GODT-1204: Handle importing too big messages

pkg/pmapi/import.go

@@ -27,7 +27,10 @@ import (
 	"github.com/go-resty/resty/v2"
 )
 
-const MaxImportMessageRequestLength = 10
+const (
+	MaxImportMessageRequestLength = 10
+	MaxImportMessageRequestSize   = 25 * 1024 * 1024 // 25 MB total limit
+)
 
 type ImportMsgReq struct {
 	Metadata *ImportMetadata // Metadata about the message to import.
@@ -91,6 +94,14 @@ func (c *client) Import(ctx context.Context, reqs ImportMsgReqs) ([]*ImportMsgRe
 		return nil, errors.New("request is too long")
 	}
 
+	remainingSize := MaxImportMessageRequestSize
+	for _, req := range reqs {
+		remainingSize -= len(req.Message)
+		if remainingSize < 0 {
+			return nil, errors.New("request size is too big")
+		}
+	}
+
 	fields, err := reqs.buildMultipartFormData()
 	if err != nil {
 		return nil, err

pkg/pmapi/import_test.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"math/rand"
 	"mime/multipart"
 	"net/http"
 	"testing"
@@ -115,3 +116,32 @@ func TestClient_Import(t *testing.T) { // nolint[funlen]
 	r.Equal(t, 1, len(imported))
 	r.Equal(t, testImportRes, imported[0])
 }
+
+func TestClientImportBigSize(t *testing.T) {
+	s, c := newTestClient(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		r.FailNow(t, "request is not dropped")
+	}))
+	defer s.Close()
+
+	const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	const size = MaxImportMessageRequestSize + 1
+	msg := make([]byte, size)
+	for i := 0; i < size; i++ {
+		msg[i] = letterBytes[rand.Intn(len(letterBytes))]
+	}
+
+	importRequest := []*ImportMsgReq{
+		{
+			Metadata: &ImportMetadata{
+				AddressID: "addressID",
+				Unread:    Boolean(false),
+				Flags:     FlagReceived | FlagImported,
+				LabelIDs:  []string{ArchiveLabel},
+			},
+			Message: msg,
+		},
+	}
+
+	_, err := c.Import(context.Background(), importRequest)
+	r.EqualError(t, err, "request size is too big")
+}