Introduce new DB columns for storing PyPi metadata

What does this MR do and why?

This adds metadata columns for PyPi packages.

Reasoning behind the column length constraints

DB Column	Metadata field	Limit	Why?
metadata_version	Metadata-Version	16	This is a version number string. We use 16 chars for ci_runners.semver, let's do the same here.
summary	Summary	255	According to the specification, this is a one-line description
author_email	Author-email	2048	This is an array of email address strings, e.g. "Rad Batnag <rbatnag@gitlab.com>". I erred on the side of making this bigger than what we'll need for the average use case because we get occasional errors with NPM around packages with a large contributors field in package.json
description	Description	4000	This is the contents of the README file. We used 4000 chars for packages_nuget_metadata.description; let's do the same here.
description_content_type	Description-Content-Type	128	The specification allows for only a few specific values, and the longest example value with all the options added is 41 characters long.
keywords	Keywords	255	It's a comma-separated array of words

Database Review

rake db:migrate:up

main: == [advisory_lock_connection] object_id: 228020, pg_backend_pid: 23874
main: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: migrating =========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- add_column(:packages_pypi_metadata, :metadata_version, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0785s
main: -- add_column(:packages_pypi_metadata, :summary, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0013s
main: -- add_column(:packages_pypi_metadata, :keywords, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0009s
main: -- add_column(:packages_pypi_metadata, :author_email, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0012s
main: -- add_column(:packages_pypi_metadata, :description, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0013s
main: -- add_column(:packages_pypi_metadata, :description_content_type, :text, {:null=>true, :if_not_exists=>true})
main:    -> 0.0014s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_2d3ed32225\nCHECK ( char_length(metadata_version) <= 16 )\nNOT VALID;\n")
main:    -> 0.0006s
main: -- execute("SET statement_timeout TO 0")
main:    -> 0.0001s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_2d3ed32225;")
main:    -> 0.0008s
main: -- execute("RESET statement_timeout")
main:    -> 0.0003s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_76afb6d4f3\nCHECK ( char_length(summary) <= 255 )\nNOT VALID;\n")
main:    -> 0.0006s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_76afb6d4f3;")
main:    -> 0.0004s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_02be2c39af\nCHECK ( char_length(keywords) <= 255 )\nNOT VALID;\n")
main:    -> 0.0003s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_02be2c39af;")
main:    -> 0.0004s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_65d8dbbd9f\nCHECK ( char_length(author_email) <= 2048 )\nNOT VALID;\n")
main:    -> 0.0003s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_65d8dbbd9f;")
main:    -> 0.0003s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_80308aa9bd\nCHECK ( char_length(description) <= 4000 )\nNOT VALID;\n")
main:    -> 0.0003s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_80308aa9bd;")
main:    -> 0.0003s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_b1f32be96c\nCHECK ( char_length(description_content_type) <= 128 )\nNOT VALID;\n")
main:    -> 0.0004s
main: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_b1f32be96c;")
main:    -> 0.0004s
main: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: migrated (0.1183s) 

main: == [advisory_lock_connection] object_id: 228020, pg_backend_pid: 23874
ci: == [advisory_lock_connection] object_id: 228560, pg_backend_pid: 23876
ci: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: migrating =========
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- add_column(:packages_pypi_metadata, :metadata_version, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0022s
ci: -- add_column(:packages_pypi_metadata, :summary, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0011s
ci: -- add_column(:packages_pypi_metadata, :keywords, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0009s
ci: -- add_column(:packages_pypi_metadata, :author_email, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0010s
ci: -- add_column(:packages_pypi_metadata, :description, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0010s
ci: -- add_column(:packages_pypi_metadata, :description_content_type, :text, {:null=>true, :if_not_exists=>true})
ci:    -> 0.0015s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_2d3ed32225\nCHECK ( char_length(metadata_version) <= 16 )\nNOT VALID;\n")
ci:    -> 0.0006s
ci: -- execute("SET statement_timeout TO 0")
ci:    -> 0.0001s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_2d3ed32225;")
ci:    -> 0.0035s
ci: -- execute("RESET statement_timeout")
ci:    -> 0.0003s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_76afb6d4f3\nCHECK ( char_length(summary) <= 255 )\nNOT VALID;\n")
ci:    -> 0.0003s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_76afb6d4f3;")
ci:    -> 0.0003s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_02be2c39af\nCHECK ( char_length(keywords) <= 255 )\nNOT VALID;\n")
ci:    -> 0.0003s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_02be2c39af;")
ci:    -> 0.0004s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_65d8dbbd9f\nCHECK ( char_length(author_email) <= 2048 )\nNOT VALID;\n")
ci:    -> 0.0003s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_65d8dbbd9f;")
ci:    -> 0.0003s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_80308aa9bd\nCHECK ( char_length(description) <= 4000 )\nNOT VALID;\n")
ci:    -> 0.0004s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_80308aa9bd;")
ci:    -> 0.0004s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- execute("ALTER TABLE packages_pypi_metadata\nADD CONSTRAINT check_b1f32be96c\nCHECK ( char_length(description_content_type) <= 128 )\nNOT VALID;\n")
ci:    -> 0.0005s
ci: -- execute("ALTER TABLE packages_pypi_metadata VALIDATE CONSTRAINT check_b1f32be96c;")
ci:    -> 0.0003s
ci: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: migrated (0.0425s) 

ci: == [advisory_lock_connection] object_id: 228560, pg_backend_pid: 23876

rake db:migrate:down

main: == [advisory_lock_connection] object_id: 225860, pg_backend_pid: 24289
main: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: reverting =========
main: -- transaction_open?()
main:    -> 0.0000s
main: -- remove_column(:packages_pypi_metadata, :metadata_version, {:if_exists=>true})
main:    -> 0.0710s
main: -- remove_column(:packages_pypi_metadata, :summary, {:if_exists=>true})
main:    -> 0.0014s
main: -- remove_column(:packages_pypi_metadata, :keywords, {:if_exists=>true})
main:    -> 0.0011s
main: -- remove_column(:packages_pypi_metadata, :author_email, {:if_exists=>true})
main:    -> 0.0011s
main: -- remove_column(:packages_pypi_metadata, :description, {:if_exists=>true})
main:    -> 0.0012s
main: -- remove_column(:packages_pypi_metadata, :description_content_type, {:if_exists=>true})
main:    -> 0.0012s
main: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: reverted (0.0881s) 

main: == [advisory_lock_connection] object_id: 225860, pg_backend_pid: 24289
ci: == [advisory_lock_connection] object_id: 227020, pg_backend_pid: 24677
ci: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: reverting =========
ci: -- transaction_open?()
ci:    -> 0.0000s
ci: -- remove_column(:packages_pypi_metadata, :metadata_version, {:if_exists=>true})
ci:    -> 0.0668s
ci: -- remove_column(:packages_pypi_metadata, :summary, {:if_exists=>true})
ci:    -> 0.0017s
ci: -- remove_column(:packages_pypi_metadata, :keywords, {:if_exists=>true})
ci:    -> 0.0010s
ci: -- remove_column(:packages_pypi_metadata, :author_email, {:if_exists=>true})
ci:    -> 0.0011s
ci: -- remove_column(:packages_pypi_metadata, :description, {:if_exists=>true})
ci:    -> 0.0009s
ci: -- remove_column(:packages_pypi_metadata, :description_content_type, {:if_exists=>true})
ci:    -> 0.0010s
ci: == 20230906100001 AddMetadataColumnsToPackagesPyPiMetadata: reverted (0.0878s) 

ci: == [advisory_lock_connection] object_id: 227020, pg_backend_pid: 24677

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #423529 (closed)