Do not store username/password information in our Image resource. (#28)

docker/image.ts

@@ -84,7 +84,7 @@ export class Image extends pulumi.ComponentResource {
     public digest: pulumi.Output<string | undefined>;
 
     constructor(name: string, args: ImageArgs, opts?: pulumi.ComponentResourceOptions) {
-        super("docker:image:Image", name, args, opts);
+        super("docker:image:Image", name, argsWithoutRegistry(args), opts);
 
         const imageData = pulumi.output(args).apply(async (imageArgs) => {
             let localImageName = imageArgs.localImageName;
@@ -123,3 +123,13 @@ export class Image extends pulumi.ComponentResource {
         });
     }
 }
+
+// Take out the registry information from the args.  It is needed to build and push the image.  But
+// it's not an intrinsic part of this Image resource.  We do not want to store it, otherwise a
+// change to something like a registry password would cause this to be recreated.  Instead, we only
+// want to recreate if our actual digests change.
+function argsWithoutRegistry(args: ImageArgs): ImageArgs {
+    const result = {...args};
+    delete result.registry;
+    return result;
+}