container-debug-support

README

Container Runtime Debugging Support (aka Duct Tape)

This repository gathers additional dependencies required to debug particular language runtimes with skaffold debug. These dependencies are packaged as a set of container images suitable for use as initContainers on a pod. When executed, a container image copies these dependencies to /dbg/<runtimeId>.

The idea is that skaffold debug will transform k8s manifests to make available any support files required to debug specific language runtimes. For example, a Kubernetes podspec would be transformed to

• mount a volume on /dbg to hold the debugging support files
• run one or more of these initContainers to populate the volume
• mount the volume on the applicable containers as /dbg

Current language runtimes:

• go: provides Delve
• python: provides ptvsd, a debug adapter that can be used for VS Code and more, for Python 2.7 and 3.5+
• nodejs: provides a node wrapper that propagates --inspect args to the application invokation
• netcore: provides vsdbg for .NET Core

Development

This project uses Skaffold's multiple config support to allow developing for each language runtime separately.

Each language runtime is broken out to a separate directory with a skaffold.yaml for development of the duct-tape initContainer image. Each image is expected to be standalone and not require downloading content across the network. To add support for a new language runtime, an image definition should download the necessary files into the container image. The image's entrypoint should then copy those files into place at /dbg/<runtime>. The image should be added to the respective skaffold.yaml and referenced within test/k8s-*-installation.yaml.

Testing

Integration tests are found in test/. These tests build and launch applications as pods that are similar to the transformed form produced by skaffold debug. To run:

sh run-its.sh