Add additional options to redis session prov

Adding option for frequency of checking timed out connections as well as
an option to specify retries.

These changes make redis provider more stable since connection problems
are becoming fewer.

Since redigo does not have this options and since redis_sentinel and
redis_cluster are using go-redis as a client, this commit changes from
redigo to go-redis for redis session provider.

Added tests for redis session provider as well.

pkg/session/redis_sentinel/sess_redis_sentinel.go

@@ -34,7 +34,7 @@ package redis_sentinel
 
 import (
 	"github.com/astaxie/beego/pkg/session"
-	"github.com/go-redis/redis"
+	"github.com/go-redis/redis/v7"
 	"net/http"
 	"strconv"
 	"strings"
@@ -157,6 +157,27 @@ func (rp *Provider) SessionInit(maxlifetime int64, savePath string) error {
 	} else {
 		rp.masterName = "mymaster"
 	}
+	var idleTimeout time.Duration = 0
+	if len(configs) > 5 {
+		timeout, err := strconv.Atoi(configs[4])
+		if err == nil && timeout > 0 {
+			idleTimeout = time.Duration(timeout) * time.Second
+		}
+	}
+	var idleCheckFrequency time.Duration = 0
+	if len(configs) > 6 {
+		checkFrequency, err := strconv.Atoi(configs[5])
+		if err == nil && checkFrequency > 0 {
+			idleCheckFrequency = time.Duration(checkFrequency) * time.Second
+		}
+	}
+	var maxRetries = 0
+	if len(configs) > 7 {
+		retries, err := strconv.Atoi(configs[6])
+		if err == nil && retries > 0 {
+			maxRetries = retries
+		}
+	}
 
 	rp.poollist = redis.NewFailoverClient(&redis.FailoverOptions{
 		SentinelAddrs: strings.Split(rp.savePath, ";"),
@@ -164,6 +185,9 @@ func (rp *Provider) SessionInit(maxlifetime int64, savePath string) error {
 		PoolSize:      rp.poolsize,
 		DB:            rp.dbNum,
 		MasterName:    rp.masterName,
+		IdleTimeout: idleTimeout,
+		IdleCheckFrequency: idleCheckFrequency,
+		MaxRetries: maxRetries,
 	})
 
 	return rp.poollist.Ping().Err()