Cluster test: Tcl cluster library initial skeleton.

2 files changed, 95 insertions, 2 deletions

diff --git a/tests/support/cluster.tcl b/tests/support/cluster.tcl
new file mode 100644
index 000000000..7097fbb48
--- /dev/null
+++ b/tests/support/cluster.tcl
@@ -0,0 +1,93 @@
+# Tcl redis cluster client as a wrapper of redis.rb.
+# Copyright (C) 2014 Salvatore Sanfilippo
+# Released under the BSD license like Redis itself
+#
+# Example usage:
+#
+# set c [redis_cluster 127.0.0.1 6379 127.0.0.1 6380]
+# $c set foo
+# $c get foo
+# $c close
+
+package require Tcl 8.5
+package provide redis_cluster 0.1
+
+namespace eval redis_cluster {}
+set ::redis_cluster::id 0
+array set ::redis_cluster::start_nodes {}
+array set ::redis_cluster::nodes {}
+array set ::redis_cluster::slots {}
+
+# List of "plain" commands, which are commands where the sole key is always
+# the first argument.
+set ::redis_cluster::plain_commands {
+    get set setnx setex psetex append strlen exists setbit getbit
+    setrange getrange substr incr decr rpush lpush rpushx lpushx
+    linsert rpop lpop brpop llen lindex lset lrange ltrim lrem
+    sadd srem sismember scard spop srandmember smembers sscan zadd
+    zincrby zrem zremrangebyscore zremrangebyrank zremrangebylex zrange
+    zrangebyscore zrevrangebyscore zrangebylex zrevrangebylex zcount
+    zlexcount zrevrange zcard zscore zrank zrevrank zscan hset hsetnx
+    hget hmset hmget hincrby hincrbyfloat hdel hlen hkeys hvals
+    hgetall hexists hscan incrby decrby incrbyfloat getset move
+    expire expireat pexpire pexpireat type ttl pttl persist restore
+    dump bitcount bitpos pfadd pfcount
+}
+
+proc redis_cluster {nodes} {
+    set id [incr ::redis_cluster::id]
+    set ::redis_cluster::start_nodes($id) $nodes
+    set ::redis_cluster::nodes($id) {}
+    set ::redis_cluster::slots($id) {}
+    set handle [interp alias {} ::redis_cluster::instance$id {} ::redis_cluster::__dispatch__ $id]
+    $handle refresh_nodes_map
+    return $handle
+}
+
+proc ::redis_cluster::__dispatch__ {id method args} {
+    if {[info command ::redis_cluster::__method__$method] eq {}} {
+        # Get the keys from the command.
+        set keys [::redis_cluster::get_keys_from_command $method $args]
+        if {$keys eq {}} {
+            error "Redis command '$method' is not supported by redis_cluster."
+        }
+
+        # Resolve the keys in the corresponding hash slot they hash to.
+        set slot [::redis_cluster::get_slot_from_keys $keys]
+        if {$slot eq {}} {
+            error "Invalid command: multiple keys not hashing to the same slot."
+        }
+
+        # Get the node mapped to this slot.
+        set node_id [dict get $::redis_cluster::slots($id) $slot]
+        if {$node_id eq {}} {
+            error "No mapped node for slot $slot."
+        }
+
+        # Execute the command in the node we think is the slot owner.
+        set node [dict get $::redis_cluster::nodes($id) $node_id]
+        set link [dict get $node link]
+        if {[catch {$link $method {*}$args} e]} {
+            # TODO: trap redirection error
+        }
+        return $e
+    } else {
+        uplevel 1 [list ::redis_cluster::__method__$method $id $fd] $args
+    }
+}
+
+proc ::redis_cluster::get_keys_from_command {cmd argv} {
+    set cmd [string tolower $cmd]
+    # Most Redis commands get just one key as first argument.
+    if {[lsearch -exact $::redis_cluster::plain_commands $cmd] != -1} {
+        return [list [lindex $argv 0]]
+    }
+
+    # Special handling for other commands
+    switch -exact $cmd {
+        mget {return $argv}
+    }
+
+    # All the other commands are not handled.
+    return {}
+}
diff --git a/tests/support/redis.tcl b/tests/support/redis.tcl
index 36b005a17..256fbc899 100644
--- a/tests/support/redis.tcl
+++ b/tests/support/redis.tcl
@@ -1,5 +1,5 @@
-# Tcl clinet library - used by test-redis.tcl script for now
-# Copyright (C) 2009 Salvatore Sanfilippo
+# Tcl client library - used by the Redis test
+# Copyright (C) 2009-2014 Salvatore Sanfilippo
 # Released under the BSD license like Redis itself
 #
 # Example usage: