[Refactoring] Layered architecture

Makefile

@@ -1,7 +1,7 @@
 
 NAME := volt
 SRC := $(shell find . -type d -name 'vendor' -prune -o -type f -name '*.go' -print)
-VERSION := $(shell sed -n -E 's/var voltVersion = "([^"]+)"/\1/p' subcmd/version.go)
+VERSION := $(shell sed -n -E 's/var VoltVersion = "([^"]+)"/\1/p' usecase/version.go)
 RELEASE_LDFLAGS := -s -w -extldflags '-static'
 RELEASE_OS := linux windows darwin
 RELEASE_ARCH := amd64 386

_docs/layer.md

@@ -0,0 +1,20 @@
+
+## Layered architecture
+
+The volt commands like `volt get` which may modify lock.json, config.toml,
+filesystem, are executed in several steps:
+
+1. (UI layer): Passes subcommand arguments, lock.json & config.toml structure to Gateway layer
+2. (Gateway layer): Invokes usecase(s). This layer cannot touch filesystem, do network requests, because it makes unit testing difficult
+3. (Usecase layer): Modify files, do network requests, and other business logic
+
+Below is the dependency graph:
+
+```
+UI --> Gateway --> Usecase
+```
+
+* UI only depends Gateway
+* Gateway doesn't know UI
+* Gateway only depends Usecase
+* Usecase doesn't know Gateway

subcmd/build.go → gateway/build.go

@@ -1,12 +1,12 @@
-package subcmd
+package gateway
 
 import (
 	"flag"
 	"fmt"
 	"os"
 
+	"github.com/vim-volt/volt/gateway/builder"
 	"github.com/vim-volt/volt/logger"
-	"github.com/vim-volt/volt/subcmd/builder"
 	"github.com/vim-volt/volt/transaction"
 )
 
@@ -53,10 +53,10 @@ Description
 	return fs
 }
 
-func (cmd *buildCmd) Run(args []string) *Error {
+func (cmd *buildCmd) Run(cmdctx *CmdContext) *Error {
 	// Parse args
 	fs := cmd.FlagSet()
-	fs.Parse(args)
+	fs.Parse(cmdctx.Args)
 	if cmd.helped {
 		return nil
 	}
@@ -69,7 +69,7 @@ func (cmd *buildCmd) Run(args []string) *Error {
 	}
 	defer transaction.Remove()
 
-	err = builder.Build(cmd.full)
+	err = builder.Build(cmd.full, cmdctx.Config, cmdctx.LockJSON)
 	if err != nil {
 		logger.Error()
 		return &Error{Code: 12, Msg: "Failed to build: " + err.Error()}

subcmd/build_test.go → gateway/build_test.go

@@ -1,4 +1,4 @@
-package subcmd
+package gateway
 
 import (
 	"bytes"
@@ -13,10 +13,10 @@ import (
 	"github.com/haya14busa/go-vimlparser"
 	"github.com/vim-volt/volt/config"
 	"github.com/vim-volt/volt/fileutil"
+	"github.com/vim-volt/volt/gateway/builder"
 	"github.com/vim-volt/volt/internal/testutil"
 	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/pathutil"
-	"github.com/vim-volt/volt/subcmd/builder"
 )
 
 // Checks:

subcmd/builder/base.go → gateway/builder/base.go

@@ -12,10 +12,10 @@ import (
 
 	"github.com/hashicorp/go-multierror"
 	"github.com/vim-volt/volt/fileutil"
+	"github.com/vim-volt/volt/gateway/buildinfo"
 	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/pathutil"
-	"github.com/vim-volt/volt/subcmd/buildinfo"
 )
 
 // BaseBuilder is a base struct which all builders must implement

subcmd/builder/builder.go → gateway/builder/builder.go

@@ -1,30 +1,26 @@
 package builder
 
 import (
-	"github.com/pkg/errors"
 	"os"
 
+	"github.com/pkg/errors"
+
 	"github.com/vim-volt/volt/config"
+	"github.com/vim-volt/volt/gateway/buildinfo"
+	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/pathutil"
-	"github.com/vim-volt/volt/subcmd/buildinfo"
 )
 
 // Builder creates/updates ~/.vim/pack/volt directory
 type Builder interface {
-	Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos) error
+	Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos, lockJSON *lockjson.LockJSON) error
 }
 
 const currentBuildInfoVersion = 2
 
 // Build creates/updates ~/.vim/pack/volt directory
-func Build(full bool) error {
-	// Read config.toml
-	cfg, err := config.Read()
-	if err != nil {
-		return errors.Wrap(err, "could not read config.toml")
-	}
-
+func Build(full bool, cfg *config.Config, lockJSON *lockjson.LockJSON) error {
 	// Get builder
 	blder, err := getBuilder(cfg.Build.Strategy)
 	if err != nil {
@@ -75,7 +71,7 @@ func Build(full bool) error {
 		}
 	}
 
-	return blder.Build(buildInfo, buildReposMap)
+	return blder.Build(buildInfo, buildReposMap, lockJSON)
 }
 
 func getBuilder(strategy string) (Builder, error) {

subcmd/builder/copy.go → gateway/builder/copy.go

@@ -10,12 +10,12 @@ import (
 
 	"github.com/hashicorp/go-multierror"
 	"github.com/vim-volt/volt/fileutil"
+	"github.com/vim-volt/volt/gateway/buildinfo"
 	"github.com/vim-volt/volt/gitutil"
 	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/pathutil"
 	"github.com/vim-volt/volt/plugconf"
-	"github.com/vim-volt/volt/subcmd/buildinfo"
 	"gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/plumbing/object"
@@ -25,19 +25,13 @@ type copyBuilder struct {
 	BaseBuilder
 }
 
-func (builder *copyBuilder) Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos) error {
+func (builder *copyBuilder) Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos, lockJSON *lockjson.LockJSON) error {
 	// Exit if vim executable was not found in PATH
 	vimExePath, err := pathutil.VimExecutable()
 	if err != nil {
 		return err
 	}
 
-	// Read lock.json
-	lockJSON, err := lockjson.Read()
-	if err != nil {
-		return errors.New("could not read lock.json: " + err.Error())
-	}
-
 	// Get current profile's repos list
 	reposList, err := lockJSON.GetCurrentReposList()
 	if err != nil {

subcmd/builder/symlink.go → gateway/builder/symlink.go

@@ -11,30 +11,26 @@ import (
 
 	"gopkg.in/src-d/go-git.v4"
 
+	"github.com/vim-volt/volt/gateway/buildinfo"
 	"github.com/vim-volt/volt/gitutil"
 	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/pathutil"
 	"github.com/vim-volt/volt/plugconf"
-	"github.com/vim-volt/volt/subcmd/buildinfo"
 )
 
 type symlinkBuilder struct {
 	BaseBuilder
 }
 
 // TODO: rollback when return err (!= nil)
-func (builder *symlinkBuilder) Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos) error {
+func (builder *symlinkBuilder) Build(buildInfo *buildinfo.BuildInfo, buildReposMap map[pathutil.ReposPath]*buildinfo.Repos, lockJSON *lockjson.LockJSON) error {
 	// Exit if vim executable was not found in PATH
 	if _, err := pathutil.VimExecutable(); err != nil {
 		return err
 	}
 
 	// Get current profile's repos list
-	lockJSON, err := lockjson.Read()
-	if err != nil {
-		return errors.Wrap(err, "could not read lock.json")
-	}
 	reposList, err := lockJSON.GetCurrentReposList()
 	if err != nil {
 		return err

gateway/cmd.go

@@ -0,0 +1,42 @@
+package gateway
+
+import (
+	"flag"
+
+	"github.com/vim-volt/volt/config"
+	"github.com/vim-volt/volt/lockjson"
+)
+
+var cmdMap = make(map[string]Cmd)
+
+// LookUpCmd looks up subcommand by name.
+func LookUpCmd(cmd string) Cmd {
+	return cmdMap[cmd]
+}
+
+// Cmd represents volt's subcommand interface.
+// All subcommands must implement this.
+type Cmd interface {
+	ProhibitRootExecution(args []string) bool
+	Run(cmdctx *CmdContext) *Error
+	FlagSet() *flag.FlagSet
+}
+
+// CmdContext is a data transfer object between Subcmd and Gateway layer.
+type CmdContext struct {
+	Cmd      string
+	Args     []string
+	LockJSON *lockjson.LockJSON
+	Config   *config.Config
+}
+
+// Error is a command error.
+// It also has a exit code.
+type Error struct {
+	Code int
+	Msg  string
+}
+
+func (e *Error) Error() string {
+	return e.Msg
+}

subcmd/get.go → gateway/get.go

@@ -1,4 +1,4 @@
-package subcmd
+package gateway
 
 import (
 	"flag"
@@ -17,12 +17,12 @@ import (
 
 	"github.com/vim-volt/volt/config"
 	"github.com/vim-volt/volt/fileutil"
+	"github.com/vim-volt/volt/gateway/builder"
 	"github.com/vim-volt/volt/gitutil"
 	"github.com/vim-volt/volt/lockjson"
 	"github.com/vim-volt/volt/logger"
 	"github.com/vim-volt/volt/pathutil"
 	"github.com/vim-volt/volt/plugconf"
-	"github.com/vim-volt/volt/subcmd/builder"
 	"github.com/vim-volt/volt/transaction"
 
 	multierror "github.com/hashicorp/go-multierror"
@@ -116,31 +116,25 @@ Options`)
 	return fs
 }
 
-func (cmd *getCmd) Run(args []string) *Error {
+func (cmd *getCmd) Run(cmdctx *CmdContext) *Error {
 	// Parse args
-	args, err := cmd.parseArgs(args)
+	args, err := cmd.parseArgs(cmdctx.Args)
 	if err == ErrShowedHelp {
 		return nil
 	}
 	if err != nil {
 		return &Error{Code: 10, Msg: "Failed to parse args: " + err.Error()}
 	}
 
-	// Read lock.json
-	lockJSON, err := lockjson.Read()
-	if err != nil {
-		return &Error{Code: 11, Msg: "Could not read lock.json: " + err.Error()}
-	}
-
-	reposPathList, err := cmd.getReposPathList(args, lockJSON)
+	reposPathList, err := cmd.getReposPathList(args, cmdctx.LockJSON)
 	if err != nil {
 		return &Error{Code: 12, Msg: "Could not get repos list: " + err.Error()}
 	}
 	if len(reposPathList) == 0 {
 		return &Error{Code: 13, Msg: "No repositories are specified"}
 	}
 
-	err = cmd.doGet(reposPathList, lockJSON)
+	err = cmd.doGet(reposPathList, cmdctx.Config, cmdctx.LockJSON)
 	if err != nil {
 		return &Error{Code: 20, Msg: err.Error()}
 	}
@@ -187,7 +181,7 @@ func (cmd *getCmd) getReposPathList(args []string, lockJSON *lockjson.LockJSON)
 	return reposPathList, nil
 }
 
-func (cmd *getCmd) doGet(reposPathList []pathutil.ReposPath, lockJSON *lockjson.LockJSON) error {
+func (cmd *getCmd) doGet(reposPathList []pathutil.ReposPath, cfg *config.Config, lockJSON *lockjson.LockJSON) error {
 	// Find matching profile
 	profile, err := lockJSON.Profiles.FindByName(lockJSON.CurrentProfileName)
 	if err != nil {
@@ -203,12 +197,6 @@ func (cmd *getCmd) doGet(reposPathList []pathutil.ReposPath, lockJSON *lockjson.
 	}
 	defer transaction.Remove()
 
-	// Read config.toml
-	cfg, err := config.Read()
-	if err != nil {
-		return errors.Wrap(err, "could not read config.toml")
-	}
-
 	done := make(chan getParallelResult, len(reposPathList))
 	getCount := 0
 	// Invoke installing / upgrading tasks
@@ -255,7 +243,7 @@ func (cmd *getCmd) doGet(reposPathList []pathutil.ReposPath, lockJSON *lockjson.
 	}
 
 	// Build ~/.vim/pack/volt dir
-	err = builder.Build(false)
+	err = builder.Build(false, cfg, lockJSON)
 	if err != nil {
 		return errors.Wrap(err, "could not build "+pathutil.VimVoltDir())
 	}

subcmd/get_test.go → gateway/get_test.go

@@ -1,4 +1,4 @@
-package subcmd
+package gateway
 
 import (
 	"bytes"

subcmd/help.go → gateway/help.go

@@ -1,4 +1,4 @@
-package subcmd
+package gateway
 
 import (
 	"flag"
@@ -99,7 +99,8 @@ Command
 	return fs
 }
 
-func (cmd *helpCmd) Run(args []string) *Error {
+func (cmd *helpCmd) Run(cmdctx *CmdContext) *Error {
+	args := cmdctx.Args
 	if len(args) == 0 {
 		cmd.FlagSet().Usage()
 		return nil
@@ -112,7 +113,7 @@ func (cmd *helpCmd) Run(args []string) *Error {
 	if !exists {
 		return &Error{Code: 1, Msg: fmt.Sprintf("Unknown command '%s'", args[0])}
 	}
-	args = append([]string{"-help"}, args[1:]...)
-	fs.Run(args)
+	cmdctx.Args = append([]string{"-help"}, args[1:]...)
+	fs.Run(cmdctx)
 	return nil
 }

subcmd/help_test.go → gateway/help_test.go

@@ -1,4 +1,4 @@
-package subcmd
+package gateway
 
 import (
 	"strings"