# FAQs

## How do I integrate with existing servers?

Every Macaron [instance](/core_concepts.md#instances) implements [`http.Handler`](https://gowalker.org/net/http#Handler), so it can easily be used to serve subtrees on existing Go servers. For example this is a working Macaron app for Google App Engine:

```go
package hello

import (
    "net/http"

    "gopkg.in/macaron.v1"
)

func init() {
    m := macaron.Classic()
    m.Get("/", func() string {
        return "Hello world!"
    })
    http.Handle("/", m)
}
```

## How do I change the port/host?

Macaron's `Run` function looks for the `PORT` and `HOST` environment variables and uses those. Otherwise Macaron will default to [localhost:4000](http://localhost:4000). To have more flexibility over port and host, use the [`http.ListenAndServe`](https://gowalker.org/net/http#ListenAndServe) function instead.

```go
m := macaron.Classic()
// ...
log.Fatal(http.ListenAndServe(":8080", m))
```

Or following ways:

* `m.Run("0.0.0.0")`, listen on `0.0.0.0:4000`
* `m.Run(8080)`, listen on `0.0.0.0:8080`
* `m.Run("0.0.0.0", 8080)`, listen on `0.0.0.0:8080`

## How do I graceful shutdown?

```go
package main

import (
    ...
    "net/http"

    "gopkg.in/macaron.v1"
    "gopkg.in/tylerb/graceful.v1"
)

func main() {
    m := macaron.Classic()

    ...

    mux := http.NewServeMux()
    mux.Handle("/", m)
    graceful.Run(":4000", 60*time.Second, mux)
}
```

## How do I pass data in request-level other than service inject?

There is a field called `Data` with type `map[string]interface{}` in [`*macaron.Context`](https://gowalker.org/github.com/go-macaron/macaron#Context) where you can store and retrieve any type of data. It comes with [`*macaron.Context`](https://gowalker.org/github.com/go-macaron/macaron#Context) so every request is independent.

See example [here](https://github.com/go-macaron/docs/tree/ef61f3e63eebd43a1fcd2e6e4fdb3bffffb4059d/middlewares/routing.md#advanced-routing).

## What's the idea behind this other than Martini?

* Integrate frequently used middlewares and helper methods with less reflection.
* Replace default router with faster multi-tree router.
* Make it much easier to power [Gogs](https://gogs.io) project.
* Make a deep source study against Martini.

## Why Logo is a dragon?

Shouldn't it be some sort of dessert?

The transliteration of Macaron in Chinese is `Maca Long`, `Long` means dragon, so actually the Logo is a dragon whose name is `Maca`. Hah!

## Live code reload?

[Bra](https://github.com/unknwon/bra) is the prefect fit for live reloading Macaron and other apps.


---

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