ticketd

A distributed service for monotonically increasing tickets.

Features

• Generates unique tickets
• Simple API, uses the Redis Protocol
• Fault-tolerant, uses Raft Consensus Algorithm

Building

Go is required.

make

Running

It's ideal to have three, five, or seven nodes in your cluster.

Let's create the first node.

ticketd --id 1 --saddr :11001 --raddr :12001

This will create a node named 1 and bind the client service address to :11001 and the Raft network transport to :12001

Now let's create two more nodes and add them to the cluster

ticketd --id 2 --saddr :11002 --raddr :12002 --join :11001
ticketd --id 3 --saddr :11003 --raddr :12003 --join :11001

Now we have a fault-tolerant three node cluster up and running.

Using

You can use any Redis compatible client, the redis-cli, telnet, or netcat.

I'll use the redis-cli in the example below.

Connect to the leader. This will probably be the first node you created.

redis-cli -p 11001

Send the server a TICKET command and receive the first ticket.

redis> TICKET
1

From here on every TICKET command will guarentee to generate a value larger than the previous TICKETcommand.

redis> TICKET
2
redis> TICKET
3
redis> TICKET
4
redis> TICKET
5

Pipelining and Client Multiplexing

ticketd supports pipelining commands, which means you can put multiple TICKET commands into a single network packet. This is a performance enhancement and will multiply the speed of applying new tickets by the number of tickets per packet.

Client multiplexing is also supported, which means the server will read as many TICKET commands from all connected clients as possible and apply them as a group. This can be a big performance enhancement on a multi-core server with lots of concurrently connected clients.

Other Commands

PING
QUIT
RAFT.ADDVOTER id addr
RAFT.CONFIGURATION
RAFT.LASTCONTACT
RAFT.LEADER 
RAFT.REMOVESERVER id addr
RAFT.SNAPSHOT
RAFT.STATS

Durability

By default ticketd is highly durable, ensuring every command is applied to disk and fsynced. You can optionally choose to one of three durability levels (high,medium,low) when the server starts up. For example:

ticketd --id 1 --saddr :11001 --raddr :12001 --durability low

Contact

Josh Baker @tidwall

License

ticketd source code is available under the MIT License.