Declarative Management hand-off (#882)

server/dm.go

@@ -0,0 +1,78 @@
+package server
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+)
+
+const enrollmentIDHeader = "X-Enrollment-ID"
+
+type DeclarativeManagementHTTPCaller struct {
+	url    *url.URL
+	client *http.Client
+}
+
+// NewDeclarativeManagementHTTPCaller creates a new DeclarativeManagementHTTPCaller
+func NewDeclarativeManagementHTTPCaller(urlPrefix string, client *http.Client) (*DeclarativeManagementHTTPCaller, error) {
+	url, err := url.Parse(urlPrefix)
+	return &DeclarativeManagementHTTPCaller{url: url, client: client}, err
+}
+
+type HTTPStatusError struct {
+	Err    error
+	Status int
+}
+
+func (e HTTPStatusError) Error() string {
+	return e.Err.Error()
+}
+
+func (e HTTPStatusError) StatusCode() int {
+	return e.Status
+}
+
+// DeclarativeManagement calls out to an HTTP URL to handle the actual Declarative Management protocol
+func (c *DeclarativeManagementHTTPCaller) DeclarativeManagement(ctx context.Context, id, endpoint string, data []byte) ([]byte, error) {
+	if c.url == nil {
+		return nil, errors.New("missing URL")
+	}
+	endpointURL, err := url.Parse(endpoint)
+	if err != nil {
+		return nil, fmt.Errorf("parsing endpoint URL: %w", err)
+	}
+	u := c.url.ResolveReference(endpointURL)
+	method := http.MethodGet
+	if len(data) > 0 {
+		method = http.MethodPut
+	}
+	req, err := http.NewRequestWithContext(ctx, method, u.String(), bytes.NewBuffer(data))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set(enrollmentIDHeader, id)
+	if len(data) > 0 {
+		req.Header.Set("Content-Type", "application/json")
+	}
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	bodyBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != 200 {
+		// return the same HTTP status with a Go-kit StatusCoder
+		return bodyBytes, HTTPStatusError{
+			Err:    fmt.Errorf("unexpected HTTP status: %d", resp.StatusCode),
+			Status: resp.StatusCode,
+		}
+	}
+	return bodyBytes, nil
+}

server/server.go

@@ -66,6 +66,7 @@ type Server struct {
 	ValidateSCEPExpiration bool
 	UDIDCertAuthWarnOnly   bool
 	Queue                  string
+	DMURL                  string
 
 	APNSPushService apns.Service
 	CommandService  command.Service
@@ -202,7 +203,15 @@ func (c *Server) setupCommandQueue(logger log.Logger) error {
 
 	var mdmService mdm.Service
 	{
-		svc := mdm.NewService(c.PubClient, q, devDB)
+		var dm mdm.DeclarativeManagement
+		if c.DMURL != "" {
+			dm, err = NewDeclarativeManagementHTTPCaller(c.DMURL, http.DefaultClient)
+			if err != nil {
+				return fmt.Errorf("setting up declarative management: %w", err)
+			}
+		}
+
+		svc := mdm.NewService(c.PubClient, q, devDB, dm)
 		mdmService = svc
 		mdmService = block.RemoveMiddleware(c.RemoveDB)(mdmService)