esctl/pkg/cfg/transport.go

/*
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"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
)

// 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: %w", err)
		}

		content = pretty.String()
		contentline = buf.String()
	}

	if req.Header.Get("Accept") != "" {
		req.Header.Del("Accept")
		req.Header.Add("Accept", "application/json")
	}

	slog.Info("req", "host", req.URL.Host, "uri", req.URL.Path,
		"body", content, "bodyline", contentline,
		"headers", req.Header,
	)

	return t.Transport.RoundTrip(req)
}

// Fixes https://codeberg.org/scip/esctl/issues/79:
// the API client has this Accept header hardcoded everywhere:
// req.Header.Set("Accept", "application/vnd.elasticsearch+json;compatible-with=9")
// While this works pretty well with ES9, it doesn't with ES8. So, we replace
// this header with a new one without the compatibility part.
type CompatibilityTransport struct {
	Transport http.RoundTripper
}

func (t *CompatibilityTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	if req.Header.Get("Accept") != "" {
		req.Header.Del("Accept")
		req.Header.Add("Accept", "application/json")
	}

	return t.Transport.RoundTrip(req)
}