From 4fd8e37f68dd34f8e07a07f8d81feba2db68978d Mon Sep 17 00:00:00 2001
From: Dan Anglin <daangling@gmail.com>
Date: Thu, 30 May 2024 11:51:54 +0100
Subject: [PATCH] chore: update project template

- update the Go version in forgejo workflow
- add a __build directory
- build the binary to the __build directory
- by default, do quick builds (builds without rebuilding all packages)
- add the install target
- add functions to generate the binary's build information
- add a skeleton run function in main.go
---
 .forgejo/workflows/workflow.yaml |  4 +-
 .gitignore                       |  2 +
 __build/.gitkeep                 |  0
 magefiles/mage.go                | 95 +++++++++++++++++++++++++++++---
 main.go                          | 20 +++++++
 5 files changed, 112 insertions(+), 9 deletions(-)
 create mode 100644 __build/.gitkeep

diff --git a/.forgejo/workflows/workflow.yaml b/.forgejo/workflows/workflow.yaml
index b4b5e20..e08ccb4 100644
--- a/.forgejo/workflows/workflow.yaml
+++ b/.forgejo/workflows/workflow.yaml
@@ -18,7 +18,7 @@ jobs:
     - name: Setup Go
       uses: https://code.forgejo.org/actions/setup-go@v5
       with:
-        go-version: '1.21'
+        go-version: '1.22'
     - name: Test
       run: go run magefiles/main.go -v test
 
@@ -30,7 +30,7 @@ jobs:
     - name: Setup Go
       uses: https://code.forgejo.org/actions/setup-go@v5
       with:
-        go-version: '1.21'
+        go-version: '1.22'
     - name: Lint
       uses: https://github.com/golangci/golangci-lint-action@v3
       with:
diff --git a/.gitignore b/.gitignore
index e69de29..e200850 100644
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/__build/*
+!__build/.gitkeep
diff --git a/__build/.gitkeep b/__build/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/magefiles/mage.go b/magefiles/mage.go
index 567949c..1a12267 100644
--- a/magefiles/mage.go
+++ b/magefiles/mage.go
@@ -3,28 +3,44 @@
 package main
 
 import (
+	"fmt"
 	"os"
+	"path/filepath"
+	"runtime"
+	"time"
 
+	"github.com/magefile/mage/mg"
 	"github.com/magefile/mage/sh"
 )
 
-var Default = Build
+const (
+	app                  = "binary"
+	defaultInstallPrefix = "/usr/local"
+	envInstallPrefix     = "PROJECT_INSTALL_PREFIX"
+	envTestVerbose       = "PROJECT_TEST_VERBOSE"
+	envTestCover         = "PROJECT_TEST_COVER"
+	envBuildRebuildAll   = "PROJECT_BUILD_REBUILD_ALL"
+	envBuildVerbose      = "PROJECT_BUILD_VERBOSE"
+)
 
-var binary = "app"
+var (
+	Default = Build
+	binary  = "./__build/" + app
+)
 
 // Test run the go tests.
-// To enable verbose mode set GO_TEST_VERBOSE=1.
-// To enable coverage mode set GO_TEST_COVER=1.
+// To enable verbose mode set PROJECT_TEST_VERBOSE=1.
+// To enable coverage mode set PROJECT_TEST_COVER=1.
 func Test() error {
 	goTest := sh.RunCmd("go", "test")
 
 	args := []string{"./..."}
 
-	if os.Getenv("GO_TEST_VERBOSE") == "1" {
+	if os.Getenv(envTestVerbose) == "1" {
 		args = append(args, "-v")
 	}
 
-	if os.Getenv("GO_TEST_COVER") == "1" {
+	if os.Getenv(envTestCover) == "1" {
 		args = append(args, "-cover")
 	}
 
@@ -37,9 +53,46 @@ func Lint() error {
 }
 
 // Build build the executable.
+// To rebuild packages that are already up-to-date set PROJECT_BUILD_REBUILD_ALL=1
+// To enable verbose mode set PROJECT_BUILD_VERBOSE=1
 func Build() error {
 	main := "main.go"
-	return sh.Run("go", "build", "-o", binary, main)
+	flags := ldflags()
+	build := sh.RunCmd("go", "build")
+	args := []string{"-ldflags=" + flags, "-o", binary}
+
+	if os.Getenv(envBuildRebuildAll) == "1" {
+		args = append(args, "-a")
+	}
+
+	if os.Getenv(envBuildVerbose) == "1" {
+		args = append(args, "-v")
+	}
+
+	args = append(args, main)
+
+	return build(args...)
+}
+
+// Install install the executable.
+func Install() error {
+	mg.Deps(Build)
+
+	installPrefix := os.Getenv(envInstallPrefix)
+
+	if installPrefix == "" {
+		installPrefix = defaultInstallPrefix
+	}
+
+	dest := filepath.Join(installPrefix, "bin", app)
+
+	if err := sh.Copy(dest, binary); err != nil {
+		return fmt.Errorf("unable to install %s; %w", dest, err)
+	}
+
+	fmt.Printf("%s successfully installed to %s\n", app, dest)
+
+	return nil
 }
 
 // Clean clean the workspace.
@@ -54,3 +107,31 @@ func Clean() error {
 
 	return nil
 }
+
+// ldflags returns the build flags.
+func ldflags() string {
+	ldflagsfmt := "-s -w -X main.binaryVersion=%s -X main.gitCommit=%s -X main.goVersion=%s -X main.buildTime=%s"
+	buildTime := time.Now().UTC().Format(time.RFC3339)
+
+	return fmt.Sprintf(ldflagsfmt, version(), gitCommit(), runtime.Version(), buildTime)
+}
+
+// version returns the latest git tag using git describe.
+func version() string {
+	version, err := sh.Output("git", "describe", "--tags")
+	if err != nil {
+		version = "N/A"
+	}
+
+	return version
+}
+
+// gitCommit returns the current git commit
+func gitCommit() string {
+	commit, err := sh.Output("git", "rev-parse", "--short", "HEAD")
+	if err != nil {
+		commit = "N/A"
+	}
+
+	return commit
+}
diff --git a/main.go b/main.go
index da29a2c..a3255e8 100644
--- a/main.go
+++ b/main.go
@@ -1,4 +1,24 @@
 package main
 
+import (
+	"fmt"
+	"os"
+)
+
+var (
+	binaryVersion string
+	buildTime     string
+	goVersion     string
+	gitCommit     string
+)
+
 func main() {
+	if err := run(); err != nil {
+		fmt.Printf("ERROR: %v.\n", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	return nil
 }