go version — Hands-on Tasks¶

Go 1.21+. Each task has explicit acceptance criteria.

Task 1: Identify your toolchain¶

Report your environment.

Acceptance criteria - [ ] go version prints go versionX.Y.Z os/arch. - [ ] You can name the version, OS, and architecture from the line. - [ ] go env GOTOOLCHAIN shows your toolchain policy.

Task 2: Inspect a built binary¶

Check what built an executable.

Acceptance criteria - [ ] go build -o app . then go version app prints the Go version. - [ ] You confirm the version matches go version.

Task 3: Read the build manifest¶

Use -m.

Acceptance criteria - [ ] go version -m app lists mod/dep entries and build settings. - [ ] Building with -trimpath makes that appear under build. - [ ] From a clean git tree, vcs.modified=false appears; from a dirty tree, true.

Task 4: Distinguish toolchain from the go directive¶

Compare the two version concepts.

Acceptance criteria - [ ] You set go 1.22 in go.mod and explain it is the minimum, not the installed version. - [ ] You explain when a go directive newer than your toolchain triggers an action.

Task 5: Toolchain selection¶

Experiment with GOTOOLCHAIN.

Acceptance criteria - [ ] Adding toolchain go1.XX.Y (a version you have) and running go version reflects the selection logic. - [ ] GOTOOLCHAIN=local go version uses the installed toolchain. - [ ] You explain what GOTOOLCHAIN=auto would do if the directive required a newer version.

Task 6: Run a specific version¶

Install and use an alternate toolchain.

Acceptance criteria - [ ] go install golang.org/dl/go1.22.5@latest && go1.22.5 download works (network required). - [ ] go1.22.5 version reports that exact version. - [ ] Your default go version is unchanged.

Task 7: Audit a binary for provenance¶

Treat -m as an ops tool.

Acceptance criteria - [ ] go version -m app | grep vcs.revision shows the commit. - [ ] You identify a dependency version from the dep lines. - [ ] You optionally run govulncheck -mode=binary app to scan the embedded versions.

Task 8: CI toolchain assertion (reflection)¶

Write a check that enforces a version.

Acceptance criteria - [ ] A script compares go version | awk '{print $3}' to an expected value and exits non-zero on mismatch. - [ ] You write 2 sentences on why version consistency matters for reproducible builds.