feat(buildtool): fetch and use correct go version

.github/workflows/goversion.yml

@@ -0,0 +1,28 @@
+# Ensures that ./internal/cmd/buildtool works with different go versions
+
+name: goversion
+on:
+  push:
+    branches:
+      - "release/**"
+      - "fullbuild"
+    tags:
+      - "v*"
+  schedule:
+    - cron: "17 7 * * *"
+
+jobs:
+  build_with_unexpected_go_version:
+    strategy:
+      matrix:
+        goversion: ["1.17", "1.18", "1.19", "1.21"]
+        system: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: "${{ matrix.system }}"
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-go@v4
+        with:
+          go-version: "${{ matrix.goversion }}"
+
+      - run: go run ./internal/cmd/buildtool generic miniooni

internal/cmd/buildtool/android.go

@@ -78,7 +78,6 @@ func androidSubcommand() *cobra.Command {
 // androidBuildGomobile invokes the gomobile build.
 func androidBuildGomobile(deps buildtoolmodel.Dependencies) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 
 	androidHome := deps.AndroidSDKCheck()
 	ndkDir := deps.AndroidNDKCheck(androidHome)
@@ -146,7 +145,6 @@ func androidNDKCheck(androidHome string) string {
 // androidBuildCLIAll builds all products in CLI mode for Android
 func androidBuildCLIAll(deps buildtoolmodel.Dependencies) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 
 	androidHome := deps.AndroidSDKCheck()
 	ndkDir := deps.AndroidNDKCheck(androidHome)
@@ -177,7 +175,7 @@ func androidBuildCLIProductArch(
 
 	log.Infof("building %s for android/%s", product.Pkg, ooniArch)
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(deps.GolangBinary(), "build"))
 	if deps.PsiphonFilesExist() {
 		argv.Append("-tags", "ooni_psiphon_config,ooni_libtor")
 	} else {

internal/cmd/buildtool/android_test.go

@@ -121,7 +121,7 @@ func TestAndroidBuildGomobile(t *testing.T) {
 				buildtooltest.TagGOPATH:                      2,
 				buildtooltest.TagAndroidNDKCheck:             1,
 				buildtooltest.TagAndroidSDKCheck:             1,
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           1,
 			}
@@ -406,7 +406,7 @@ func TestAndroidBuildCLIAll(t *testing.T) {
 			expectCalls := map[string]int{
 				buildtooltest.TagAndroidNDKCheck:             1,
 				buildtooltest.TagAndroidSDKCheck:             1,
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           8,
 			}

internal/cmd/buildtool/builddeps.go

@@ -38,9 +38,9 @@ func (*buildDeps) GOPATH() string {
 	return golangGOPATH()
 }
 
-// GolangCheck implements buildtoolmodel.Dependencies
-func (*buildDeps) GolangCheck() {
-	golangCheck("GOVERSION")
+// GolangBinary implements buildtoolmodel.Dependencies
+func (*buildDeps) GolangBinary() string {
+	return golangBinary()
 }
 
 // LinuxReadGOVERSION implements buildtoolmodel.Dependencies

internal/cmd/buildtool/darwin.go

@@ -27,7 +27,6 @@ func darwinSubcommand() *cobra.Command {
 // darwinBuildAll builds all the packages for darwin.
 func darwinBuildAll(deps buildtoolmodel.Dependencies) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 	archs := []string{"amd64", "arm64"}
 	products := []*product{productMiniooni, productOoniprobe}
 	for _, arch := range archs {
@@ -41,7 +40,7 @@ func darwinBuildAll(deps buildtoolmodel.Dependencies) {
 func darwinBuildPackage(deps buildtoolmodel.Dependencies, goarch string, product *product) {
 	log.Infof("building %s for darwin/%s", product.Pkg, goarch)
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(deps.GolangBinary(), "build"))
 	if deps.PsiphonFilesExist() {
 		argv.Append("-tags", "ooni_psiphon_config")
 	}

internal/cmd/buildtool/darwin_test.go

@@ -130,7 +130,7 @@ func TestDarwinBuildAll(t *testing.T) {
 			})
 
 			expectCalls := map[string]int{
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           4,
 			}

internal/cmd/buildtool/generic.go

@@ -48,14 +48,15 @@ func genericSubcommand() *cobra.Command {
 	return cmd
 }
 
+// TODO(bassosimone): golangBinary() MUST be a method of the buildtoolmodel.Dependencies
+
 // genericBuildPackage is the generic function for building a package.
 func genericBuildPackage(deps buildtoolmodel.Dependencies, product *product) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 
 	log.Infof("building %s for %s/%s", product.Pkg, runtime.GOOS, runtime.GOARCH)
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(golangBinary(), "build"))
 	if deps.PsiphonFilesExist() {
 		argv.Append("-tags", "ooni_psiphon_config")
 	}
@@ -67,7 +68,6 @@ func genericBuildPackage(deps buildtoolmodel.Dependencies, product *product) {
 
 // genericBuildLibrary is the generic function for building a library.
 func genericBuildLibrary(deps buildtoolmodel.Dependencies, product *product) {
-	deps.GolangCheck()
 	os := deps.GOOS()
 
 	log.Infof("building %s for %s/%s", product.Pkg, os, runtime.GOARCH)
@@ -76,7 +76,7 @@ func genericBuildLibrary(deps buildtoolmodel.Dependencies, product *product) {
 	// packages paths are separated by forward slashes!
 	library := runtimex.Try1(generateLibrary(path.Base(product.Pkg), os))
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(golangBinary(), "build"))
 	argv.Append("-buildmode", "c-shared")
 	argv.Append("-o", library)
 	argv.Append(product.Pkg)

internal/cmd/buildtool/generic_test.go

@@ -83,7 +83,7 @@ func TestGenericBuildPackage(t *testing.T) {
 			})
 
 			expectCalls := map[string]int{
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           1,
 			}
@@ -164,8 +164,8 @@ func TestCheckGenericBuildLibrary(t *testing.T) {
 			})
 
 			expectCalls := map[string]int{
-				buildtooltest.TagGolangCheck: 1,
-				buildtooltest.TagGOOS:        1,
+				buildtooltest.TagGolangBinary: 1,
+				buildtooltest.TagGOOS:         1,
 			}
 
 			if diff := cmp.Diff(expectCalls, deps.Counter); diff != "" {

internal/cmd/buildtool/golang.go

@@ -5,23 +5,73 @@ package main
 //
 
 import (
+	"fmt"
+	"path/filepath"
 	"strings"
+	"sync"
 
 	"github.com/apex/log"
 	"github.com/ooni/probe-cli/v3/internal/must"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
-// golangCheck checks whether the "go" binary is the correct version
-func golangCheck(filename string) {
+// golangCheckCorrectVersion returns true if the version of Go is correct.
+func golangCheckCorrectVersion(filename string) bool {
+	// read the version of go that we would like to use
 	expected := string(must.FirstLineBytes(must.ReadFile(filename)))
+
+	// read the version of go that we're using
 	firstline := string(must.FirstLineBytes(must.RunOutput(log.Log, "go", "version")))
 	vec := strings.Split(firstline, " ")
 	runtimex.Assert(len(vec) == 4, "expected four tokens")
-	if got := vec[2]; got != "go"+expected {
-		log.Fatalf("expected go%s but got %s", expected, got)
+
+	// make sure they're equal
+	return vec[2] == "go"+expected
+}
+
+// golangInstall installs and returns the path to the correct version of Go.
+func golangInstall(filename string) string {
+	// read the version of Go we would like to use
+	expected := string(must.FirstLineBytes(must.ReadFile(filename)))
+
+	// install the downloaded script
+	packageName := fmt.Sprintf("golang.org/dl/go%s@latest", expected)
+	must.Run(log.Log, "go", "install", "-v", packageName)
+
+	// run the downloader script
+	gobinary := filepath.Join(
+		string(must.FirstLineBytes(must.RunOutput(log.Log, "go", "env", "GOPATH"))),
+		"bin",
+		fmt.Sprintf("go%s", expected),
+	)
+	must.Run(log.Log, gobinary, "download")
+
+	// if all is good, then we have the right gobinary
+	return gobinary
+}
+
+// golangBinaryWithoutCache returns the path to the correct golang binary to use.
+func golangBinaryWithoutCache() string {
+	if !golangCheckCorrectVersion("GOVERSION") {
+		return golangInstall("GOVERSION")
+	}
+	return "go"
+}
+
+// golangCachedBinary is the cached golang binary.
+var golangCachedBinary string
+
+// golangCacheMu synchronizes accesses to [golangCachedBinary].
+var golangCacheMu sync.Mutex
+
+// golangBinary returns the path to the correct golang binary to use.
+func golangBinary() string {
+	defer golangCacheMu.Unlock()
+	golangCacheMu.Lock()
+	if golangCachedBinary == "" {
+		golangCachedBinary = golangBinaryWithoutCache()
 	}
-	log.Infof("using go%s", expected)
+	return golangCachedBinary
 }
 
 // golangGOPATH returns the GOPATH value.

internal/cmd/buildtool/golang_test.go

@@ -1,11 +1,13 @@
 package main
 
 import (
-	"path/filepath"
 	"testing"
+
+	"github.com/ooni/probe-cli/v3/internal/must"
 )
 
-func TestGolangCheck(t *testing.T) {
-	// make sure the code does not panic when it runs
-	golangCheck(filepath.Join("..", "..", "..", "GOVERSION"))
+func TestGolangBinary(t *testing.T) {
+	// make sure the code does not panic when it runs and returns a valid binary
+	value := golangBinary()
+	must.RunQuiet(value, "version")
 }

internal/cmd/buildtool/gomobile.go

@@ -35,16 +35,16 @@ type gomobileConfig struct {
 // gomobileBuild runs a build based on gomobile.
 func gomobileBuild(config *gomobileConfig) {
 	// Undoes the effects of go-getting golang.org/x/mobile/cmd/gomobile
-	defer must.Run(log.Log, "go", "mod", "tidy")
+	defer must.Run(log.Log, config.deps.GolangBinary(), "mod", "tidy")
 
-	must.Run(log.Log, "go", "install", "golang.org/x/mobile/cmd/gomobile@latest")
+	must.Run(log.Log, config.deps.GolangBinary(), "install", "golang.org/x/mobile/cmd/gomobile@latest")
 
 	gopath := config.deps.GOPATH()
 	gomobile := filepath.Join(gopath, "bin", "gomobile")
 	must.Run(log.Log, gomobile, "init")
 
 	// Adding gomobile to go.mod as documented by golang.org/wiki/Mobile
-	must.Run(log.Log, "go", "get", "-d", "golang.org/x/mobile/cmd/gomobile")
+	must.Run(log.Log, config.deps.GolangBinary(), "get", "-d", "golang.org/x/mobile/cmd/gomobile")
 
 	argv := runtimex.Try1(shellx.NewArgv(gomobile, "bind"))
 	argv.Append("-target", config.target)

internal/cmd/buildtool/internal/buildtoolmodel/buildtoolmodel.go

@@ -24,9 +24,8 @@ type Dependencies interface {
 	// GOPATH returns the current GOPATH.
 	GOPATH() string
 
-	// GolangCheck ensures we have the correct
-	// version of golang as the "go" binary.
-	GolangCheck()
+	// GolangBinary returns the golang binary to use.
+	GolangBinary() string
 
 	// LinuxWriteDockerfile writes the dockerfile for linux.
 	LinuxWriteDockerfile(filename string, content []byte, mode fs.FileMode)

internal/cmd/buildtool/internal/buildtooltest/buildtooltest.go

@@ -139,7 +139,7 @@ const (
 	TagAndroidNDKCheck             = "androidNDK"
 	TagAndroidSDKCheck             = "androidSDK"
 	TagGOPATH                      = "GOPATH"
-	TagGolangCheck                 = "golangCheck"
+	TagGolangBinary                = "golangBinary"
 	TagLinuxReadGOVERSION          = "linuxReadGOVERSION"
 	TagLinuxWriteDockerfile        = "linuxWriteDockerfile"
 	TagMustChdir                   = "mustChdir"
@@ -188,8 +188,9 @@ func (cc *DependenciesCallCounter) GOPATH() string {
 }
 
 // golangCheck implements buildtoolmodel.Dependencies
-func (cc *DependenciesCallCounter) GolangCheck() {
-	cc.increment(TagGolangCheck)
+func (cc *DependenciesCallCounter) GolangBinary() string {
+	cc.increment(TagGolangBinary)
+	return "go"
 }
 
 // linuxReadGOVERSION implements buildtoolmodel.Dependencies

internal/cmd/buildtool/internal/buildtooltest/buildtooltest_test.go

@@ -203,10 +203,13 @@ func TestDependenciesCallCounter(t *testing.T) {
 
 	t.Run("GolangCheck", func(t *testing.T) {
 		cc := &DependenciesCallCounter{}
-		cc.GolangCheck()
-		if cc.Counter[TagGolangCheck] != 1 {
+		value := cc.GolangBinary()
+		if cc.Counter[TagGolangBinary] != 1 {
 			t.Fatal("did not increment")
 		}
+		if value != "go" {
+			t.Fatal("expected 'go', got", value)
+		}
 	})
 
 	t.Run("LinuxReadGOVERSION", func(t *testing.T) {

internal/cmd/buildtool/ios.go

@@ -53,7 +53,6 @@ func iosSubcommand() *cobra.Command {
 // iosBuildGomobile invokes the gomobile build.
 func iosBuildGomobile(deps buildtoolmodel.Dependencies) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 
 	config := &gomobileConfig{
 		deps:       deps,

internal/cmd/buildtool/ios_test.go

@@ -107,7 +107,7 @@ func TestIOSBuildGomobile(t *testing.T) {
 
 			expectCalls := map[string]int{
 				buildtooltest.TagGOPATH:                      1,
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           1,
 			}

internal/cmd/buildtool/linuxstatic.go

@@ -47,7 +47,6 @@ func (b *linuxStaticBuilder) main(*cobra.Command, []string) {
 // linuxStaticBuildAll builds all the packages on a linux-static environment.
 func linuxStaticBuilAll(deps buildtoolmodel.Dependencies, goarch string, goarm int64) {
 	deps.PsiphonMaybeCopyConfigFiles()
-	deps.GolangCheck()
 
 	// TODO(bassosimone): I am running the container with the right userID but
 	// apparently this is not enough to make git happy--why?
@@ -73,7 +72,7 @@ func linuxStaticBuildPackage(
 
 	ooniArch := linuxStaticBuildOONIArch(goarch, goarm)
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(deps.GolangBinary(), "build"))
 	if deps.PsiphonFilesExist() {
 		argv.Append("-tags", "ooni_psiphon_config")
 	}

internal/cmd/buildtool/linuxstatic_test.go

@@ -198,7 +198,7 @@ func TestLinuxStaticBuildAll(t *testing.T) {
 			})
 
 			expectCalls := map[string]int{
-				buildtooltest.TagGolangCheck:                 1,
+				buildtooltest.TagGolangBinary:                1,
 				buildtooltest.TagPsiphonMaybeCopyConfigFiles: 1,
 				buildtooltest.TagPsiphonFilesExist:           2,
 			}

internal/cmd/buildtool/oohelperd.go

@@ -42,8 +42,6 @@ func oohelperdSubcommand() *cobra.Command {
 // oohelperdBuildAndMaybeDeploy builds oohelperd for linux/amd64 and
 // possibly deploys the build to the 0.th.ooni.org server.
 func oohelperdBuildAndMaybeDeploy(deps buildtoolmodel.Dependencies, deploy bool) {
-	deps.GolangCheck()
-
 	log.Info("building oohelperd for linux/amd64")
 	oohelperdBinary := filepath.Join("CLI", "oohelperd-linux-amd64")
 
@@ -52,7 +50,7 @@ func oohelperdBuildAndMaybeDeploy(deps buildtoolmodel.Dependencies, deploy bool)
 	envp.Append("GOOS", "linux")
 	envp.Append("GOARCH", "amd64")
 
-	argv := runtimex.Try1(shellx.NewArgv("go", "build"))
+	argv := runtimex.Try1(shellx.NewArgv(deps.GolangBinary(), "build"))
 	argv.Append("-o", oohelperdBinary)
 	argv.Append("-tags", "netgo")
 	argv.Append("-ldflags", "-s -w -extldflags -static")