x/pkgsite: add postgres.GetLicenses function to return licenses for a given path

[julieqiu]

As part of the new data model migration (#39629), we will have a single function get licenses for a given path (regardless of whether that path is a package, module, or directory).

This function will replace the existing LegacyGetPackageLicenses and LegacyGetModuleLicenses.

The function signature will be:

GetLicenses(ctx context.Context, fullpath, modulePath, resolvedVersion string)([]*licenses.License, error)

The function will execute the query below:

SELECT
    l.types,
    l.file_path,
    l.contents,
    l.coverage
FROM
    licenses l
INNER JOIN
    paths p
ON
    p.module_id=l.module_id
INNER JOIN
    modules m
ON
    p.module_id=m.id
WHERE
    p.path = $1
    AND m.module_path = $2
    AND m.version = $3;

Only licenses relevant to the path should be returned. A license applies to the path if the license is in the path directory, or any of its parent directories.

[amarjeetanandsingh]

Hi @julieqiu
If allowed, may I pick this up?

[julieqiu]

Please do! :)

[amarjeetanandsingh]

Hi @julieqiu
Thanks for allowing me to work on this issue ))

Just to confirm if I understood it correctly, we need to implement -
func (db *DB) GetLicenses(ctx context.Context, fullPath, modulePath, resolvedVersion string) (_ []*licenses.License, err error) {
in internal/postgres/postgres.go file to fetch the list of licenses for given fullPath & modulePath.

I am correct?

If yes, then internal.DataSource interface will have GetLicenses( ) as contract.
As a result, DataSource in internal/proxydatasource will also need an implementation of GetLicenses().

[julieqiu]

Thank you for contributing! :)

That is correct. I would add the function to internal/postgres/licenses.go though, as opposed to internal/postgres/postgres.go.

[amarjeetanandsingh]

ohh yeah...
Thanks @julieqiu for correcting me.
Will try to implement tomorrow.

[amarjeetanandsingh]

@julieqiu
Is there a way to load some initial sample data in my local docker postgres? Any doc you can point to?

[julieqiu]

Yup! Check out doc/worker.md#populating-data-locally-using-the-worker for instructions.

By the way, if you have other questions, feel free to reach out in the #pkgsite channel on Gophers Slack!

[gopherbot]

Change https://golang.org/cl/241718 mentions this issue: internal: add GetLicenses by path

[gopherbot]

Change https://golang.org/cl/242617 mentions this issue: internal: add GetLicenses by path