feat: Introduce new readme element to Kraftfile

Simultaneously propagate this information to the OCI manifest.

Signed-off-by: Alexander Jung <[email protected]>

Author: nderjung

internal/cli/kraft/pkg/packager_kraftfile_runtime.go

@@ -332,6 +332,14 @@ func (p *packagerKraftfileRuntime) Pack(ctx context.Context, opts *PkgOptions, a
 		return nil, err
 	}
 
+	if len(opts.Readme) == 0 {
+		opts.Readme = opts.Project.Readme()
+	} else {
+		if readmeBytes, err := os.ReadFile(opts.Readme); err == nil {
+			opts.Readme = string(readmeBytes)
+		}
+	}
+
 	var result []pack.Package
 	norender := log.LoggerTypeFromString(config.G[config.KraftKit](ctx).Log.Type) != log.FANCY
 
@@ -352,6 +360,7 @@ func (p *packagerKraftfileRuntime) Pack(ctx context.Context, opts *PkgOptions, a
 					packmanager.PackKConfig(!opts.NoKConfig),
 					packmanager.PackName(opts.Name),
 					packmanager.PackOutput(opts.Output),
+					packmanager.PackReadme(opts.Readme),
 				)
 
 				if ukversion, ok := targ.KConfig().Get(unikraft.UK_FULLVERSION); ok {

internal/cli/kraft/pkg/packager_kraftfile_unikraft.go

@@ -8,6 +8,7 @@ package pkg
 import (
 	"context"
 	"fmt"
+	"os"
 	"strings"
 
 	"github.com/mattn/go-shellwords"
@@ -117,6 +118,14 @@ func (p *packagerKraftfileUnikraft) Pack(ctx context.Context, opts *PkgOptions,
 			return nil, err
 		}
 
+		if len(opts.Readme) == 0 {
+			opts.Readme = opts.Project.Readme()
+		} else {
+			if readmeBytes, err := os.ReadFile(opts.Readme); err == nil {
+				opts.Readme = string(readmeBytes)
+			}
+		}
+
 		// When i > 0, we have already applied the merge strategy.  Now, for all
 		// targets, we actually do wish to merge these because they are part of
 		// the same execution lifecycle.
@@ -136,6 +145,7 @@ func (p *packagerKraftfileUnikraft) Pack(ctx context.Context, opts *PkgOptions,
 					packmanager.PackKConfig(!opts.NoKConfig),
 					packmanager.PackName(opts.Name),
 					packmanager.PackOutput(opts.Output),
+					packmanager.PackReadme(opts.Readme),
 				)
 
 				if ukversion, ok := targ.KConfig().Get(unikraft.UK_FULLVERSION); ok {

internal/cli/kraft/pkg/pkg.go

@@ -48,6 +48,7 @@ type PkgOptions struct {
 	Platform     string                    `local:"true" long:"plat" short:"p" usage:"Filter the creation of the package by platform of known targets"`
 	Project      app.Application           `noattribute:"true"`
 	Push         bool                      `local:"true" long:"push" short:"P" usage:"Push the package on if successfully packaged"`
+	Readme       string                    `local:"true" long:"readme" usage:"Verbatim text or path to a README file to include in the package"`
 	Rootfs       string                    `local:"true" long:"rootfs" usage:"Specify a path to use as root file system (can be volume or initramfs)"`
 	Strategy     packmanager.MergeStrategy `noattribute:"true"`
 	Target       string                    `local:"true" long:"target" short:"t" usage:"Package a particular known target"`

oci/annotations.go

@@ -11,6 +11,7 @@ const (
 	AnnotationURL                  = "org.unikraft.image.url"
 	AnnotationCreated              = "org.unikraft.image.created"
 	AnnotationDescription          = "org.unikraft.image.description"
+	AnnotationReadme               = "org.unikraft.image.readme"
 	AnnotationKernelPath           = "org.unikraft.kernel.image"
 	AnnotationKernelVersion        = "org.unikraft.kernel.version"
 	AnnotationKernelInitrdPath     = "org.unikraft.kernel.initrd"

oci/pack.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/tls"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -72,6 +73,7 @@ type ociPackage struct {
 	kernelDbg string
 	initrd    initrd.Initrd
 	command   []string
+	readme    string
 
 	original *ociPackage
 }
@@ -100,6 +102,7 @@ func NewPackageFromTarget(ctx context.Context, targ target.Target, opts ...packm
 		kernel:    targ.Kernel(),
 		kernelDbg: targ.KernelDbg(),
 		command:   popts.Args(),
+		readme:    popts.Readme(),
 	}
 
 	// It is possible that `NewPackageFromTarget` is called with an existing
@@ -380,6 +383,11 @@ func NewPackageFromTarget(ctx context.Context, targ target.Target, opts ...packm
 		return nil, fmt.Errorf("could not add manifest to index: %w", err)
 	}
 
+	if len(ocipack.readme) > 0 {
+		encoded := base64.StdEncoding.EncodeToString([]byte(ocipack.readme))
+		ocipack.manifest.SetAnnotation(ctx, AnnotationReadme, encoded)
+	}
+
 	if _, err = ocipack.index.Save(ctx, ocipack.ref.String(), nil); err != nil {
 		return nil, fmt.Errorf("could not save index: %w", err)
 	}

packmanager/pack_options.go

@@ -17,6 +17,7 @@ type PackOptions struct {
 	kernelSourceFiles                bool
 	kernelVersion                    string
 	name                             string
+	readme                           string
 	output                           string
 	mergeStrategy                    MergeStrategy
 }
@@ -81,6 +82,11 @@ func (popts *PackOptions) Name() string {
 	return popts.name
 }
 
+// Readme returns the readme of the package.
+func (popts *PackOptions) Readme() string {
+	return popts.readme
+}
+
 // Output returns the location of the package.
 func (popts *PackOptions) Output() string {
 	return popts.output
@@ -167,6 +173,13 @@ func PackName(name string) PackOption {
 	}
 }
 
+// PackReadme sets the readme of the package.
+func PackReadme(readme string) PackOption {
+	return func(popts *PackOptions) {
+		popts.readme = readme
+	}
+}
+
 // PackOutput sets the location of the output artifact package.
 func PackOutput(output string) PackOption {
 	return func(popts *PackOptions) {

schema/v0.6.json

@@ -11,6 +11,8 @@
 
     "/^name$/": { "type": "string" },
 
+    "/^readme$/": { "type": "string" },
+
     "/^outdir$/": { "type": "string" },
 
     "/^template$/": {

unikraft/app/application.go

@@ -39,6 +39,9 @@ import (
 type Application interface {
 	component.Component
 
+	// Readme contains the application's README text.
+	Readme() string
+
 	// WorkingDir returns the path to the application's working directory
 	WorkingDir() string
 
@@ -150,6 +153,7 @@ type Application interface {
 
 type application struct {
 	name          string
+	readme        string
 	version       string
 	source        string
 	path          string
@@ -173,6 +177,10 @@ func (app application) Name() string {
 	return app.name
 }
 
+func (app application) Readme() string {
+	return app.readme
+}
+
 func (app application) String() string {
 	return app.name
 }

unikraft/app/application_options.go

@@ -70,6 +70,14 @@ func WithName(name string) ApplicationOption {
 	}
 }
 
+// WithReadme sets the application's readme
+func WithReadme(readme string) ApplicationOption {
+	return func(ac *application) error {
+		ac.readme = readme
+		return nil
+	}
+}
+
 // WithVersion sets the application version
 func WithVersion(version string) ApplicationOption {
 	return func(ac *application) error {

unikraft/app/loader.go

@@ -20,6 +20,7 @@ package app
 import (
 	"context"
 	"fmt"
+	"os"
 	"strings"
 
 	interp "github.com/compose-spec/compose-go/interpolation"
@@ -43,6 +44,17 @@ func NewApplicationFromInterface(ctx context.Context, iface map[string]interface
 		}
 	}
 
+	if r, ok := iface["readme"]; ok {
+		app.readme, ok = r.(string)
+		if !ok {
+			return nil, errors.New("readme must be a string")
+		}
+
+		if readmeBytes, err := os.ReadFile(app.readme); err == nil {
+			app.readme = string(readmeBytes)
+		}
+	}
+
 	app.name = name
 	app.path = popts.workdir