cmd/go: GOTELEMETRY is not documented by go help environment

[stapelberg]

Go version

go version go1.23.0 linux/amd64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/michael/.cache/go-build'
GOENV='/home/michael/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/michael/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/michael/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/michael/sdk/go1.23.0'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/michael/sdk/go1.23.0/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.23.0'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/michael/.config/go/telemetry'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/dev/null'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1379730748=/tmp/go-build -gno-record-gcc-switches'

What did you do?

In a complex integration test setup which runs the go tool with a custom (ephemeral) XDG_CONFIG_HOME and HOME directory, I want to entirely turn off go telemetry: I found telemetry to trigger go module downloads that end up polluting my ephemeral module cache:

testing.go:1232: TempDir RemoveAll cleanup: unlinkat /tmp/TestGokRun3431683770/001/go/pkg/mod/golang.org/x/telemetry/config@v0.29.0/doc.go: permission denied

(This failure seems to have started with Go 1.23, but I’m having trouble reproducing it outside of GitHub Actions.)

What did you see happen?

I tried setting GOTELEMETRY in the environment, but it has no effect:

% go env GOTELEMETRY
local
% GOTELEMETRY=off go env GOTELEMETRY 
local

I also tried setting GOTELEMETRY in GOROOT/go.env, but it has no effect there either (whereas GOAMD64 has, so I’m editing the right file):

% go env GOAMD64                                          
v1                         
% echo 'GOAMD64=v3' >> '/home/michael/sdk/go1.23.0'/go.env
% go env GOAMD64                                          
v3
% echo 'GOTELEMETRY=off' >> '/home/michael/sdk/go1.23.0'/go.env
% go env GOTELEMETRY                                           
local

What did you expect to see?

I would have expected GOTELEMETRY=off to be honored.

In #67111, I can see mention of GOTELEMETRY being an unsettable environment variable. While I understand the rationale for go telemetry on being the only way to enable telemetry, I don’t think that applies to turning off telemetry, which I think should be possible via the environment.

[gabyhelp]

Related Issues and Documentation

• Unknown go command variable GOTELEMETRY - how to disable telemetry? #67424 (closed)
• x/telemetry/internal/counter: ErrDisabled references non-existent GOTELEMETRY environment variable #65503 (closed)
• telemetry.go.dev/privacy: "Internal Server Error" #68859 (closed)
• x/tools/gopls: no datas for gotelemetry #67781 (closed)
• x/telemetry: `go install` / `go run` fails for `golang.org/x/telemetry/cmd/gotelemetry@latest`: "no matching versions for query "latest"" #63825 (closed)
• Go Telemetry > Configuration
• cmd/go: TestScript/env_changed fails when modifying go.env for Go distributions #67793 (closed)
• cmd/go: go env -changed prints changed values for variables in go.env #67542 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[seankhliao]

like GOMOD, it's there only to report the current state, not to allow modifications.

[zigo101]

like GOMOD, it's there only to report the current state, not to allow modifications.

It is absolutely not the case.

This issue should be re-opened.

[ianlancetaylor]

@golang/telemetry :

Should setting the GOTELEMETRY environment variable affect whether we record telemetry? Do we ever document that that is how it behaves? Thanks.

[findleyr]

Should setting the GOTELEMETRY environment variable affect whether we record telemetry? Do we ever document that that is how it behaves? Thanks.

That's not how it behaves. See this comment from the proposal: #67111 (comment).

I think this needs to be documented, at least at the bottom of go help environment, but also at go help telemetry and go.dev/doc/telemetry.

I also recall that we've discussed making GOTELEMETRY settable, and I believe there has been no objection to supporting that, apart from the confusing asymmetry that we'd never support GOTELEMETRY=on (as @stapelberg astutely assessed). Let's reopen this issue to track improving the documentation, and open a separate issue for making GOTELEMETRY=off settable.

The issue with GOMODCACHE is tracked by #68946, and I consider it a bug that we should fix for 1.23.1.

[findleyr]

Filed #68960 to formally consider supporting GOTELEMETRY=off in the environment.