More comprehensive build info collection

buildinfo.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"runtime/debug"
+	"sort"
+	"strconv"
+	"time"
+)
+
+var version = "dev" // has to be set by ldflags
+
+const (
+	buildInfoModuleStart byte = iota
+	buildInfoModuleFinish
+	buildInfoModuleDelimeter
+)
+
+func getVersion() string {
+	goVersion, date, commit, modulesChecksum, dirty := getVersionData()
+
+	dirtySuffix := ""
+	if dirty {
+		dirtySuffix = " [dirty]"
+	}
+
+	return fmt.Sprintf("%s (%s: %s on %s%s, modules checksum %s)",
+		version,
+		goVersion,
+		date.Format(time.RFC3339),
+		commit,
+		dirtySuffix,
+		modulesChecksum)
+}
+
+func getVersionData() (goVersion string, date time.Time, commit string, modulesChecksum string, dirty bool) {
+	date = time.Now()
+
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+
+	goVersion = buildInfo.GoVersion
+
+	for _, setting := range buildInfo.Settings {
+		switch setting.Key {
+		case "vcs.time":
+			date, _ = time.Parse(time.RFC3339, setting.Value)
+		case "vcs.revision":
+			commit = setting.Value
+		case "vcs.modified":
+			dirty, _ = strconv.ParseBool(setting.Value)
+		}
+	}
+
+	hasher := sha256.New()
+	if _, err := io.WriteString(hasher, buildInfo.Path); err != nil {
+		panic(err)
+	}
+	binary.Write(hasher, binary.LittleEndian, uint64(1+len(buildInfo.Deps)))
+
+	sort.Slice(buildInfo.Deps, func(i, j int) bool {
+		return buildInfo.Deps[i].Path > buildInfo.Deps[j].Path
+	})
+
+	buildInfoCheckSumModule(hasher, &buildInfo.Main)
+	for _, module := range buildInfo.Deps {
+		buildInfoCheckSumModule(hasher, module)
+	}
+
+	modulesChecksum = base64.StdEncoding.EncodeToString(hasher.Sum(nil))
+
+	return
+}
+
+func buildInfoCheckSumModule(w io.Writer, module *debug.Module) {
+	w.Write([]byte{buildInfoModuleStart})
+
+	if _, err := io.WriteString(w, module.Path); err != nil {
+		panic(err)
+	}
+
+	w.Write([]byte{buildInfoModuleDelimeter})
+
+	if _, err := io.WriteString(w, module.Version); err != nil {
+		panic(err)
+	}
+
+	w.Write([]byte{buildInfoModuleDelimeter})
+
+	if _, err := io.WriteString(w, module.Sum); err != nil {
+		panic(err)
+	}
+
+	w.Write([]byte{buildInfoModuleFinish})
+}

main.go

@@ -9,10 +9,7 @@
 package main
 
 import (
-	"fmt"
 	"math/rand"
-	"runtime/debug"
-	"strconv"
 	"time"
 
 	"github.com/9seconds/mtg/v2/internal/cli"
@@ -20,8 +17,6 @@ import (
 	"github.com/alecthomas/kong"
 )
 
-var version = "dev" // has to be set by ldflags
-
 func main() {
 	rand.Seed(time.Now().UTC().UnixNano())
 
@@ -29,35 +24,9 @@ func main() {
 		panic(err)
 	}
 
-	if buildInfo, ok := debug.ReadBuildInfo(); ok {
-		vcsCommit := "<no-commit>"
-		vcsDate := time.Now()
-		vcsDirty := ""
-
-		for _, setting := range buildInfo.Settings {
-			switch setting.Key {
-			case "vcs.time":
-				vcsDate, _ = time.Parse(time.RFC3339, setting.Value)
-			case "vcs.revision":
-				vcsCommit = setting.Value
-			case "vcs.modified":
-				if isDirty, _ := strconv.ParseBool(setting.Value); isDirty {
-					vcsDirty = " [dirty]"
-				}
-			}
-		}
-
-		version = fmt.Sprintf("%s (%s: %s on %s%s)",
-			version,
-			buildInfo.GoVersion,
-			vcsDate.Format(time.RFC3339),
-			vcsCommit,
-			vcsDirty)
-	}
-
 	cli := &cli.CLI{}
 	ctx := kong.Parse(cli, kong.Vars{
-		"version": version,
+		"version": getVersion(),
 	})
 
 	ctx.FatalIfErrorf(ctx.Run(cli, version))