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Fast messaging with Nats and Go

Federico Paolinelli
October 23, 2018
1.1k

Fast messaging with Nats and Go

Quick intro about Nats messaging system

Federico Paolinelli

October 23, 2018
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Transcript

  1. 6

  2. What to look for ▷ Messaging patterns ▷ Durability of

    the messages ▷ Ordering guarantees ▷ Routing capabilities ▷ Dev / Ops experience ▷ Performance ▷ Auth / authz 7
  3. “ We've seen many products and approaches that stress putting

    significant smarts into the communication mechanism itself [..] The microservice community favours an alternative approach: smart endpoints and dumb pipes 10 Martin Fowler
  4. The protocol PUB Publish a message to a subject, with

    optional reply subject SUB Subscribe to a subject (or subject wildcard) MSG Delivers a message payload to a subscriber UNSUB Unsubscribe (or auto-unsubscribe) from subject 12
  5. The server ▷ Single go executable ▷ Full mesh of

    servers ▷ Gossip based autodiscovery 15 gnatsd -p 4222 -cluster nats://localhost:4248 gnatsd -p 5222 -routes nats://localhost:4248
  6. 16 Nats Server 1 Nats Server 2 Nats Server 3

    Client 1 PUB HI.ALL HELLO Client 2 MSG HI.ALL HELLO Full Mesh of servers
  7. Queueing 21 Nats Server 2 Client 1 PUB HI.ALL HELLO

    Client 2 MSG HI.ALL HELLO Client 2 PUB HI.ALL HELLO1 MSG HI.ALL HELLO1
  8. Request - Reply 22 Nats Server 2 Client 1 PUB

    HI.ALL REPLY_HERE HELLO ? Client 2 MSG HI.ALL HELLO? Client 2 MSG HI.ALL HELLO? MSG REPLY_HERE GOLAB! MSG REPLY_HERE GOLAB!
  9. The Go client ▷ Knows about all the nodes of

    the mesh ▷ Reconnects gracefully ▷ Buffers the messages to be sent (up to 8MB) ▷ Buffers the messages to be consumed (65k / 65Kb) 24
  10. The Go client: pub/sub 25 nc, _ := nats.Connect(nats.DefaultURL) nc.Publish("foo",

    []byte("Hello World")) nc.Subscribe("foo", func(m *nats.Msg) { // handle the message }) nc.Flush() // chan subscribe ch := make(chan *nats.Msg, 64) sub, err := nc.ChanSubscribe("foo", ch) msg := <- ch
  11. The Go client: request 26 // Requests var response string

    err := c.Request("help", "help me", &response, 10*time.Millisecond) if err != nil { fmt.Printf("Request failed: %v\n", err) } // Replying c.Subscribe("help", func(subj, reply string, msg string) { c.Publish(reply, "I can help!") }) // Queue group reply nc.QueueSubscribe("help", "workers", func(msg *Msg) { c.Publish(msg.Reply, "I can help!") })
  12. The Go client ▷ Connection lifecycle callbacks ▷ Sync /

    async api ▷ Type safe encoders ▷ Context based requests 27
  13. Nats benchmarking tool 35 go run ./nats-bench.go -ms 16 -np

    1 -ns 5 -n 1000000 foo Starting benchmark [msgs=1000000, msgsize=16, pubs=1, subs=5] NATS Pub/Sub stats: 8,729,005 msgs/sec ~ 133.19 MB/sec Pub stats: 1,457,683 msgs/sec ~ 22.24 MB/sec Sub stats: 7,276,675 msgs/sec ~ 111.03 MB/sec [1] 1,456,749 msgs/sec ~ 22.23 MB/sec (1000000 msgs) [2] 1,455,785 msgs/sec ~ 22.21 MB/sec (1000000 msgs) [3] 1,455,848 msgs/sec ~ 22.21 MB/sec (1000000 msgs) [4] 1,455,864 msgs/sec ~ 22.21 MB/sec (1000000 msgs) [5] 1,455,335 msgs/sec ~ 22.21 MB/sec (1000000 msgs) min 1,455,335 | avg 1,455,916 | max 1,456,749 | stddev 459 msgs
  14. Other features ▷ TLS support ▷ Monitoring endpoints ▷ Authorization

    scheme ▷ Configuration reload ▷ Authentication ▷ K8s operator ▷ Prometheus exporter 37
  15. 39

  16. Features ▷ At least once guarantee ▷ Messages encoded with

    protobuf ▷ Durable subscriptions ▷ Queue groups ▷ Message Replay (date/time, offset, seqnum) 40
  17. Features ▷ SQL, File or memory storage ▷ Partitioning ▷

    Clustering ▷ Active / Passive ▷ No wildcarding 41
  18. LiftBridge ▷ A nats streaming alternative ▷ github.com/liftbridge-io/liftbridge ▷ Promises

    some features missing from nats streaming ▷ Can work together with Nats 43