1 files changed, 151 insertions, 0 deletions
diff --git a/caddyconfig/httploader.go b/caddyconfig/httploader.go
new file mode 100644
index 0000000..aabd103
--- /dev/null
+++ b/caddyconfig/httploader.go
@@ -0,0 +1,151 @@
+package caddyconfig
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/caddyserver/caddy/v2"
+)
+
+func init() {
+	caddy.RegisterModule(HTTPLoader{})
+}
+
+// HTTPLoader can load Caddy configs over HTTP(S). It can adapt the config
+// based on the Content-Type header of the HTTP response.
+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"`
+
+	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) {
+	client, err := hl.makeClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	method := hl.Method
+	if method == "" {
+		method = http.MethodGet
+	}
+
+	req, err := http.NewRequest(method, hl.URL, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header = hl.Headers
+
+	resp, err := client.Do(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 := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	result, warnings, err := adaptByContentType(resp.Header.Get("Content-Type"), body)
+	if err != nil {
+		return nil, err
+	}
+	for _, warn := range warnings {
+		ctx.Logger(hl).Warn(warn.String())
+	}
+
+	return result, nil
+}
+
+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(hl))
+			if err != nil {
+				return nil, fmt.Errorf("getting server identity credentials: %v", err)
+			}
+			if tlsConfig == nil {
+				tlsConfig = new(tls.Config)
+			}
+			tlsConfig.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
+			}
+			if tlsConfig == nil {
+				tlsConfig = new(tls.Config)
+			}
+			tlsConfig.Certificates = []tls.Certificate{cert}
+		}
+
+		// trusted server certs
+		if len(hl.TLS.RootCAPEMFiles) > 0 {
+			rootPool := x509.NewCertPool()
+			for _, pemFile := range hl.TLS.RootCAPEMFiles {
+				pemData, err := ioutil.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)