Configure project so that Docker container code can be debugged visually in VS Code

[MBARIMike]

Some resources:

• https://youtu.be/x7lZAmMVo2M
• Error for debug python application in docker microsoft/vscode-docker#2327 (comment)
• VS Code Dev Container setup cookiecutter/cookiecutter-django#2580
• https://code.visualstudio.com/docs/remote/devcontainerjson-reference
• https://code.visualstudio.com/docs/remote/containers
• https://code.visualstudio.com/docs/python/tutorial-django

[MBARIMike]

Struggling to get a debug.yml to build inside VS Code. Ran into a weird error message:

failed to compute cache key: "/compose/production/postgres/maintenance" not found: not found
[2021-07-20T19:37:45.724Z] ERROR: Service 'postgres' failed to build : Build failed

This comment seems to provide a hint as to how to fix. Sure enough, commenting out the **/compose* line from the smdb/.dockerignore file that VS Code created makes the error go away:

**/__pycache__
**/.classpath
**/.dockerignore
**/.env
**/.git
**/.gitignore
**/.project
**/.settings
**/.toolstarget
**/.vs
**/.vscode
**/*.*proj.user
**/*.dbmdl
**/*.jfm
**/azds.yaml
**/bin
**/charts
**/docker-compose*
##**/compose*
**/Dockerfile*
**/node_modules
**/npm-debug.log
**/obj
**/secrets.dev.yaml
**/values.dev.yaml
README.md

[MBARIMike]

With these commits am able to build the devcontainer in VS Code, but haven't figured out how to stop on a breakpoint in views.py or load.py. Still a WIP.

[MBARIMike]

Am able to set a breakpoint in VS Code for a manage.py shell_plus command when launched from this configuration.

[MBARIMike]

Still struggling with setting a VS Code breakpoint in views.py with manage.py runserver running...

Am able to get into command line debugging with the debug.yml (with a breakpoint() added in smdb/smdb/views.py`) thusly:

export COMPOSE_FILE=$SMDB_HOME/smdb/debug.yml
docker-compose up -d
docker-compose stop django
(base) ➜  SeafloorMappingDB git:(main) ✗ docker-compose run --rm --service-ports django python manage.py runserver_plus 0.0.0.0:8000
Creating smdb_django_run ... done
PostgreSQL is available
 * Running on http://0.0.0.0:8000/ (Press CTRL+C to quit)
 * Restarting with stat
Performing system checks...

System check identified no issues (0 silenced).

Django version 3.1.10, using settings 'config.settings.local'
Development server is running at http://0.0.0.0:8000/
Using the Werkzeug debugger (http://werkzeug.pocoo.org/)
Quit the server with CONTROL-C.
 * Debugger is active!
 * Debugger PIN: 282-534-888
 # Make request from http://localhost:8000/
INFO 2021-07-23 15:44:04,955 views.py get_context_data():26 Serializing 1384 missions to geojson...
> /app/smdb/views.py(28)get_context_data()
-> context["missions"] = json.loads(
(Pdb)

This does not work unless I use the --service-ports option for docker-compose. I'm thinking that somehow I need to do what --service-ports does inside the container that VS Code is using.

I looked at adding the --service-ports run argument in devcontainer.json, but the "runArgs" directive appears to work only for the "docker" command, not "docker-compose".

I'm also exploring using debugpy in the manage.py runserver command executed in the container. So far no joy.

[MBARIMike]

The online tutorials for getting Django debugging to work in VS Code are varied. I had to overlook the ones that did not focus on a Docker container deployed installation. Rather than trying to get debugging working via the command: /start in the container I made a launch.json configuration and had /start execute runserver_plus on port 8001. PR #22 now works pretty well. The new instructions in README.md can be followed to debug code in VS Code.

[MBARIMike]

The developer experience is fairly good now with SeafloorMappingDB in VS Code. Am able to:

• Operate runserver_plus, shell_plus, and scripts/load.py using the visual debugger
• Perform Source Control operations (add, commit, push, pull) from the UI
• Have code introspection, automated pep-8, linting, and black formatting in the editor
• Get a functional development system up and running by simply opening the cloned SeafloorMappingDB directory in VS Code – note that Docker Dashboard on the Mac provides a button to do just this!
• Execute all the tests only from the top level – individual tests and debugging of tests does not work

The last item is apparently a known Issue which I'll leave open in #25