xcaddy/README.md

`xcaddy` - Custom Caddy Builder
===============================

This command line tool and associated Go package makes it easy to make custom builds of the [Caddy Web Server](https://github.com/caddyserver/caddy).

It is used heavily by Caddy plugin developers as well as anyone who wishes to make custom `caddy` binaries (with or without plugins).

Stay updated, be aware of changes, and please submit feedback! Thanks!

## Requirements

- [Go installed](https://golang.org/doc/install)

## Install

You can [download binaries](https://github.com/caddyserver/xcaddy/releases) that are already compiled for your platform from the Release tab. 

You may also build `xcaddy` from source:

```bash
go install github.com/caddyserver/xcaddy/cmd/xcaddy@latest
```

For Debian, Ubuntu, and Raspbian, an `xcaddy` package is available from our [Cloudsmith repo](https://cloudsmith.io/~caddy/repos/xcaddy/packages/):

```bash
sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/xcaddy/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-xcaddy-archive-keyring.gpg
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/xcaddy/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-xcaddy.list
sudo apt update
sudo apt install xcaddy
```

## :warning: Pro tip

If you find yourself fighting xcaddy in relation to your custom or proprietary build or development process, **it might be easier to just build Caddy manually!**

Caddy's [main.go file](https://github.com/caddyserver/caddy/blob/master/cmd/caddy/main.go), the main entry point to the application, has instructions in the comments explaining how to build Caddy essentially the same way xcaddy does it. But when you use the `go` command directly, you have more control over the whole thing and it may save you a lot of trouble.

The manual build procedure is very easy: just copy the main.go into a new folder, initialize a Go module, plug in your plugins (add an `import` for each one) and then run `go build`. Of course, you may wish to customize the go.mod file to your liking (specific dependency versions, replacements, etc).


## Command usage

The `xcaddy` command has two primary uses:

1. Compile custom `caddy` binaries
2. A replacement for `go run` while developing Caddy plugins

The `xcaddy` command will use the latest version of Caddy by default. You can customize this for all invocations by setting the `CADDY_VERSION` environment variable.

As usual with `go` command, the `xcaddy` command will pass the `GOOS`, `GOARCH`, and `GOARM` environment variables through for cross-compilation.

Note that `xcaddy` will ignore the `vendor/` folder with `-mod=readonly`.


### Custom builds

Syntax:

```
$ xcaddy build [<caddy_version>]
    [--output <file>]
    [--with <module[@version][=replacement]>...]
    [--replace <module[@version]=replacement>...]
    [--embed <[alias]:path/to/dir>...]
```

- `<caddy_version>` is the core Caddy version to build; defaults to `CADDY_VERSION` env variable or latest.<br>
  This can be the keyword `latest`, which will use the latest stable tag, or any git ref such as:
  - A tag like `v2.0.1`
  - A branch like `master`
  - A commit like `a58f240d3ecbb59285303746406cab50217f8d24`

- `--output` changes the output file.
- `--with` can be used multiple times to add plugins by specifying the Go module name and optionally its version, similar to `go get`. Module name is required, but specific version and/or local replacement are optional.
- `--replace` can be used multiple times to replace dependencies to specific forks or local replacements. Useful in development environment to fix bugs in dependencies.
- `--embed` can be used multiple times to embed directories into the built Caddy executable. The directory can be prefixed with a custom alias and a colon `:` to use it with the `root` directive and sub-directive. 

Examples:

```bash
$ xcaddy build \
    --with github.com/caddyserver/ntlm-transport

$ xcaddy build v2.0.1 \
    --with github.com/caddyserver/ntlm-transport@v0.1.1

$ xcaddy build master \
    --with github.com/caddyserver/ntlm-transport

$ xcaddy build a58f240d3ecbb59285303746406cab50217f8d24 \
    --with github.com/caddyserver/ntlm-transport

$ xcaddy build \
    --with github.com/caddyserver/ntlm-transport=../../my-fork

$ xcaddy build \
    --with github.com/caddyserver/ntlm-transport@v0.1.1=../../my-fork
```

You can even replace Caddy core using the `--replace` flag:

```
$ xcaddy build \
    --replace github.com/caddyserver/caddy/v2=../../my-caddy-fork
    
$ xcaddy build \
    --replace github.com/caddyserver/caddy/v2=github.com/my-user/caddy/v2@some-branch
```

This allows you to hack on Caddy core (and optionally plug in extra modules at the same time!) with relative ease.

```
$ xcaddy build --embed foo:./sites/foo --embed bar:./sites/bar
$ cat Caddyfile
foo.localhost {
	root * /foo
	file_server {
		fs embedded
	}
}

bar.localhost {
	root * /bar
	file_server {
		fs embedded
	}
}
```
This allows you to serve 2 sites from 2 different embedded directories, which are referenced by aliases, from a single Caddy executable.

### For plugin development

If you run `xcaddy` from within the folder of the Caddy plugin you're working on _without the `build` subcommand_, it will build Caddy with your current module and run it, as if you manually plugged it in and invoked `go run`.

The binary will be built and run from the current directory, then cleaned up.

The current working directory must be inside an initialized Go module.

Syntax:

```
$ xcaddy <args...>
```
- `<args...>` are passed through to the `caddy` command.

For example:

```bash
$ xcaddy list-modules
$ xcaddy run
$ xcaddy run --config caddy.json
```

The race detector can be enabled by setting `XCADDY_RACE_DETECTOR=1`. The DWARF debug info can be enabled by setting `XCADDY_DEBUG=1`.


### Getting `xcaddy`'s version

```
$ xcaddy version
```


## Library usage

```go
builder := xcaddy.Builder{
	CaddyVersion: "v2.0.0",
	Plugins: []xcaddy.Dependency{
		{
			ModulePath: "github.com/caddyserver/ntlm-transport",
			Version:    "v0.1.1",
		},
	},
}
err := builder.Build(context.Background(), "./caddy")
```

Versions can be anything compatible with `go get`.



## Environment variables

Because the subcommands and flags are constrained to benefit rapid plugin prototyping, xcaddy does read some environment variables to take cues for its behavior and/or configuration when there is no room for flags.

- `CADDY_VERSION` sets the version of Caddy to build.
- `XCADDY_RACE_DETECTOR=1` enables the Go race detector in the build.
- `XCADDY_DEBUG=1` enables the DWARF debug information in the build.
- `XCADDY_SETCAP=1` will run `sudo setcap cap_net_bind_service=+ep` on the resulting binary. By default, the `sudo` command will be used if it is found; set `XCADDY_SUDO=0` to avoid using `sudo` if necessary.
- `XCADDY_SKIP_BUILD=1` causes xcaddy to not compile the program, it is used in conjunction with build tools such as [GoReleaser](https://goreleaser.com). Implies `XCADDY_SKIP_CLEANUP=1`.
- `XCADDY_SKIP_CLEANUP=1` causes xcaddy to leave build artifacts on disk after exiting.
- `XCADDY_WHICH_GO` sets the go command to use when for example more then 1 version of go is installed.
- `XCADDY_GO_BUILD_FLAGS` overrides default build arguments. Supports Unix-style shell quoting, for example: XCADDY_GO_BUILD_FLAGS="-ldflags '-w -s'". The provided flags are applied to `go` commands: build, clean, get, install, list, run, and test
- `XCADDY_GO_MOD_FLAGS` overrides default `go mod` arguments. Supports Unix-style shell quoting.

---

&copy; 2020 Matthew Holt