Add buildTag support

Adds a new `buildTag` marker, to allow the definition of multiple
go build tags, to be passed via the build config.

Signed-off-by: Todd Short <todd.short@me.com>

Author: tmshort

pkg/genall/genall.go

@@ -215,10 +215,11 @@ func (g GenerationContext) ReadFile(path string) ([]byte, error) {
 	return io.ReadAll(file)
 }
 
-// ForRoots produces a Runtime to run the given generators against the
-// given packages.  It outputs to /dev/null by default.
-func (g Generators) ForRoots(rootPaths ...string) (*Runtime, error) {
-	roots, err := loader.LoadRoots(rootPaths...)
+// ForRootsWithConfig produces a Runtime to run the given generators against the
+// given packages, but with the specified configuration. It outputs to /dev/null
+// by default.
+func (g Generators) ForRootsWithConfig(cfg *packages.Config, rootPaths ...string) (*Runtime, error) {
+	roots, err := loader.LoadRootsWithConfig(cfg, rootPaths...)
 	if err != nil {
 		return nil, err
 	}
@@ -242,6 +243,12 @@ func (g Generators) ForRoots(rootPaths ...string) (*Runtime, error) {
 	return rt, nil
 }
 
+// ForRoots produces a Runtime to run the given generators against the
+// given packages.  It outputs to /dev/null by default.
+func (g Generators) ForRoots(rootPaths ...string) (*Runtime, error) {
+	return g.ForRootsWithConfig(&packages.Config{}, rootPaths...)
+}
+
 // Run runs the Generators in this Runtime against its packages, printing
 // errors (except type errors, which common result from using TypeChecker with
 // filters), returning true if errors were found.

pkg/genall/options.go

@@ -20,11 +20,13 @@ import (
 	"fmt"
 	"strings"
 
+	"golang.org/x/tools/go/packages"
 	"sigs.k8s.io/controller-tools/pkg/markers"
 )
 
 var (
 	InputPathsMarker = markers.Must(markers.MakeDefinition("paths", markers.DescribesPackage, InputPaths(nil)))
+	BuildTagsMarker  = markers.MustOptional(markers.MakeDefinition("buildTag", markers.DescribesPackage, InputBuildTags(nil)))
 )
 
 // +controllertools:marker:generateHelp:category=""
@@ -34,6 +36,13 @@ var (
 // Multiple paths can be specified using "{path1, path2, path3}".
 type InputPaths []string
 
+// +controllertools:marker:generateHelp:category=""
+
+// InputBuildTags represents go build tags used when including or excluding code during builds.
+//
+// Multiple tags can be specified by using this marker multiple times: buildTag=tag1 buildTag=tag2
+type InputBuildTags []string
+
 // RegisterOptionsMarkers registers "mandatory" options markers for FromOptions into the given registry.
 // At this point, that's just InputPaths.
 func RegisterOptionsMarkers(into *markers.Registry) error {
@@ -44,6 +53,14 @@ func RegisterOptionsMarkers(into *markers.Registry) error {
 	if helpGiver, hasHelp := ((interface{})(InputPaths(nil))).(HasHelp); hasHelp {
 		into.AddHelp(InputPathsMarker, helpGiver.Help())
 	}
+
+	if err := into.Register(BuildTagsMarker); err != nil {
+		return err
+	}
+	if helpGiver, hasHelp := ((interface{})(InputBuildTags(nil))).(HasHelp); hasHelp {
+		into.AddHelp(BuildTagsMarker, helpGiver.Help())
+	}
+
 	return nil
 }
 
@@ -78,9 +95,8 @@ func FromOptions(optionsRegistry *markers.Registry, options []string) (*Runtime,
 	if err != nil {
 		return nil, err
 	}
-
 	// make the runtime
-	genRuntime, err := protoRt.Generators.ForRoots(protoRt.Paths...)
+	genRuntime, err := protoRt.Generators.ForRootsWithConfig(protoRt.getConfig(), protoRt.Paths...)
 	if err != nil {
 		return nil, err
 	}
@@ -112,6 +128,7 @@ func protoFromOptions(optionsRegistry *markers.Registry, options []string) (prot
 		ByGenerator: make(map[*Generator]OutputRule),
 	}
 	var paths []string
+	var tags []string
 
 	// collect the generators first, so that we can key the output on the actual
 	// generator, which matters if there's settings in the gen object and it's not a pointer.
@@ -151,6 +168,8 @@ func protoFromOptions(optionsRegistry *markers.Registry, options []string) (prot
 			continue
 		case InputPaths:
 			paths = append(paths, val...)
+		case InputBuildTags:
+			tags = append(tags, val...)
 		default:
 			return protoRuntime{}, fmt.Errorf("unknown option marker %q", defn.Name)
 		}
@@ -171,6 +190,7 @@ func protoFromOptions(optionsRegistry *markers.Registry, options []string) (prot
 		Generators:       gens,
 		OutputRules:      rules,
 		GeneratorsByName: gensByName,
+		Tags:             tags,
 	}, nil
 }
 
@@ -181,6 +201,7 @@ type protoRuntime struct {
 	Generators       Generators
 	OutputRules      OutputRules
 	GeneratorsByName map[string]*Generator
+	Tags             []string
 }
 
 // splitOutputRuleOption splits a marker name of "output:rule:gen" or "output:rule"
@@ -194,3 +215,13 @@ func splitOutputRuleOption(name string) (ruleName string, genName string) {
 	// output:<rule>
 	return parts[1], ""
 }
+
+// getConfig generates the intiial config based on the the optional arguments,
+// which are currently only tags
+func (p protoRuntime) getConfig() *packages.Config {
+	cfg := &packages.Config{}
+	for _, tag := range p.Tags {
+		cfg.BuildFlags = append(cfg.BuildFlags, "-tags", tag)
+	}
+	return cfg
+}

pkg/genall/zz_generated.markerhelp.go

@@ -16,6 +16,8 @@ limitations under the License.
 
 package markers
 
+import "fmt"
+
 // Must panics on errors creating definitions.
 func Must(def *Definition, err error) *Definition {
 	if err != nil {
@@ -24,6 +26,17 @@ func Must(def *Definition, err error) *Definition {
 	return def
 }
 
+func MustOptional(def *Definition, err error) *Definition {
+	def = Must(def, err)
+	if !def.AnonymousField() {
+		def = Must(def, fmt.Errorf("not an anonymous field: %v", def))
+	}
+	field := def.Fields[""]
+	field.Optional = true
+	def.Fields[""] = field
+	return def
+}
+
 // RegisterAll attempts to register all definitions against the given registry,
 // stopping and returning if an error occurs.
 func RegisterAll(reg *Registry, defs ...*Definition) error {