refactor cmds into subcmd package names and files (#373)

* add InfoConfigCmd

* return exit(0) when no args

* return status code 0 if no args

* impl topaz config info

* impl topaz config info

* refactor flow env as kong vars, via cc.*

* refactor map to struct to preserve field ordering

* refactor cmds into subcmd package names and files

pkg/cli/cmd/certs/certs.go

@@ -0,0 +1,80 @@
+package certs
+
+import (
+	"fmt"
+	"path/filepath"
+)
+
+type CertsCmd struct {
+	List     ListCertsCmd      `cmd:"" help:"list dev certs"`
+	Generate GenerateCertsCmd  `cmd:"" help:"generate dev certs"`
+	Trust    TrustCertsCmd     `cmd:"" help:"trust/untrust dev certs"`
+	Remove   RemoveCertFileCmd `cmd:"" help:"remove dev certs"`
+}
+
+const (
+	gatewayFileName = "gateway"
+	grpcFileName    = "grpc"
+	certCommonName  = "topaz"
+)
+
+type fileListArgs struct {
+	inclCACerts bool
+	inclCerts   bool
+	inclKeys    bool
+}
+
+type fileListOption func(*fileListArgs)
+
+func withAll() fileListOption {
+	return func(arg *fileListArgs) {
+		arg.inclCACerts = true
+		arg.inclCerts = true
+		arg.inclKeys = true
+	}
+}
+
+func withCerts() fileListOption {
+	return func(arg *fileListArgs) {
+		arg.inclCerts = true
+		arg.inclCACerts = true
+	}
+}
+
+func withCACerts() fileListOption {
+	return func(arg *fileListArgs) {
+		arg.inclCACerts = true
+	}
+}
+
+func getFileList(certsDir string, opts ...fileListOption) []string {
+	args := &fileListArgs{}
+	for _, opt := range opts {
+		opt(args)
+	}
+
+	filePaths := []string{}
+
+	if args.inclCACerts {
+		filePaths = append(filePaths,
+			filepath.Join(certsDir, fmt.Sprintf("%s-ca.crt", grpcFileName)),
+			filepath.Join(certsDir, fmt.Sprintf("%s-ca.crt", gatewayFileName)),
+		)
+	}
+
+	if args.inclCerts {
+		filePaths = append(filePaths,
+			filepath.Join(certsDir, fmt.Sprintf("%s.crt", grpcFileName)),
+			filepath.Join(certsDir, fmt.Sprintf("%s.crt", gatewayFileName)),
+		)
+	}
+
+	if args.inclKeys {
+		filePaths = append(filePaths,
+			filepath.Join(certsDir, fmt.Sprintf("%s.key", grpcFileName)),
+			filepath.Join(certsDir, fmt.Sprintf("%s.key", gatewayFileName)),
+		)
+	}
+
+	return filePaths
+}