Parquet to JSON CLI

p2j.go

//p2j: Parquet to JSON
package main

import (
        "encoding/json"
        "flag"
        "fmt"
        log "github.com/sirupsen/logrus"
        "os"

        "github.com/xitongsys/parquet-go-source/local"
        "github.com/xitongsys/parquet-go/reader"
)

func main() {
        log.SetOutput(os.Stderr)

        var err error
        var count = flag.Bool("count", false, "Print number of records")
        var file = flag.String("file", "", "Parquet File to Parse")

        flag.Parse()

        if file == nil || len(*file) == 0 {
                flag.Usage()
                log.Fatalf("Please specify File")
        }

        fr, err := local.NewLocalFileReader(*file)
        if err != nil {
                log.Fatalf("Can't open File: %s", file)
        }

        pr, err := reader.NewParquetReader(fr, nil, 4)
        if err != nil {
                log.Fatalf("Can't create Parquet reader: %v", err)
        }

        num := int(pr.GetNumRows())

        if *count {
                fmt.Println(num)
                return
        }

        os.Stdout.WriteString("[")
        for i := 0; i < num; i++ {
                res, err := pr.ReadByNumber(num)
                if err != nil {
                        log.Fatalf("Can't read record: %d %v", num, err)
                }
                jsonBytes, err := json.MarshalIndent(res, "", "  ")
                if err != nil {
                        log.Fatalf("Can't convert to JSON: %v", err)
                }
                if i > 0 {
                        os.Stdout.WriteString(",")
                }
                os.Stdout.Write(jsonBytes)
        }
        os.Stdout.WriteString("]")

        pr.ReadStop()
        fr.Close()
}