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
+}