Split the sbom.Format interface by encode and decode use cases (#2186)

* split up sbom.Format into encode and decode ops

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* update cmd pkg to inject format configs

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* bump cyclonedx schema to 1.5

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* redact image metadata from github encoder tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add more testing around format decoder identify

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add test case for format version options

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix cli tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix CLI test

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* [wip] - review comments

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* keep encoder creation out of post load function

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* keep decider and identify functions

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add a few more doc comments

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* remove format encoder default function helpers

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* address PR feedback

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* move back to streaming based decode functions

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* with common convention for encoder constructors

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix tests and allow for encoders to be created from cli options

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix cli tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* fix linting

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* buffer reads from stdin to support seeking

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

cmd/syft/cli/commands/packages.go

@@ -14,7 +14,6 @@ import (
 	"github.com/anchore/syft/internal/file"
 	"github.com/anchore/syft/internal/log"
 	"github.com/anchore/syft/syft/artifact"
-	"github.com/anchore/syft/syft/formats/template"
 	"github.com/anchore/syft/syft/sbom"
 	"github.com/anchore/syft/syft/source"
 )
@@ -55,14 +54,14 @@ const (
 
 type packagesOptions struct {
 	options.Config      `yaml:",inline" mapstructure:",squash"`
-	options.MultiOutput `yaml:",inline" mapstructure:",squash"`
+	options.Output      `yaml:",inline" mapstructure:",squash"`
 	options.UpdateCheck `yaml:",inline" mapstructure:",squash"`
 	options.Catalog     `yaml:",inline" mapstructure:",squash"`
 }
 
 func defaultPackagesOptions() *packagesOptions {
 	return &packagesOptions{
-		MultiOutput: options.DefaultOutput(),
+		Output:      options.DefaultOutput(),
 		UpdateCheck: options.DefaultUpdateCheck(),
 		Catalog:     options.DefaultCatalog(),
 	}
@@ -108,11 +107,6 @@ func validateArgs(cmd *cobra.Command, args []string, error string) error {
 
 // nolint:funlen
 func runPackages(id clio.Identification, opts *packagesOptions, userInput string) error {
-	err := validatePackageOutputOptions(&opts.MultiOutput)
-	if err != nil {
-		return err
-	}
-
 	writer, err := opts.SBOMWriter()
 	if err != nil {
 		return err
@@ -235,19 +229,3 @@ func mergeRelationships(cs ...<-chan artifact.Relationship) (relationships []art
 
 	return relationships
 }
-
-func validatePackageOutputOptions(cfg *options.MultiOutput) error {
-	var usesTemplateOutput bool
-	for _, o := range cfg.Outputs {
-		if o == template.ID.String() {
-			usesTemplateOutput = true
-			break
-		}
-	}
-
-	if usesTemplateOutput && cfg.OutputTemplatePath == "" {
-		return fmt.Errorf(`must specify path to template file when using "template" output format`)
-	}
-
-	return nil
-}