// NewCustom is like New except you can specify a DialFunc which will be
// used when creating new connections for the pool. The common use-case is to do
// authentication for new connections.
func NewCustom(network, addr string, size int, df DialFunc) (*Pool, error) {
var client *redis.Client
var err error
pool := make([]*redis.Client, 0, size)
for i := 0; i < size; i++ {
client, err = df(network, addr)
if err != nil {
for _, client = range pool {
client.Close()
}
pool = pool[0:]
break
}
pool = append(pool, client)
}
p := Pool{
Network: network,
Addr: addr,
pool: make(chan *redis.Client, len(pool)),
df: df,
}
for i := range pool {
p.pool <- pool[i]
}
return &p, err
}
// Put returns a client back to the pool. If the pool is full the client is
// closed instead. If the client is already closed (due to connection failure or
// what-have-you) it will not be put back in the pool
func (p *Pool) Put(conn *redis.Client) {
if conn.LastCritical == nil {
select {
case p.pool <- conn:
default:
conn.Close()
}
}
}
// Empty removes and calls Close() on all the connections currently in the pool.
// Assuming there are no other connections waiting to be Put back this method
// effectively closes and cleans up the pool.
func (p *Pool) Empty() {
var conn *redis.Client
for {
select {
case conn = <-p.pool:
conn.Close()
default:
return
}
}
}
// Put putss the connection back in its pool. To be used alongside any of the
// Get* methods once use of the redis.Client is done
func (c *Cluster) Put(conn *redis.Client) {
c.callCh <- func(c *Cluster) {
p := c.pools[conn.Addr]
if p == nil {
conn.Close()
return
}
p.Put(conn)
}
}
func (c *Cluster) clientCmd(
client *redis.Client, cmd string, args []interface{}, ask bool,
tried map[string]bool, haveReset bool,
) *redis.Resp {
var err error
var r *redis.Resp
defer c.Put(client)
if ask {
r = client.Cmd("ASKING")
ask = false
}
// If we asked and got an error, we continue on with error handling as we
// would normally do. If we didn't ask or the ask succeeded we do the
// command normally, and see how that goes
if r == nil || r.Err == nil {
r = client.Cmd(cmd, args...)
}
if err = r.Err; err == nil {
return r
}
// At this point we have some kind of error we have to deal with. The above
// code is what will be run 99% of the time and is pretty streamlined,
// everything after this point is allowed to be hairy and gross
haveTriedBefore := haveTried(tried, client.Addr)
tried = justTried(tried, client.Addr)
// Deal with network error
if r.IsType(redis.IOErr) {
// If this is the first time trying this node, try it again
if !haveTriedBefore {
if client, try2err := c.getConn("", client.Addr); try2err == nil {
return c.clientCmd(client, cmd, args, false, tried, haveReset)
}
}
// Otherwise try calling Reset() and getting a random client
if !haveReset {
if resetErr := c.Reset(); resetErr != nil {
return errorRespf("Could not get cluster info: %s", resetErr)
}
client, getErr := c.getConn("", "")
if getErr != nil {
return errorResp(getErr)
}
return c.clientCmd(client, cmd, args, false, tried, true)
}
// Otherwise give up and return the most recent error
return r
}
// Here we deal with application errors that are either MOVED or ASK
msg := err.Error()
moved := strings.HasPrefix(msg, "MOVED ")
ask = strings.HasPrefix(msg, "ASK ")
if moved || ask {
_, addr := redirectInfo(msg)
c.callCh <- func(c *Cluster) {
select {
case c.MissCh <- struct{}{}:
default:
}
}
// If we've already called Reset and we're getting MOVED again than the
// cluster is having problems, likely telling us to try a node which is
// not reachable. Not much which can be done at this point
if haveReset {
return errorRespf("Cluster doesn't make sense, %s might be gone", addr)
}
if resetErr := c.Reset(); resetErr != nil {
return errorRespf("Could not get cluster info: %s", resetErr)
}
haveReset = true
// At this point addr is whatever redis told us it should be. However,
// if we can't get a connection to it we'll never actually mark it as
// tried, resulting in an infinite loop. Here we mark it as tried
// regardless of if it actually was or not
tried = justTried(tried, addr)
client, getErr := c.getConn("", addr)
if getErr != nil {
return errorResp(getErr)
}
return c.clientCmd(client, cmd, args, ask, tried, haveReset)
}
// It's a normal application error (like WRONG KEY TYPE or whatever), return
// that to the client
return r
}