feat(image-build): add the ability to build images (#1672)

api/http/proxy/build.go

@@ -0,0 +1,56 @@
+package proxy
+
+import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"strings"
+
+	"github.com/portainer/portainer/archive"
+)
+
+type postDockerfileRequest struct {
+	Content string
+}
+
+// buildOperation inspects the "Content-Type" header to determine if it needs to alter the request.
+// If the value of the header is empty, it means that a Dockerfile is posted via upload, the function
+// will extract the file content from the request body, tar it, and rewrite the body.
+// If the value of the header contains "application/json", it means that the content of a Dockerfile is posted
+// in the request payload as JSON, the function will create a new file called Dockerfile inside a tar archive and
+// rewrite the body of the request.
+// In any other case, it will leave the request unaltered.
+func buildOperation(request *http.Request) error {
+	contentTypeHeader := request.Header.Get("Content-Type")
+	if contentTypeHeader != "" && !strings.Contains(contentTypeHeader, "application/json") {
+		return nil
+	}
+
+	var dockerfileContent []byte
+
+	if contentTypeHeader == "" {
+		body, err := ioutil.ReadAll(request.Body)
+		if err != nil {
+			return err
+		}
+		dockerfileContent = body
+	} else {
+		var req postDockerfileRequest
+		if err := json.NewDecoder(request.Body).Decode(&req); err != nil {
+			return err
+		}
+		dockerfileContent = []byte(req.Content)
+	}
+
+	buffer, err := archive.TarFileInBuffer(dockerfileContent, "Dockerfile")
+	if err != nil {
+		return err
+	}
+
+	request.Body = ioutil.NopCloser(bytes.NewReader(buffer))
+	request.ContentLength = int64(len(buffer))
+	request.Header.Set("Content-Type", "application/x-tar")
+
+	return nil
+}

api/http/proxy/transport.go

@@ -27,6 +27,7 @@ type (
 		labelBlackList   []portainer.Pair
 	}
 	restrictedOperationRequest func(*http.Request, *http.Response, *operationExecutor) error
+	operationRequest           func(*http.Request) error
 )
 
 func (p *proxyTransport) RoundTrip(request *http.Request) (*http.Response, error) {
@@ -59,6 +60,8 @@ func (p *proxyTransport) proxyDockerRequest(request *http.Request) (*http.Respon
 		return p.proxyNodeRequest(request)
 	case strings.HasPrefix(path, "/tasks"):
 		return p.proxyTaskRequest(request)
+	case strings.HasPrefix(path, "/build"):
+		return p.proxyBuildRequest(request)
 	default:
 		return p.executeDockerRequest(request)
 	}
@@ -228,6 +231,10 @@ func (p *proxyTransport) proxyTaskRequest(request *http.Request) (*http.Response
 	}
 }
 
+func (p *proxyTransport) proxyBuildRequest(request *http.Request) (*http.Response, error) {
+	return p.interceptAndRewriteRequest(request, buildOperation)
+}
+
 // restrictedOperation ensures that the current user has the required authorizations
 // before executing the original request.
 func (p *proxyTransport) restrictedOperation(request *http.Request, resourceID string) (*http.Response, error) {
@@ -300,6 +307,15 @@ func (p *proxyTransport) rewriteOperation(request *http.Request, operation restr
 	return p.executeRequestAndRewriteResponse(request, operation, executor)
 }
 
+func (p *proxyTransport) interceptAndRewriteRequest(request *http.Request, operation operationRequest) (*http.Response, error) {
+	err := operation(request)
+	if err != nil {
+		return nil, err
+	}
+
+	return p.executeDockerRequest(request)
+}
+
 func (p *proxyTransport) executeRequestAndRewriteResponse(request *http.Request, operation restrictedOperationRequest, executor *operationExecutor) (*http.Response, error) {
 	response, err := p.executeDockerRequest(request)
 	if err != nil {