refactor: introduce dedicated config package for cmds

Signed-off-by: Philippe Scorsolini <p.scorsolini@gmail.com>

cmd/function-runtime-oci/internal/config/config.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2022 The Crossplane Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package config contains the global config for all commands
+package config
+
+// Args contains the default registry used to pull XFN containers.
+type Args struct {
+	Registry string `short:"r" help:"Default registry used to fetch containers when not specified in tag." default:"${default_registry}" env:"REGISTRY"`
+}

cmd/function-runtime-oci/main.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/crossplane/crossplane-runtime/pkg/logging"
 
+	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/internal/config"
 	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/run"
 	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/spark"
 	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/start"
@@ -44,8 +45,8 @@ var KongVars = kong.Vars{
 var cli struct {
 	Debug debugFlag `short:"d" help:"Print verbose logging statements."`
 
-	Version  versionFlag `short:"v" help:"Print version and quit."`
-	Registry string      `short:"r" help:"Default registry used to fetch containers when not specified in tag." default:"${default_registry}" env:"REGISTRY"`
+	Version     versionFlag `short:"v" help:"Print version and quit."`
+	config.Args `embed:""`
 
 	Start start.Command `cmd:"" help:"Start listening for Composition Function runs over gRPC." default:"1"`
 	Run   run.Command   `cmd:"" help:"Run a Composition Function."`
@@ -76,8 +77,9 @@ func main() {
 		kong.Name("function-runtime-oci"),
 		kong.Description("Crossplane Composition Functions."),
 		kong.BindTo(logging.NewLogrLogger(zl), (*logging.Logger)(nil)),
+		kong.BindTo(cli.Args, (*config.Args)(nil)),
 		kong.UsageOnError(),
 		KongVars,
 	)
-	ctx.FatalIfErrorf(ctx.Run(&start.Args{Registry: cli.Registry}))
+	ctx.FatalIfErrorf(ctx.Run())
 }

cmd/function-runtime-oci/run/run.go

@@ -29,7 +29,7 @@ import (
 
 	"github.com/crossplane/crossplane-runtime/pkg/errors"
 
-	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/start"
+	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/internal/config"
 	"github.com/crossplane/function-runtime-oci/internal/container"
 	"github.com/crossplane/function-runtime-oci/internal/proto/v1alpha1"
 )
@@ -60,7 +60,7 @@ type Command struct {
 }
 
 // Run a Composition container function.
-func (c *Command) Run(args *start.Args) error {
+func (c *Command) Run(args *config.Args) error {
 	// If we don't have CAP_SETUID or CAP_SETGID, we'll only be able to map our
 	// own UID and GID to root inside the user namespace.
 	rootUID := os.Getuid()

cmd/function-runtime-oci/spark/spark.go

@@ -34,7 +34,7 @@ import (
 
 	"github.com/crossplane/crossplane-runtime/pkg/errors"
 
-	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/start"
+	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/internal/config"
 	"github.com/crossplane/function-runtime-oci/internal/oci"
 	"github.com/crossplane/function-runtime-oci/internal/oci/spec"
 	"github.com/crossplane/function-runtime-oci/internal/oci/store"
@@ -81,7 +81,7 @@ type Command struct {
 // Run a Composition Function inside an unprivileged user namespace. Reads a
 // protocol buffer serialized RunFunctionRequest from stdin, and writes a
 // protocol buffer serialized RunFunctionResponse to stdout.
-func (c *Command) Run(args *start.Args) error { //nolint:gocyclo // TODO(negz): Refactor some of this out into functions, add tests.
+func (c *Command) Run(args *config.Args) error { //nolint:gocyclo // TODO(negz): Refactor some of this out into functions, add tests.
 	pb, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		return errors.Wrap(err, errReadRequest)

cmd/function-runtime-oci/start/start.go

@@ -25,6 +25,7 @@ import (
 	"github.com/crossplane/crossplane-runtime/pkg/errors"
 	"github.com/crossplane/crossplane-runtime/pkg/logging"
 
+	"github.com/crossplane/function-runtime-oci/cmd/function-runtime-oci/internal/config"
 	"github.com/crossplane/function-runtime-oci/internal/container"
 )
 
@@ -33,12 +34,6 @@ const (
 	errListenAndServe = "cannot listen for and serve gRPC API"
 )
 
-// Args contains the default registry used to pull function-runtime-oci
-// containers.
-type Args struct {
-	Registry string
-}
-
 // Command starts a gRPC API to run Composition Functions.
 type Command struct {
 	CacheDir   string `short:"c" help:"Directory used for caching function images and containers." default:"/function-runtime-oci"`
@@ -49,7 +44,7 @@ type Command struct {
 }
 
 // Run a Composition Function gRPC API.
-func (c *Command) Run(args *Args, log logging.Logger) error {
+func (c *Command) Run(args *config.Args, log logging.Logger) error {
 	// If we don't have CAP_SETUID or CAP_SETGID, we'll only be able to map our
 	// own UID and GID to root inside the user namespace.
 	rootUID := os.Getuid()