fix(librarian): read version from version.txt file (#2347)

Fixes #2348

Moves version.txt to the `internal/cli` package so it can be read by the
`embed` package as a variable.
When constructing the synthetic version number, use this release version
as the base.

Author: chingor13

.librarian/state.yaml

@@ -1,4 +1,4 @@
-image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/librarian-release-container@sha256:50dd9b59bcf4f55178f9a35dcd4f81a8db20609da386357fa05a457a8da3b4e9
+image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/librarian-release-container:latest
 libraries:
   - id: librarian
     version: 0.2.0

infra/container/run.sh

@@ -23,7 +23,7 @@ ls -al /output
 new_version=$(jq -r '.libraries[0].version' /librarian/release-init-request.json)
 echo "release version: ${new_version}"
 mkdir /output/internal/
-echo "${new_version}" > /output/internal/version.txt
+echo "${new_version}" > /output/internal/cli/version.txt
 
 ls -al /output
 

internal/cli/version.go

@@ -15,11 +15,15 @@
 package cli
 
 import (
+	_ "embed"
 	"runtime/debug"
 	"strings"
 	"time"
 )
 
+//go:embed version.txt
+var versionString string
+
 // Version return the version information for the binary, which is constructed
 // following https://go.dev/ref/mod#versions.
 func Version() string {
@@ -52,7 +56,7 @@ func version(info *debug.BuildInfo) string {
 	// Construct the pseudo-version string per
 	// https://go.dev/ref/mod#pseudo-versions.
 	var buf strings.Builder
-	buf.WriteString("0.0.0")
+	buf.WriteString(strings.TrimSpace(versionString))
 	if revision != "" {
 		buf.WriteString("-")
 		// Per https://go.dev/ref/mod#pseudo-versions, only use the first 12

internal/version.txt renamed to internal/cli/version.txt

@@ -15,11 +15,14 @@
 package cli
 
 import (
+	"fmt"
 	"runtime/debug"
+	"strings"
 	"testing"
 )
 
 func TestVersion(t *testing.T) {
+	baseVersion := strings.TrimSpace(versionString)
 	for _, test := range []struct {
 		name      string
 		want      string
@@ -36,7 +39,7 @@ func TestVersion(t *testing.T) {
 		},
 		{
 			name: "pseudoversion",
-			want: "0.0.0-123456789000-20230125195754",
+			want: fmt.Sprintf("%s-123456789000-20230125195754", baseVersion),
 			buildinfo: &debug.BuildInfo{
 				Settings: []debug.BuildSetting{
 					{Key: "vcs.revision", Value: "1234567890001234"},
@@ -46,7 +49,7 @@ func TestVersion(t *testing.T) {
 		},
 		{
 			name: "pseudoversion only revision",
-			want: "0.0.0-123456789000",
+			want: fmt.Sprintf("%s-123456789000", baseVersion),
 			buildinfo: &debug.BuildInfo{
 				Settings: []debug.BuildSetting{
 					{Key: "vcs.revision", Value: "1234567890001234"},
@@ -55,7 +58,7 @@ func TestVersion(t *testing.T) {
 		},
 		{
 			name: "pseudoversion only time",
-			want: "0.0.0-20230102150405",
+			want: fmt.Sprintf("%s-20230102150405", baseVersion),
 			buildinfo: &debug.BuildInfo{
 				Settings: []debug.BuildSetting{
 					{Key: "vcs.time", Value: "2023-01-02T15:04:05Z"},
@@ -64,7 +67,7 @@ func TestVersion(t *testing.T) {
 		},
 		{
 			name: "pseudoversion invalid time",
-			want: "0.0.0-123456789000",
+			want: fmt.Sprintf("%s-123456789000", baseVersion),
 			buildinfo: &debug.BuildInfo{
 				Settings: []debug.BuildSetting{
 					{Key: "vcs.revision", Value: "123456789000"},
@@ -74,7 +77,7 @@ func TestVersion(t *testing.T) {
 		},
 		{
 			name: "revision less than 12 chars",
-			want: "0.0.0-shortrev-20230125195754",
+			want: fmt.Sprintf("%s-shortrev-20230125195754", baseVersion),
 			buildinfo: &debug.BuildInfo{
 				Settings: []debug.BuildSetting{
 					{Key: "vcs.revision", Value: "shortrev"},