build: replace make with mage

- Replace the makefile with the magefile
- Update the Dockerfile
- Update go.mod

Makefile

@@ -1,21 +0,0 @@
-BINARY = spruce
-INSTALL_PREFIX ?= /usr/local
-CGO_ENABLED ?= 0
-GOOS ?= linux
-GOARCH ?= amd64
-VERSION = 0.1.0
-
-LDFLAGS = "-s -w -X main.version=$(VERSION) -X main.installPrefix=$(INSTALL_PREFIX)"
-
-$(BINARY):
-	go build -ldflags=$(LDFLAGS) -v -a -o $(BINARY)
-
-install: spruce
-	cp -f $(BINARY) $(INSTALL_PREFIX)/bin
-	chmod 0755 $(INSTALL_PREFIX)/bin/$(BINARY)
-
-uninstall:
-	rm -f $(INSTALL_PREFIX)/bin/$(BINARY)
-
-clean:
-	go clean

docker/Dockerfile

@@ -1,4 +1,5 @@
-FROM golang:1.19-buster AS spruce-builder
+# syntax=docker/dockerfile:1
+FROM golang:1.21-buster AS spruce-builder
 
 ENV CGO_ENABLED=0
 ENV GOOS=linux
@@ -10,7 +11,7 @@ WORKDIR /workspace
 
 RUN go build -a -v -o /workspace/spruce
 
-FROM alpine:3.17
+FROM alpine:3.18
 
 COPY --from=spruce-builder /workspace/spruce /usr/local/bin
 

go.mod

@@ -1,3 +1,5 @@
 module codeflow.dananglin.me.uk/apollo/spruce
 
-go 1.20
+go 1.21
+
+require github.com/magefile/mage v1.15.0

go.sum

@@ -0,0 +1,2 @@
+github.com/magefile/mage v1.15.0 h1:BvGheCMAsG3bWUDbZ8AyXXpCNwU9u5CB6sM+HNb9HYg=
+github.com/magefile/mage v1.15.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=

magefiles/mage.go

@@ -0,0 +1,71 @@
+//go:build mage
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/magefile/mage/mg"
+	"github.com/magefile/mage/sh"
+)
+
+var (
+	Default              = Build
+	binary               = "spruce"
+	defaultInstallPrefix = "/usr/local"
+)
+
+// Build builds the binary.
+func Build() error {
+	flags := ldflags()
+	return sh.Run("go", "build", "-ldflags="+flags, "-v", "-a", "-o", binary, ".")
+}
+
+// Install installs the binary to the execution path.
+func Install() error {
+	mg.Deps(Build)
+
+	installPrefix := os.Getenv("SPRUCE_INSTALL_PREFIX")
+	if installPrefix == "" {
+		installPrefix = defaultInstallPrefix
+	}
+
+	dest := filepath.Join(installPrefix, "bin", binary)
+
+	if err := sh.Copy(binary, dest); err != nil {
+		return fmt.Errorf("unable to install %s; %w", binary, err)
+	}
+
+	return nil
+}
+
+// Clean cleans the workspace
+func Clean() error {
+	if err := sh.Rm(binary); err != nil {
+		return fmt.Errorf("unable to remove %s; %w", binary, err)
+	}
+
+	if err := sh.Run("go", "clean", "./..."); err != nil {
+		return fmt.Errorf("unable to run 'go clean'; %w", err)
+	}
+	return nil
+}
+
+// ldflags returns the build flags.
+func ldflags() string {
+	ldflagsfmt := "-s -w -X main.version=%s"
+
+	return fmt.Sprintf(ldflagsfmt, version())
+}
+
+// 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
+}