x/pkgsite: API for pkg.go.dev

[rhcarvalho]

Prior to pkg.go.dev, godoc.org has had a JSON API that can be used to, among other things, discover importers of a given package.

Example: https://api.godoc.org/importers/golang.org/x/net/html

Given that pkg.go.dev does a much better job at tracking importers thanks to Go Modules and the Module Proxy, it would be nice if the community could get access to a public API similar to that of godoc.org.

[julieqiu]

@rhcarvalho - it would be helpful to get a sense of what your current use cases are for api.godoc.org, and feature requests are for an API for pkg.go.dev.

It sounds like getting the importers for a package is one of them. With pkg.go.dev being module aware, what specific information about importers would be useful to surface via an API?

For example:

• importers for a specific version of a package
• only importers of the latest version of a package
• any importer for all versions of a package
• something else?

Additionally, what other information would be useful to you to surface via an API?

/cc @tbpg who has also mentioned wanting an API for pkg.go.dev

[rhcarvalho]

Without much thought, having an API to answer the more specific question "what are the importers of a specific version of a package" would make plausible to derive the answer to the other items in your list.

At the moment I consume the godoc.org API and scrape data from pkg.go.dev to answer the question "who uses my package". As far as I can tell the data in the "Imported By" go.dev tab is unrelated to the version of the package I'm currently browsing.

Here are the other endpoints in the GoDoc API: https://github.com/golang/gddo/blob/7365cb292b8bfd13dfe514a18b207b9cc70e6ceb/gddo-server/main.go#L901-L904

• /search: takes a q parameter. Can be useful to explore known packages/modules.
• /packages: attempts to return all known packages, no pagination. Doesn't seem too usable as is.
• /importers/: useful, hard to compute without central knowledge.
• /imports/: dispensable, easy to compute offline with go list.

So if we need a more specific request, here it is:

api.go.dev MVP

• /importers/{module-or-package}/@v/<version>: returns the list of importers of a given module/package at a given version. URL scheme could be tuned to match the Go Proxy specification (go help goproxy).
• /search/: matches the functionality of https://pkg.go.dev/search?q=hello, returns JSON instead.

[tbpg]

Another endpoint idea (standalone or as part of a set of info returned for a module): available versions of a given module.

[myitcv]

@tbpg

Another endpoint idea (standalone or as part of a set of info returned for a module): available versions of a given module.

Shouldn't people use cmd/go for that? Not least because of the fall-through semantics of the go env GOPROXY` variable. Noting #37367

[julieqiu]

What information beyond https://proxy.golang.org/<module>/@v/list would be provided by that endpoint?

[tbpg]

Shouldn't people use cmd/go for that? Not least because of the fall-through semantics of the go env GOPROXY` variable. Noting #37367

There are some cases where cmd/go might not be available and a normal web API would be helpful. I think it's reasonable to assume pkg.go.dev will only return the modules/versions it knows about.

What information beyond https://proxy.golang.org/<module>/@v/list would be provided by that endpoint?

None. That works. :)

[myitcv]

There are some cases where cmd/go might not be available and a normal web API would be helpful

I'd be wary of encouraging tool authors to query pkg.go.dev/a proxy directly. Because it could well introduce skew compared to the answers from cmd/go.

[adamdecaf]

In my use-case I don't want to execute cmd/go binaries as I just want to grab some metadata (i.e. detected license of all dependencies) from a dozen modules and organize it on a webpage. If I need local clones of those modules it really complicates this internal tool.

[myitcv]

In #37952 I raised the question of whether module/package license file information could be surfaced in the output of cmd/go list. Following a conversation on yesterday's golang-tools call, we concluded that doing so would be a bad idea; reasons summarised in #37952 (comment).

@ianthehat instead suggested exposing the information via a pkg.go.dev API, leveraging the fact that the content and presentation on pkg.go.dev has already jumped through the relevant legal hoops.

This comment is therefore to explicitly request that we include license file information in the API. Thank you!

[tiegz]

👋 Thanks for all the new Go tools like pkg.go.dev, they're super useful. Some input on this topic from the perspective of Libraries.io:

• +1 to a /search/ endpoint, or maybe just adding pagination to this url so it's possible to get a list of all packages: https://index.golang.org/index?since=TIME&limit=LIMIT. Many popular package repositories offer a full listing like this, e.g. https://packagist.org/packages/list.json for Packagist

• What information beyond https://proxy.golang.org//@v/list would be provided by that endpoint?

Currently to get the publish times for all versions, you have to make N+1 requests: one for @v/list and then @v/xxx.info for each version and grab the "Time" value for each one. Assuming it's difficult to change the Go proxy spec, an API endpoint that returns all versions with metadata would be really nice.

• As far as I can tell the data in the "Imported By" go.dev tab is unrelated to the version of the package I'm currently browsing.

Anyone know if there are plans to fix this?

[jba]

• As far as I can tell the data in the "Imported By" go.dev tab is unrelated to the version of the package I'm currently browsing.

Anyone know if there are plans to fix this?

No immediate plans. We currently gather that information from import statements in the code, so there is no version information attached. The go.mod file doesn't have all the version information we need.

So we understand it's an approximation and we want to fix it, but it's going to take some time.

[pombredanne]

@julieqiu my use for an API would be to:

1. search and list packages
2. for a package, access all the information as available for a given package in each of the tabs, such as here https://pkg.go.dev/github.com/gin-gonic/gin?tab=licenses ... basically everything that is available as HTML in the frontend https://github.com/golang/pkgsite/tree/master/internal/frontend should be available in a JSON api

[pombredanne]

@julieqiu oh and please do not retire http://api.godoc.org/packages unless there is an alternative!

[eclipseo]

it would be helpful to get a sense of what your current use cases are for api.godoc.org, and feature requests are for an API for pkg.go.dev.

As a downstream package maintainer for Fedora, I'm also interested in an API. We have our own tool, Anitya, to track package releases, but it was not designed to track GIT commits. And many Go packages still don't publish version. So any information about latest published commit, with info like date of the commit, new dependencies, would be very helpful. I would gather data from the API in Python and compare it to the latest version we have for a given package.

I'm also interested in getting the License info, so we could find recursively all the licenses used in a static binary.

[restuwahyu13]

But is api.godoc.org the same as pkg.go.dev sir @jba ?

[fzipp]

@restuwahyu13 pkg.go.dev doesn't have an API yet, that's why this issue is open and not closed.

[shellscape]

Stopping by to ask that any first version of an API provide some means to glean the source code / repo location of a package that uses a vanity path/url/name.

[guseggert]

I have similar use cases as others, so I resorted to scraping the UI as well (🤢), and put it behind an API/CLI: https://github.com/guseggert/pkggodev-client

[sig-aarena]

The /packages api endpoint, https://api.godoc.org/packages, is returning {"error":{"message":"Internal Server Error"}} .

Has this endpoint been migrated?

[tills13]

Seems like most api.godoc.org endpoints are erroring, currently?

e.g. https://api.godoc.org/packages, https://api.godoc.org/imports/github.com/goburrow/cache, etc.

I'm particularly interested in the imports endpoint. Has this moved somewhere else or is there a mirror I can use?

[pombredanne]

This is starting to be really problematic. @jba could someone kindly look into this? This is really looking bad

[pombredanne]

@julieqiu do you know what happened?

[jba]

Will get on this today.

[pombredanne]

@jba you rock... that's very kind of you! 🙇

[pombredanne]

Note that only alternative today would be to resort to extensive pseudo-random screen scraping of https://pkg.go.dev/search laced in with some extensive recursive hitting of https://index.golang.org/index to get a complete package picture. It can work if this is what is recommended, but it would feel a bit like it is 1999 all over again. ;)
If anything and if that's the way to go, then at least I could create a common service that does this for everyone?

[jba]

api.godoc.org should be back up.

[srenatus]

@ZiViZiViZ https://github.com/golang/gddo/wiki/API

[seankhliao]

please keep this issue on topic and refer questions to
https://github.com/golang/go/wiki/Questions

[shellscape]

Rather than hiding what I'd consider a lot of really useful comments by folks (because I landed here for many of the same reasons they did, and there is extremely little available with regard to go package APIs) it would be infinitely more useful to explain to folks how to use the wiki for questions - or specify that tangential and related questions here are not welcome, and folks should seek the answers on the wiki. As it is now, that curt reply seems to imply that we should post questions on the wiki itself, which I doubt is what you're actually after.

The go team has been kicking this can for years, so users are naturally going to have a lot of questions. This reply #36785 (comment) specifically asks users what features they're after in an API - thus the issue is fair game for feature-related questions. Go packages are the very last major ecosystem package registry to lack a comprehensive API and that which doesn't make its data readily available. Because of this, people are naturally going to have a myriad of questions about trying to access that data. I'd humbly ask @seankhliao to be a bit more gracious in your moderation of this issue.

[golightlyb]

• Use case: generating static documentation, or running a local documentation server, but wanting to be able to query (with javascript, at the time of the page view by a web browser) the "[Imported by: NNN]" number that appears if instead viewed on pkg.go.dev.

• currently api.godoc.org/importers is returning {"error":{"message":"Internal Server Error"}}