logger.go

package logger

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"time"

	"github.com/go-chi/chi/v5/middleware"
	"github.com/sirupsen/logrus"
)

const maxBodyLog = 512

// HTTPMiddleware ...
func HTTPMiddleware(logBody bool) func(next http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		fn := func(w http.ResponseWriter, r *http.Request) {
			l := GetLogger(r.Context())
			scheme := "http"
			if r.TLS != nil {
				scheme = "https"
			}

			requestFields := logrus.Fields{
				"uri":         fmt.Sprintf("%s://%s%s", scheme, r.Host, r.RequestURI),
				"http_proto":  r.Proto,
				"http_method": r.Method,
				"remote_addr": r.RemoteAddr,
				"user_agent":  r.UserAgent(),
			}

			if logBody {
				body, err := io.ReadAll(r.Body)
				if err != nil {
					l.WithError(err).Error("failed read body")
				} else {
					r.Body = io.NopCloser(bytes.NewBuffer(body))
				}
				if len(body) > 0 {
					requestFields["request_body"] = bodyWithLimit(body, maxBodyLog)
				}
			}
			l = l.WithFields(requestFields)

			responseBodyBuffer := bytes.NewBufferString("")
			if logBody {
				w = &responseWriterWithBodyReader{
					ResponseWriter: w,
					body:           responseBodyBuffer,
				}
			}

			ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
			startTime := time.Now()

			next.ServeHTTP(ww, r.WithContext(SetLogger(r.Context(), l)))

			responseFields := logrus.Fields{
				"response_status":       ww.Status(),
				"response_bytes_length": ww.BytesWritten(),
				"response_elapsed_ms":   float64(time.Since(startTime).Nanoseconds()) / 1e6,
			}
			if logBody && responseBodyBuffer.Len() > 0 {
				responseFields["response_body"] = bodyWithLimit(responseBodyBuffer.Bytes(), maxBodyLog)
			}
			l = l.WithFields(responseFields)
			l.Debug("request")
			SetLogger(r.Context(), l)
		}
		return http.HandlerFunc(fn)
	}
}

type responseWriterWithBodyReader struct {
	http.ResponseWriter
	body *bytes.Buffer
}

func (r *responseWriterWithBodyReader) Write(b []byte) (int, error) {
	r.body.Write(b)
	return r.ResponseWriter.Write(b)
}

func bodyWithLimit(b []byte, n int) string {
	if len(b) > n {
		return string(b[:512])
	}
	return string(b)
}