X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/407798c1e1552e1f5e583ead63ed6b7c8ea20299..4b1f6ad3e7a5c7c28618e43e7539c9a937bf8521:/src/redis-trib.rb

diff --git a/src/redis-trib.rb b/src/redis-trib.rb
index d83c9f8e..1b83e19c 100755
--- a/src/redis-trib.rb
+++ b/src/redis-trib.rb
@@ -1,12 +1,213 @@
 #!/usr/bin/env ruby
 
+# TODO (temporary here, we'll move this into the Github issues once
+#       redis-trib initial implementation is complted).
+#
+# - Make sure that if the rehashing fails in the middle redis-trib will try
+#   to recover.
+# - When redis-trib performs a cluster check, if it detects a slot move in
+#   progress it should prompt the user to continue the move from where it
+#   stopped.
+# - Gracefully handle Ctrl+C in move_slot to prompt the user if really stop
+#   while rehashing, and performing the best cleanup possible if the user
+#   forces the quit.
+# - When doing "fix" set a global Fix to true, and prompt the user to
+#   fix the problem if automatically fixable every time there is something
+#   to fix. For instance:
+#   1) If there is a node that pretend to receive a slot, or to migrate a
+#      slot, but has no entries in that slot, fix it.
+#   2) If there is a node having keys in slots that are not owned by it
+#      fix this condiiton moving the entries in the same node.
+#   3) Perform more possibly slow tests about the state of the cluster.
+#   4) When aborted slot migration is detected, fix it.
+
 require 'rubygems'
 require 'redis'
 
+ClusterHashSlots = 4096
+
+def xputs(s)
+    printf s
+    STDOUT.flush
+end
+
+class ClusterNode
+    def initialize(addr)
+        s = addr.split(":")
+        if s.length != 2
+            puts "Invalid node name #{addr}"
+            exit 1
+        end
+        @r = nil
+        @info = {}
+        @info[:host] = s[0]
+        @info[:port] = s[1]
+        @info[:slots] = {}
+        @dirty = false # True if we need to flush slots info into node.
+        @friends = []
+    end
+
+    def friends
+        @friends
+    end
+
+    def slots 
+        @info[:slots]
+    end
+
+    def to_s
+        "#{@info[:host]}:#{@info[:port]}"
+    end
+
+    def connect(o={})
+        return if @r
+        xputs "Connecting to node #{self}: "
+        begin
+            @r = Redis.new(:host => @info[:host], :port => @info[:port])
+            @r.ping
+        rescue
+            puts "ERROR"
+            puts "Sorry, can't connect to node #{self}"
+            exit 1 if o[:abort]
+            @r = nil
+        end
+        puts "OK"
+    end
+
+    def assert_cluster
+        info = @r.info
+        if !info["cluster_enabled"] || info["cluster_enabled"].to_i == 0
+            puts "Error: Node #{self} is not configured as a cluster node."
+            exit 1
+        end
+    end
+
+    def assert_empty
+        if !(@r.cluster("info").split("\r\n").index("cluster_known_nodes:1")) ||
+            (@r.info['db0'])
+            puts "Error: Node #{self} is not empty. Either the node already knows other nodes (check with nodes-info) or contains some key in database 0."
+            exit 1
+        end
+    end
+
+    def load_info(o={})
+        self.connect
+        nodes = @r.cluster("nodes").split("\n")
+        nodes.each{|n|
+            # name addr flags role ping_sent ping_recv link_status slots
+            split = n.split
+            name,addr,flags,role,ping_sent,ping_recv,link_status = split[0..6]
+            slots = split[7..-1]
+            info = {
+                :name => name,
+                :addr => addr,
+                :flags => flags.split(","),
+                :role => role,
+                :ping_sent => ping_sent.to_i,
+                :ping_recv => ping_recv.to_i,
+                :link_status => link_status
+            }
+            if info[:flags].index("myself")
+                @info = @info.merge(info)
+                @info[:slots] = {}
+                slots.each{|s|
+                    if s[0..0] == '['
+                        # Fixme: for now skipping migration entries
+                    elsif s.index("-")
+                        start,stop = s.split("-")
+                        self.add_slots((start.to_i)..(stop.to_i))
+                    else
+                        self.add_slots((s.to_i)..(s.to_i))
+                    end
+                } if slots
+                @dirty = false
+                @r.cluster("info").split("\n").each{|e|    
+                    k,v=e.split(":")
+                    k = k.to_sym
+                    v.chop!
+                    if k != :cluster_state
+                        @info[k] = v.to_i
+                    else
+                        @info[k] = v
+                    end
+                }
+            elsif o[:getfriends]
+                @friends << info
+            end
+        }
+    end
+
+    def add_slots(slots)
+        slots.each{|s|
+            @info[:slots][s] = :new
+        }
+        @dirty = true
+    end
+
+    def flush_node_config
+        return if !@dirty
+        new = []
+        @info[:slots].each{|s,val|
+            if val == :new
+                new << s
+                @info[:slots][s] = true
+            end
+        }
+        @r.cluster("addslots",*new)
+        @dirty = false
+    end
+
+    def info_string
+        # We want to display the hash slots assigned to this node
+        # as ranges, like in: "1-5,8-9,20-25,30"
+        #
+        # Note: this could be easily written without side effects,
+        # we use 'slots' just to split the computation into steps.
+        
+        # First step: we want an increasing array of integers
+        # for instance: [1,2,3,4,5,8,9,20,21,22,23,24,25,30]
+        slots = @info[:slots].keys.sort
+
+        # As we want to aggregate adiacent slots we convert all the
+        # slot integers into ranges (with just one element)
+        # So we have something like [1..1,2..2, ... and so forth.
+        slots.map!{|x| x..x}
+
+        # Finally we group ranges with adiacent elements.
+        slots = slots.reduce([]) {|a,b|
+            if !a.empty? && b.first == (a[-1].last)+1
+                a[0..-2] + [(a[-1].first)..(b.last)]
+            else
+                a + [b]
+            end
+        }
+
+        # Now our task is easy, we just convert ranges with just one
+        # element into a number, and a real range into a start-end format.
+        # Finally we join the array using the comma as separator.
+        slots = slots.map{|x|
+            x.count == 1 ? x.first.to_s : "#{x.first}-#{x.last}"
+        }.join(",")
+
+        "[#{@info[:cluster_state].upcase}] #{self.info[:name]} #{self.to_s} slots:#{slots} (#{self.slots.length} slots)"
+    end
+
+    def info
+        @info
+    end
+    
+    def is_dirty?
+        @dirty
+    end
+
+    def r
+        @r
+    end
+end
+
 class RedisTrib
-    def xputs(s)
-        printf s
-        STDOUT.flush
+    def initialize
+        @nodes = []
     end
 
     def check_arity(req_args, num_args)
@@ -17,44 +218,265 @@ class RedisTrib
         end
     end
 
-    def parse_node(node)
-        s = node.split(":")
-        if s.length != 2
-            puts "Invalid node name #{node}"
+    def add_node(node)
+        @nodes << node
+    end
+
+    def get_node_by_name(name)
+        @nodes.each{|n|
+            return n if n.info[:name] == name.downcase
+        }
+        return nil
+    end
+
+    def check_cluster
+        puts "Performing Cluster Check (using node #{@nodes[0]})"
+        errors = []
+        show_nodes
+        # Check if all the slots are covered
+        slots = {}
+        @nodes.each{|n|
+            slots = slots.merge(n.slots)
+        }
+        if slots.length == 4096
+            puts "[OK] All 4096 slots covered."
+        else
+            errors << "[ERR] Not all 4096 slots are covered by nodes."
+            puts errors[-1]
+        end
+        return errors
+    end
+
+    def alloc_slots
+        slots_per_node = ClusterHashSlots/@nodes.length
+        i = 0
+        @nodes.each{|n|
+            first = i*slots_per_node
+            last = first+slots_per_node-1
+            last = ClusterHashSlots-1 if i == @nodes.length-1
+            n.add_slots first..last
+            i += 1
+        }
+    end
+
+    def flush_nodes_config
+        @nodes.each{|n|
+            n.flush_node_config
+        }
+    end
+
+    def show_nodes
+        @nodes.each{|n|
+            puts n.info_string
+        }
+    end
+
+    def join_cluster
+        # We use a brute force approach to make sure the node will meet
+        # each other, that is, sending CLUSTER MEET messages to all the nodes
+        # about the very same node.
+        # Thanks to gossip this information should propagate across all the
+        # cluster in a matter of seconds.
+        first = false
+        @nodes.each{|n|
+            if !first then first = n.info; next; end # Skip the first node
+            n.r.cluster("meet",first[:host],first[:port])
+        }
+    end
+
+    def yes_or_die(msg)
+        print "#{msg} (type 'yes' to accept): "
+        STDOUT.flush
+        if !(STDIN.gets.chomp.downcase == "yes")
+            puts "Aborting..."
             exit 1
         end
-        return {:host => s[0], :port => s[1].to_i}
     end
 
-    def connect_to_node(naddr)
-        xputs "Connecting to node #{naddr[:host]}:#{naddr[:port]}: "
-        begin
-            r = Redis.new(:host => naddr[:host], :port => naddr[:port])
-            r.ping
-        rescue
-            puts "ERROR"
-            puts "Sorry, can't connect to node #{naddr[:host]}:#{naddr[:port]}"
+    def load_cluster_info_from_node(nodeaddr)
+        node = ClusterNode.new(ARGV[1])
+        node.connect(:abort => true)
+        node.assert_cluster
+        node.load_info(:getfriends => true)
+        add_node(node)
+        node.friends.each{|f|
+            fnode = ClusterNode.new(f[:addr])
+            fnode.connect()
+            fnode.load_info()
+            add_node(fnode)
+        }
+    end
+
+    # Given a list of source nodes return a "resharding plan"
+    # with what slots to move in order to move "numslots" slots to another
+    # instance.
+    def compute_reshard_table(sources,numslots)
+        moved = []
+        # Sort from bigger to smaller instance, for two reasons:
+        # 1) If we take less slots than instanes it is better to start getting from
+        #    the biggest instances.
+        # 2) We take one slot more from the first instance in the case of not perfect
+        #    divisibility. Like we have 3 nodes and need to get 10 slots, we take
+        #    4 from the first, and 3 from the rest. So the biggest is always the first.
+        sources = sources.sort{|a,b| b.slots.length <=> a.slots.length}
+        source_tot_slots = sources.inject(0) {|sum,source| sum+source.slots.length}
+        sources.each_with_index{|s,i|
+            # Every node will provide a number of slots proportional to the
+            # slots it has assigned.
+            n = (numslots.to_f/source_tot_slots*s.slots.length)
+            if i == 0
+                n = n.ceil
+            else
+                n = n.floor
+            end
+            s.slots.keys.sort[(0...n)].each{|slot|
+                if moved.length < numslots
+                    moved << {:source => s, :slot => slot}
+                end
+            }
+        }
+        return moved
+    end
+
+    def show_reshard_table(table)
+        table.each{|e|
+            puts "    Moving slot #{e[:slot]} from #{e[:source].info[:name]}"
+        }
+    end
+
+    def move_slot(source,target,slot,o={})
+        # We start marking the slot as importing in the destination node,
+        # and the slot as migrating in the target host. Note that the order of
+        # the operations is important, as otherwise a client may be redirected to
+        # the target node that does not yet know it is importing this slot.
+        print "Moving slot #{slot} from #{source.info_string}: "; STDOUT.flush
+        target.r.cluster("setslot",slot,"importing",source.info[:name])
+        source.r.cluster("setslot",slot,"migrating",source.info[:name])
+        # Migrate all the keys from source to target using the MIGRATE command
+        while true
+            keys = source.r.cluster("getkeysinslot",slot,10)
+            break if keys.length == 0
+            keys.each{|key|
+                source.r.migrate(target.info[:host],target.info[:port],key,0,1000)
+                print "." if o[:verbose]
+                STDOUT.flush
+            }
+        end
+        puts
+        # Set the new node as the owner of the slot in all the known nodes.
+        @nodes.each{|n|
+            n.r.cluster("setslot",slot,"node",target.info[:name])
+        }
+    end
+
+    # redis-trib subcommands implementations
+
+    def check_cluster_cmd   
+        load_cluster_info_from_node(ARGV[1])
+        check_cluster
+    end
+
+    def reshard_cluster_cmd
+        load_cluster_info_from_node(ARGV[1])
+        errors = check_cluster
+        if errors.length != 0
+            puts "Please fix your cluster problems before resharding."
             exit 1
         end
-        puts "OK"
+        numslots = 0
+        while numslots <= 0 or numslots > 4096
+            print "How many slots do you want to move (from 1 to 4096)? "
+            numslots = STDIN.gets.to_i
+        end
+        target = nil
+        while not target
+            print "What is the receiving node ID? "
+            target = get_node_by_name(STDIN.gets.chop)
+            if not target
+                puts "The specified node is not known, please retry."
+            end
+        end
+        sources = []
+        puts "Please enter all the source node IDs."
+        puts "  Type 'all' to use all the nodes as source nodes for the hash slots."
+        puts "  Type 'done' once you entered all the source nodes IDs."
+        while true
+            print "Source node ##{sources.length+1}:"
+            line = STDIN.gets.chop
+            src = get_node_by_name(line)
+            if line == "done"
+                if sources.length == 0
+                    puts "No source nodes given, operation aborted"
+                    exit 1
+                else
+                    break
+                end
+            elsif line == "all"
+                @nodes.each{|n|
+                    next if n.info[:name] == target.info[:name]
+                    sources << n
+                }
+                break
+            elsif not src
+                puts "The specified node is not known, please retry."
+            elsif src.info[:name] == target.info[:name]
+                puts "It is not possible to use the target node as source node."
+            else
+                sources << src
+            end
+        end
+        puts "\nReady to move #{numslots} slots."
+        puts "  Source nodes:"
+        sources.each{|s| puts "    "+s.info_string}
+        puts "  Destination node:"
+        puts "    #{target.info_string}"
+        reshard_table = compute_reshard_table(sources,numslots)
+        puts "  Resharding plan:"
+        show_reshard_table(reshard_table)
+        print "Do you want to proceed with the proposed reshard plan (yes/no)? "
+        yesno = STDIN.gets.chop
+        exit(1) if (yesno != "yes")
+        reshard_table.each{|e|
+            move_slot(e[:source],target,e[:slot],:verbose=>true)
+        }
     end
 
-    def create_cluster
+    def create_cluster_cmd
         puts "Creating cluster"
-        ARGV[1..-1].each{|node|
-            naddr = parse_node(node)
-            r = connect_to_node(naddr)
+        ARGV[1..-1].each{|n|
+            node = ClusterNode.new(n)
+            node.connect(:abort => true)
+            node.assert_cluster
+            node.load_info
+            node.assert_empty
+            add_node(node)
         }
+        puts "Performing hash slots allocation on #{@nodes.length} nodes..."
+        alloc_slots
+        show_nodes
+        yes_or_die "Can I set the above configuration?"
+        flush_nodes_config
+        puts "** Nodes configuration updated"
+        puts "** Sending CLUSTER MEET messages to join the cluster"
+        join_cluster
+        check_cluster
     end
 end
 
 COMMANDS={
-    "create-cluster" => ["create_cluster", -2]
+    "create" => ["create_cluster_cmd", -2, "host1:port host2:port ... hostN:port"],
+    "check" =>  ["check_cluster_cmd", 2, "host:port"],
+    "reshard" =>  ["reshard_cluster_cmd", 2, "host:port"]
 }
 
 # Sanity check
 if ARGV.length == 0
     puts "Usage: redis-trib <command> <arguments ...>"
+    puts
+    COMMANDS.each{|k,v|
+        puts "  #{k.ljust(20)} #{v[2]}"
+    }
+    puts
     exit 1
 end