Documentation
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Overview ¶
Package cluster implements an almost drop-in replacement for a normal Client which accounts for a redis cluster setup. It will transparently redirect requests to the correct nodes, as well as keep track of which slots are mapped to which nodes and updating them accordingly so requests can remain as fast as possible.
This package will initially call `cluster slots` in order to retrieve an initial idea of the topology of the cluster, but other than that will not make any other extraneous calls.
All methods on a Cluster are thread-safe, and connections are automatically pooled
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // BadCmdNoKey is an error reply returned when no key is given to the Cmd // method BadCmdNoKey = &redis.CmdError{errors.New("bad command, no key")} )
Functions ¶
Types ¶
type Cluster ¶
type Cluster struct {
// Number of slot misses. This is incremented everytime a command's reply is
// a MOVED or ASK message. This should be accessed in a thread-safe manner,
// i.e. when no other routines can be calling any methods on this Cluster
Misses uint64
// contains filtered or unexported fields
}
Cluster wraps a Client and accounts for all redis cluster logic
func NewCluster ¶
NewCluster will perform the following steps to initialize:
- Connect to the node given in the argument
- Use that node to call CLUSTER SLOTS. The return from this is used to build a mapping of slot number -> connection. At the same time any new connections which need to be made are created here.
- *Cluster is returned
At this point the Cluster has a complete view of the cluster's topology and can immediately start performing commands with (theoretically) zero slot misses
func NewClusterTimeout ¶
NewClusterTimeout is the Same as NewCluster, but will use timeout as the read/write timeout when communicating with cluster nodes
func NewClusterWithOpts ¶ added in v0.5.2
NewClusterWithOpts is the same as NewCluster, but with more fine-tuned configuration options. See ClusterOpts for more available options
func (*Cluster) ClientForKey ¶
ClientForKey returns the Client which *ought* to handle the given key (along with the node address for that client), based on Cluster's understanding of the cluster topology at the given moment. If the slot isn't known or there is an error contacting the correct node, a random client is returned.
The client retrieved by this method cannot be returned back to the pool inside Cluster, meaning you must call Close() on it when you're done with it. Cluster will generate new connections for its pool if need be, so don't worry about not having to return it.
func (*Cluster) Close ¶
func (c *Cluster) Close()
Close calls Close on all connected clients. Once this is called no other methods should be called on this instance of Cluster
func (*Cluster) Cmd ¶
Cmd performs the given command on the correct cluster node and gives back the command's reply. The command *must* have a key parameter (i.e. len(args) >= 1). If any MOVED or ASK errors are returned they will be transparently handled by this method. This method will also increment the Misses field on the Cluster struct whenever a redirection occurs
func (*Cluster) Reset ¶
Reset will re-retrieve the cluster topology and set up/teardown connections as necessary. It begins by calling CLUSTER SLOTS on a random known connection. The return from that is used to re-create the topology, create any missing clients, and close any clients which are no longer needed.
This call is inherently throttled, so that multiple clients can call it at the same time and it will only actually occur once (subsequent clients will have nil returned immediately).
type Opts ¶ added in v0.5.2
type Opts struct {
// Required. The address of a single node in the cluster
Addr string
// Read and write timeout which should be used on individual redis clients.
// Default is to not set the timeout and let the connection use it's default
Timeout time.Duration
// The size of the connection pool to use for each host. Default is 10
PoolSize int
// The time which must elapse between subsequent calls to create a new
// connection pool (on a per redis instance basis) in certain circumstances.
// The default is 500 milliseconds
PoolThrottle time.Duration
// The time which must elapse between subsequent calls to Reset(). The
// default is 500 milliseconds
ResetThrottle time.Duration
}
Opts are Options which can be passed in to NewClusterWithOpts. If any are set to their zero value the default value will be used instead
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