Error handling. Vendoring

Signed-off-by: Ettore Dreucci <ettore.dreucci@gmail.com>

src/redisAPI.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/go-redis/redis"
+)
+
+const (
+	tkSet = "botTokens"
+)
+
+var (
+	//ErrRedisConnection is thrown when a redis connection error occurs
+	ErrRedisConnection = errors.New("redis: couldn't connect to remote instance")
+	//ErrRedisAddSet is thrown when it's not possible to add a key in a set
+	ErrRedisAddSet = errors.New("redis: couldn't add key in set")
+	//ErrRedisRetriveSet is thrown when it's not possible to retrive keys from a set
+	ErrRedisRetriveSet = errors.New("redis: couldn't retrive keys from set")
+	//ErrTokenParsing is thrown when it's not possible to parse the bot token
+	ErrTokenParsing = errors.New("botToken: cannot parse token")
+	//ErrTokenInvalid is thrown when the string parsed isn't a valid telegram bot token
+	ErrTokenInvalid = errors.New("botToken: string isn't a valid telegram bot token")
+	//ErrAddToken is thrown when one or more bot token hasn't been added
+	ErrAddToken = errors.New("couldn't add one or more token")
+)
+
+func redisInit(addr string, pwd string, db int) (*redis.Client, error) {
+	redisClient := redis.NewClient(&redis.Options{
+		Addr:     addr,
+		Password: pwd,
+		DB:       db,
+	})
+	err := redisClient.Ping().Err()
+	if err != nil {
+		log.Printf("Error in connecting to redis instance: %v", err)
+		return nil, ErrRedisConnection
+	}
+	return redisClient, nil
+}
+
+func addBotToken(newToken string, client *redis.Client) error {
+	token := strings.TrimSpace(newToken)
+	matched, err := regexp.MatchString("^\\d+\\:([0-9]|[A-z]|\\_|\\-)+", token)
+	if err != nil {
+		log.Printf("Error in parsing bot token: %v", err)
+		return ErrTokenParsing
+	}
+	if !matched {
+		return ErrTokenInvalid
+	}
+
+	err = client.SAdd(tkSet, token).Err()
+	if err != nil {
+		log.Printf("Error in adding new bot token: %v", err)
+		return ErrRedisAddSet
+	}
+	return nil
+}
+
+func addBotTokens(client *redis.Client) error {
+	fmt.Println("Add the new tokens, comma-separated:")
+	reader := bufio.NewReader(os.Stdin)
+	line, err := reader.ReadString('\n')
+	if err != nil {
+		log.Printf("Error in reading new bot tokens: %v", err)
+		return ErrStdRead
+	}
+	newTokens := strings.Split(line, ",")
+	for _, newToken := range newTokens {
+		err = addBotToken(newToken, client)
+		if err != nil {
+			log.Printf("Error in adding new bot token %s: %v", newToken, err)
+		}
+	}
+	return nil
+}
+
+func getBotTokens(client *redis.Client) ([]string, error) {
+	tkNum, err := client.SCard(tkSet).Result()
+	if err != nil {
+		log.Printf("Couldn't retrive number of bot tokens: %v", err)
+		return nil, ErrRedisRetriveSet
+	}
+	if tkNum == 0 {
+		fmt.Println("No bot token found.")
+		err := addBotTokens(client)
+		if err != nil {
+			log.Printf("Couldn't add new bot tokens: %v", err)
+			return nil, ErrAddToken
+		}
+	}
+
+	tokens, err := client.SMembers(tkSet).Result()
+	if err != nil {
+		log.Printf("Couldn't retrive bot tokens: %v", err)
+		return nil, ErrRedisRetriveSet
+	}
+
+	return tokens, nil
+}