build: Build-metadata usage via go:embed

Refactor build metadata injection logic:
- Introduced `build_info` package to manage version, commit, and date details.
- Removed ldflags-based metadata injection.
- Updated workflows and Dockerfile to prepare `build_info` files.
- Added unit tests for `build_info` initialization and formatting.
Because: Since build-metadata no longer needs compiling to binary, this information can already be defined at the source code level.
Related github#630

Author: SchulteDev

.github/workflows/go.yml

@@ -1,5 +1,5 @@
 name: Build and Test Go Project
-on: [push, pull_request]
+on: [ push, pull_request ]
 
 permissions:
   contents: read
@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
+        os: [ ubuntu-latest, windows-latest, macos-latest ]
 
     runs-on: ${{ matrix.os }}
 
@@ -28,5 +28,17 @@ jobs:
       - name: Run unit tests
         run: script/test
 
+      - name: Prepare build_info files
+        shell: bash
+        run: |
+          BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+          mkdir -p cmd/github-mcp-server/build_info
+          echo "${{ github.sha }}" > cmd/github-mcp-server/build_info/commit.txt
+          echo "$BUILD_DATE" > cmd/github-mcp-server/build_info/date.txt
+          if [ "${{ github.event_name }}" = "push" ]; then
+            echo "${{ github.ref_name }}" > cmd/github-mcp-server/build_info/version.txt
+          else
+            echo "pr-${{ github.event.pull_request.number }}" > cmd/github-mcp-server/build_info/version.txt
+          fi
       - name: Build
         run: go build -v ./cmd/github-mcp-server

.goreleaser.yaml

@@ -4,12 +4,16 @@ before:
   hooks:
     - go mod tidy
     - go generate ./...
+    - mkdir -p cmd/github-mcp-server/build_info
+    - echo "{{.Commit}}" > cmd/github-mcp-server/build_info/commit.txt
+    - echo "{{.Date}}" > cmd/github-mcp-server/build_info/date.txt
+    - echo "{{.Version}}" > cmd/github-mcp-server/build_info/version.txt
 
 builds:
   - env:
       - CGO_ENABLED=0
     ldflags:
-      - -s -w -X main.version={{.Version}} -X main.commit={{.Commit}} -X main.date={{.Date}}
+      - -s -w
     goos:
       - linux
       - windows

Dockerfile

@@ -8,12 +8,19 @@ WORKDIR /build
 RUN --mount=type=cache,target=/var/cache/apk \
     apk add git
 
+# Prepare build_info files
+RUN --mount=type=bind,target=. \
+    mkdir -p cmd/github-mcp-server/build_info && \
+    git rev-parse HEAD > cmd/github-mcp-server/build_info/commit.txt && \
+    date -u +%Y-%m-%dT%H:%M:%SZ > cmd/github-mcp-server/build_info/date.txt && \
+    echo "${VERSION}" > cmd/github-mcp-server/build_info/version.txt
+
 # Build the server
 # go build automatically download required module dependencies to /go/pkg/mod
 RUN --mount=type=cache,target=/go/pkg/mod \
     --mount=type=cache,target=/root/.cache/go-build \
     --mount=type=bind,target=. \
-    CGO_ENABLED=0 go build -ldflags="-s -w -X main.version=${VERSION} -X main.commit=$(git rev-parse HEAD) -X main.date=$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
+    CGO_ENABLED=0 go build -ldflags="-s -w" \
     -o /bin/github-mcp-server cmd/github-mcp-server/main.go
 
 # Make a stage to run the app

cmd/github-mcp-server/build_info.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"embed"
+	"fmt"
+	"strings"
+)
+
+//go:embed build_info/commit.txt build_info/date.txt build_info/version.txt
+var versionFS embed.FS
+
+type buildInfoStruct struct {
+	commit  string
+	date    string
+	version string
+}
+
+func (b buildInfoStruct) String() string {
+	return fmt.Sprintf("Commit: %s\nBuild Date: %s\nVersion: %s", b.commit, b.date, b.version)
+}
+
+var buildInfo = func() buildInfoStruct {
+	readFile := func(path, fallback string) string {
+		if content, err := versionFS.ReadFile(path); err == nil {
+			return strings.TrimSpace(string(content))
+		}
+		return fallback
+	}
+
+	return buildInfoStruct{
+		commit:  readFile("build_info/commit.txt", "unknown commit"),
+		date:    readFile("build_info/date.txt", "unknown date"),
+		version: readFile("build_info/version.txt", "unknown version"),
+	}
+}()

cmd/github-mcp-server/build_info/commit.txt

@@ -0,0 +1 @@
+commit

cmd/github-mcp-server/build_info/date.txt

@@ -0,0 +1 @@
+date

cmd/github-mcp-server/build_info/version.txt

@@ -0,0 +1 @@
+version

cmd/github-mcp-server/build_info_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuildInfoStruct_String(t *testing.T) {
+	tests := []struct {
+		name     string
+		info     buildInfoStruct
+		expected string
+	}{
+		{
+			name: "all fields populated",
+			info: buildInfoStruct{
+				commit:  "abc123",
+				date:    "2024-01-01",
+				version: "1.0.0",
+			},
+			expected: "Commit: abc123\nBuild Date: 2024-01-01\nVersion: 1.0.0",
+		},
+		{
+			name:     "initialized struct",
+			info:     buildInfoStruct{},
+			expected: "Commit: \nBuild Date: \nVersion: ",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.info.String()
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestBuildInfo_Initialization(t *testing.T) {
+	assert.Equal(t, "commit", buildInfo.commit)
+	assert.Equal(t, "date", buildInfo.date)
+	assert.Equal(t, "version", buildInfo.version)
+}

cmd/github-mcp-server/main.go

@@ -13,17 +13,12 @@ import (
 	"github.com/spf13/viper"
 )
 
-// These variables are set by the build process using ldflags.
-var version = "version"
-var commit = "commit"
-var date = "date"
-
 var (
 	rootCmd = &cobra.Command{
 		Use:     "server",
 		Short:   "GitHub MCP Server",
 		Long:    `A GitHub MCP server that handles various tools and resources.`,
-		Version: fmt.Sprintf("Version: %s\nCommit: %s\nBuild Date: %s", version, commit, date),
+		Version: buildInfo.String(),
 	}
 
 	stdioCmd = &cobra.Command{
@@ -46,7 +41,7 @@ var (
 			}
 
 			stdioServerConfig := ghmcp.StdioServerConfig{
-				Version:              version,
+				Version:              buildInfo.version,
 				Host:                 viper.GetString("host"),
 				Token:                token,
 				EnabledToolsets:      enabledToolsets,

cmd/github-mcp-server/main_test.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_RootCmdVersion(t *testing.T) {
+	expectedVersion := buildInfo.String()
+	actualVersion := rootCmd.Version
+
+	assert.Equal(t, expectedVersion, actualVersion)
+}