opm serve: pre-compute and store api.Bundles to disk; requests read from disk

[joelanford]

Signed-off-by: Joe Lanford joe.lanford@gmail.com

Description of the change:
When serving the registry from the model, pre-compute the api.Bundle blobs, save them to disk, and reduce the size of the in-memory model to contain only enough to answer requests by looking up and reading bundles from disk.

Motivation for the change:
This change provides a major memory optimization. Using a real-world file-based catalog (created by migrating a production sqlite-based catalog), the steady state RSS is reduced from 373Mb to 55Mb, an 85% decrease.

Reviewer Checklist

• Implementation matches the proposed design, or proposal is updated to match implementation
• Sufficient unit test coverage
• Sufficient end-to-end test coverage
• Docs updated or added to /docs
• Commit messages sensible and descriptive

[kevinrizza]

/lgtm

[openshift-bot]

/retest-required

Please review the full test history for this PR and help us cut down flakes.

[openshift-bot]

/retest-required

Please review the full test history for this PR and help us cut down flakes.

[openshift-bot]

/retest-required

Please review the full test history for this PR and help us cut down flakes.

[codecov]

Codecov Report

Merging #783 (97b731c) into master (3880486) will increase coverage by 0.01%.
The diff coverage is 66.66%.

❗ Current head 97b731c differs from pull request most recent head d490d74. Consider uploading reports for the commit d490d74 to get more accurate results

@@            Coverage Diff             @@
##           master     #783      +/-   ##
==========================================
+ Coverage   50.64%   50.65%   +0.01%     
==========================================
  Files         102      102              
  Lines        8846     8879      +33     
==========================================
+ Hits         4480     4498      +18     
- Misses       3522     3530       +8     
- Partials      844      851       +7     

Impacted Files	Coverage Δ
pkg/registry/parse.go	73.68% <ø> (ø)
pkg/registry/query.go	60.41% <66.66%> (-1.22%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3880486...d490d74. Read the comment docs.

[anik120]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: anik120, joelanford

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [joelanford]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment