shim.go

package api

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"regexp"
	"strings"

	"github.com/project-flogo/cli/common"
	"github.com/project-flogo/cli/util"
)

const (
	fileShimSupportGo string = "shim_support.go"
	fileShimGo        string = "shim.go"
	fileBuildGo       string = "build.go"
	fileMakefile      string = "Makefile"
	dirShim           string = "shim"
)

var fileSampleShimSupport = filepath.Join("examples", "engine", "shim", fileShimSupportGo)

var flogoImportPattern = regexp.MustCompile(`^(([^ ]*)[ ]+)?([^@:]*)@?([^:]*)?:?(.*)?$`)


type ShimBuilder struct {
	appBuilder common.Builder
	shim string
}

func (sb *ShimBuilder) Build(project common.AppProject) error {

	err := backupMain(project)
	if err != nil {
		return err
	}

	defer shimCleanup(project)

	err = createShimSupportGoFile(project)
	if err != nil {
		return err
	}

	if Verbose() {
		fmt.Println("Preparing shim...")
	}
	built, err := prepareShim(project, sb.shim)
	if err != nil {
		return err
	}

	if !built {
		fmt.Println("Using go build to build shim...")

		err := simpleGoBuild(project)
		if err != nil {
			return err
		}
	}

	return nil
}

func prepareShim(project common.AppProject, shim string) (bool, error) {

	buf, err := ioutil.ReadFile(filepath.Join(project.Dir(), fileFlogoJson))
	if err != nil {
		return false, err
	}

	flogoJSON := string(buf)

	descriptor, err := util.ParseAppDescriptor(flogoJSON)
	if err != nil {
		return false, err
	}

	err = registerImports(project, descriptor)
	if err != nil {
		return false, err
	}

	for _, trgCfg := range descriptor.Triggers {
		if trgCfg.Id == shim {

			ref := trgCfg.Ref

			if trgCfg.Ref != "" {
				found := false
				ref, found = GetAliasRef("flogo:trigger", trgCfg.Ref)
				if !found {
					return false, fmt.Errorf("unable to determine ref for trigger: %s", trgCfg.Id)
				}
			}

			refImport, err := util.NewFlogoImportFromPath(ref)
			if err != nil {
				return false, err
			}

			impPath, err := project.GetPath(refImport)
			if err != nil {
				return false, err
			}

			var shimFilePath string

			shimFilePath = filepath.Join(impPath, dirShim, fileShimGo)

			if _, err := os.Stat(shimFilePath); err == nil {

				err = util.CopyFile(shimFilePath, filepath.Join(project.SrcDir(), fileShimGo))
				if err != nil {
					return false, err
				}

				// Check if this shim based trigger has a gobuild file. If the trigger has a gobuild
				// execute that file, otherwise check if there is a Makefile to execute
				goBuildFilePath := filepath.Join(impPath, dirShim, fileBuildGo)

				makefilePath := filepath.Join(shimFilePath, dirShim, fileMakefile)

				if _, err := os.Stat(goBuildFilePath); err == nil {
					fmt.Println("Using build.go to build shim......")

					err = util.CopyFile(goBuildFilePath, filepath.Join(project.SrcDir(), fileBuildGo))
					if err != nil {
						return false, err
					}

					// Execute go run gobuild.go
					err = util.ExecCmd(exec.Command("go", "run", fileBuildGo), project.SrcDir())
					if err != nil {
						return false, err
					}

					return true, nil
				} else if _, err := os.Stat(makefilePath); err == nil {
					//look for Makefile and execute it
					fmt.Println("Using make file to build shim...")

					err = util.CopyFile(makefilePath, filepath.Join(project.SrcDir(), fileMakefile))
					if err != nil {
						return false, err
					}

					if Verbose() {
						fmt.Println("Make File:", makefilePath)
					}

					// Execute make
					cmd := exec.Command("make", "-C", project.SrcDir())
					cmd.Stdout = os.Stdout
					cmd.Stderr = os.Stderr
					cmd.Env = util.ReplaceEnvValue(os.Environ(), "GOPATH", project.Dir())

					err = cmd.Run()
					if err != nil {
						return false, err
					}

					return true, nil
				} else {
					return false, nil
				}
			}

			break
		}
	}

	return false, fmt.Errorf("unable to to find shim trigger: %s", shim)
}

func shimCleanup(project common.AppProject) {

	if Verbose() {
		fmt.Println("Cleaning up shim support files...")
	}

	err := util.DeleteFile(filepath.Join(project.SrcDir(), fileShimSupportGo))
	if err != nil {
		fmt.Printf("Unable to delete: %s", fileShimSupportGo)
	}
	err = util.DeleteFile(filepath.Join(project.SrcDir(), fileShimGo))
	if err != nil {
		fmt.Printf("Unable to delete: %s", fileShimGo)
	}
	err = util.DeleteFile(filepath.Join(project.SrcDir(), fileBuildGo))
	if err != nil {
		fmt.Printf("Unable to delete: %s", fileBuildGo)
	}
}

func createShimSupportGoFile(project common.AppProject) error {

	shimSrcPath := filepath.Join(project.SrcDir(), fileShimSupportGo)

	if Verbose() {
		fmt.Println("Creating shim support files...")
	}

	flogoCoreImport, err := util.NewFlogoImportFromPath(flogoCoreRepo)
	if err != nil {
		return err
	}

	corePath, err := project.GetPath(flogoCoreImport)
	if err != nil {
		return err
	}

	bytes, err := ioutil.ReadFile(filepath.Join(corePath, fileSampleShimSupport))
	if err != nil {
		return err
	}

	err = ioutil.WriteFile(shimSrcPath, bytes, 0644)
	if err != nil {
		return err
	}

	return nil
}

func registerImports(project common.AppProject, appDesc *util.FlogoAppDescriptor) error {

	for _, anImport := range appDesc.Imports {
		err := registerImport(project, anImport)
		if err != nil {
			return err
		}
	}

	return nil
}

func registerImport(project common.AppProject, anImport string) error {

	matches := flogoImportPattern.FindStringSubmatch(anImport)

	parts := strings.Split(matches[3], " ")

	var alias string
	var ref string
	numParts := len(parts)
	if numParts == 1 {
		ref = parts[0]
		alias = path.Base(ref)

	} else if numParts == 2 {
		alias = parts[0]
		ref = parts[1]
	} else {
		return fmt.Errorf("invalid import %s", anImport)
	}

	if alias == "" || ref == "" {
		return fmt.Errorf("invalid import %s", anImport)
	}

	ct, err := util.GetContribType(project.DepManager(), ref)
	if err != nil {
		return err
	}

	if ct != "" {
		RegisterAlias(ct, alias, ref)
	}

	return nil
}

var aliases = make(map[string]map[string]string)

func RegisterAlias(contribType string, alias, ref string) {

	aliasToRefMap, exists := aliases[contribType]
	if !exists {
		aliasToRefMap = make(map[string]string)
		aliases[contribType] = aliasToRefMap
	}

	aliasToRefMap[alias] = ref
}

func GetAliasRef(contribType string, alias string) (string, bool) {
	if alias == "" {
		return "", false
	}

	if alias[0] == '#' {
		alias = alias[1:]
	}
	aliasToRefMap, exists := aliases[contribType]
	if !exists {
		return "", false
	}

	ref, exists := aliasToRefMap[alias]
	if !exists {
		return "", false
	}

	return ref, true
}