feat: initial version

cmd/dam/dam.go

@@ -0,0 +1,108 @@
+// Copyright (C) 2023 CGI France
+//
+// This file is part of dam.
+//
+// dam is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// dam is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with dam.  If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+)
+
+const linebreak byte = 10
+
+type Dam struct {
+	input  *bufio.Scanner
+	buffer chan []byte
+	output *bufio.Writer
+}
+
+func NewDam(input io.Reader, output io.Writer, capacity int) *Dam {
+	return &Dam{
+		input:  bufio.NewScanner(input),
+		buffer: make(chan []byte, capacity),
+		output: bufio.NewWriter(output),
+	}
+}
+
+func (d *Dam) GetSize() int {
+	return len(d.buffer)
+}
+
+func (d *Dam) IsEmpty() bool {
+	return d.GetSize() == 0
+}
+
+func (d *Dam) Drop() error {
+	if _, err := d.output.Write(append(<-d.buffer, linebreak)); err != nil {
+		return fmt.Errorf("%w", err)
+	}
+
+	return nil
+}
+
+func (d *Dam) Drain() error {
+	for !d.IsEmpty() {
+		if err := d.Drop(); err != nil {
+			return fmt.Errorf("%w", err)
+		}
+	}
+
+	d.output.Flush()
+
+	return nil
+}
+
+func (d *Dam) Spill() error {
+	for d.GetSize() >= cap(d.buffer) {
+		if err := d.Drop(); err != nil {
+			return fmt.Errorf("%w", err)
+		}
+	}
+
+	d.output.Flush()
+
+	return nil
+}
+
+func (d *Dam) Add(data []byte) error {
+	if err := d.Spill(); err != nil {
+		return fmt.Errorf("%w", err)
+	}
+
+	d.buffer <- data
+
+	return nil
+}
+
+func (d *Dam) Run() error {
+	for d.input.Scan() {
+		if err := d.Add(d.input.Bytes()); err != nil {
+			return fmt.Errorf("%w", err)
+		}
+	}
+
+	if err := d.input.Err(); err != nil {
+		return fmt.Errorf("%w", err)
+	}
+
+	if err := d.Drain(); err != nil {
+		return fmt.Errorf("%w", err)
+	}
+
+	return nil
+}

cmd/dam/main.go

@@ -25,9 +25,14 @@ package main
 import (
 	"fmt"
 	"os"
+	"runtime"
+	"strconv"
+	"strings"
 
+	"github.com/mattn/go-isatty"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
+	"github.com/spf13/cobra"
 )
 
 // Provisioned by ldflags.
@@ -37,13 +42,86 @@ var (
 	commit    string //nolint: gochecknoglobals
 	buildDate string //nolint: gochecknoglobals
 	builtBy   string //nolint: gochecknoglobals
+
+	verbosity string //nolint: gochecknoglobals
+	jsonlog   bool   //nolint: gochecknoglobals
+	debug     bool   //nolint: gochecknoglobals
+	colormode string //nolint: gochecknoglobals
 )
 
 func main() {
-	//nolint: exhaustruct
-	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
+	cobra.OnInitialize(initLog)
+
+	rootCmd := &cobra.Command{ //nolint:exhaustruct
+		Use: name,
+		Version: fmt.Sprintf(`%v (commit=%v date=%v by=%v)
+Copyright (C) 2024 CGI France
+License GPLv3: GNU GPL version 3 <https://gnu.org/licenses/gpl.html>.
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.`, version, commit, buildDate, builtBy),
+		Args: cobra.ExactArgs(1),
+		RunE: func(_ *cobra.Command, args []string) error {
+			capacity, err := strconv.ParseInt(args[0], 10, 32)
+			if err != nil {
+				return fmt.Errorf("%w", err)
+			}
+
+			dam := NewDam(os.Stdin, os.Stdout, int(capacity))
+
+			return dam.Run()
+		},
+	}
+
+	rootCmd.PersistentFlags().StringVarP(&verbosity, "verbosity", "v", "warn",
+		"set level of log verbosity : none (0), error (1), warn (2), info (3), debug (4), trace (5)")
+	rootCmd.PersistentFlags().BoolVar(&debug, "debug", false, "add debug information to logs (very slow)")
+	rootCmd.PersistentFlags().BoolVar(&jsonlog, "log-json", false, "output logs in JSON format")
+	rootCmd.PersistentFlags().StringVar(&colormode, "color", "auto", "use colors in log outputs : yes, no or auto")
+
+	if err := rootCmd.Execute(); err != nil {
+		log.Err(err).Msg("error when executing command")
+		os.Exit(1)
+	}
+}
+
+func initLog() {
+	color := false
+
+	switch strings.ToLower(colormode) {
+	case "auto":
+		if isatty.IsTerminal(os.Stdout.Fd()) && runtime.GOOS != "windows" {
+			color = true
+		}
+	case "yes", "true", "1", "on", "enable":
+		color = true
+	}
 
-	log.Info().Msgf("%v %v (commit=%v date=%v by=%v)", name, version, commit, buildDate, builtBy)
+	if jsonlog {
+		log.Logger = zerolog.New(os.Stderr)
+	} else {
+		log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr, NoColor: !color}) //nolint:exhaustruct
+	}
+
+	if debug {
+		log.Logger = log.Logger.With().Caller().Logger()
+	}
+
+	setVerbosity()
+}
 
-	fmt.Println()
+func setVerbosity() {
+	switch verbosity {
+	case "trace", "5":
+		zerolog.SetGlobalLevel(zerolog.TraceLevel)
+	case "debug", "4":
+		zerolog.SetGlobalLevel(zerolog.DebugLevel)
+	case "info", "3":
+		zerolog.SetGlobalLevel(zerolog.InfoLevel)
+	case "warn", "2":
+		zerolog.SetGlobalLevel(zerolog.WarnLevel)
+	case "error", "1":
+		zerolog.SetGlobalLevel(zerolog.ErrorLevel)
+	default:
+		zerolog.SetGlobalLevel(zerolog.Disabled)
+	}
 }

go.mod

@@ -2,10 +2,15 @@ module github.com/cgi-fr/dam
 
 go 1.21
 
-require github.com/rs/zerolog v1.28.0
+require (
+	github.com/mattn/go-isatty v0.0.20
+	github.com/rs/zerolog v1.32.0
+	github.com/spf13/cobra v1.8.0
+)
 
 require (
-	github.com/mattn/go-colorable v0.1.12 // indirect
-	github.com/mattn/go-isatty v0.0.14 // indirect
-	golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	golang.org/x/sys v0.12.0 // indirect
 )

go.sum

@@ -1,14 +1,26 @@
-github.com/coreos/go-systemd/v22 v22.3.3-0.20220203105225-a9a7ef127534/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
-github.com/mattn/go-colorable v0.1.12 h1:jF+Du6AlPIjs2BiUiQlKOX0rt3SujHxPnksPKZbaA40=
-github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb520KVy5xxl4=
-github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
-github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/rs/xid v1.4.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
-github.com/rs/zerolog v1.28.0 h1:MirSo27VyNi7RJYP3078AA1+Cyzd2GB66qy3aUHvsWY=
-github.com/rs/zerolog v1.28.0/go.mod h1:NILgTygv/Uej1ra5XxGf82ZFSLk58MFGAUS2o6usyD0=
-golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9wrfxYyCjk0KbXjhR55s=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+github.com/rs/zerolog v1.32.0 h1:keLypqrlIjaFsbmJOBdB/qvyF8KEtCWHwobLp5l/mQ0=
+github.com/rs/zerolog v1.32.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/spf13/cobra v1.8.0 h1:7aJaZx1B85qltLMc546zn58BxxfZdR/W22ej9CFoEf0=
+github.com/spf13/cobra v1.8.0/go.mod h1:WXLWApfZ71AjXPya3WOlMsY9yMs7YeiHhFVlvLyhcho=
+github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
+github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=