GO111MODULE="on"
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/seaguest/Library/Caches/go-build"
GOENV="/Users/seaguest/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/seaguest/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/seaguest/go"
GOPRIVATE=""
GOPROXY="https://goproxy.cn"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.17"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/seaguest/Work/test/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/kp/cvx3fsfn5jggmgdlkvh9km500000gn/T/go-build689013652=/tmp/go-build -gno-record-gcc-switches -fno-common"

package main

import (
	"bytes"
	"compress/gzip"
	"encoding/csv"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
)

func main() {
	writeCSV("user.csv")
	compress("user.csv")
}

func writeCSV(fileName string) {
	records := [][]string{
		{"first", "last", "occupation"},
		{"John", "Doe", "gardener"},
		{"Lucy", "Smith", "teacher"},
		{"Brian", "Bethamy", "programmer"},
	}

	f, err := os.Create(fileName)
	defer f.Close()

	if err != nil {
		log.Fatalln("failed to open file", err)
	}

	w := csv.NewWriter(f)
	defer w.Flush()
	for _, record := range records {
		if err := w.Write(record); err != nil {
			log.Fatalln("error writing record to file", err)
		}
	}
}

func compress(fileName string) error {
	var bf bytes.Buffer
	w := gzip.NewWriter(&bf)

	dat, err := ioutil.ReadFile(fileName)
	if err != nil {
		log.Println(err)
		return err
	}
	w.Write(dat)
	w.Close()

	err = ioutil.WriteFile(filepath.Base(fileName)+".gz", bf.Bytes(), 0777)
	log.Println(err)
	return nil
}