Fix cacheFrom and cacheTo implementation

Author: benesch

cmd/pulumi-resource-docker-buildkit/main.go

@@ -275,15 +275,13 @@ func (k *dockerBuildkitProvider) dockerBuild(
 		platforms = append(platforms, v.StringValue())
 	}
 
-	cacheFrom := name
-	if !inputs["cacheFrom"].IsNull() {
-			index = inputs["cacheFrom"]
-	}
-
-	cacheTo := "type=inline"
-	if !inputs["cacheTo"].IsNull() {
-			index = inputs["cacheTo"]
+	var cacheFrom string
+	if inputs["cacheFrom"].IsNull() {
+		cacheFrom = name
+	} else {
+		cacheFrom = inputs["cacheFrom"].StringValue()
 	}
+	cacheTo := inputs["cacheTo"].StringValue()
 
 	args := []string{
 		"buildx", "build",
@@ -335,12 +333,14 @@ func (k *dockerBuildkitProvider) dockerBuild(
 		"contextDigest":  contextDigest,
 		"repoDigest":     repoDigest,
 		"registryServer": registry["server"].StringValue(),
-		"cacheFrom":      cacheFrom,
 		"cacheTo":        cacheTo,
 	}
 	if buildArgs != nil {
 		outputs["args"] = buildArgs
 	}
+	if !inputs["cacheFrom"].IsNull() {
+		outputs["cacheFrom"] = inputs["cacheFrom"].StringValue()
+	}
 	return plugin.MarshalProperties(
 		resource.NewPropertyMapFromMap(outputs),
 		plugin.MarshalOptions{KeepUnknowns: true, SkipNulls: true},

cmd/pulumi-sdkgen-docker-buildkit/main.go

@@ -89,11 +89,11 @@ func run(version string) error {
 							TypeSpec:    schema.TypeSpec{Type: "string"},
 						},
 						"cacheFrom": {
-							Description: "Value for --cache-from when executing docker buildx, default to image name",
+							Description: "An external cache source to use for the build. Defaults to the name of the image.",
 							TypeSpec:    schema.TypeSpec{Type: "string"},
 						},
 						"cacheTo": {
-							Description: "Value for --cache-to when executing docker buildx, default to type=inline",
+							Description: "An external cache destination to export the build cache to.",
 							TypeSpec:    schema.TypeSpec{Type: "string"},
 						},
 					},
@@ -137,12 +137,13 @@ func run(version string) error {
 						Default:     "",
 					},
 					"cacheFrom": {
-						Description: "Value for --cache-from when executing docker buildx, default to image name",
+						Description: "An external cache source to use for the build. Defaults to the name of the image.",
 						TypeSpec:    schema.TypeSpec{Type: "string"},
 					},
 					"cacheTo": {
-						Description: "Value for --cache-to when executing docker buildx, default to type=inline",
+						Description: "An external cache destination to export the build cache to.",
 						TypeSpec:    schema.TypeSpec{Type: "string"},
+						Default:     "type=inline",
 					},
 					"args": {
 						Description: "The build arguments.",