1# Tcl redis cluster client as a wrapper of redis.rb. 2# Copyright (C) 2014 Salvatore Sanfilippo 3# Released under the BSD license like Redis itself 4# 5# Example usage: 6# 7# set c [redis_cluster 127.0.0.1 6379 127.0.0.1 6380] 8# $c set foo 9# $c get foo 10# $c close 11 12package require Tcl 8.5 13package provide redis_cluster 0.1 14 15namespace eval redis_cluster {} 16set ::redis_cluster::id 0 17array set ::redis_cluster::startup_nodes {} 18array set ::redis_cluster::nodes {} 19array set ::redis_cluster::slots {} 20 21# List of "plain" commands, which are commands where the sole key is always 22# the first argument. 23set ::redis_cluster::plain_commands { 24 get set setnx setex psetex append strlen exists setbit getbit 25 setrange getrange substr incr decr rpush lpush rpushx lpushx 26 linsert rpop lpop brpop llen lindex lset lrange ltrim lrem 27 sadd srem sismember scard spop srandmember smembers sscan zadd 28 zincrby zrem zremrangebyscore zremrangebyrank zremrangebylex zrange 29 zrangebyscore zrevrangebyscore zrangebylex zrevrangebylex zcount 30 zlexcount zrevrange zcard zscore zrank zrevrank zscan hset hsetnx 31 hget hmset hmget hincrby hincrbyfloat hdel hlen hkeys hvals 32 hgetall hexists hscan incrby decrby incrbyfloat getset move 33 expire expireat pexpire pexpireat type ttl pttl persist restore 34 dump bitcount bitpos pfadd pfcount 35} 36 37proc redis_cluster {nodes} { 38 set id [incr ::redis_cluster::id] 39 set ::redis_cluster::startup_nodes($id) $nodes 40 set ::redis_cluster::nodes($id) {} 41 set ::redis_cluster::slots($id) {} 42 set handle [interp alias {} ::redis_cluster::instance$id {} ::redis_cluster::__dispatch__ $id] 43 $handle refresh_nodes_map 44 return $handle 45} 46 47# Totally reset the slots / nodes state for the client, calls 48# CLUSTER NODES in the first startup node available, populates the 49# list of nodes ::redis_cluster::nodes($id) with an hash mapping node 50# ip:port to a representation of the node (another hash), and finally 51# maps ::redis_cluster::slots($id) with an hash mapping slot numbers 52# to node IDs. 53# 54# This function is called when a new Redis Cluster client is initialized 55# and every time we get a -MOVED redirection error. 56proc ::redis_cluster::__method__refresh_nodes_map {id} { 57 # Contact the first responding startup node. 58 set idx 0; # Index of the node that will respond. 59 set errmsg {} 60 foreach start_node $::redis_cluster::startup_nodes($id) { 61 lassign [split $start_node :] start_host start_port 62 if {[catch { 63 set r {} 64 set r [redis $start_host $start_port] 65 set nodes_descr [$r cluster nodes] 66 $r close 67 } e]} { 68 if {$r ne {}} {catch {$r close}} 69 incr idx 70 if {[string length $errmsg] < 200} { 71 append errmsg " $start_node: $e" 72 } 73 continue ; # Try next. 74 } else { 75 break; # Good node found. 76 } 77 } 78 79 if {$idx == [llength $::redis_cluster::startup_nodes($id)]} { 80 error "No good startup node found. $errmsg" 81 } 82 83 # Put the node that responded as first in the list if it is not 84 # already the first. 85 if {$idx != 0} { 86 set l $::redis_cluster::startup_nodes($id) 87 set left [lrange $l 0 [expr {$idx-1}]] 88 set right [lrange $l [expr {$idx+1}] end] 89 set l [concat [lindex $l $idx] $left $right] 90 set ::redis_cluster::startup_nodes($id) $l 91 } 92 93 # Parse CLUSTER NODES output to populate the nodes description. 94 set nodes {} ; # addr -> node description hash. 95 foreach line [split $nodes_descr "\n"] { 96 set line [string trim $line] 97 if {$line eq {}} continue 98 set args [split $line " "] 99 lassign $args nodeid addr flags slaveof pingsent pongrecv configepoch linkstate 100 set slots [lrange $args 8 end] 101 if {$addr eq {:0}} { 102 set addr $start_host:$start_port 103 } 104 lassign [split $addr :] host port 105 106 # Connect to the node 107 set link {} 108 catch {set link [redis $host $port]} 109 110 # Build this node description as an hash. 111 set node [dict create \ 112 id $nodeid \ 113 addr $addr \ 114 host $host \ 115 port $port \ 116 flags $flags \ 117 slaveof $slaveof \ 118 slots $slots \ 119 link $link \ 120 ] 121 dict set nodes $addr $node 122 lappend ::redis_cluster::startup_nodes($id) $addr 123 } 124 125 # Close all the existing links in the old nodes map, and set the new 126 # map as current. 127 foreach n $::redis_cluster::nodes($id) { 128 catch { 129 [dict get $n link] close 130 } 131 } 132 set ::redis_cluster::nodes($id) $nodes 133 134 # Populates the slots -> nodes map. 135 dict for {addr node} $nodes { 136 foreach slotrange [dict get $node slots] { 137 lassign [split $slotrange -] start end 138 if {$end == {}} {set end $start} 139 for {set j $start} {$j <= $end} {incr j} { 140 dict set ::redis_cluster::slots($id) $j $addr 141 } 142 } 143 } 144 145 # Only retain unique entries in the startup nodes list 146 set ::redis_cluster::startup_nodes($id) [lsort -unique $::redis_cluster::startup_nodes($id)] 147} 148 149# Free a redis_cluster handle. 150proc ::redis_cluster::__method__close {id} { 151 catch { 152 set nodes $::redis_cluster::nodes($id) 153 dict for {addr node} $nodes { 154 catch { 155 [dict get $node link] close 156 } 157 } 158 } 159 catch {unset ::redis_cluster::startup_nodes($id)} 160 catch {unset ::redis_cluster::nodes($id)} 161 catch {unset ::redis_cluster::slots($id)} 162 catch {interp alias {} ::redis_cluster::instance$id {}} 163} 164 165proc ::redis_cluster::__dispatch__ {id method args} { 166 if {[info command ::redis_cluster::__method__$method] eq {}} { 167 # Get the keys from the command. 168 set keys [::redis_cluster::get_keys_from_command $method $args] 169 if {$keys eq {}} { 170 error "Redis command '$method' is not supported by redis_cluster." 171 } 172 173 # Resolve the keys in the corresponding hash slot they hash to. 174 set slot [::redis_cluster::get_slot_from_keys $keys] 175 if {$slot eq {}} { 176 error "Invalid command: multiple keys not hashing to the same slot." 177 } 178 179 # Get the node mapped to this slot. 180 set node_addr [dict get $::redis_cluster::slots($id) $slot] 181 if {$node_addr eq {}} { 182 error "No mapped node for slot $slot." 183 } 184 185 # Execute the command in the node we think is the slot owner. 186 set retry 100 187 while {[incr retry -1]} { 188 if {$retry < 5} {after 100} 189 set node [dict get $::redis_cluster::nodes($id) $node_addr] 190 set link [dict get $node link] 191 if {[catch {$link $method {*}$args} e]} { 192 if {$link eq {} || \ 193 [string range $e 0 4] eq {MOVED} || \ 194 [string range $e 0 2] eq {I/O} \ 195 } { 196 # MOVED redirection. 197 ::redis_cluster::__method__refresh_nodes_map $id 198 set node_addr [dict get $::redis_cluster::slots($id) $slot] 199 continue 200 } elseif {[string range $e 0 2] eq {ASK}} { 201 # ASK redirection. 202 set node_addr [lindex $e 2] 203 continue 204 } else { 205 # Non redirecting error. 206 error $e $::errorInfo $::errorCode 207 } 208 } else { 209 # OK query went fine 210 return $e 211 } 212 } 213 error "Too many redirections or failures contacting Redis Cluster." 214 } else { 215 uplevel 1 [list ::redis_cluster::__method__$method $id] $args 216 } 217} 218 219proc ::redis_cluster::get_keys_from_command {cmd argv} { 220 set cmd [string tolower $cmd] 221 # Most Redis commands get just one key as first argument. 222 if {[lsearch -exact $::redis_cluster::plain_commands $cmd] != -1} { 223 return [list [lindex $argv 0]] 224 } 225 226 # Special handling for other commands 227 switch -exact $cmd { 228 mget {return $argv} 229 } 230 231 # All the remaining commands are not handled. 232 return {} 233} 234 235# Returns the CRC16 of the specified string. 236# The CRC parameters are described in the Redis Cluster specification. 237set ::redis_cluster::XMODEMCRC16Lookup { 238 0x0000 0x1021 0x2042 0x3063 0x4084 0x50a5 0x60c6 0x70e7 239 0x8108 0x9129 0xa14a 0xb16b 0xc18c 0xd1ad 0xe1ce 0xf1ef 240 0x1231 0x0210 0x3273 0x2252 0x52b5 0x4294 0x72f7 0x62d6 241 0x9339 0x8318 0xb37b 0xa35a 0xd3bd 0xc39c 0xf3ff 0xe3de 242 0x2462 0x3443 0x0420 0x1401 0x64e6 0x74c7 0x44a4 0x5485 243 0xa56a 0xb54b 0x8528 0x9509 0xe5ee 0xf5cf 0xc5ac 0xd58d 244 0x3653 0x2672 0x1611 0x0630 0x76d7 0x66f6 0x5695 0x46b4 245 0xb75b 0xa77a 0x9719 0x8738 0xf7df 0xe7fe 0xd79d 0xc7bc 246 0x48c4 0x58e5 0x6886 0x78a7 0x0840 0x1861 0x2802 0x3823 247 0xc9cc 0xd9ed 0xe98e 0xf9af 0x8948 0x9969 0xa90a 0xb92b 248 0x5af5 0x4ad4 0x7ab7 0x6a96 0x1a71 0x0a50 0x3a33 0x2a12 249 0xdbfd 0xcbdc 0xfbbf 0xeb9e 0x9b79 0x8b58 0xbb3b 0xab1a 250 0x6ca6 0x7c87 0x4ce4 0x5cc5 0x2c22 0x3c03 0x0c60 0x1c41 251 0xedae 0xfd8f 0xcdec 0xddcd 0xad2a 0xbd0b 0x8d68 0x9d49 252 0x7e97 0x6eb6 0x5ed5 0x4ef4 0x3e13 0x2e32 0x1e51 0x0e70 253 0xff9f 0xefbe 0xdfdd 0xcffc 0xbf1b 0xaf3a 0x9f59 0x8f78 254 0x9188 0x81a9 0xb1ca 0xa1eb 0xd10c 0xc12d 0xf14e 0xe16f 255 0x1080 0x00a1 0x30c2 0x20e3 0x5004 0x4025 0x7046 0x6067 256 0x83b9 0x9398 0xa3fb 0xb3da 0xc33d 0xd31c 0xe37f 0xf35e 257 0x02b1 0x1290 0x22f3 0x32d2 0x4235 0x5214 0x6277 0x7256 258 0xb5ea 0xa5cb 0x95a8 0x8589 0xf56e 0xe54f 0xd52c 0xc50d 259 0x34e2 0x24c3 0x14a0 0x0481 0x7466 0x6447 0x5424 0x4405 260 0xa7db 0xb7fa 0x8799 0x97b8 0xe75f 0xf77e 0xc71d 0xd73c 261 0x26d3 0x36f2 0x0691 0x16b0 0x6657 0x7676 0x4615 0x5634 262 0xd94c 0xc96d 0xf90e 0xe92f 0x99c8 0x89e9 0xb98a 0xa9ab 263 0x5844 0x4865 0x7806 0x6827 0x18c0 0x08e1 0x3882 0x28a3 264 0xcb7d 0xdb5c 0xeb3f 0xfb1e 0x8bf9 0x9bd8 0xabbb 0xbb9a 265 0x4a75 0x5a54 0x6a37 0x7a16 0x0af1 0x1ad0 0x2ab3 0x3a92 266 0xfd2e 0xed0f 0xdd6c 0xcd4d 0xbdaa 0xad8b 0x9de8 0x8dc9 267 0x7c26 0x6c07 0x5c64 0x4c45 0x3ca2 0x2c83 0x1ce0 0x0cc1 268 0xef1f 0xff3e 0xcf5d 0xdf7c 0xaf9b 0xbfba 0x8fd9 0x9ff8 269 0x6e17 0x7e36 0x4e55 0x5e74 0x2e93 0x3eb2 0x0ed1 0x1ef0 270} 271 272proc ::redis_cluster::crc16 {s} { 273 set s [encoding convertto ascii $s] 274 set crc 0 275 foreach char [split $s {}] { 276 scan $char %c byte 277 set crc [expr {(($crc<<8)&0xffff) ^ [lindex $::redis_cluster::XMODEMCRC16Lookup [expr {(($crc>>8)^$byte) & 0xff}]]}] 278 } 279 return $crc 280} 281 282# Hash a single key returning the slot it belongs to, Implemented hash 283# tags as described in the Redis Cluster specification. 284proc ::redis_cluster::hash {key} { 285 # TODO: Handle hash slots. 286 expr {[::redis_cluster::crc16 $key] & 16383} 287} 288 289# Return the slot the specified keys hash to. 290# If the keys hash to multiple slots, an empty string is returned to 291# signal that the command can't be run in Redis Cluster. 292proc ::redis_cluster::get_slot_from_keys {keys} { 293 set slot {} 294 foreach k $keys { 295 set s [::redis_cluster::hash $k] 296 if {$slot eq {}} { 297 set slot $s 298 } elseif {$slot != $s} { 299 return {} ; # Error 300 } 301 } 302 return $slot 303} 304