Move to sync subcommand, use contexts to drive runflags

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log"
@@ -11,53 +12,75 @@ const (
 	// ANSI color codes for log messages
 	colorErr   = "\033[31m" // red
 	colorDebug = "\033[33m" // yellow
+	colorInfo  = "\033[36m" // cyan
 	colorHappy = "\033[32m" // green
 	colorReset = "\033[0m"
 )
 
 var (
-	// CLI args
+	// Subcommands
+	syncCmd = flag.NewFlagSet("sync", flag.ExitOnError)
+
+	subcommands = map[string]*flag.FlagSet{
+		syncCmd.Name(): syncCmd,
+	}
+
+	// CLI args common to each subcommand
 	debug        bool
 	specFilePath string
 
 	// Loggers, which include embedded ANSI color codes
-	infoLogger  = log.New(os.Stderr, fmt.Sprintf("%s[vdm] ", colorReset), 0)
+	infoLogger  = log.New(os.Stderr, fmt.Sprintf("%s%s[vdm]%s ", colorReset, colorInfo, colorReset), 0)
 	errLogger   = log.New(os.Stderr, fmt.Sprintf("%s%s[vdm]%s ", colorReset, colorErr, colorReset), 0)
 	debugLogger = log.New(os.Stderr, fmt.Sprintf("%s%s[vdm]%s ", colorReset, colorDebug, colorReset), 0)
 	happyLogger = log.New(os.Stderr, fmt.Sprintf("%s%s[vdm]%s ", colorReset, colorHappy, colorReset), 0)
 )
 
-// In case I need to pass these around, so we're not relying on globals
-type runFlags struct {
-	SpecFilePath string
-	Debug        bool
+func setCommonFlags() {
+	for _, cmd := range subcommands {
+		cmd.StringVar(&specFilePath, "spec-file", "./.vdm", "vdm dependency spec file")
+		cmd.BoolVar(&debug, "debug", false, "Print debug logs")
+	}
 }
 
-func main() {
-	flag.StringVar(&specFilePath, "spec-file", "./.vdm", "vdm dependency spec file")
-	flag.BoolVar(&debug, "debug", false, "Print debug logs")
-	flag.Parse()
+func isDebug(ctx context.Context) bool {
+	debugVal := ctx.Value("debug")
+	if debugVal == nil {
+		panic("somehow the debug context key ended up as <nil>")
+	}
 
-	runFlags := runFlags{
-		SpecFilePath: specFilePath,
-		Debug:        debug,
+	return debugVal.(bool)
+}
+
+func main() {
+	if len(os.Args) == 1 {
+		errLogger.Fatal("You must provide a command to vdm")
 	}
+	cmd, ok := subcommands[os.Args[1]]
+	if !ok {
+		errLogger.Fatalf("Unrecognized vmd subcommand '%s'", os.Args[1])
+	}
+	setCommonFlags()
+	cmd.Parse(os.Args[2:])
+
+	ctx := context.WithValue(context.Background(), "debug", debug)
+	ctx = context.WithValue(ctx, "specFilePath", specFilePath)
 
-	err := checkGitAvailable()
+	err := checkGitAvailable(ctx)
 	if err != nil {
 		os.Exit(1)
 	}
 
-	specs := getSpecsFromFile(specFilePath, runFlags)
+	specs := getSpecsFromFile(ctx, specFilePath)
 
 	for _, spec := range specs {
-		err := spec.Validate()
+		err := spec.Validate(ctx)
 		if err != nil {
-			errLogger.Fatalf("your vdm spec file is malformed: %v", err)
+			errLogger.Fatalf("Your vdm spec file is malformed: %v", err)
 		}
 	}
 
-	sync(specs)
+	sync(ctx, specs)
 
 	happyLogger.Print("All done!")
 }

spec.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
 	"errors"
 	"os"
@@ -11,8 +12,6 @@ type vdmSpec struct {
 	Remote    string `json:"remote"`
 	Version   string `json:"version"`
 	LocalPath string `json:"local_path"`
-	// so we can pass these around for each spec
-	runFlags runFlags `json:"-"`
 }
 
 func (spec vdmSpec) writeVDMMeta() error {
@@ -61,13 +60,13 @@ func (spec vdmSpec) getVDMMeta() vdmSpec {
 	return vdmMeta
 }
 
-func getSpecsFromFile(specFilePath string, runFlags runFlags) []vdmSpec {
+func getSpecsFromFile(ctx context.Context, specFilePath string) []vdmSpec {
 	specFile, err := os.ReadFile(specFilePath)
 	if err != nil {
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("error reading specFile from disk: %v", err)
 		}
-		errLogger.Fatalf("There was a problem reading your vdm file from '%s' -- does it not exist?", specFilePath)
+		errLogger.Fatalf("There was a problem reading your vdm file from '%s' -- does it not exist? Either pass the -spec-file flag, or create one in the default location (details in the README)", specFilePath)
 	}
 	if debug {
 		debugLogger.Printf("specFile contents read:\n%s", string(specFile))
@@ -76,18 +75,14 @@ func getSpecsFromFile(specFilePath string, runFlags runFlags) []vdmSpec {
 	var specs []vdmSpec
 	err = json.Unmarshal(specFile, &specs)
 	if err != nil {
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("error during specFile unmarshal: %v", err)
 		}
 		errLogger.Fatal("There was a problem reading the contents of your vdm spec file")
 	}
-	if debug {
+	if isDebug(ctx) {
 		debugLogger.Printf("vdmSpecs unmarshalled: %+v", specs)
 	}
 
-	for _, spec := range specs {
-		spec.runFlags = runFlags
-	}
-
 	return specs
 }

spec_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"os"
 	"path/filepath"
 	"testing"
@@ -56,16 +57,12 @@ func TestSpecGetVDMMeta(t *testing.T) {
 
 	t.Run("getSpecsFromFile", func(t *testing.T) {
 		specFilePath := "./testdata/.vdm"
-		runFlags := runFlags{
-			SpecFilePath: "./testdata/.vdm",
-		}
 
-		specs := getSpecsFromFile(specFilePath, runFlags)
+		specs := getSpecsFromFile(context.Background(), specFilePath)
 		assert.Equal(t, 4, len(specs))
 
 		t.Cleanup(func() {
 			os.RemoveAll(testVDMMetaFilePath)
 		})
 	})
-
 }

staticcheck.conf

@@ -1 +1,4 @@
-checks = ["all"]
+checks = [
+  "all",
+  "-SA1029" # context string keys, for now
+]

sync.go

@@ -1,14 +1,15 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
 )
 
 // sync ensures that the only local dependencies are ones defined in the specfile
-func sync(specs []vdmSpec) {
+func sync(ctx context.Context, specs []vdmSpec) {
 	for _, spec := range specs {
 		// Common log line prefix
 		operationMsg := fmt.Sprintf("%s@%s --> %s", spec.Remote, spec.Version, spec.LocalPath)
@@ -21,19 +22,19 @@ func sync(specs []vdmSpec) {
 			if vdmMeta.Version != spec.Version {
 				infoLogger.Printf("Changing '%s' from current local version spec '%s' to '%s'...", spec.Remote, vdmMeta.Version, spec.Version)
 			} else {
-				if debug {
+				if isDebug(ctx) {
 					debugLogger.Printf("Version unchanged (%s) in specfile for '%s' --> '%s'", spec.Version, spec.Remote, spec.LocalPath)
 				}
 			}
 		}
 
 		// TODO: pull this up so that it only runs if the version changed or the user requested a wipe
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("removing any old data for '%s'", spec.LocalPath)
 		}
 		os.RemoveAll(spec.LocalPath)
 
-		gitClone(spec, operationMsg)
+		gitClone(ctx, spec, operationMsg)
 
 		if spec.Version != "latest" {
 			infoLogger.Printf("%s -- Setting specified version...", operationMsg)
@@ -44,7 +45,7 @@ func sync(specs []vdmSpec) {
 			}
 		}
 
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("removing .git dir for local path '%s'", spec.LocalPath)
 		}
 		os.RemoveAll(filepath.Join(spec.LocalPath, ".git"))
@@ -58,18 +59,18 @@ func sync(specs []vdmSpec) {
 	}
 }
 
-func gitClone(spec vdmSpec, operationMsg string) {
+func gitClone(ctx context.Context, spec vdmSpec, operationMsg string) {
 	// If users want "latest", then we can just do a depth-one clone and
 	// skip the checkout operation. But if they want non-latest, we need the
 	// full history to be able to find a specified revision
 	var cloneCmdArgs []string
 	if spec.Version == "latest" {
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("%s -- version specified as 'latest', so making shallow clone and skipping separate checkout operation", operationMsg)
 		}
 		cloneCmdArgs = []string{"clone", "--depth=1", spec.Remote, spec.LocalPath}
 	} else {
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("%s -- version specified as NOT latest, so making regular clone and will make separate checkout operation", operationMsg)
 		}
 		cloneCmdArgs = []string{"clone", spec.Remote, spec.LocalPath}

sync_test.go

@@ -1,19 +1,22 @@
 package main
 
 import (
+	"context"
 	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestSync(t *testing.T) {
+	ctx := context.Background()
+
 	const testVDMRoot = "./testdata"
 	specFilePath := filepath.Join(testVDMRoot, ".vdm")
 
-	specs := getSpecsFromFile(specFilePath, runFlags{SpecFilePath: specFilePath})
+	specs := getSpecsFromFile(ctx, specFilePath)
 
-	sync(specs)
+	sync(ctx, specs)
 
 	t.Run("spec[0] used a tag", func(t *testing.T) {
 		vdmMeta := specs[0].getVDMMeta()

system.go

@@ -1,20 +1,21 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"os/exec"
 )
 
-func checkGitAvailable() error {
+func checkGitAvailable(ctx context.Context) error {
 	cmd := exec.Command("git", "--version")
 	sysOutput, err := cmd.CombinedOutput()
 	if err != nil {
-		if debug {
+		if isDebug(ctx) {
 			debugLogger.Printf("%s: %s", err.Error(), string(sysOutput))
 		}
 		return errors.New("git does not seem to be available on your PATH, so cannot continue")
 	}
-	if debug {
+	if isDebug(ctx) {
 		debugLogger.Print("git was found on PATH")
 	}
 	return nil

system_test.go

@@ -1,19 +1,22 @@
 package main
 
 import (
+	"context"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestCheckAvailable(t *testing.T) {
+	ctx := context.Background()
+
 	t.Run("git", func(t *testing.T) {
 		// Host of this test better have git available lol
-		gitAvailable := checkGitAvailable()
+		gitAvailable := checkGitAvailable(ctx)
 		assert.NoError(t, gitAvailable)
 
 		t.Setenv("PATH", "")
-		gitAvailable = checkGitAvailable()
+		gitAvailable = checkGitAvailable(ctx)
 		assert.Error(t, gitAvailable)
 	})
 }

validate.go

@@ -1,15 +1,16 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"regexp"
 )
 
-func (spec vdmSpec) Validate() error {
+func (spec vdmSpec) Validate(ctx context.Context) error {
 	var allErrors []error
 
-	if spec.runFlags.Debug {
+	if isDebug(ctx) {
 		debugLogger.Printf("validating field 'Remote' for %+v", spec)
 	}
 	if len(spec.Remote) == 0 {
@@ -23,14 +24,14 @@ func (spec vdmSpec) Validate() error {
 		)
 	}
 
-	if spec.runFlags.Debug {
+	if isDebug(ctx) {
 		debugLogger.Printf("validating field 'Version' for %+v", spec)
 	}
 	if len(spec.Version) == 0 {
 		allErrors = append(allErrors, errors.New("all 'version' fields must be non-zero length. If you don't care about the version (even though you should), then use 'latest'"))
 	}
 
-	if spec.runFlags.Debug {
+	if isDebug(ctx) {
 		debugLogger.Printf("validating field 'LocalPath' for %+v", spec)
 	}
 	if len(spec.LocalPath) == 0 {