Docker adaptor can retrieve an image from the local docker service

[mih]

Closes: #199

@bpinsard would be great if you could give this a spin!

Demo

❯ datalad create busydemo
❯ cd busydemo
❯ datalad containers-add -u dhub://busybox:latest busy
❯ datalad drop .datalad/environments --reckless availability
❯ git annex info | grep 'local annex'
local annex keys: 0
local annex size: 0 bytes
❯ cat .datalad/config
[datalad "dataset"]
        id = b7adee52-a65a-43fc-a85b-c0d5e2d5b67c
[datalad "containers.busy"]
        image = .datalad/environments/busy/image
        cmdexec = {python} -m datalad_container.adapters.docker run {img} {cmd}
❯ datalad containers-run -n busy uname
[INFO   ] Saved busybox:latest to /tmp/busydemo/.datalad/environments/busy/image/tmpzrdd7mj2
[INFO   ] Making sure inputs are available (this may take some time)
[INFO   ] == Command start (output follows) =====
Linux
[INFO   ] == Command exit (modification check follows) =====
run(ok): /tmp/busydemo (dataset) [/home/mih/env/datalad-dev/bin/python -m ...]

[qlty-cloud-legacy]

Code Climate has analyzed commit 24a11ce and detected 11 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Security	11

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[codecov]

Codecov Report

Attention: 18 lines in your changes are missing coverage. Please review.

Comparison is base (c505e52) 94.69% compared to head (24a11ce) 93.23%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #246      +/-   ##
==========================================
- Coverage   94.69%   93.23%   -1.46%     
==========================================
  Files          25       25              
  Lines        1093     1124      +31     
==========================================
+ Hits         1035     1048      +13     
- Misses         58       76      +18     

Files	Coverage Δ
datalad_container/containers_run.py	84.00% <77.77%> (-0.85%)	⬇️
datalad_container/adapters/docker.py	82.08% <27.27%> (-10.77%)	⬇️

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[bpinsard]

Works for me, it seems to retrieve the layers correctly.

I currently no longer have a specific usecase for the docker adapter, but that is a great performance enhancement.

[yarikoptic]

sorry, not grasping atm the whole machinery... if code works for you -- go ahead with the merge.

[mih]

Thanks for the feedback! I am not sure whether I will have the chance to try the practicality of this implementation sufficiently. The next week will tell me that. For now, I will convert this to a draft PR.

If I get this chance to try this out sufficiently I will finish it out and repropose.

If this message is read after two weeks from now, and the PR is still in draft. Please close without waiting for me. Thanks!