Google Sheets API v4 と サービスアカウントと Go でスプレッドシートを操作する ref: http://qiita.com/bati11/items/a4cd922149dac07981bc

spread_sheets_api_sample.go

package main

import (
    "errors"
    "fmt"
    "io/ioutil"
    "log"
    "net/http"

    "golang.org/x/oauth2"
    "golang.org/x/oauth2/google"
    "google.golang.org/api/sheets/v4"
)

func httpClient(credentialFilePath string) (*http.Client, error) {
    data, err := ioutil.ReadFile(credentialFilePath)
    if err != nil {
        return nil, err
    }
    conf, err := google.JWTConfigFromJSON(data, "https://www.googleapis.com/auth/spreadsheets")
    if err != nil {
        return nil, err
    }

    return conf.Client(oauth2.NoContext), nil
}

func sheetId(s *sheets.Spreadsheet, sheetName string) (int64, error) {
    for _, sheet := range s.Sheets {
        if sheet.Properties.Title == sheetName {
            return sheet.Properties.SheetId, nil
        }
    }
    return 0, errors.New(sheetName + " is not exists.")
}

func insertRow(sheetService *sheets.Service, spreadsheetId string, sheetId int64) (*sheets.BatchUpdateSpreadsheetResponse, error) {
    req := sheets.Request{
        InsertDimension: &sheets.InsertDimensionRequest{
            InheritFromBefore: false,
            Range: &sheets.DimensionRange{
                Dimension:  "ROWS",
                StartIndex: 1,
                EndIndex:   3,
                SheetId:    sheetId,
            },
        },
    }
    insertRowReq := sheets.BatchUpdateSpreadsheetRequest{
        Requests: []*sheets.Request{&req},
    }
    return sheetService.Spreadsheets.BatchUpdate(spreadsheetId, &insertRowReq).Do()
}

func main() {
    spreadsheetId := "スプレッドシートのURLから抽出したID"
    credentialFilePath := "秘密鍵のJSONファイルのパス"
    sheetName := "シート1"

    client, err := httpClient(credentialFilePath)
    if err != nil {
        log.Fatal(err)
    }

    sheetService, err := sheets.New(client)
    if err != nil {
        log.Fatalf("Unable to retrieve Sheets Client %v", err)
    }

    spreadsheet, err := sheetService.Spreadsheets.Get(spreadsheetId).Do()
    if err != nil {
        log.Fatalf("Unable to get Spreadsheets. %v", err)
    }

    sheetId, err := sheetId(spreadsheet, sheetName)
    if err != nil {
        log.Fatal(err)
    }

    _, err = insertRow(sheetService, spreadsheetId, sheetId)
    if err != nil {
        log.Fatalf("Unable to insert row. %v", err)
    }

    valueRange := &sheets.ValueRange{
        MajorDimension: "ROWS",
        Values: [][]interface{}{
            []interface{}{"hoge", 1},
            []interface{}{"fuga", 2},
        },
    }
    _, err = sheetService.Spreadsheets.Values.Update(spreadsheetId, sheetName+"!A2:B3", valueRange).ValueInputOption("USER_ENTERED").Do()
    if err != nil {
        log.Fatalf("Unable to write value. %v", err)
    }

    fmt.Printf("success!\n")
}

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