Let docker build output eap-file

Dockerfile

@@ -95,3 +95,7 @@ RUN <<EOF
 EOF
 
 ENTRYPOINT [ "/opt/axis/acapsdk/sysroots/x86_64-pokysdk-linux/usr/bin/eap-install.sh" ]
+
+FROM scratch AS binaries
+
+COPY --from=build /opt/app/*.eap /

README.md

@@ -229,16 +229,12 @@ To build the Docker ACAP use docker buildx with the provided Dockerfile:
 
 ```sh
 # Build Docker ACAP image
-docker buildx build --file Dockerfile --tag docker-acap:<ARCH> --build-arg ACAPARCH=<ARCH> .
+docker buildx build --file Dockerfile --tag docker-acap:<ARCH> --build-arg ACAPARCH=<ARCH> --output <build-folder> .
 ```
 
-where `<ARCH>` is either `armv7hf` or `aarch64`.
-
-To extract the Docker ACAP eap-file use docker cp to copy it to a `build` folder:
-
-```sh
-docker cp "$(docker create "docker-acap:<ARCH>")":/opt/app/ ./build
-```
+where `<ARCH>` is either `armv7hf` or `aarch64`. `<build-folder>` is the path to an output folder
+on your machine, eg. `build`. This will be created for you if not already existing.
+Once the build has completed the Docker ACAP eap-file can be found in the `<build-folder>`.
 
 ## Installing a locally built Docker ACAP
 

build.sh

@@ -46,6 +46,5 @@ docker buildx build --build-arg ACAPARCH="$arch" \
 	--file Dockerfile \
 	$progress_arg \
 	$cache_arg \
-	--tag "$imagetag" .
-
-docker cp "$(docker create "$imagetag")":/opt/app/ ./build-"$arch"
+	--tag "$imagetag" \
+	--output build-"$arch" .