add pkg-root flag

README.md

@@ -16,6 +16,9 @@ The forgotten go tool that executes and caches binaries included in go.mod files
 
   # Convert a JSON object to a Go struct, properly passing in stdin.
   echo example.json | gomodrun gojson > example.go
+
+  # Specifiy alternative root directory containing a go.mod and tools file.
+  gomodrun -r ./alternative-tools-dir golangci-lint run
 ```
 
 ## Installation
@@ -98,11 +101,12 @@ import (
 )
 
 func main() {
-	exitCode, err := gomodrun.Run("golangci-lint", []string{"run"}, gomodrun.Options{
-		Stdin:  os.Stdin,
-		Stdout: os.Stdout,
-		Stderr: os.Stderr,
-		Env:    os.Environ(),
+	exitCode, err := gomodrun.Run("golangci-lint", []string{"run"}, &gomodrun.Options{
+		Stdin:   os.Stdin,
+		Stdout:  os.Stdout,
+		Stderr:  os.Stderr,
+		Env:     os.Environ(),
+		PkgRoot: "",
 	})
 }
 ```

cmd/gomodrun/main.go

@@ -34,20 +34,36 @@ https://github.com/dustinblackman/gomodrun/commit/%s
 The forgotten go tool that executes and caches binaries included in go.mod files.
 
 Usage:
-	gomodrun cli-name [parameters]
+	gomodrun [flags] cli-name [parameters]
 
 Example:
 	gomodrun golangci-lint run
-	echo example.json | gomodrun gojson > example.go`, version, date, commit)
+	echo example.json | gomodrun gojson > example.go
+	gomodrun -r ./alternative-tools-dir golangci-lint run
+
+Flags:
+  -r, --pkg-root string  Specify alternative root directory containing a go.mod and tools file. Defaults to walking up the file tree to locate go.mod.`, version, date, commit)
 		os.Exit(0)
 	}
 
-	exitCode, err := gomodrun.Run(os.Args[1], os.Args[2:], gomodrun.Options{
-		Stdin:  os.Stdin,
-		Stdout: os.Stdout,
-		Stderr: os.Stderr,
-		Env:    os.Environ(),
+	cmdPosition := 1
+	argsPosition := 2
+	pkgRoot := ""
+
+	if os.Args[1] == "-r" || os.Args[1] == "--pkg-root" {
+		pkgRoot = os.Args[2]
+		cmdPosition += 2
+		argsPosition += 2
+	}
+
+	exitCode, err := gomodrun.Run(os.Args[cmdPosition], os.Args[argsPosition:], &gomodrun.Options{
+		Stdin:   os.Stdin,
+		Stdout:  os.Stdout,
+		Stderr:  os.Stderr,
+		Env:     os.Environ(),
+		PkgRoot: pkgRoot,
 	})
+
 	if err != nil {
 		exitWithError(err)
 	}

pkg.go

@@ -19,10 +19,11 @@ import (
 
 // Options contains parameters that are passed to `exec.Command` when running the binary.
 type Options struct {
-	Stdin  io.Reader
-	Stdout io.Writer
-	Stderr io.Writer
-	Env    []string
+	Stdin   io.Reader // Stdin passed to tool.
+	Stdout  io.Writer // Stdout passed to tool.
+	Stderr  io.Writer // Stderr passed to tool.
+	Env     []string  // Array of environment variables passed to tool.
+	PkgRoot string    // Root directory of go.mod with tools
 }
 
 // GetPkgRoot gets your projects package root, allowing you to run gomodrun from any sub directory.
@@ -31,6 +32,7 @@ func GetPkgRoot() (string, error) {
 	if err != nil {
 		return "", err
 	}
+
 	for {
 		if _, err := os.Stat(path.Join(currentDir, "go.mod")); !os.IsNotExist(err) {
 			absPath, err := filepath.Abs(currentDir)
@@ -170,10 +172,15 @@ func GetCachedBin(pkgRoot, binName, cmdPath string) (string, error) {
 }
 
 // Run executes your binary.
-func Run(binName string, args []string, options Options) (int, error) {
-	pkgRoot, err := GetPkgRoot()
-	if err != nil {
-		return -1, err
+func Run(binName string, args []string, options *Options) (int, error) {
+	var err error
+	pkgRoot := options.PkgRoot
+
+	if pkgRoot == "" {
+		pkgRoot, err = GetPkgRoot()
+		if err != nil {
+			return -1, err
+		}
 	}
 
 	cmdPath, err := GetCommandVersionedPkgPath(pkgRoot, binName)

pkg_test.go

@@ -74,21 +74,45 @@ var _ = Describe("pkg", func() {
 
 	Context("Run", func() {
 		It("should return exit code 0 when binary exits with 0", func() {
-			exitCode, err := gomodrun.Run("hello-world", []string{}, gomodrun.Options{})
+			exitCode, err := gomodrun.Run("hello-world", []string{}, &gomodrun.Options{})
 			Expect(err).To(BeNil())
 			Expect(exitCode).To(Equal(0))
 		})
 
 		It("should return exit code 1 when the binary exists with 1", func() {
-			exitCode, err := gomodrun.Run("hello-world", []string{"1"}, gomodrun.Options{})
+			exitCode, err := gomodrun.Run("hello-world", []string{"1"}, &gomodrun.Options{})
 			Expect(err).To(BeNil())
 			Expect(exitCode).To(Equal(1))
 		})
 
 		It("should return an error when the binary does not exist", func() {
-			exitCode, err := gomodrun.Run("not-real", []string{}, gomodrun.Options{})
+			exitCode, err := gomodrun.Run("not-real", []string{}, &gomodrun.Options{})
 			Expect(err).ToNot(BeNil())
 			Expect(exitCode).To(Equal(-1))
 		})
+
+		Context("Alternative tools directory", func() {
+			options := &gomodrun.Options{
+				PkgRoot: path.Join(cwd, "./tests/alternative-tools-dir"),
+			}
+
+			It("should return exit code 0 when binary exits with 0", func() {
+				exitCode, err := gomodrun.Run("hello-world", []string{}, options)
+				Expect(err).To(BeNil())
+				Expect(exitCode).To(Equal(0))
+			})
+
+			It("should return exit code 1 when the binary exists with 1", func() {
+				exitCode, err := gomodrun.Run("hello-world", []string{"1"}, options)
+				Expect(err).To(BeNil())
+				Expect(exitCode).To(Equal(1))
+			})
+
+			It("should return an error when the binary does not exist", func() {
+				exitCode, err := gomodrun.Run("not-real", []string{}, options)
+				Expect(err).ToNot(BeNil())
+				Expect(exitCode).To(Equal(-1))
+			})
+		})
 	})
 })

tests/alternative-tools-dir/go.mod

@@ -0,0 +1,5 @@
+module github.com/dustinblackman/gomodrun-test
+
+go 1.13
+
+require github.com/dustinblackman/go-hello-world-test v0.0.2

tests/alternative-tools-dir/go.sum

@@ -0,0 +1,2 @@
+github.com/dustinblackman/go-hello-world-test v0.0.2 h1:DcAbKiyeohJ/c/3m5c7h3tQGKA8q7J9eahZpAjo3ZZs=
+github.com/dustinblackman/go-hello-world-test v0.0.2/go.mod h1:wbYSnWUoM4tqbraqvRvVuK6jV7YV4Gv+d/lTltepZyA=

tests/alternative-tools-dir/go.tools.go

@@ -0,0 +1,7 @@
+// +build tools
+
+package gomodrun
+
+import (
+	_ "github.com/dustinblackman/go-hello-world-test/hello-world"
+)