// sendRPC takes an RPC call, and will send it to the correct region server. If
// the correct region server is offline or otherwise unavailable, sendRPC will
// continually retry until the deadline set on the RPC's context is exceeded.
func (c *Client) sendRPC(rpc hrpc.Call) (proto.Message, error) {
log.WithFields(log.Fields{
"Type": rpc.GetName(),
"Table": string(rpc.Table()),
"Key": string(rpc.Key()),
}).Debug("Sending RPC")
err := c.queueRPC(rpc)
if err == ErrDeadline {
return nil, err
} else if err != nil {
log.WithFields(log.Fields{
"Type": rpc.GetName(),
"Table": string(rpc.Table()),
"Key": string(rpc.Key()),
}).Debug("We hit an error queuing the RPC. Resending.")
// There was an error locating the region for the RPC, or the client
// for the region encountered an error and has shut down.
return c.sendRPC(rpc)
}
if err == nil {
var res hrpc.RPCResult
resch := rpc.GetResultChan()
select {
case res = <-resch:
case <-rpc.GetContext().Done():
return nil, ErrDeadline
}
err := res.Error
log.WithFields(log.Fields{
"Type": rpc.GetName(),
"Table": string(rpc.Table()),
"Key": string(rpc.Key()),
"Result": res.Msg,
"Error": err,
}).Debug("Successfully sent RPC. Returning.")
if _, ok := err.(region.RetryableError); ok {
return c.sendRPC(rpc)
} else if _, ok := err.(region.UnrecoverableError); ok {
// Prevents dropping into the else block below,
// error handling happens a few lines down
} else {
return res.Msg, res.Error
}
}
// There was an issue related to the network, so we're going to mark the
// region as unavailable, and generate the channel used for announcing
// when it's available again
region := rpc.GetRegion()
log.WithFields(log.Fields{
"Type": rpc.GetName(),
"Table": string(rpc.Table()),
"Key": string(rpc.Key()),
}).Debug("Encountered a network error. Region unavailable?")
if region != nil {
succ := region.MarkUnavailable()
if succ {
go c.reestablishRegion(region)
}
}
log.WithFields(log.Fields{
"Type": rpc.GetName(),
"Table": string(rpc.Table()),
"Key": string(rpc.Key()),
}).Debug("Retrying sendRPC")
return c.sendRPC(rpc)
}
