feat(golang-rewrite): PluginAdd function

* Add go-git as a dependency
* Remove plugins dir from gitignore
* Move config code to config package
* Create validatePluginName function
* Create PluginDirectory function
* Create PluginExists function
* Implement PluginAdd function
* Add testify as a dependency
* Write test for PluginAdd happy path

.gitignore

@@ -1,6 +1,5 @@
 /installs
 /downloads
-/plugins
 /shims
 repository
 .vagrant

config/config.go

@@ -1,4 +1,4 @@
-package main
+package config
 
 import (
 	"context"

config/config_test.go

@@ -1,4 +1,4 @@
-package main
+package config
 
 import (
 	"testing"

go.mod

@@ -3,15 +3,40 @@ module asdf
 go 1.21.5
 
 require (
+	github.com/go-git/go-git/v5 v5.11.0
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/sethvargo/go-envconfig v1.0.0
+	github.com/stretchr/testify v1.8.4
 	github.com/urfave/cli/v2 v2.27.1
 	gopkg.in/ini.v1 v1.67.0
 )
 
 require (
+	dario.cat/mergo v1.0.0 // indirect
+	github.com/Microsoft/go-winio v0.6.1 // indirect
+	github.com/ProtonMail/go-crypto v0.0.0-20230828082145-3c4c8a2d2371 // indirect
+	github.com/cloudflare/circl v1.3.3 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.3 // indirect
+	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/emirpasic/gods v1.18.1 // indirect
+	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
+	github.com/go-git/go-billy/v5 v5.5.0 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
+	github.com/kevinburke/ssh_config v1.2.0 // indirect
+	github.com/pjbgf/sha1cd v0.3.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	github.com/stretchr/testify v1.8.4 // indirect
+	github.com/sergi/go-diff v1.1.0 // indirect
+	github.com/skeema/knownhosts v1.2.1 // indirect
+	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
+	golang.org/x/crypto v0.16.0 // indirect
+	golang.org/x/mod v0.12.0 // indirect
+	golang.org/x/net v0.19.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/tools v0.13.0 // indirect
+	gopkg.in/warnings.v0 v0.1.2 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,24 +1,158 @@
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+github.com/ProtonMail/go-crypto v0.0.0-20230828082145-3c4c8a2d2371/go.mod h1:EjAoLdwvbIOoOQr3ihjnSoLZRtE8azugULFRteWMNc0=
+github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be h1:9AeTilPcZAjCFIImctFaOjnTIavg87rW78vTPkQqLI8=
+github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be/go.mod h1:ySMOLuWl6zY27l47sB3qLNK6tF2fkHG55UZxx8oIVo4=
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+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
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plugins/main.go

@@ -0,0 +1,81 @@
+package plugins
+
+import (
+	"asdf/config"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+
+	"github.com/go-git/go-git/v5"
+)
+
+const dataDirPlugins = "plugins"
+const invalidPluginNameMsg = "'%q' is invalid. Name may only contain lowercase letters, numbers, '_', and '-'"
+const pluginAlreadyExists = "plugin named %q already added"
+
+func PluginAdd(config config.Config, pluginName, pluginUrl string) error {
+	err := validatePluginName(pluginName)
+
+	if err != nil {
+		return err
+	}
+
+	exists, err := PluginExists(config.DataDir, pluginName)
+
+	if err != nil {
+		return fmt.Errorf("unable to check if plugin already exists: %w", err)
+	}
+
+	if exists {
+		return fmt.Errorf(pluginAlreadyExists, pluginName)
+	}
+
+	pluginDir := PluginDirectory(config.DataDir, pluginName)
+
+	if err != nil {
+		return fmt.Errorf("unable to create plugin directory: %w", err)
+	}
+
+	_, err = git.PlainClone(pluginDir, false, &git.CloneOptions{
+		URL: pluginUrl,
+	})
+
+	if err != nil {
+		return fmt.Errorf("unable to clone plugin: %w", err)
+	}
+
+	return nil
+}
+
+func PluginExists(dataDir, pluginName string) (bool, error) {
+	pluginDir := PluginDirectory(dataDir, pluginName)
+	fileInfo, err := os.Stat(pluginDir)
+	if errors.Is(err, os.ErrNotExist) {
+		return false, nil
+	}
+
+	if err != nil {
+		return false, err
+	}
+
+	return fileInfo.IsDir(), nil
+}
+
+func PluginDirectory(dataDir, pluginName string) string {
+	return filepath.Join(dataDir, dataDirPlugins, pluginName)
+}
+
+func validatePluginName(name string) error {
+	match, err := regexp.MatchString("^[[:lower:][:digit:]_-]+$", name)
+	if err != nil {
+		return err
+	}
+
+	if !match {
+		return fmt.Errorf(invalidPluginNameMsg, name)
+	}
+
+	return nil
+}

plugins/main_test.go

@@ -0,0 +1,180 @@
+package plugins
+
+import (
+	"asdf/config"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TODO: Switch to local repo so tests don't go over the network
+const (
+	testRepo       = "https://github.com/Stratus3D/asdf-lua"
+	testPluginName = "lua"
+)
+
+func TestPluginAdd(t *testing.T) {
+	testDataDir := t.TempDir()
+
+	t.Run("when given an invalid plugin name prints an error", func(t *testing.T) {
+		var invalids = []string{"plugin^name", "plugin%name", "plugin name", "PLUGIN_NAME"}
+
+		for _, invalid := range invalids {
+			t.Run(invalid, func(t *testing.T) {
+				err := PluginAdd(config.Config{}, invalid, testRepo)
+
+				expectedErrMsg := "is invalid. Name may only contain lowercase letters, numbers, '_', and '-'"
+				if !strings.Contains(err.Error(), expectedErrMsg) {
+					t.Errorf("Expected an error with message %v", expectedErrMsg)
+				}
+			})
+		}
+	})
+
+	t.Run("when plugin with same name already exists prints an error", func(t *testing.T) {
+		conf := config.Config{DataDir: testDataDir}
+
+		// Add plugin
+		err := PluginAdd(conf, testPluginName, testRepo)
+
+		if err != nil {
+			t.Fatal("Expected to be able to add plugin")
+		}
+
+		// Add it again to trigger error
+		err = PluginAdd(conf, testPluginName, testRepo)
+
+		if err == nil {
+			t.Fatal("expected error got nil")
+		}
+
+		expectedErrMsg := "plugin named \"lua\" already added"
+		if !strings.Contains(err.Error(), expectedErrMsg) {
+			t.Errorf("Expected an error with message %v", expectedErrMsg)
+		}
+	})
+
+	t.Run("when plugin name is valid but URL is invalid prints an error", func(t *testing.T) {
+		conf := config.Config{DataDir: testDataDir}
+
+		err := PluginAdd(conf, "foo", "foobar")
+
+		assert.ErrorContains(t, err, "unable to clone plugin: repository not found")
+	})
+
+	t.Run("when plugin name and URL are valid installs plugin", func(t *testing.T) {
+		testDataDir := t.TempDir()
+		conf := config.Config{DataDir: testDataDir}
+
+		err := PluginAdd(conf, testPluginName, testRepo)
+
+		assert.Nil(t, err, "Expected to be able to add plugin")
+
+		// Assert plugin directory contains Git repo with bin directory
+		pluginDir := PluginDirectory(testDataDir, testPluginName)
+
+		_, err = os.ReadDir(pluginDir + "/.git")
+		assert.Nil(t, err)
+
+		entries, err := os.ReadDir(pluginDir + "/bin")
+		assert.Nil(t, err)
+		assert.Equal(t, 5, len(entries))
+	})
+}
+
+func TestPluginExists(t *testing.T) {
+	testDataDir := t.TempDir()
+	pluginDir := PluginDirectory(testDataDir, testPluginName)
+	err := os.MkdirAll(pluginDir, 0777)
+	if err != nil {
+		t.Errorf("got %v, expected nil", err)
+	}
+
+	t.Run("returns true when plugin exists", func(t *testing.T) {
+		exists, err := PluginExists(testDataDir, testPluginName)
+
+		if err != nil {
+			t.Errorf("got %v, expected nil", err)
+		}
+
+		if exists != true {
+			t.Error("got false, expected true")
+		}
+	})
+
+	t.Run("returns false when plugin path is file and not dir", func(t *testing.T) {
+		pluginName := "file"
+		pluginDir := PluginDirectory(testDataDir, pluginName)
+		err := touchFile(pluginDir)
+		if err != nil {
+			t.Errorf("got %v, expected nil", err)
+		}
+
+		exists, err := PluginExists(testDataDir, pluginName)
+
+		if err != nil {
+			t.Errorf("got %v, expected nil", err)
+		}
+
+		if exists != false {
+			t.Error("got false, expected true")
+		}
+	})
+
+	t.Run("returns false when plugin dir does not exist", func(t *testing.T) {
+		exists, err := PluginExists(testDataDir, "non-existant")
+
+		if err != nil {
+			t.Errorf("got %v, expected nil", err)
+		}
+
+		if exists != false {
+			t.Error("got false, expected true")
+		}
+	})
+}
+
+func TestPluginDirectory(t *testing.T) {
+	t.Run("returns new path with plugin name as last segment", func(t *testing.T) {
+		pluginDir := PluginDirectory("~/.asdf/", testPluginName)
+		expected := "~/.asdf/plugins/lua"
+		if pluginDir != expected {
+			t.Errorf("got %v, expected %v", pluginDir, expected)
+		}
+	})
+}
+
+func TestValidatePluginName(t *testing.T) {
+	t.Run("returns no error when plugin name is valid", func(t *testing.T) {
+		err := validatePluginName(testPluginName)
+		refuteError(t, err)
+	})
+
+	var invalids = []string{"plugin^name", "plugin%name", "plugin name", "PLUGIN_NAME"}
+
+	for _, invalid := range invalids {
+		t.Run(invalid, func(t *testing.T) {
+			err := validatePluginName(invalid)
+
+			if err == nil {
+				t.Error("Expected an error")
+			}
+		})
+	}
+}
+
+func refuteError(t *testing.T, err error) {
+	if err != nil {
+		t.Fatal("Returned unexpected error", err)
+	}
+}
+
+func touchFile(name string) error {
+	file, err := os.OpenFile(name, os.O_RDONLY|os.O_CREATE, 0644)
+	if err != nil {
+		return err
+	}
+	return file.Close()
+}