tour: look for content in module cache, not GOROOT/misc/tour

Tour content hasn't been available in GOROOT since Go 1.12¹, so stop
looking for it there.

A more useful fallback place to find tour content is the module cache.
When the golang.org/x/tour is in the build list, it will be found via
build.Import. It will not be found, however, when the tour binary is
run outside of a module. This situation is more common as of Go 1.16,
since the default GO111MODULE value changed to on². If the version of
the tour binary is known, access the content for that version from the
module cache.

In the future, this complex and imperfect machinery will be replaced
with simply embedding the needed files in the binary. We can't do that
quite yet (not without duplicating a lot of code) because Go 1.15 is
supported, and because Go 1.14 is used for deployment.

It's not neccessary to provide a custom socket.Environ (which served
to provide a custom GOPATH value pointing inside GOROOT; that path
is being removed here). Delete it along with some other unused code.

¹ https://golang.org/doc/go1.12#tour
² https://golang.org/doc/go1.16#modules

Fixes golang/go#44243.

Change-Id: Ia239700170b8614d21cafe9617b51dddf3e337d5
Reviewed-on: https://go-review.googlesource.com/c/tour/+/298529
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
3 files changed
tree: 287aca5c78ac73f85c0037abbd176ac6d752ba4d
  1. .gcloudignore
  2. AUTHORS
  3. CONTRIBUTING.md
  4. CONTRIBUTORS
  5. LICENSE
  6. README.md
  7. TODO
  8. TRANSLATE
  9. app.yaml
  10. appengine.go
  11. codereview.cfg
  12. content/
  13. fmt.go
  14. go.mod
  15. go.sum
  16. gotour/
  17. local.go
  18. pic/
  19. reader/
  20. solutions/
  21. static/
  22. template/
  23. tools/
  24. tour.go
  25. tree/
  26. wc/
README.md

Go Tour

Go Reference

A Tour of Go is an introduction to the Go programming language. Visit https://tour.golang.org to start the tour.

Download/Install

To install the tour from source, first install Go and then run:

$ go get golang.org/x/tour

This will place a tour binary in your workspace's bin directory. The tour program can be run offline.

Contributing

Contributions should follow the same procedure as for the Go project: https://golang.org/doc/contribute.html

To run the tour server locally:

go run .

Your browser should now open. If not, please visit http://localhost:3999/.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The issue tracker for the tour's code is located at https://github.com/golang/go/issues. Prefix your issue with “x/tour:” in the subject line, so it is easy to find.

Issues with the tour's content itself should be reported in the issue tracker at https://github.com/golang/tour/issues.

Deploying

  1. To deploy tour.golang.org, run:

    GO111MODULE=on gcloud --project=golang-org app deploy --no-promote app.yaml
    

    This will create a new version, which can be viewed within the golang-org GCP project.

  2. Check that the deployed version looks OK (click the version link in GCP).

  3. If all is well, click “Migrate Traffic” to move 100% of the tour.golang.org traffic to the new version.

  4. You're done.

License

Unless otherwise noted, the go-tour source files are distributed under the BSD-style license found in the LICENSE file.