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// 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 caddyconfig
import (
"crypto/tls"
"crypto/x509"
"fmt"
"io"
"net/http"
"os"
"time"
"github.com/caddyserver/caddy/v2"
)
func init() {
caddy.RegisterModule(HTTPLoader{})
}
// HTTPLoader can load Caddy configs over HTTP(S).
//
// If the response is not a JSON config, a config adapter must be specified
// either in the loader config (`adapter`), or in the Content-Type HTTP header
// returned in the HTTP response from the server. The Content-Type header is
// read just like the admin API's `/load` endpoint. If you don't have control
// over the HTTP server (but can still trust its response), you can override
// the Content-Type header by setting the `adapter` property in this config.
type HTTPLoader struct {
// The method for the request. Default: GET
Method string `json:"method,omitempty"`
// The URL of the request.
URL string `json:"url,omitempty"`
// HTTP headers to add to the request.
Headers http.Header `json:"header,omitempty"`
// Maximum time allowed for a complete connection and request.
Timeout caddy.Duration `json:"timeout,omitempty"`
// The name of the config adapter to use, if any. Only needed
// if the HTTP response is not a JSON config and if the server's
// Content-Type header is missing or incorrect.
Adapter string `json:"adapter,omitempty"`
TLS *struct {
// Present this instance's managed remote identity credentials to the server.
UseServerIdentity bool `json:"use_server_identity,omitempty"`
// PEM-encoded client certificate filename to present to the server.
ClientCertificateFile string `json:"client_certificate_file,omitempty"`
// PEM-encoded key to use with the client certificate.
ClientCertificateKeyFile string `json:"client_certificate_key_file,omitempty"`
// List of PEM-encoded CA certificate files to add to the same trust
// store as RootCAPool (or root_ca_pool in the JSON).
RootCAPEMFiles []string `json:"root_ca_pem_files,omitempty"`
} `json:"tls,omitempty"`
}
// CaddyModule returns the Caddy module information.
func (HTTPLoader) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "caddy.config_loaders.http",
New: func() caddy.Module { return new(HTTPLoader) },
}
}
// LoadConfig loads a Caddy config.
func (hl HTTPLoader) LoadConfig(ctx caddy.Context) ([]byte, error) {
repl := caddy.NewReplacer()
client, err := hl.makeClient(ctx)
if err != nil {
return nil, err
}
method := repl.ReplaceAll(hl.Method, "")
if method == "" {
method = http.MethodGet
}
url := repl.ReplaceAll(hl.URL, "")
req, err := http.NewRequest(method, url, nil)
if err != nil {
return nil, err
}
for key, vals := range hl.Headers {
for _, val := range vals {
req.Header.Add(repl.ReplaceAll(key, ""), repl.ReplaceKnown(val, ""))
}
}
resp, err := doHttpCallWithRetries(ctx, client, req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode >= 400 {
return nil, fmt.Errorf("server responded with HTTP %d", resp.StatusCode)
}
body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
// adapt the config based on either manually-configured adapter or server's response header
ct := resp.Header.Get("Content-Type")
if hl.Adapter != "" {
ct = "text/" + hl.Adapter
}
result, warnings, err := adaptByContentType(ct, body)
if err != nil {
return nil, err
}
for _, warn := range warnings {
ctx.Logger().Warn(warn.String())
}
return result, nil
}
func attemptHttpCall(client *http.Client, request *http.Request) (*http.Response, error) {
resp, err := client.Do(request)
if err != nil {
return nil, fmt.Errorf("problem calling http loader url: %v", err)
} else if resp.StatusCode < 200 || resp.StatusCode > 499 {
resp.Body.Close()
return nil, fmt.Errorf("bad response status code from http loader url: %v", resp.StatusCode)
}
return resp, nil
}
func doHttpCallWithRetries(ctx caddy.Context, client *http.Client, request *http.Request) (*http.Response, error) {
var resp *http.Response
var err error
const maxAttempts = 10
for i := 0; i < maxAttempts; i++ {
resp, err = attemptHttpCall(client, request)
if err != nil && i < maxAttempts-1 {
select {
case <-time.After(time.Millisecond * 500):
case <-ctx.Done():
return resp, ctx.Err()
}
} else {
break
}
}
return resp, err
}
func (hl HTTPLoader) makeClient(ctx caddy.Context) (*http.Client, error) {
client := &http.Client{
Timeout: time.Duration(hl.Timeout),
}
if hl.TLS != nil {
var tlsConfig *tls.Config
// client authentication
if hl.TLS.UseServerIdentity {
certs, err := ctx.IdentityCredentials(ctx.Logger())
if err != nil {
return nil, fmt.Errorf("getting server identity credentials: %v", err)
}
// See https://github.com/securego/gosec/issues/1054#issuecomment-2072235199
//nolint:gosec
tlsConfig = &tls.Config{Certificates: certs}
} else if hl.TLS.ClientCertificateFile != "" && hl.TLS.ClientCertificateKeyFile != "" {
cert, err := tls.LoadX509KeyPair(hl.TLS.ClientCertificateFile, hl.TLS.ClientCertificateKeyFile)
if err != nil {
return nil, err
}
//nolint:gosec
tlsConfig = &tls.Config{Certificates: []tls.Certificate{cert}}
}
// trusted server certs
if len(hl.TLS.RootCAPEMFiles) > 0 {
rootPool := x509.NewCertPool()
for _, pemFile := range hl.TLS.RootCAPEMFiles {
pemData, err := os.ReadFile(pemFile)
if err != nil {
return nil, fmt.Errorf("failed reading ca cert: %v", err)
}
rootPool.AppendCertsFromPEM(pemData)
}
if tlsConfig == nil {
tlsConfig = new(tls.Config)
}
tlsConfig.RootCAs = rootPool
}
client.Transport = &http.Transport{TLSClientConfig: tlsConfig}
}
return client, nil
}
var _ caddy.ConfigLoader = (*HTTPLoader)(nil)
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