[WIP] Option to create a deployable runtime image

README.md

@@ -73,6 +73,8 @@ pip3 install --index-url https://test.pypi.org/simple/ ros_cross_compile
 1. Build
     1. Runs the "sysroot image" using QEmu emulation
     1. `colcon build`
+1. (Optional) Create runtime image
+    1. Creates a docker image that can be used on the target platform to run the build. See "Runtime Image" section.
 
 ## Usage
 
@@ -198,6 +200,35 @@ Now, during the sysroot creation process, you should see the contents of `someth
 NOTE: for trivial text files, as in the preceding example, you could have created those files fully within the `--custom-setup-script`. But for large or binary data such as precompiled libraries, this feature comes to the rescue.
 
 
+### Runtime Image
+
+`ros_cross_compile` can optionally create and tag a Docker image that contains all runtime dependencies and the created build of the workspace.
+
+The argument `--runtime-image` takes a single value, which is the tag used for the output image.
+
+```
+OUTPUT_IMAGE=my_registry/image_name:image_tag
+ros_cross_compile $workspace --runtime-image $OUTPUT_IMAGE
+```
+
+Now, you can deploy this to any registry to be pulled onto a target platform
+
+```
+docker push $OUTPUT_IMAGE
+```
+
+The image contains the necessary emulation binaries - or in a native build you do not need them.
+Either way, you can interactively try out the image locally.
+
+```
+docker run -it $OUTPUT_IMAGE
+# In the shell inside the running container, the setup is already sourced for the default entrypoint
+ros2 launch my_package my.launch.py
+```
+
+Note: Currently this feature is a thin layer on top of the image used for building, so it is not a fully minimal image - it contains build tools, build dependencies, and test dependencies in addition to the necessary runtime dependencies.
+
+
 ## Tutorial
 
 For a new user, this section walks you through a representative use case, step by step.

ros_cross_compile/docker/runtime.Dockerfile

@@ -0,0 +1,14 @@
+# This dockerfile creates an image containing the runtime environment for the workspace.
+# For now this is a thin layer on top of the sysroot/buildroot environment used to build.
+# It re-sets the entrypoint to a shell instead of a build script, and copies in the install.
+# The eventual plan for it is to only contain `<exec_depends>` of the workspace
+
+ARG BASE_IMAGE
+FROM $BASE_IMAGE
+WORKDIR /ros_ws
+
+ARG INSTALL_PATH
+COPY $INSTALL_PATH/ /ros_ws/install
+
+RUN echo "source /ros_ws/install/setup.bash" >> ~/.bashrc
+ENTRYPOINT /bin/bash

ros_cross_compile/ros_cross_compile.py

@@ -32,6 +32,7 @@
 from ros_cross_compile.platform import SUPPORTED_ARCHITECTURES
 from ros_cross_compile.platform import SUPPORTED_ROS2_DISTROS
 from ros_cross_compile.platform import SUPPORTED_ROS_DISTROS
+from ros_cross_compile.runtime import create_runtime_image
 from ros_cross_compile.sysroot_creator import create_workspace_sysroot_image
 from ros_cross_compile.sysroot_creator import prepare_docker_build_environment
 
@@ -128,6 +129,10 @@ def parse_args(args: List[str]) -> argparse.Namespace:
         default=[],
         nargs='+',
         help='Skip specified rosdep keys when collecting dependencies for the workspace.')
+    parser.add_argument(
+        '--create-runtime-image',
+        help='Create a Docker image with the specified name that contains all '
+             'runtime dependencies and the created "install" directory for the workspace.')
 
     return parser.parse_args(args)
 
@@ -164,6 +169,9 @@ def cross_compile_pipeline(
     assert_install_rosdep_script_exists(ros_workspace_dir, platform)
     create_workspace_sysroot_image(docker_client, platform)
     run_emulated_docker_build(docker_client, platform, ros_workspace_dir)
+    if args.create_runtime_image is not None:
+        create_runtime_image(
+            docker_client, platform, ros_workspace_dir, args.create_runtime_image)
 
 
 def main():

ros_cross_compile/runtime.py

@@ -0,0 +1,41 @@
+# Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import os
+from pathlib import Path
+
+from ros_cross_compile.docker_client import DockerClient
+from ros_cross_compile.platform import Platform
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+def create_runtime_image(
+    docker_client: DockerClient, platform: Platform, workspace_dir: Path, image_tag: str
+):
+    logger.info('----------------------')
+    logger.info('Building runtime image: {}'.format(image_tag))
+    logger.info('----------------------')
+
+    docker_client.build_image(
+        dockerfile_name=os.path.join(docker_client._default_docker_dir, 'runtime.Dockerfile'),
+        dockerfile_dir=workspace_dir,
+        tag=image_tag,
+        buildargs={
+            'BASE_IMAGE': platform.sysroot_image_tag,
+            'INSTALL_PATH': 'install_{}'.format(platform.arch),
+        },
+    )