cmd/updatestd: add experimental program to maintain standard library

We need to update dependencies vendored into the standard library at
least two times during each major Go release cycle, which is tracked
by the recurring release-blocker issue golang.org/issue/36905.

Once we find agreement on the overall strategy to do this, it will be
easier, more reliable, and more scalable to do with a program than by
hand. This experimental program serves as a starting point to get there.
It has been used to generate CL 255860 and CL 266898 so far, and more
to explore the state of changes to vendored golang.org/x packages at
tip. Code review has identified opportunities for improvement, which
was filed as an issue. Upon further investigation, it was found that
those improvements are not viable to use in the short term (see
https://golang.org/issue/41589#issuecomment-712965746), but perhaps
will be worth revisiting in the future.

The scope of update performed at this time is to update golang.org/x
modules dependencies inside the standard library, re-run go generate
-run=bundle task, and update the Go language version in go.mod files.
It's expected this will evolve over time based on experience and new
findings.

For golang/go#36905.
For golang/go#41409.

Change-Id: I0e9d42675f1d8300f661545625f3b20e3704cdca
Reviewed-on: https://go-review.googlesource.com/c/build/+/256357
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
2 files changed
tree: 275579c142d06f5f430f21d2a83ce2d2796bbf87
  1. .dockerignore
  2. .gcloudignore
  3. AUTHORS
  4. CONTRIBUTING.md
  5. CONTRIBUTORS
  6. LICENSE
  7. PATENTS
  8. README.md
  9. app/
  10. autocertcache/
  11. build.go
  12. buildenv/
  13. buildlet/
  14. cloudfns/
  15. cmd/
  16. codereview.cfg
  17. crfs/
  18. dashboard/
  19. devapp/
  20. doc/
  21. env/
  22. envutil/
  23. gerrit/
  24. go.mod
  25. go.sum
  26. internal/
  27. kubernetes/
  28. livelog/
  29. maintner/
  30. pargzip/
  31. repos/
  32. revdial/
  33. tarutil/
  34. types/
  35. update-readmes.go
  36. vcs-test/
  37. version/
README.md

Go Build Tools

Go Reference

This subrepository holds the source for various packages and tools that support Go's build system and the development of the Go programming language.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To contribute, see https://golang.org/doc/contribute.html.

The main issue tracker for the blog is located at https://github.com/golang/go/issues. Prefix your issue with “x/build/DIR:” in the subject line.

Overview

The main components of the Go build system are:

  • The dashboard, in app/, serves https://build.golang.org/. It runs on App Engine and holds the state for which builds passed or failed, and stores the build failure logs for post-submit failures. (Trybot build failure logs are stored elsewhere). The dashboard does not execute any builds on its own.

  • The coordinator, in cmd/coordinator/, serves https://farmer.golang.org/. It runs on GKE and coordinates the whole build system. It finds work to do (both pre-submit “TryBot” work, and post-submit work) and executes builds, allocating machines to run the builds. It is the owner of all machines.

  • The Go package in buildenv/ contains constants for where the dashboard and coordinator run, for prod, staging, and local development.

  • The buildlet, in cmd/buildlet/, is the HTTP server that runs on each worker machine to execute builds on the coordinator's behalf. This runs on every possible GOOS/GOARCH value. The buildlet binaries are stored on Google Cloud Storage and fetched per-build, so we can update the buildlet binary independently of the underlying machine images. The buildlet is the most insecure server possible: it has HTTP handlers to read & write arbitrary content to disk, and to execute any file on disk. It also has an SSH tunnel handler. The buildlet must never be exposed to the Internet. The coordinator provisions buildlets in one of three ways:

    1. by creating VMs on Google Compute Engine (GCE) with custom images configured to fetch & run the buildlet on boot, listening on port 80 in a private network.

    2. by running Linux containers (on either Google Kubernetes Engine or GCE with the Container-Optimized OS image), with the container images configured to fetch & run the buildlet on start, also listening on port 80 in a private network.

    3. by taking buildlets out of a pool of connected, dedicated machines. The buildlet can run in either listen mode (as on GCE and GKE) or in reverse mode. In reverse mode, the buildlet connects out to https://farmer.golang.org/ and registers itself with the coordinator. The TCP connection is then logically reversed (using revdial and when the coordinator needs to do a build, it makes HTTP requests to the coordinator over the already-open TCP connection.

    These three pools can be viewed at the coordinator's http://farmer.golang.org/#pools

  • The env/ directory describes build environments. It contains scripts to create VM images, Dockerfiles to create Kubernetes containers, and instructions and tools for dedicated machines.

  • maintner in maintner/ is a library for slurping all of Go's GitHub and Gerrit state into memory. The daemon maintnerd in maintner/maintnerd/ runs on GKE and serves https://maintner.golang.org/. The daemon watches GitHub and Gerrit and appends to a mutation log whenever it sees new activity. The logs are stored on GCS and served to clients.

  • The godata package in maintner/godata/ provides a trivial API to let anybody write programs against Go's maintner corpus (all of our GitHub and Gerrit history), live up to the second. It takes a few seconds to load into memory and a few hundred MB of RAM after it downloads the mutation log from the network.

  • pubsubhelper in cmd/pubsubhelper/ is a dependency of maintnerd. It runs on GKE, is available at https://pubsubhelper.golang.org/, and runs an HTTP server to receive Webhook updates from GitHub on new activity and an SMTP server to receive new activity emails from Gerrit. It then is a pubsub system for maintnerd to subscribe to.

  • The gitmirror server in cmd/gitmirror/ mirrors Gerrit to GitHub, and also serves a mirror of the Gerrit code to the coordinator for builds, so we don't overwhelm Gerrit and blow our quota.

  • The Go gopherbot bot logic runs on GKE. The code is in cmd/gopherbot. It depends on maintner via the godata package.

  • The developer dashboard at https://dev.golang.org/ runs on GKE. Its code is in devapp/. It also depends on maintner via the godata package.

  • cmd/retrybuilds: a Go client program to delete build results from the dashboard

Adding a Go Builder

If you wish to run a Go builder, please email golang-dev@googlegroups.com first. There is documentation at https://golang.org/wiki/DashboardBuilders, but depending on the type of builder, we may want to run it ourselves, after you prepare an environment description (resulting in a VM image) of it. See the env directory.