check for images property if cacheFrom is present (#555)

provider/image.go

@@ -82,7 +82,10 @@ func (p *dockerNativeProvider) dockerBuild(ctx context.Context,
 	if err != nil {
 		return "", nil, err
 	}
-	cache := marshalCachedImages(img, inputs["build"])
+	cache, err := marshalCachedImages(inputs["build"])
+	if err != nil {
+		return "", nil, err
+	}
 
 	build.CachedImages = cache
 	img.Build = build
@@ -390,25 +393,28 @@ func marshalBuildAndApplyDefaults(b resource.PropertyValue) (Build, error) {
 	return build, nil
 }
 
-func marshalCachedImages(img Image, b resource.PropertyValue) []string {
+func marshalCachedImages(b resource.PropertyValue) ([]string, error) {
 	var cacheImages []string
 	if b.IsNull() {
-		return cacheImages
+		return cacheImages, nil
 	}
 	c := b.ObjectValue()["cacheFrom"]
 
 	if c.IsNull() {
-		return cacheImages
+		return cacheImages, nil
 	}
 
 	// if we specify a list of stages, then we only pull those
 	cacheFrom := c.ObjectValue()
+	if cacheFrom["images"].IsNull() {
+		return cacheImages, fmt.Errorf("if you want to use cacheFrom, you must have `images` set")
+	}
 	stages := cacheFrom["images"].ArrayValue()
 	for _, img := range stages {
 		stage := img.StringValue()
 		cacheImages = append(cacheImages, stage)
 	}
-	return cacheImages
+	return cacheImages, nil
 }
 
 func marshalRegistry(r resource.PropertyValue) Registry {

provider/image_test.go

@@ -206,15 +206,6 @@ func TestMarshalArgs(t *testing.T) {
 func TestMarshalCachedImages(t *testing.T) {
 	t.Run("Test Cached Images", func(t *testing.T) {
 		expected := []string{"apple", "banana", "cherry"}
-		imgInput := Image{
-			Name:     "unicornsareawesome",
-			SkipPush: false,
-			Registry: Registry{
-				Server:   "https://index.docker.io/v1/",
-				Username: "pulumipus",
-				Password: "supersecret",
-			},
-		}
 		buildInput := resource.NewObjectProperty(resource.PropertyMap{
 			"dockerfile": resource.NewStringProperty("TheLastUnicorn"),
 			"context":    resource.NewStringProperty("/twilight/sparkle/bin"),
@@ -227,45 +218,39 @@ func TestMarshalCachedImages(t *testing.T) {
 				}),
 			}),
 		})
-
-		actual := marshalCachedImages(imgInput, buildInput)
+		actual, err := marshalCachedImages(buildInput)
+		assert.NoError(t, err)
 		assert.Equal(t, expected, actual)
 
 	})
 	t.Run("Test Cached Images No Build Input Returns Nil", func(t *testing.T) {
 		expected := []string(nil)
-		imgInput := Image{
-			Name:     "unicornsareawesome",
-			SkipPush: false,
-			Registry: Registry{
-				Server:   "https://index.docker.io/v1/",
-				Username: "pulumipus",
-				Password: "supersecret",
-			},
-		}
 		buildInput := resource.NewObjectProperty(resource.PropertyMap{})
-		actual := marshalCachedImages(imgInput, buildInput)
+		actual, err := marshalCachedImages(buildInput)
+		assert.NoError(t, err)
 		assert.Equal(t, expected, actual)
 	})
 
 	t.Run("Test Cached Images No cacheFrom Input Returns Nil", func(t *testing.T) {
 		expected := []string(nil)
-		imgInput := Image{
-			Name:     "unicornsareawesome",
-			SkipPush: false,
-			Registry: Registry{
-				Server:   "https://index.docker.io/v1/",
-				Username: "pulumipus",
-				Password: "supersecret",
-			},
-		}
 		buildInput := resource.NewObjectProperty(resource.PropertyMap{
 			"dockerfile": resource.NewStringProperty("TheLastUnicorn"),
 			"context":    resource.NewStringProperty("/twilight/sparkle/bin"),
 		})
-		actual := marshalCachedImages(imgInput, buildInput)
+		actual, err := marshalCachedImages(buildInput)
+		assert.NoError(t, err)
 		assert.Equal(t, expected, actual)
 	})
+	t.Run("Test Cached Images No images Input Returns Nil and error", func(t *testing.T) {
+		buildInput := resource.NewObjectProperty(resource.PropertyMap{
+			"dockerfile": resource.NewStringProperty("TheLastUnicorn"),
+			"context":    resource.NewStringProperty("/twilight/sparkle/bin"),
+			"cacheFrom":  resource.NewObjectProperty(resource.PropertyMap{}),
+		})
+		actual, err := marshalCachedImages(buildInput)
+		assert.Error(t, err)
+		assert.Nil(t, actual)
+	})
 }
 
 func TestMarshalBuilder(t *testing.T) {

provider/provider.go

@@ -6,6 +6,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/diag"
 	"io"
 	"io/fs"
 	"os"
@@ -189,6 +190,11 @@ func (p *dockerNativeProvider) Check(ctx context.Context, req *rpc.CheckRequest)
 				return nil, err
 			}
 		}
+
+		if _, err := marshalCachedImages(inputs["build"]); err != nil {
+			err = p.host.Log(ctx, diag.Error, urn, msg)
+			return nil, err
+		}
 	}
 
 	inputStruct, err := plugin.MarshalProperties(inputs, plugin.MarshalOptions{