fix(changelog): stage buildinfo go files

internal/cmd/buildinfo.go

@@ -0,0 +1,76 @@
+package cmd
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"runtime"
+	"strings"
+	"text/template"
+	"time"
+)
+
+const versionInfoTmpl = `
+{{.Program}}, version {{.Version}} (revision: {{.Commit}})
+  build date:       {{.Date}}
+  go version:       {{.GoVersion}}
+`
+
+// BuildInfo contains information about build
+// like version tag, commit and build date.
+type BuildInfo struct {
+	version        string
+	date           time.Time
+	commit         string
+	runtimeVersion func() string
+}
+
+// NewBuildInfo creates a new BuildInfo. The date has to be in RFC3329 format
+// and the commit hash has to be at leas 8 characters long.
+func NewBuildInfo(version, date, commit string) (*BuildInfo, error) {
+	if version == "" {
+		return nil, errors.New("version cannot be empty")
+	}
+
+	d, err := time.Parse(time.RFC3339, date)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse date %s: %w", date, err)
+	}
+
+	if len(commit) < 8 {
+		return nil, errors.New("commit hash has to be at least 8 characters long")
+	}
+
+	return &BuildInfo{
+		version:        version,
+		date:           d,
+		commit:         commit,
+		runtimeVersion: runtime.Version,
+	}, nil
+}
+
+// Version returns the version information as string.
+func (b BuildInfo) Version(program string) string {
+	t := template.Must(template.New("version").Parse(versionInfoTmpl))
+
+	data := struct {
+		Version   string
+		Date      string
+		Commit    string
+		GoVersion string
+		Program   string
+	}{
+		Version:   b.version,
+		Date:      b.date.String(),
+		Commit:    b.commit[:8],
+		GoVersion: b.runtimeVersion(),
+		Program:   program,
+	}
+
+	var buf bytes.Buffer
+	if err := t.ExecuteTemplate(&buf, "version", data); err != nil {
+		panic(err)
+	}
+
+	return strings.TrimSpace(buf.String())
+}

internal/cmd/buildinfo_test.go

@@ -0,0 +1,73 @@
+package cmd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gotest.tools/assert"
+)
+
+func TestBuildInfo(t *testing.T) {
+	var tt = []struct {
+		name         string
+		version      string
+		commit       string
+		date         string
+		expected     string
+		expectsError bool
+	}{
+		{
+			"ok",
+			"1.0.0",
+			"4a8804f18ea7560fe45fecaa052605b1a8a66fe8",
+			"2021-01-05T08:08:54+01:00",
+			`prog, version 1.0.0 (revision: 4a8804f1)
+  build date:       2021-01-05 08:08:54 +0100 CET
+  go version:       go1.15.6`,
+			false,
+		},
+		{
+			"invalid - commit to short",
+			"1.0.0",
+			"123",
+			"2021-01-05T08:08:54+01:00",
+			"",
+			true,
+		},
+		{
+			"invalid - empty version",
+			"",
+			"4a8804f18ea7560fe45fecaa052605b1a8a66fe8",
+			"2021-01-05T08:08:54+01:00",
+			"",
+			true,
+		},
+		{
+			"invalid - wrong date format",
+			"1.0.0",
+			"4a8804f18ea7560fe45fecaa052605b1a8a66fe8",
+			"2021-01-05T08:08:54",
+			"",
+			true,
+		},
+	}
+
+	for i := range tt {
+		tc := tt[i]
+		t.Run(tc.name, func(t *testing.T) {
+			b, err := NewBuildInfo(tc.version, tc.date, tc.commit)
+			if tc.expectsError {
+				require.Error(t, err)
+				return
+			}
+			b.runtimeVersion = runtimeVersionMock
+			require.NoError(t, err)
+
+			assert.Equal(t, tc.expected, b.Version("prog"))
+		})
+	}
+}
+
+func runtimeVersionMock() string {
+	return "go1.15.6"
+}