feat: variant export go SRC_DIR DST_DIR for building single executable binary of your command

Author: mumoshu

.github/workflows/ci.yml

@@ -23,4 +23,4 @@ jobs:
         which kubectl
         sudo apt-get update -y
         sudo apt-get install ruby -y
-        make test
+        make test smoke

Makefile

@@ -25,3 +25,11 @@ lint: bin/golangci-lint
 	  --disable gochecknoglobals \
 	  --disable gochecknoinits \
 	  --disable gomnd,funlen,prealloc,gocritic,lll,gocognit
+
+.PHONY: smoke
+smoke: build
+	make build
+	./variant export go examples/simple build/simple
+	go build -o build/simple/simple ./build/simple
+	build/simple/simple -h | tee smoke.log
+	grep "Namespace to interact with" smoke.log

export_go.go

@@ -0,0 +1,28 @@
+package variant
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func newExportGo(r *Runner) *cobra.Command {
+	return &cobra.Command{
+		Use:   "go SRC_DIR DST_DIR",
+		Short: "Copy and generate DST_DIR/main.go for building the single executable binary with `go build DST_DIR`",
+		Example: `$ variant export go examples/simple build
+
+$ go build -o build/simple ./build
+
+$ build/simple -h
+
+$ build/simple app deploy -n default
+`,
+		Args: cobra.ExactArgs(2),
+		RunE: func(c *cobra.Command, args []string) error {
+			err := r.ap.ExportGo(args[0], args[1])
+			if err != nil {
+				c.SilenceUsage = true
+			}
+			return err
+		},
+	}
+}

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/variantdev/vals v0.0.0-20191123083656-fc61ba6e8746
 	github.com/zclconf/go-cty v1.2.0
 	github.com/zclconf/go-cty-yaml v1.0.1
+	golang.org/x/tools v0.0.0-20191026034945-b2104f82a97d
 	gopkg.in/yaml.v2 v2.2.2
 	gopkg.in/yaml.v3 v3.0.0-20190924164351-c8b7dadae555
 )

pkg/app/app_shim.go

@@ -6,12 +6,85 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/hashicorp/hcl/v2"
 
 	"github.com/mumoshu/variant2/pkg/conf"
 )
 
+func (app *App) ExportGo(srcDir, dstDir string) error {
+	if err := os.MkdirAll(dstDir, 0755); err != nil {
+		return err
+	}
+
+	files, _, err := newConfigFromDir(srcDir)
+	if err != nil {
+		return err
+	}
+
+	merged, err := merge(files)
+	if err != nil {
+		return err
+	}
+
+	backquote := "<<<backquote>>>"
+
+	code := []byte(fmt.Sprintf(`package main
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+
+	variant "github.com/mumoshu/variant2"
+)
+
+func main() {
+	source := strings.Replace(%s, "`+backquote+`", "`+"`"+`", -1)
+
+	var args []string
+
+	if len(os.Args) > 1 {
+		args = os.Args[1:]
+	}
+
+	bin := filepath.Base(os.Args[0])
+
+	err := variant.MustEval(bin, source).Run(args)
+
+	var verr variant.Error
+
+	var code int
+
+	if err != nil {
+		if ok := errors.As(err, &verr); ok {
+			code = verr.ExitCode
+		} else {
+			code = 1
+		}
+	} else {
+		code = 0
+	}
+
+	os.Exit(code)
+}
+`, "`"+strings.Replace(string(merged)+"\n", "`", backquote, -1)+"`"))
+
+	if err := os.MkdirAll(dstDir, 0755); err != nil {
+		return err
+	}
+
+	exportDir := filepath.Join(dstDir, "main.go")
+
+	if err := ioutil.WriteFile(exportDir, code, 0644); err != nil {
+		return err
+	}
+
+	return nil
+}
+
 func (app *App) ExportShim(srcDir, dstDir string) error {
 	if err := os.MkdirAll(dstDir, 0755); err != nil {
 		return err
@@ -32,20 +105,34 @@ func (app *App) ExportShim(srcDir, dstDir string) error {
 	return exportWithShim(binName, files, dstDir)
 }
 
+func merge(files map[string]*hcl.File) ([]byte, error) {
+	buf := bytes.Buffer{}
+
+	for _, file := range files {
+		if _, err := buf.Write(file.Bytes); err != nil {
+			return nil, err
+		}
+
+		if _, err := buf.Write([]byte("\n")); err != nil {
+			return nil, err
+		}
+	}
+
+	return buf.Bytes(), nil
+}
+
 func exportWithShim(variantBin string, files map[string]*hcl.File, dstDir string) error {
 	binName := filepath.Base(dstDir)
 
 	binPath := filepath.Join(dstDir, binName)
 	cfgPath := filepath.Join(dstDir, binName+conf.VariantFileExt)
 
-	buf := bytes.Buffer{}
-
-	for _, file := range files {
-		buf.Write(file.Bytes)
-		buf.Write([]byte("\n"))
+	bs, err := merge(files)
+	if err != nil {
+		return err
 	}
 
-	if err := ioutil.WriteFile(cfgPath, buf.Bytes(), 0644); err != nil {
+	if err := ioutil.WriteFile(cfgPath, bs, 0644); err != nil {
 		return err
 	}
 

variant.go

@@ -642,6 +642,14 @@ func (r Runner) Job(job string, opts State) (JobRun, error) {
 		return nil, fmt.Errorf("job %q not added", job)
 	}
 
+	if opts.Options == nil {
+		opts.Options = map[string]interface{}{}
+	}
+
+	if opts.Parameters == nil {
+		opts.Parameters = map[string]interface{}{}
+	}
+
 	jr := f(opts)
 
 	return jr, nil
@@ -740,19 +748,23 @@ func (r *Runner) createVariantRootCommand() *cobra.Command {
 		Use:   "export SUBCOMMAND SRC_DIR OUTPUT_PATH",
 		Short: "Export the Variant command defined in SRC_DIR to OUTPUT_PATH",
 	}
-	shimCmd := &cobra.Command{
-		Use:   "shim SRC_DIR DST_DIR",
-		Short: "Copy and generate shim for the Variant command defined in the SRC",
-		Args:  cobra.ExactArgs(2),
-		RunE: func(c *cobra.Command, args []string) error {
-			err := r.ap.ExportShim(args[0], args[1])
-			if err != nil {
-				c.SilenceUsage = true
-			}
-			return err
-		},
+	{
+		shimCmd := &cobra.Command{
+			Use:   "shim SRC_DIR DST_DIR",
+			Short: "Copy and generate shim for the Variant command defined in the SRC",
+			Args:  cobra.ExactArgs(2),
+			RunE: func(c *cobra.Command, args []string) error {
+				err := r.ap.ExportShim(args[0], args[1])
+				if err != nil {
+					c.SilenceUsage = true
+				}
+				return err
+			},
+		}
+
+		exportCmd.AddCommand(shimCmd)
+		exportCmd.AddCommand(newExportGo(r))
 	}
-	exportCmd.AddCommand(shimCmd)
 
 	generateCmd := &cobra.Command{
 		Use:   "generate RESOURCE DIR",
@@ -771,6 +783,7 @@ func (r *Runner) createVariantRootCommand() *cobra.Command {
 				return err
 			},
 		}
+
 		generateCmd.AddCommand(generateShimCmd)
 	}