caddy/caddytest/integration/caddyfile_adapt/portless_upstream.txt

whoami.example.com {
	reverse_proxy whoami
}

app.example.com {
	reverse_proxy app:80
}
unix.example.com {
	reverse_proxy unix//path/to/socket
}
----------
{
	"apps": {
		"http": {
			"servers": {
				"srv0": {
					"listen": [
						":443"
					],
					"routes": [
						{
							"match": [
								{
									"host": [
										"whoami.example.com"
									]
								}
							],
							"handle": [
								{
									"handler": "subroute",
									"routes": [
										{
											"handle": [
												{
													"handler": "reverse_proxy",
													"upstreams": [
														{
															"dial": "whoami:80"
														}
													]
												}
											]
										}
									]
								}
							],
							"terminal": true
						},
						{
							"match": [
								{
									"host": [
										"unix.example.com"
									]
								}
							],
							"handle": [
								{
									"handler": "subroute",
									"routes": [
										{
											"handle": [
												{
													"handler": "reverse_proxy",
													"upstreams": [
														{
															"dial": "unix//path/to/socket"
														}
													]
												}
											]
										}
									]
								}
							],
							"terminal": true
						},
						{
							"match": [
								{
									"host": [
										"app.example.com"
									]
								}
							],
							"handle": [
								{
									"handler": "subroute",
									"routes": [
										{
											"handle": [
												{
													"handler": "reverse_proxy",
													"upstreams": [
														{
															"dial": "app:80"
														}
													]
												}
											]
										}
									]
								}
							],
							"terminal": true
						}
					]
				}
			}
		}
	}
}