refactor(parquet/cmd): replace uses of github.com/docopt/docopt-go (#764)

The github.com/docopt/docopt-go repository has not been maintained for
many Years; replace it for stdlib flags, which is slightly more code to
write, but removes the un-maintained dependency.

### Rationale for this change


### What changes are included in this PR?


### Are these changes tested?


### Are there any user-facing changes?

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

go.mod

@@ -30,7 +30,6 @@ require (
 	github.com/andybalholm/brotli v1.2.1
 	github.com/apache/thrift v0.22.0
 	github.com/cespare/xxhash/v2 v2.3.0
-	github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815
 	github.com/goccy/go-json v0.10.6
 	github.com/google/flatbuffers v25.12.19+incompatible
 	github.com/google/uuid v1.6.0

go.sum

@@ -40,8 +40,6 @@ github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815 h1:bWDMxwH3px2JBh6AyO7hdCn/PkvCZXii8TGj7sbtEbQ=
-github.com/docopt/docopt-go v0.0.0-20180111231733-ee0de3bc6815/go.mod h1:WwZ+bS3ebgob9U8Nd0kOddGdZWjyMGR8Wziv+TBNwSE=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=

parquet/cmd/parquet_reader/main.go

@@ -18,6 +18,8 @@ package main
 
 import (
 	"bufio"
+	"errors"
+	"flag"
 	"fmt"
 	"io"
 	"log"
@@ -30,8 +32,6 @@ import (
 	"github.com/apache/arrow-go/v18/parquet/file"
 	"github.com/apache/arrow-go/v18/parquet/metadata"
 	"github.com/apache/arrow-go/v18/parquet/schema"
-
-	"github.com/docopt/docopt-go"
 )
 
 var version = ""
@@ -47,33 +47,68 @@ Commands:
 
 Options:
   -h --help                     Show this screen.
-  --print-key-value-metadata    Print out the key-value metadata. [default: false]
-  --only-metadata               Stop after printing metadata, no values.
-  --no-metadata                 Do not print metadata.
-  --output=FILE                 Specify output file for data. [default: -]
-  --no-memory-map               Disable memory mapping the file.
-  --int96-timestamp             Parse INT96 as TIMESTAMP for legacy support.
-  --json                        Format output as JSON instead of text.
-  --csv                         Format output as CSV instead of text.
-  --columns=COLUMNS             Specify a subset of columns to print, comma delimited indexes.`
+`
+
+func printUsage(fs *flag.FlagSet) {
+	fmt.Fprint(fs.Output(), usage)
+	fs.VisitAll(func(f *flag.Flag) {
+		name, flagUsage := flag.UnquoteUsage(f)
+		flagName := "--" + f.Name
+		if name != "" {
+			flagName += "=" + name
+		}
+		fmt.Fprintf(fs.Output(), "  %-30s%s\n", flagName, flagUsage)
+	})
+}
 
 func main() {
-	opts, _ := docopt.ParseDoc(usage)
 	var config struct {
-		ColumnIndexes         bool `docopt:"column-indexes"`
+		ColumnIndexes         bool
 		PrintKeyValueMetadata bool
 		OnlyMetadata          bool
 		NoMetadata            bool
 		Output                string
 		NoMemoryMap           bool
-		JSON                  bool `docopt:"--json"`
-		CSV                   bool `docopt:"--csv"`
-		ParseInt96AsTimestamp bool `docopt:"--int96-timestamp"`
+		JSON                  bool
+		CSV                   bool
+		ParseInt96AsTimestamp bool
 		Columns               string
 		File                  string
 	}
-	opts.Bind(&config)
 
+	args := os.Args[1:]
+	if len(args) > 0 && args[0] == "column-indexes" {
+		config.ColumnIndexes = true
+		args = args[1:]
+	}
+
+	fs := flag.NewFlagSet("parquet_reader", flag.ContinueOnError)
+	fs.SetOutput(os.Stderr)
+	fs.BoolVar(&config.OnlyMetadata, "only-metadata", false, "Stop after printing metadata, no values.")
+	fs.BoolVar(&config.NoMetadata, "no-metadata", false, "Do not print metadata.")
+	fs.BoolVar(&config.NoMemoryMap, "no-memory-map", false, "Disable memory mapping the file.")
+	fs.BoolVar(&config.JSON, "json", false, "Format output as JSON instead of text.")
+	fs.BoolVar(&config.CSV, "csv", false, "Format output as CSV instead of text.")
+	fs.StringVar(&config.Output, "output", "-", "Specify output `FILE` for data.")
+	fs.BoolVar(&config.PrintKeyValueMetadata, "print-key-value-metadata", false, "Print out the key-value metadata.")
+	fs.BoolVar(&config.ParseInt96AsTimestamp, "int96-timestamp", false, "Parse INT96 as TIMESTAMP for legacy support.")
+	fs.StringVar(&config.Columns, "columns", "", "Specify a subset of `COLUMNS` to print, comma delimited indexes.")
+	fs.Usage = func() {
+		printUsage(fs)
+	}
+
+	if err := fs.Parse(args); err != nil {
+		if errors.Is(err, flag.ErrHelp) {
+			os.Exit(0)
+		}
+		os.Exit(1)
+	}
+	if fs.NArg() != 1 {
+		fs.Usage()
+		fmt.Fprintln(os.Stderr, "expected exactly one parquet file")
+		os.Exit(1)
+	}
+	config.File = fs.Arg(0)
 	parseInt96AsTimestamp = config.ParseInt96AsTimestamp
 
 	var dataOut io.Writer

parquet/cmd/parquet_schema/main.go

@@ -22,23 +22,39 @@ import (
 
 	"github.com/apache/arrow-go/v18/parquet/file"
 	"github.com/apache/arrow-go/v18/parquet/schema"
-	"github.com/docopt/docopt-go"
 )
 
 const usage = `Parquet Schema Dumper.
+
 Usage:
   parquet_schema -h | --help
   parquet_schema <file>
+
 Options:
-  -h --help   Show this screen.`
+  -h --help   Show this screen.
+`
 
 func main() {
-	args, _ := docopt.ParseDoc(usage)
-	rdr, err := file.OpenParquetFile(args["<file>"].(string), false)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, "Error opening parquet file: ", err)
+	args := os.Args[1:]
+
+	switch len(args) {
+	case 1:
+		switch args[0] {
+		case "-h", "--help":
+			fmt.Fprint(os.Stderr, usage)
+			os.Exit(0)
+		}
+
+		rdr, err := file.OpenParquetFile(args[0], false)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "Error opening parquet file:", err)
+			os.Exit(1)
+		}
+
+		schema.PrintSchema(rdr.MetaData().Schema.Root(), os.Stdout, 2)
+	default:
+		fmt.Fprint(os.Stderr, usage)
+		fmt.Fprintln(os.Stderr, "expected exactly one parquet file")
 		os.Exit(1)
 	}
-
-	schema.PrintSchema(rdr.MetaData().Schema.Root(), os.Stdout, 2)
 }