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reverseproxy: Refactor dial address parsing, augment command parsing (#4616)

This commit is contained in:
Francis Lavoie 2022-03-05 18:34:19 -05:00 committed by GitHub
parent 09ba9e994e
commit d058dee11d
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 134 additions and 119 deletions

View file

@ -350,7 +350,11 @@ func (d *Dispenser) Err(msg string) error {
// Errf is like Err, but for formatted error messages
func (d *Dispenser) Errf(format string, args ...interface{}) error {
err := fmt.Errorf(format, args...)
return d.WrapErr(fmt.Errorf(format, args...))
}
// WrapErr takes an existing error and adds the Caddyfile file and line number.
func (d *Dispenser) WrapErr(err error) error {
return fmt.Errorf("%s:%d - Error during parsing: %w", d.File(), d.Line(), err)
}

View file

@ -0,0 +1,112 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package reverseproxy
import (
"fmt"
"net"
"net/url"
"strings"
"github.com/caddyserver/caddy/v2"
)
// parseUpstreamDialAddress parses configuration inputs for
// the dial address, including support for a scheme in front
// as a shortcut for the port number, and a network type,
// for example 'unix' to dial a unix socket.
//
// TODO: the logic in this function is kind of sensitive, we
// need to write tests before making any more changes to it
func parseUpstreamDialAddress(upstreamAddr string) (string, string, error) {
var network, scheme, host, port string
if strings.Contains(upstreamAddr, "://") {
// we get a parsing error if a placeholder is specified
// so we return a more user-friendly error message instead
// to explain what to do instead
if strings.Contains(upstreamAddr, "{") {
return "", "", fmt.Errorf("due to parsing difficulties, placeholders are not allowed when an upstream address contains a scheme")
}
toURL, err := url.Parse(upstreamAddr)
if err != nil {
return "", "", fmt.Errorf("parsing upstream URL: %v", err)
}
// there is currently no way to perform a URL rewrite between choosing
// a backend and proxying to it, so we cannot allow extra components
// in backend URLs
if toURL.Path != "" || toURL.RawQuery != "" || toURL.Fragment != "" {
return "", "", fmt.Errorf("for now, URLs for proxy upstreams only support scheme, host, and port components")
}
// ensure the port and scheme aren't in conflict
urlPort := toURL.Port()
if toURL.Scheme == "http" && urlPort == "443" {
return "", "", fmt.Errorf("upstream address has conflicting scheme (http://) and port (:443, the HTTPS port)")
}
if toURL.Scheme == "https" && urlPort == "80" {
return "", "", fmt.Errorf("upstream address has conflicting scheme (https://) and port (:80, the HTTP port)")
}
if toURL.Scheme == "h2c" && urlPort == "443" {
return "", "", fmt.Errorf("upstream address has conflicting scheme (h2c://) and port (:443, the HTTPS port)")
}
// if port is missing, attempt to infer from scheme
if toURL.Port() == "" {
var toPort string
switch toURL.Scheme {
case "", "http", "h2c":
toPort = "80"
case "https":
toPort = "443"
}
toURL.Host = net.JoinHostPort(toURL.Hostname(), toPort)
}
scheme, host, port = toURL.Scheme, toURL.Hostname(), toURL.Port()
} else {
// extract network manually, since caddy.ParseNetworkAddress() will always add one
if idx := strings.Index(upstreamAddr, "/"); idx >= 0 {
network = strings.ToLower(strings.TrimSpace(upstreamAddr[:idx]))
upstreamAddr = upstreamAddr[idx+1:]
}
var err error
host, port, err = net.SplitHostPort(upstreamAddr)
if err != nil {
host = upstreamAddr
}
// we can assume a port if only a hostname is specified, but use of a
// placeholder without a port likely means a port will be filled in
if port == "" && !strings.Contains(host, "{") {
port = "80"
}
}
// for simplest possible config, we only need to include
// the network portion if the user specified one
if network != "" {
return caddy.JoinNetworkAddress(network, host, port), scheme, nil
}
// if the host is a placeholder, then we don't want to join with an empty port,
// because that would just append an extra ':' at the end of the address.
if port == "" && strings.Contains(host, "{") {
return host, scheme, nil
}
return net.JoinHostPort(host, port), scheme, nil
}

View file

@ -18,7 +18,6 @@ import (
"log"
"net"
"net/http"
"net/url"
"reflect"
"strconv"
"strings"
@ -123,98 +122,6 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
// prefixed with "@" for use with "handle_response" blocks
h.responseMatchers = make(map[string]caddyhttp.ResponseMatcher)
// TODO: the logic in this function is kind of sensitive, we need
// to write tests before making any more changes to it
upstreamDialAddress := func(upstreamAddr string) (string, error) {
var network, scheme, host, port string
if strings.Contains(upstreamAddr, "://") {
// we get a parsing error if a placeholder is specified
// so we return a more user-friendly error message instead
// to explain what to do instead
if strings.Contains(upstreamAddr, "{") {
return "", d.Err("due to parsing difficulties, placeholders are not allowed when an upstream address contains a scheme")
}
toURL, err := url.Parse(upstreamAddr)
if err != nil {
return "", d.Errf("parsing upstream URL: %v", err)
}
// there is currently no way to perform a URL rewrite between choosing
// a backend and proxying to it, so we cannot allow extra components
// in backend URLs
if toURL.Path != "" || toURL.RawQuery != "" || toURL.Fragment != "" {
return "", d.Err("for now, URLs for proxy upstreams only support scheme, host, and port components")
}
// ensure the port and scheme aren't in conflict
urlPort := toURL.Port()
if toURL.Scheme == "http" && urlPort == "443" {
return "", d.Err("upstream address has conflicting scheme (http://) and port (:443, the HTTPS port)")
}
if toURL.Scheme == "https" && urlPort == "80" {
return "", d.Err("upstream address has conflicting scheme (https://) and port (:80, the HTTP port)")
}
if toURL.Scheme == "h2c" && urlPort == "443" {
return "", d.Err("upstream address has conflicting scheme (h2c://) and port (:443, the HTTPS port)")
}
// if port is missing, attempt to infer from scheme
if toURL.Port() == "" {
var toPort string
switch toURL.Scheme {
case "", "http", "h2c":
toPort = "80"
case "https":
toPort = "443"
}
toURL.Host = net.JoinHostPort(toURL.Hostname(), toPort)
}
scheme, host, port = toURL.Scheme, toURL.Hostname(), toURL.Port()
} else {
// extract network manually, since caddy.ParseNetworkAddress() will always add one
if idx := strings.Index(upstreamAddr, "/"); idx >= 0 {
network = strings.ToLower(strings.TrimSpace(upstreamAddr[:idx]))
upstreamAddr = upstreamAddr[idx+1:]
}
var err error
host, port, err = net.SplitHostPort(upstreamAddr)
if err != nil {
host = upstreamAddr
}
// we can assume a port if only a hostname is specified, but use of a
// placeholder without a port likely means a port will be filled in
if port == "" && !strings.Contains(host, "{") {
port = "80"
}
}
// the underlying JSON does not yet support different
// transports (protocols or schemes) to each backend,
// so we remember the last one we see and compare them
if commonScheme != "" && scheme != commonScheme {
return "", d.Errf("for now, all proxy upstreams must use the same scheme (transport protocol); expecting '%s://' but got '%s://'",
commonScheme, scheme)
}
commonScheme = scheme
// for simplest possible config, we only need to include
// the network portion if the user specified one
if network != "" {
return caddy.JoinNetworkAddress(network, host, port), nil
}
// if the host is a placeholder, then we don't want to join with an empty port,
// because that would just append an extra ':' at the end of the address.
if port == "" && strings.Contains(host, "{") {
return host, nil
}
return net.JoinHostPort(host, port), nil
}
// appendUpstream creates an upstream for address and adds
// it to the list. If the address starts with "srv+" it is
// treated as a SRV-based upstream, and any port will be
@ -224,10 +131,21 @@ func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
if isSRV {
address = strings.TrimPrefix(address, "srv+")
}
dialAddr, err := upstreamDialAddress(address)
dialAddr, scheme, err := parseUpstreamDialAddress(address)
if err != nil {
return err
return d.WrapErr(err)
}
// the underlying JSON does not yet support different
// transports (protocols or schemes) to each backend,
// so we remember the last one we see and compare them
if commonScheme != "" && scheme != commonScheme {
return d.Errf("for now, all proxy upstreams must use the same scheme (transport protocol); expecting '%s://' but got '%s://'",
commonScheme, scheme)
}
commonScheme = scheme
if isSRV {
if host, _, err := net.SplitHostPort(dialAddr); err == nil {
dialAddr = host

View file

@ -18,7 +18,6 @@ import (
"encoding/json"
"flag"
"fmt"
"net"
"net/http"
"strconv"
@ -104,32 +103,14 @@ func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
}
// set up the upstream address; assume missing information from given parts
toAddr, err := httpcaddyfile.ParseAddress(to)
toAddr, toScheme, err := parseUpstreamDialAddress(to)
if err != nil {
return caddy.ExitCodeFailedStartup, fmt.Errorf("invalid upstream address %s: %v", to, err)
}
if toAddr.Path != "" {
return caddy.ExitCodeFailedStartup, fmt.Errorf("paths are not allowed: %s", to)
}
if toAddr.Scheme == "" {
if toAddr.Port == httpsPort {
toAddr.Scheme = "https"
} else {
toAddr.Scheme = "http"
}
}
if toAddr.Port == "" {
if toAddr.Scheme == "http" {
toAddr.Port = httpPort
} else if toAddr.Scheme == "https" {
toAddr.Port = httpsPort
}
}
// proceed to build the handler and server
ht := HTTPTransport{}
if toAddr.Scheme == "https" {
if toScheme == "https" {
ht.TLS = new(TLSConfig)
if insecure {
ht.TLS.InsecureSkipVerify = true
@ -138,7 +119,7 @@ func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
handler := Handler{
TransportRaw: caddyconfig.JSONModuleObject(ht, "protocol", "http", nil),
Upstreams: UpstreamPool{{Dial: net.JoinHostPort(toAddr.Host, toAddr.Port)}},
Upstreams: UpstreamPool{{Dial: toAddr}},
}
if changeHost {
@ -185,7 +166,7 @@ func cmdReverseProxy(fs caddycmd.Flags) (int, error) {
return caddy.ExitCodeFailedStartup, err
}
fmt.Printf("Caddy proxying %s -> %s\n", fromAddr.String(), toAddr.String())
fmt.Printf("Caddy proxying %s -> %s\n", fromAddr.String(), toAddr)
select {}
}