Check if image exists before skipping compilation

pkg/compiler/backend/simpledocker.go

@@ -90,6 +90,19 @@ func (*SimpleDocker) DownloadImage(opts compiler.CompilerBackendOptions) error {
 	return nil
 }
 
+func (*SimpleDocker) ImageExists(imagename string) bool {
+	buildarg := []string{"inspect", "--type=image", imagename}
+	Debug(":whale: Checking existance of docker image: " + imagename)
+	cmd := exec.Command("docker", buildarg...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		Warning("Image not present")
+		Debug(out)
+		return false
+	}
+	return true
+}
+
 func (*SimpleDocker) RemoveImage(opts compiler.CompilerBackendOptions) error {
 	name := opts.ImageName
 	buildarg := []string{"rmi", name}

pkg/compiler/backend/simpleimg.go

@@ -97,6 +97,13 @@ func (*SimpleImg) CopyImage(src, dst string) error {
 	return nil
 }
 
+func (*SimpleImg) ImageExists(imagename string) bool {
+	// NOOP: not implemented
+	// TODO: Since img doesn't have an inspect command,
+	// we need to parse the ls output manually
+	return false
+}
+
 func (s *SimpleImg) ImageDefinitionToTar(opts compiler.CompilerBackendOptions) error {
 	if err := s.BuildImage(opts); err != nil {
 		return errors.Wrap(err, "Failed building image")

pkg/compiler/compiler.go

@@ -229,8 +229,16 @@ func (cs *LuetCompiler) stripIncludesFromRootfs(includes []string, rootfs string
 }
 
 func (cs *LuetCompiler) compileWithImage(image, buildertaggedImage, packageImage string, concurrency int, keepPermissions, keepImg bool, p CompilationSpec) (Artifact, error) {
+	fp := p.GetPackage().HashFingerprint()
+	if buildertaggedImage == "" {
+		buildertaggedImage = cs.ImageRepository + "-" + fp + "-builder"
+	}
+	if packageImage == "" {
+		packageImage = cs.ImageRepository + "-" + fp
+	}
 	if !cs.Clean {
-		if art, err := LoadArtifactFromYaml(p); err == nil {
+		exists := cs.Backend.ImageExists(buildertaggedImage) && cs.Backend.ImageExists(packageImage)
+		if art, err := LoadArtifactFromYaml(p); err == nil && exists {
 			Debug("Artifact reloaded. Skipping build")
 			return art, err
 		}
@@ -265,14 +273,6 @@ func (cs *LuetCompiler) compileWithImage(image, buildertaggedImage, packageImage
 		}
 	}
 
-	fp := p.GetPackage().HashFingerprint()
-	if buildertaggedImage == "" {
-		buildertaggedImage = cs.ImageRepository + "-" + fp + "-builder"
-	}
-	if packageImage == "" {
-		packageImage = cs.ImageRepository + "-" + fp
-	}
-
 	Info(pkgTag, "Generating :whale: definition for builder image from", image)
 
 	// First we create the builder image

pkg/compiler/interface.go

@@ -82,6 +82,8 @@ type CompilerBackend interface {
 	DownloadImage(opts CompilerBackendOptions) error
 
 	Push(opts CompilerBackendOptions) error
+
+	ImageExists(string) bool
 }
 
 type Artifact interface {