cobrautil v2

cobrautil.go

@@ -53,7 +53,7 @@ func SyncViperPreRunE(prefix string) CobraRunFunc {
 // CobraRunFunc is the signature of cobra.Command RunFuncs.
 type CobraRunFunc func(cmd *cobra.Command, args []string) error
 
-// RunFuncStack chains together a collection of CobraCommandFuncs into one.
+// CommandStack chains together a collection of CobraCommandFuncs into one.
 func CommandStack(cmdfns ...CobraRunFunc) CobraRunFunc {
 	return func(cmd *cobra.Command, args []string) error {
 		for _, cmdfn := range cmdfns {
@@ -65,7 +65,10 @@ func CommandStack(cmdfns ...CobraRunFunc) CobraRunFunc {
 	}
 }
 
-func prefixJoiner(prefix string) func(...string) string {
+// PrefixJoiner joins a list of strings with the "-" separator, including the provided prefix string
+//
+// example: PrefixJoiner("hi")("how", "are", "you") = "hi-how-are-you"
+func PrefixJoiner(prefix string) func(...string) string {
 	return func(xs ...string) string {
 		return stringz.Join("-", append([]string{prefix}, xs...)...)
 	}

example_test.go

@@ -4,35 +4,36 @@ import (
 	"github.com/rs/zerolog"
 	"github.com/spf13/cobra"
 
-	"github.com/jzelinskie/cobrautil"
+	"github.com/jzelinskie/cobrautil/v2"
+	zl "github.com/jzelinskie/cobrautil/v2/zerolog"
 )
 
 func ExampleCommandStack() {
 	cmd := &cobra.Command{
 		Use: "mycmd",
 		PreRunE: cobrautil.CommandStack(
 			cobrautil.SyncViperPreRunE("myprogram"),
-			cobrautil.ZeroLogRunE("log", zerolog.InfoLevel),
+			zl.RunE("log", zerolog.InfoLevel),
 		),
 	}
 
-	cobrautil.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
+	zl.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
 }
 
 func ExampleRegisterZeroLogFlags() {
 	cmd := &cobra.Command{
 		Use:     "mycmd",
-		PreRunE: cobrautil.ZeroLogRunE("log", zerolog.InfoLevel),
+		PreRunE: zl.RunE("log", zerolog.InfoLevel),
 	}
 
-	cobrautil.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
+	zl.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
 }
 
-func ExampleZeroLogRunE() {
+func ExampleRunE() {
 	cmd := &cobra.Command{
 		Use:     "mycmd",
-		PreRunE: cobrautil.ZeroLogRunE("log", zerolog.InfoLevel),
+		PreRunE: zl.RunE("log", zerolog.InfoLevel),
 	}
 
-	cobrautil.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
+	zl.RegisterZeroLogFlags(cmd.PersistentFlags(), "log")
 }

go.mod

@@ -1,8 +1,9 @@
-module github.com/jzelinskie/cobrautil
+module github.com/jzelinskie/cobrautil/v2
 
 go 1.18
 
 require (
+	github.com/go-logr/logr v1.2.3
 	github.com/jzelinskie/stringz v0.0.1
 	github.com/mattn/go-isatty v0.0.16
 	github.com/rs/zerolog v1.28.0
@@ -23,7 +24,6 @@ require (
 require (
 	github.com/cenkalti/backoff/v4 v4.1.3 // indirect
 	github.com/fsnotify/fsnotify v1.5.4 // indirect
-	github.com/go-logr/logr v1.2.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0 // indirect

grpc/grpc.go

@@ -0,0 +1,198 @@
+package grpc
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/jzelinskie/cobrautil/v2"
+
+	"github.com/go-logr/logr"
+	"github.com/jzelinskie/stringz"
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/keepalive"
+)
+
+// ConfigureFunc is a function used to configure this CobraUtil
+type ConfigureFunc = func(cu *CobraUtil)
+
+// New creates a configuration that exposes RegisterFlags and RunE
+// to integrate with cobra
+func New(serviceName string, configurations ...ConfigureFunc) *CobraUtil {
+	cu := CobraUtil{
+		serviceName:    stringz.DefaultEmpty(serviceName, "grpc"),
+		preRunLevel:    0,
+		logger:         logr.Discard(),
+		defaultAddr:    ":50051",
+		defaultEnabled: false,
+		flagPrefix:     "grpc",
+	}
+	for _, configure := range configurations {
+		configure(&cu)
+	}
+	return &cu
+}
+
+// CobraUtil carries the configuration for a otel CobraRunFunc
+type CobraUtil struct {
+	flagPrefix     string
+	serviceName    string
+	defaultAddr    string
+	defaultEnabled bool
+	logger         logr.Logger
+	preRunLevel    int
+}
+
+// RegisterGrpcServerFlags adds the following flags for use with
+// GrpcServerFromFlags:
+// - "$PREFIX-addr"
+// - "$PREFIX-tls-cert-path"
+// - "$PREFIX-tls-key-path"
+// - "$PREFIX-max-conn-age"
+func RegisterGrpcServerFlags(flags *pflag.FlagSet, flagPrefix, serviceName, defaultAddr string, defaultEnabled bool) {
+	serviceName = stringz.DefaultEmpty(serviceName, "grpc")
+	defaultAddr = stringz.DefaultEmpty(defaultAddr, ":50051")
+	prefixed := cobrautil.PrefixJoiner(stringz.DefaultEmpty(flagPrefix, "grpc"))
+
+	flags.String(prefixed("addr"), defaultAddr, "address to listen on to serve "+serviceName)
+	flags.String(prefixed("network"), "tcp", "network type to serve "+serviceName+` ("tcp", "tcp4", "tcp6", "unix", "unixpacket")`)
+	flags.String(prefixed("tls-cert-path"), "", "local path to the TLS certificate used to serve "+serviceName)
+	flags.String(prefixed("tls-key-path"), "", "local path to the TLS key used to serve "+serviceName)
+	flags.Duration(prefixed("max-conn-age"), 30*time.Second, "how long a connection serving "+serviceName+" should be able to live")
+	flags.Bool(prefixed("enabled"), defaultEnabled, "enable "+serviceName+" gRPC server")
+}
+
+// RegisterGrpcServerFlags adds the following flags for use with
+// GrpcServerFromFlags:
+// - "$PREFIX-addr"
+// - "$PREFIX-tls-cert-path"
+// - "$PREFIX-tls-key-path"
+// - "$PREFIX-max-conn-age"
+func (cu CobraUtil) RegisterGrpcServerFlags(flags *pflag.FlagSet) {
+	RegisterGrpcServerFlags(flags, cu.flagPrefix, cu.serviceName, cu.defaultAddr, cu.defaultEnabled)
+}
+
+// ServerFromFlags creates an *grpc.Server as configured by the flags from
+// RegisterGrpcServerFlags().
+func ServerFromFlags(cmd *cobra.Command, flagPrefix string, opts ...grpc.ServerOption) (*grpc.Server, error) {
+	return New("", WithFlagPrefix(flagPrefix)).ServerFromFlags(cmd, opts...)
+}
+
+// ServerFromFlags creates an *grpc.Server as configured by the flags from
+// RegisterGrpcServerFlags().
+func (cu CobraUtil) ServerFromFlags(cmd *cobra.Command, opts ...grpc.ServerOption) (*grpc.Server, error) {
+	prefixed := cobrautil.PrefixJoiner(cu.flagPrefix)
+
+	opts = append(opts, grpc.KeepaliveParams(keepalive.ServerParameters{
+		MaxConnectionAge: cobrautil.MustGetDuration(cmd, prefixed("max-conn-age")),
+	}))
+
+	certPath := cobrautil.MustGetStringExpanded(cmd, prefixed("tls-cert-path"))
+	keyPath := cobrautil.MustGetStringExpanded(cmd, prefixed("tls-key-path"))
+
+	switch {
+	case isInsecure(certPath, keyPath):
+		return grpc.NewServer(opts...), nil
+
+	case isSecure(certPath, keyPath):
+		creds, err := credentials.NewServerTLSFromFile(certPath, keyPath)
+		if err != nil {
+			return nil, err
+		}
+		opts = append(opts, grpc.Creds(creds))
+		return grpc.NewServer(opts...), nil
+
+	default:
+		return nil, fmt.Errorf(
+			"failed to start gRPC server: must provide both --%s-tls-cert-path and --%s-tls-key-path",
+			cu.flagPrefix,
+			cu.flagPrefix,
+		)
+	}
+}
+
+// ListenFromFlags listens on an gRPC server using the configuration stored
+// in the cobra command that was registered with RegisterGrpcServerFlags.
+func ListenFromFlags(cmd *cobra.Command, flagPrefix string, srv *grpc.Server, preRunLevel int) error {
+	return New("", WithPreRunLevel(preRunLevel), WithFlagPrefix(flagPrefix)).ListenFromFlags(cmd, srv)
+}
+
+// ListenFromFlags listens on an gRPC server using the configuration stored
+// in the cobra command that was registered with RegisterGrpcServerFlags.
+func (cu CobraUtil) ListenFromFlags(cmd *cobra.Command, srv *grpc.Server) error {
+	prefixed := cobrautil.PrefixJoiner(cu.flagPrefix)
+
+	if !cobrautil.MustGetBool(cmd, prefixed("enabled")) {
+		return nil
+	}
+
+	network := cobrautil.MustGetString(cmd, prefixed("network"))
+	addr := cobrautil.MustGetStringExpanded(cmd, prefixed("addr"))
+
+	l, err := net.Listen(network, addr)
+	if err != nil {
+		return fmt.Errorf("failed to listen on addr for gRPC server: %w", err)
+	}
+
+	certPath := cobrautil.MustGetStringExpanded(cmd, prefixed("tls-cert-path"))
+	keyPath := cobrautil.MustGetStringExpanded(cmd, prefixed("tls-key-path"))
+	cu.logger.V(cu.preRunLevel).Info(
+		"grpc server started listening",
+		"addr", addr,
+		"network", network,
+		"prefix", cu.flagPrefix,
+		"insecure", isInsecure(certPath, keyPath))
+
+	if err := srv.Serve(l); err != nil {
+		return fmt.Errorf("failed to serve gRPC: %w", err)
+	}
+
+	return nil
+}
+
+// WithLogger defines the logger used to log messages in this package
+func WithLogger(logger logr.Logger) ConfigureFunc {
+	return func(cu *CobraUtil) {
+		cu.logger = logger
+	}
+}
+
+// WithDefaultAddress defines the default value of the address the server will listen at.
+// Defaults to ":50051"
+func WithDefaultAddress(addr string) ConfigureFunc {
+	return func(cu *CobraUtil) {
+		cu.defaultAddr = addr
+	}
+}
+
+// WithDefaultEnabled defines whether the gRPC server is enabled by default. Defaults to "false".
+func WithDefaultEnabled(enabled bool) ConfigureFunc {
+	return func(cu *CobraUtil) {
+		cu.defaultEnabled = enabled
+	}
+}
+
+// WithFlagPrefix defines prefix used with the generated flags. Defaults to "grpc".
+func WithFlagPrefix(flagPrefix string) ConfigureFunc {
+	return func(cu *CobraUtil) {
+		cu.flagPrefix = flagPrefix
+	}
+}
+
+// WithPreRunLevel defines the logging level used for pre-run log messages. Defaults to "debug".
+func WithPreRunLevel(preRunLevel int) ConfigureFunc {
+	return func(cu *CobraUtil) {
+		cu.preRunLevel = preRunLevel
+	}
+}
+
+func isInsecure(certPath, keyPath string) bool {
+	return certPath == "" && keyPath == ""
+}
+
+func isSecure(certPath, keyPath string) bool {
+	return certPath != "" && keyPath != ""
+}