Recover Middleware¶

Catches panics and returns a 500 Internal Server Error instead of crashing the server.

Usage¶

Basic Usage¶

app.Use(middleware.Recover)

With Configuration¶

app.Use(middleware.RecoverWithConfig(middleware.RecoverConfig{
    LogPanics: true,
    OnPanic: func(c *marten.Ctx, err any) error {
        return c.JSON(500, marten.M{
            "error": "internal error",
            "request_id": c.RequestID(),
        })
    },
}))

JSON Error Response¶

app.Use(middleware.RecoverJSON)

Configuration¶

Option	Type	Description
`LogPanics`	`bool`	Log panics to stdout (default: true)
`OnPanic`	`func(*Ctx, any) error`	Custom panic handler

Behavior¶

When a panic occurs:

The panic is caught
The error is logged
A 500 response is returned
The server continues running

Example¶

package main

import (
    "github.com/gomarten/marten"
    "github.com/gomarten/marten/middleware"
)

func main() {
    app := marten.New()

    app.Use(middleware.Recover)

    app.GET("/panic", func(c *marten.Ctx) error {
        panic("something went wrong!")
        return nil
    })

    app.Run(":3000")
}

Request to /panic returns:

HTTP/1.1 500 Internal Server Error
Content-Type: text/plain; charset=utf-8

Internal Server Error

Log Output¶

2026/01/13 10:30:00 panic recovered: something went wrong!

Custom Recovery¶

With Custom Handler¶

app.Use(middleware.RecoverWithHandler(func(c *marten.Ctx, err any) error {
    // Log with stack trace
    log.Printf("panic: %v\n%s", err, debug.Stack())

    // Custom response
    return c.JSON(500, marten.M{
        "error":      "internal error",
        "request_id": c.RequestID(),
    })
}))

JSON Response¶

app.Use(middleware.RecoverJSON)

Returns:

{"error": "internal server error", "message": "panic message here"}

Full Custom Recovery¶

For more control, create your own middleware:

func CustomRecover(next marten.Handler) marten.Handler {
    return func(c *marten.Ctx) (err error) {
        defer func() {
            if r := recover(); r != nil {
                // Log with stack trace
                log.Printf("panic: %v\n%s", r, debug.Stack())

                // Custom response
                err = c.JSON(500, marten.M{
                    "error":      "internal error",
                    "request_id": c.RequestID(),
                })
            }
        }()
        return next(c)
    }
}

Best Practices¶

Always use Recover - Prevents server crashes
Place early in middleware chain - Catches panics from all handlers
Log panics - For debugging
Don't expose panic details - Security risk