idomatic buildinfo with branch

Makefile

@@ -1,11 +1,5 @@
 NOW_RFC3339 = $(shell date -u +"%Y-%m-%dT%H:%M:%SZ")
-GIT_SHA = $(shell git rev-parse HEAD 2>/dev/null || no_git)
 GIT_BRANCH = $(shell git symbolic-ref --short HEAD 2>/dev/null ||:)
-ifneq ($(GIT_BRANCH),)
-GIT_COMMIT = $(GIT_SHA) ($(GIT_BRANCH))
-else
-GIT_COMMIT = $(GIT_SHA)
-endif
 
 all: build cmddocs
 
@@ -15,7 +9,7 @@ generate:
 
 build: generate
 	@echo Running Build
-	go build -o bin/flyctl -ldflags="-X 'github.com/superfly/flyctl/internal/buildinfo.buildDate=$(NOW_RFC3339)' -X 'github.com/superfly/flyctl/internal/buildinfo.commit=$(GIT_COMMIT)'" .
+	go build -o bin/flyctl -ldflags="-X 'github.com/superfly/flyctl/internal/buildinfo.buildDate=$(NOW_RFC3339)' -X 'github.com/superfly/flyctl/internal/buildinfo.branchName=$(GIT_BRANCH)'" .
 
 test: FORCE
 	go test ./... -ldflags="-X 'github.com/superfly/flyctl/internal/buildinfo.buildDate=$(NOW_RFC3339)'" --run=$(T)

internal/buildinfo/buildinfo.go

@@ -32,27 +32,33 @@ type info struct {
 	Name         string
 	Version      semver.Version
 	Commit       string
+	BranchName   string
 	BuildDate    time.Time
 	OS           string
 	Architecture string
 	Environment  string
 }
 
 func (i info) String() string {
-	return fmt.Sprintf("%s v%s %s/%s Commit: %s BuildDate: %s",
+	res := fmt.Sprintf("%s v%s %s/%s Commit: %s BuildDate: %s",
 		i.Name,
 		i.Version,
 		i.OS,
 		i.Architecture,
 		i.Commit,
 		i.BuildDate.Format(time.RFC3339))
+	if i.BranchName != "" {
+		res += fmt.Sprintf(" BranchName: %s", i.BranchName)
+	}
+	return res
 }
 
 func Info() info {
 	return info{
 		Name:         Name(),
 		Version:      Version(),
 		Commit:       Commit(),
+		BranchName:   BranchName(),
 		BuildDate:    BuildDate(),
 		OS:           OS(),
 		Architecture: Arch(),

internal/buildinfo/version.go

@@ -3,6 +3,7 @@ package buildinfo
 import (
 	"errors"
 	"os"
+	"runtime/debug"
 	"strconv"
 	"time"
 
@@ -11,9 +12,9 @@ import (
 )
 
 var (
-	buildDate = "<date>"
-	version   = "<version>"
-	commit    = "<commit>"
+	buildDate  = "<date>"
+	version    = "<version>"
+	branchName = ""
 )
 
 var (
@@ -66,7 +67,26 @@ func loadMeta() {
 }
 
 func Commit() string {
-	return commit
+	info, _ := debug.ReadBuildInfo()
+	var rev string = "<none>"
+	var dirty string = ""
+	for _, v := range info.Settings {
+		if v.Key == "vcs.revision" {
+			rev = v.Value
+		}
+		if v.Key == "vcs.modified" {
+			if v.Value == "true" {
+				dirty = "-dirty"
+			} else {
+				dirty = ""
+			}
+		}
+	}
+	return rev + dirty
+}
+
+func BranchName() string {
+	return branchName
 }
 
 func Version() semver.Version {

internal/buildinfo/version_test.go

@@ -12,22 +12,18 @@ func TestProdMeta(t *testing.T) {
 	environment = "production"
 	version = "1.2.3"
 	buildDate = "2020-06-05T13:32:23Z"
-	commit = "c8f7b8f"
 
 	loadMeta()
 
 	assert.Equal(t, "1.2.3", Version().String())
 	assert.Equal(t, "2020-06-05T13:32:23Z", BuildDate().Format(time.RFC3339))
-	assert.Equal(t, "c8f7b8f", Commit())
 }
 
 func TestDevMeta(t *testing.T) {
 	environment = "development"
 	version = "<version>"
-	commit = "<commit>"
 
 	loadMeta()
 
 	assert.Equal(t, fmt.Sprintf("0.0.0-%d+dev", BuildDate().Unix()), Version().String())
-	assert.Equal(t, "<commit>", Commit())
 }