	raw, err := yaml.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("failed to marshal cluster config: %w", err)
+	}
+
+	outfile := getDefaultPath()
+	if conf.ConfigFile != "" {
+		outfile = conf.ConfigFile
+	}
+
+	if err := os.WriteFile(outfile, raw, 0600); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (conf *Config) SetupES() error {
+	// These headers are  not needed with ES 9, but with  ES 8, we set
+	// them here  so every API call uses it.  The only exception being
+	// the api repl, which does it on its own.
+	headers := http.Header{}
+	headers.Add("content-type", "application/json")
+	headers.Add("Accept", "application/json")
+
+	for _, cluster := range conf.Clusters {
+		es, err := elasticsearch.NewTyped(
+			elasticsearch.WithAddresses(cluster.Uri),
+			elasticsearch.WithBasicAuth(cluster.User, cluster.Pass),
+			elasticsearch.WithTransportOptions(
+				conf.getTransport(),
+				elastictransport.WithHeader(headers),
+			),
+		)
+
+		if err != nil {
+			return fmt.Errorf("failed to setup elasticsearch connection: %w", err)
+		}
+
+		cluster.SetClient(es)
+	}
+
+	return nil
+}

pkg/cfg/config.go

@@ -17,25 +17,18 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package cfg
 
 import (
-	"bytes"
-	"context"
-	"crypto/tls"
-	"encoding/json"
 	"errors"
 	"fmt"
-	"log/slog"
-	"net/http"
 	"os"
+	"path/filepath"
 	"reflect"
 
 	"github.com/alecthomas/repr"
-	"github.com/elastic/elastic-transport-go/v8/elastictransport"
-	"github.com/elastic/go-elasticsearch/v9"
 	"gopkg.in/yaml.v3"
 )
 
 const (
-	Version string = `v0.0.20`
+	Version string = `v0.0.21`
 )
 
 var (
@@ -43,11 +36,6 @@ var (
 	APIVERSION, GOVERSION, BUILD, COMMIT, BRANCH string
 )
 
-type Cluster struct {
-	Uri, User, Pass string
-	ES              *elasticsearch.TypedClient
-}
-
 type Config struct {
 	ConfigFile     string // -c
 	CurrentCluster string // -C
@@ -119,8 +107,12 @@ func NewConfig() *Config {
 	return &Config{Clusters: map[string]*Cluster{}}
 }
 
+func getDefaultPath() string {
+	return filepath.Join([]string{os.Getenv("HOME"), ".config", "esctl", "config.yaml"}...)
+}
+
 func (conf *Config) Init() error {
-	DefaultConfig := os.Getenv("HOME") + "/.config/esctl/config.yaml"
+	DefaultConfig := getDefaultPath()
 
 	switch {
 	case fileExists(DefaultConfig):
@@ -141,29 +133,35 @@ func (conf *Config) Init() error {
 	}
 
 	if conf.CurrentCluster != "" {
+		// -C specified, set current cluster explicitly, no matter what the config says
 		current, exists := conf.Clusters[conf.CurrentCluster]
 		if !exists {
 			return fmt.Errorf("no cluster with alias %s configured", conf.CurrentCluster)
 		} else {
 			conf.DefaultCluster = current
+
+			// disable all others
+			for _, cluster := range conf.Clusters {
+				cluster.Default = false
+			}
+
+			conf.DefaultCluster.Default = true
 		}
 	} else {
+		// we need to determine ourselfes
 		if len(conf.Clusters) == 1 {
+			// ok, just one cluster configured, use this, of course
 			for name, cluster := range conf.Clusters {
 				conf.DefaultCluster = cluster
 				conf.CurrentCluster = name
+				conf.DefaultCluster.Default = true
 			}
 		} else {
+			// multiple ones exists, look if one is set as default
 			for name, cluster := range conf.Clusters {
-				_, err := cluster.ES.Cluster.Health().
-					Header("content-type", "application/json").
-					Header("accept", "application/json").
-					Do(context.Background())
-
-				if err == nil {
+				if cluster.Default {
 					conf.DefaultCluster = cluster
 					conf.CurrentCluster = name
-					break
 				}
 			}
 		}
@@ -250,86 +248,21 @@ func (conf *Config) LoadConfig() error {
 	if len(newconf.Clusters) > 0 {
 		conf.Clusters = newconf.Clusters
 
-		_, exists := conf.Clusters["default"]
-		if !exists {
-			// no "default", just use the first we stumble upon
-			for _, cluster := range conf.Clusters {
+		for _, cluster := range conf.Clusters {
+			if cluster.Default {
 				conf.DefaultCluster = cluster
 				break
 			}
-		} else {
-			conf.DefaultCluster = newconf.Clusters["default"]
+		}
+
+		if conf.DefaultCluster == nil {
+			conf.DefaultCluster = &Cluster{}
 		}
 	}
 
 	return nil
 }
 
-func (conf *Config) getTransport() elastictransport.Option {
-	transport := &http.Transport{
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-
-	if conf.DebugHTTP {
-		return elastictransport.WithTransport(
-			&DebugTransport{Transport: transport},
-		)
-	}
-
-	return elastictransport.WithTransport(transport)
-}
-
-func (conf *Config) SetupES() error {
-	for _, cluster := range conf.Clusters {
-		es, err := elasticsearch.NewTyped(
-			elasticsearch.WithAddresses(cluster.Uri),
-			elasticsearch.WithBasicAuth(cluster.User, cluster.Pass),
-			elasticsearch.WithTransportOptions(conf.getTransport()),
-		)
-
-		if err != nil {
-			return fmt.Errorf("failed to setup elasticsearch connection: %w", err)
-		}
-
-		cluster.ES = es
-	}
-
-	return nil
-}
-
-// used to print uri, path and body of a request made by the go-client
-type DebugTransport struct {
-	Transport http.RoundTripper
-}
-
-func (t *DebugTransport) RoundTrip(req *http.Request) (*http.Response, error) {
-	content := ""
-	contentline := ""
-
-	if req.ContentLength > 0 {
-		buf := new(bytes.Buffer)
-		body, _ := req.GetBody()
-
-		_, err := buf.ReadFrom(body)
-		if err != nil {
-			return nil, err
-		}
-
-		var pretty bytes.Buffer
-		err = json.Indent(&pretty, buf.Bytes(), "", "\t")
-		if err != nil {
-			return nil, fmt.Errorf("json parse error: %s", err)
-		}
-
-		content = pretty.String()
-		contentline = buf.String()
-	}
-
-	slog.Info("req", "host", req.URL.Host, "uri", req.URL.Path, "body", content, "bodyline", contentline)
-
-	return t.Transport.RoundTrip(req)
-}
-
 func fileExists(filename string) bool {
 	info, err := os.Stat(filename)
 

pkg/cfg/transport.go

@@ -0,0 +1,78 @@
+/*
+Copyright © 2026 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+package cfg
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+
+	"github.com/elastic/elastic-transport-go/v8/elastictransport"
+)
+
+// used to print uri, path and body of a request made by the go-client
+type DebugTransport struct {
+	Transport http.RoundTripper
+}
+
+func (t *DebugTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	content := ""
+	contentline := ""
+
+	if req.ContentLength > 0 {
+		buf := new(bytes.Buffer)
+		body, _ := req.GetBody()
+
+		_, err := buf.ReadFrom(body)
+		if err != nil {
+			return nil, err
+		}
+
+		var pretty bytes.Buffer
+		err = json.Indent(&pretty, buf.Bytes(), "", "\t")
+		if err != nil {
+			return nil, fmt.Errorf("json parse error: %s", err)
+		}
+
+		content = pretty.String()
+		contentline = buf.String()
+	}
+
+	slog.Info("req", "host", req.URL.Host, "uri", req.URL.Path,
+		"body", content, "bodyline", contentline,
+		"headers", req.Header,
+	)
+
+	return t.Transport.RoundTrip(req)
+}
+
+func (conf *Config) getTransport() elastictransport.Option {
+	transport := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+
+	if conf.DebugHTTP {
+		return elastictransport.WithTransport(
+			&DebugTransport{Transport: transport},
+		)
+	}
+
+	return elastictransport.WithTransport(transport)
+}