Response Log

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Overview

• Response monitoring
• Debugging response issues
• Performance tracking

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Installation

import "github.com/go-mizu/mizu/middlewares/responselog"

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Quick Start

app := mizu.New()

app.Use(responselog.New())

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Configuration

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Options

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Examples

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Basic Logging

app.Use(responselog.New())

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Include Response Body

app.Use(responselog.WithOptions(responselog.Options{
    IncludeBody: true,
    MaxBodySize: 4096,
}))

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With Custom Logger

logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
app.Use(responselog.WithLogger(logger))

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API Reference

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Functions

// New creates response log middleware
func New() mizu.Middleware

// WithLogger creates with custom logger
func WithLogger(logger *slog.Logger) mizu.Middleware

// WithOptions creates with configuration
func WithOptions(opts Options) mizu.Middleware

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Technical Details

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Response Capture Mechanism

• Intercepts WriteHeader() to capture the status code
• Intercepts Write() to capture response body up to MaxBodySize
• Automatically restores the original writer after processing

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Logging Behavior

• Method: HTTP request method
• Path: Request URL path
• Status: HTTP status code
• Duration: Time taken to process the request
• Size: Response body size in bytes
• Headers: Response headers (if LogHeaders is enabled)
• Body: Response body content (if LogBody is enabled, truncated to MaxBodySize)

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Log Levels

• Status >= 400: Logged as ERROR
• Status < 400: Logged as INFO

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Filtering

• SkipPaths: Paths that should not be logged at all
• SkipStatuses: Status codes that should not be logged

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Default Values

• MaxBodySize: 4KB (4096 bytes)
• LogBody: false
• LogHeaders: false
• Logger: Default slog text handler to stdout

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Best Practices

• Be careful with body logging (sensitive data)
• Use for debugging only
• Set reasonable body size limits
• Combine with request logging

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Testing

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Related Middlewares

• requestlog - Request logging
• bodydump - Body dumping
• logger - Simple logging