Add specific field to resolve final images

This commit starts deprecation of `join` keyword in favor of
`requires_final_images` as boolean in the compilation spec.

The change is driven by two reasons: syntax and guarantee unique hashes.

- the hashtree when computing a hash it analizes the requires field of
  each spec, ignoring the join field
- the join field doesn't add much value. Having it separate suggests
  that a spec can contain both `requires` and `join`, but that's not
  actually true. We just act differently on the same list.

Signed-off-by: Ettore Di Giacinto <mudler@sabayon.org>

pkg/compiler/compiler.go

@@ -774,22 +774,31 @@ func (cs *LuetCompiler) getSpecHash(pkgs pkg.DefaultPackages, salt string) (stri
 	return fmt.Sprintf("%x", h.Sum(nil)), nil
 }
 
-func (cs *LuetCompiler) resolveJoinImages(concurrency int, keepPermissions bool, p *compilerspec.LuetCompilationSpec) error {
+func (cs *LuetCompiler) resolveFinalImages(concurrency int, keepPermissions bool, p *compilerspec.LuetCompilationSpec) error {
 
-	joinTag := ">:loop: join<"
-	if len(p.Join) != 0 {
-		Info(joinTag, "Generating a joint parent image from final packages")
+	joinTag := ">:loop: final images<"
+	var fromPackages pkg.DefaultPackages
+
+	if len(p.Join) > 0 {
+		fromPackages = p.Join
+		Warning(joinTag, `
+	Attention! the 'join' keyword is going to be deprecated in Luet >=0.18.x. 
+	Use 'requires_final_images: true' instead in the build.yaml file`)
+	} else if p.RequiresFinalImages {
+		Info(joinTag, "Generating a parent image from final packages")
+		fromPackages = p.Package.GetRequires()
 	} else {
+		// No source image to resolve
 		return nil
 	}
 
 	// First compute a hash and check if image is available. if it is, then directly consume that
-	overallFp, err := cs.getSpecHash(p.Join, "join")
+	overallFp, err := cs.getSpecHash(fromPackages, "join")
 	if err != nil {
 		return errors.Wrap(err, "could not generate image hash")
 	}
 
-	Info(joinTag, "Searching existing image with hash ", overallFp)
+	Info(joinTag, "Searching existing image with hash", overallFp)
 
 	image := cs.findImageHash(overallFp, p)
 	if image != "" {
@@ -811,12 +820,12 @@ func (cs *LuetCompiler) resolveJoinImages(concurrency int, keepPermissions bool,
 	}
 	defer os.RemoveAll(joinDir) // clean up
 
-	for _, p := range p.Join { //highly dependent on the order
+	for _, p := range fromPackages {
 		Info(joinTag, ":arrow_right_hook:", p.HumanReadableString(), ":leaves:")
 	}
 
 	current := 0
-	for _, c := range p.Join {
+	for _, c := range fromPackages {
 		current++
 		if c != nil && c.Name != "" && c.Version != "" {
 			joinTag2 := fmt.Sprintf("%s %d/%d ⤑ :hammer: build %s", joinTag, current, len(p.Join), c.HumanReadableString())
@@ -924,7 +933,7 @@ func (cs *LuetCompiler) compile(concurrency int, keepPermissions bool, generateF
 
 	//Before multistage : join - same as multistage, but keep artifacts, join them, create a new one and generate a final image.
 	// When the image is there, use it as a source here, in place of GetImage().
-	if err := cs.resolveJoinImages(concurrency, keepPermissions, p); err != nil {
+	if err := cs.resolveFinalImages(concurrency, keepPermissions, p); err != nil {
 		return nil, errors.Wrap(err, "while resolving join images")
 	}
 
@@ -1028,7 +1037,7 @@ func (cs *LuetCompiler) compile(concurrency int, keepPermissions bool, generateF
 				Assert:      assertion,
 			})
 
-			if err := cs.resolveJoinImages(concurrency, keepPermissions, compileSpec); err != nil {
+			if err := cs.resolveFinalImages(concurrency, keepPermissions, compileSpec); err != nil {
 				return nil, errors.Wrap(err, "while resolving join images")
 			}
 

pkg/compiler/types/spec/spec.go

@@ -115,39 +115,42 @@ type LuetCompilationSpec struct {
 
 	Copy []CopyField `json:"copy"`
 
-	Join pkg.DefaultPackages `json:"join"`
+	Join                pkg.DefaultPackages `json:"join"`
+	RequiresFinalImages bool                `json:"requires_final_images" yaml:"requires_final_images"`
 }
 
 // Signature is a portion of the spec that yields a signature for the hash
 type Signature struct {
-	Image      string
-	Steps      []string
-	PackageDir string
-	Prelude    []string
-	Seed       string
-	Env        []string
-	Retrieve   []string
-	Unpack     bool
-	Includes   []string
-	Excludes   []string
-	Copy       []CopyField
-	Join       pkg.DefaultPackages
+	Image               string
+	Steps               []string
+	PackageDir          string
+	Prelude             []string
+	Seed                string
+	Env                 []string
+	Retrieve            []string
+	Unpack              bool
+	Includes            []string
+	Excludes            []string
+	Copy                []CopyField
+	Join                pkg.DefaultPackages
+	RequiresFinalImages bool
 }
 
 func (cs *LuetCompilationSpec) signature() Signature {
 	return Signature{
-		Image:      cs.Image,
-		Steps:      cs.Steps,
-		PackageDir: cs.PackageDir,
-		Prelude:    cs.Prelude,
-		Seed:       cs.Seed,
-		Env:        cs.Env,
-		Retrieve:   cs.Retrieve,
-		Unpack:     cs.Unpack,
-		Includes:   cs.Includes,
-		Excludes:   cs.Excludes,
-		Copy:       cs.Copy,
-		Join:       cs.Join,
+		Image:               cs.Image,
+		Steps:               cs.Steps,
+		PackageDir:          cs.PackageDir,
+		Prelude:             cs.Prelude,
+		Seed:                cs.Seed,
+		Env:                 cs.Env,
+		Retrieve:            cs.Retrieve,
+		Unpack:              cs.Unpack,
+		Includes:            cs.Includes,
+		Excludes:            cs.Excludes,
+		Copy:                cs.Copy,
+		Join:                cs.Join,
+		RequiresFinalImages: cs.RequiresFinalImages,
 	}
 }