internal/api/middleware/anthropic_debug.go

package middleware

import (
	"bytes"
	"io"
	"strings"

	"github.com/gin-gonic/gin"
	log "github.com/sirupsen/logrus"
)

// LogAnthropicRequest creates a middleware that logs detailed debug info for Anthropic requests.
// It logs headers (masking sensitive ones) and a preview of the request body.
func LogAnthropicRequest() gin.HandlerFunc {
	return func(c *gin.Context) {
		path := c.Request.URL.Path
		method := c.Request.Method
		userAgent := c.GetHeader("User-Agent")

		// Check if it's Claude Code
		isClaudeCode := strings.Contains(userAgent, "claude-code") || strings.Contains(userAgent, "claude-cli")

		fields := log.Fields{
			"prefix":         "CLAUDE_CODE_AUTH_DEBUG",
			"method":         method,
			"path":           path,
			"user_agent":     userAgent,
			"is_claude_code": isClaudeCode,
		}

		// Log Headers (masked)
		headers := make(map[string]string)
		for k, v := range c.Request.Header {
			if strings.EqualFold(k, "Authorization") || strings.EqualFold(k, "x-api-key") {
				headers[k] = "[MASKED]"
			} else {
				headers[k] = strings.Join(v, ";")
			}
		}
		fields["headers"] = headers

		// Peek Body
		var bodyBytes []byte
		if c.Request.Body != nil {
			bodyBytes, _ = io.ReadAll(c.Request.Body)
			c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))

			previewLen := 200
			if len(bodyBytes) < previewLen {
				previewLen = len(bodyBytes)
			}
			fields["body_preview"] = string(bodyBytes[:previewLen])
		}

		log.WithFields(fields).Debug("Incoming Anthropic Request")

		c.Next()
	}
}