feat: add arbitrary metadata GET/POST endpoints

[corban-beaird]

Ticket

ET-48

Description

Add support for storing arbitrary metadata associated with a given run. Additionally, this sets the groundwork for filtering runs based on flat_key-value pairs.

Test Plan

• Automated integration testing for API
• Automated unit testing

Checklist

• [ ] Changes have been manually QA'd
• [ ] User-facing API changes need the "User-facing API Change" label.
• [ ] Release notes should be added as a separate file under docs/release-notes/. See Release Note for details.
• [ ] Licenses should be included for new code which was copied and/or modified from any external code.

[netlify[bot]]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	2367ef8027e390d5280dbd13bc7d9c5468cec90b
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/666b1727e0c43a00087055c8

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 54.29688% with 117 lines in your changes missing coverage. Please review.

Project coverage is 48.99%. Comparing base (e3d01c1) to head (2367ef8). Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #9130    +/-   ##
========================================
  Coverage   48.98%   48.99%            
========================================
  Files        1238     1240     +2     
  Lines      160518   160772   +254     
  Branches     2783     2784     +1     
========================================
+ Hits        78629    78763   +134     
- Misses      81714    81834   +120     
  Partials      175      175            

Flag	Coverage Δ
backend	43.91% <62.79%> (+0.05%)	:arrow_up:
harness	63.80% <36.90%> (-0.06%)	:arrow_down:
web	44.13% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
master/internal/api_experiment.go	56.79% <100.00%> (+0.02%)	:arrow_up:
master/internal/db/postgres_trial.go	62.61% <100.00%> (ø)
master/pkg/model/experiment.go	14.63% <100.00%> (+0.34%)	:arrow_up:
master/internal/api_runs.go	63.19% <82.75%> (+0.89%)	:arrow_up:
harness/determined/core/_train.py	39.83% <33.33%> (-1.08%)	:arrow_down:
master/internal/run/runs.go	87.09% <87.09%> (ø)
harness/determined/common/api/bindings.py	40.21% <37.33%> (-0.02%)	:arrow_down:
master/internal/db/postgres_runs.go	0.00% <0.00%> (ø)

... and 3 files with indirect coverage changes

[azhou-determined]

is there a way for someone to delete keys from the metadata or is that out of scope for this?

[corban-beaird]

is there a way for someone to delete keys from the metadata or is that out of scope for this?

@azhou-determined Not currently, I do believe it's out of scope for this PR, but I don't see a reason why we shouldn't add it to the backlog of items to knock out with this project.

How granular are we wanting to allow a metadata to be deleted? I would be in favor of allowing requests to be made on at a key level + the ability to delete all arbitrary metadata on a given run at once.

[azhou-determined]

is there a way for someone to delete keys from the metadata or is that out of scope for this?

@azhou-determined Not currently, I do believe it's out of scope for this PR, but I don't see a reason why we shouldn't add it to the backlog of items to knock out with this project.

How granular are we wanting to allow a metadata to be deleted? I would be in favor of allowing requests to be made on at a key level + the ability to delete all arbitrary metadata on a given run at once.

i guess if we're going with the "only set/update, never add/merge" approach, we don't really need to surface a way to delete. as you mentioned, set_metadata(metadata=None) seems logical to me. i think we should have remove if we go with add though.