Dynamic leaderboards feature. Merge #43

The format is based on [keep a changelog](http://keepachangelog.com/) and this project uses [semantic versioning](http://semver.org/).

## [Unreleased]

### Added

- Dynamic leaderboards feature.

- Presence updates now report the user's handle.

### Changed

- The build system now strips up to current dir in recorded source file paths at compile.

// Copyright 2017 The Nakama Authors

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

package cmd

import (

	"database/sql"

	"encoding/base64"

	"encoding/json"

	"flag"

	"fmt"

	"github.com/gorhill/cronexpr"

	"github.com/satori/go.uuid"

	"github.com/uber-go/zap"

	"net/url"

	"os"

)

type adminService struct {

	DSNS   string

	logger zap.Logger

}

func AdminParse(args []string, logger zap.Logger) {

	if len(args) == 0 {

		logger.Fatal("Admin requires a subcommand. Available commands are: 'create-leaderboard'.")

	}

	var exec func([]string, zap.Logger)

	switch args[0] {

	case "create-leaderboard":

		exec = createLeaderboard

	default:

		logger.Fatal("Unrecognized admin subcommand. Available commands are: 'create-leaderboard'.")

	}

	exec(args[1:], logger)

	os.Exit(0)

}

func createLeaderboard(args []string, logger zap.Logger) {

	var dsns string

	var id string

	var authoritative bool

	var sortOrder string

	var resetSchedule string

	var metadata string

	flags := flag.NewFlagSet("admin", flag.ExitOnError)

	flags.StringVar(&dsns, "db", "root@localhost:26257", "CockroachDB JDBC connection details.")

	flags.StringVar(&id, "id", "", "ID to assign to the leaderboard.")

	flags.BoolVar(&authoritative, "authoritative", false, "True if clients may not submit scores directly, false otherwise.")

	flags.StringVar(&sortOrder, "sort", "descending", "Leaderboard sort order, 'asc' or 'desc'.")

	flags.StringVar(&resetSchedule, "reset", "", "Optional reset schedule in CRON format.")

	flags.StringVar(&metadata, "metadata", "{}", "Optional additional metadata as a JSON string.")

	if err := flags.Parse(args); err != nil {

		logger.Fatal("Could not parse admin flags.")

	}

	if dsns == "" {

		logger.Fatal("Database connection details are required.")

	}

	query := `INSERT INTO leaderboard (id, authoritative, sort_order, reset_schedule, metadata)

	VALUES ($1, $2, $3, $4, $5)`

	params := []interface{}{}

	// ID.

	if id == "" {

		params = append(params, uuid.NewV4().Bytes())

	} else {

		params = append(params, []byte(id))

	}

	// Authoritative.

	params = append(params, authoritative)

	// Sort order.

	if sortOrder == "asc" {

		params = append(params, 0)

	} else if sortOrder == "desc" {

		params = append(params, 1)

	} else {

		logger.Fatal("Invalid sort value, must be 'asc' or 'desc'.")

	}

	// Count is hardcoded in the INSERT above.

	// Reset schedule.

	if resetSchedule != "" {

		_, err := cronexpr.Parse(resetSchedule)

		if err != nil {

			logger.Fatal("Reset schedule must be a valid CRON expression.")

		}

		params = append(params, resetSchedule)

	} else {

		params = append(params, nil)

	}

	// Metadata.

	metadataBytes := []byte(metadata)

	var maybeJSON map[string]interface{}

	if json.Unmarshal(metadataBytes, &maybeJSON) != nil {

		logger.Fatal("Metadata must be a valid JSON string.")

	}

	params = append(params, metadataBytes)

	rawurl := fmt.Sprintf("postgresql://%s?sslmode=disable", dsns)

	url, err := url.Parse(rawurl)

	if err != nil {

		logger.Fatal("Bad connection URL", zap.Error(err))

	}

	logger.Info("Database connection", zap.String("dsns", dsns))

	// Default to "nakama" as DB name.

	dbname := "nakama"

	if len(url.Path) > 1 {

		dbname = url.Path[1:]

	}

	url.Path = fmt.Sprintf("/%s", dbname)

	db, err := sql.Open(dialect, url.String())

	if err != nil {

		logger.Fatal("Failed to open database", zap.Error(err))

	}

	if err = db.Ping(); err != nil {

		logger.Fatal("Error pinging database", zap.Error(err))

	}

	res, err := db.Exec(query, params...)

	if err != nil {

		logger.Fatal("Error creating leaderboard", zap.Error(err))

	}

	if rowsAffected, _ := res.RowsAffected(); rowsAffected != 1 {

		logger.Fatal("Error creating leaderboard, unexpected insert result")

	}

	logger.Info("Leaderboard created", zap.String("base64(id)", base64.StdEncoding.EncodeToString(params[0].([]byte))))

}

hash: 8320f72a78e69c58350e25d60a59f6b36fc5cf4da055ce9c9a0c6a63083912d1

updated: 2017-01-13T19:42:47.231844584Z

hash: d332790eaf0dd90a5d91b4fddfd82897055e261ff360d616cf363c0e689ab4f6

updated: 2017-03-10T18:12:22.221261057Z

imports:

- name: github.com/armon/go-metrics

  version: 97c69685293dce4c0a2d0b19535179bbc976e4d2

- name: github.com/gogo/protobuf

  version: 909568be09de550ed094403c2bf8a261b5bb730a

  subpackages:

  - gogoproto

  - proto

  - protoc-gen-gogo/descriptor

- name: github.com/golang/protobuf

  version: 8ee79997227bf9b34611aee7946ae64735e6fd93

- name: github.com/gorhill/cronexpr

  version: a557574d6c024ed6e36acc8b610f5f211c91568a

- name: github.com/gorilla/context

  version: 08b5f424b9271eedf6f9f0ce86cb9396ed337a42

- name: github.com/gorilla/handlers

  version: 1f512fc3f05332ba7117626cdfb4e07474e58e60

- name: github.com/lib/pq

  version: 22cb3e4c487ce6242e2b03369219e5631eed1221

  subpackages:

  - oid

- name: github.com/rubenv/sql-migrate

  version: a3ed23a40ebd39f82bf2a36768ed7d595f2bdc1e

  subpackages:

  - sqlparse

- name: github.com/satori/go.uuid

  version: b061729afc07e77a8aa4fad0a2fd840958f1942a

- name: github.com/uber-go/atomic

  version: f6b343c37ca80bfa8ea539da67a0b621f84fab1d

  subpackages:

  - bcrypt

  - blowfish

- name: golang.org/x/net

  version: 69d4b8aa71caaaa75c3dfc11211d1be495abec7c

  subpackages:

- name: Mo Firouz

  email: mo@herioclabs.com

import:

- package: golang.org/x/net/context

- package: golang.org/x/crypto/bcrypt

- package: golang.org/x/net

  subpackages:

  - context

- package: golang.org/x/crypto

  subpackages:

  - bcrypt

- package: github.com/golang/protobuf

- package: github.com/gogo/protobuf

  version: ~0.3.0

  version: ~1.1

- package: github.com/lib/pq

- package: github.com/rubenv/sql-migrate

- package: github.com/go-gorp/gorp/

- package: github.com/go-gorp/gorp

  version: ~2.0.0

- package: github.com/go-yaml/yaml

  version: v2

- package: github.com/satori/go.uuid

- package: github.com/dgrijalva/jwt-go

  version: ~3.0.0

- package: github.com/elazarl/go-bindata-assetfs/...

- package: github.com/elazarl/go-bindata-assetfs

  subpackages:

  - '...'

- package: github.com/gorhill/cronexpr

  version: ~1.0.0

			cmd.DoctorParse(os.Args[2:])

		case "migrate":

			cmd.MigrateParse(os.Args[2:], clogger)

		case "admin":

			cmd.AdminParse(os.Args[2:], clogger)

		}

	}