Observability in micro-service architectures

Lightning talk at dotGo 2014.
Video available here: https://www.youtube.com/watch?v=VoFfhEbcEG0

Introduces how we implement distributed request tracing at Hailo within our platform composed from micro-services built almost entirely in Go.

Using Go's Channels and Selects allows us to forward traces when possible, but not at the expense of serving requests to our end users.

Transcript

1. OBSERVABILITY IN MICROSERVICE ARCHITECTURES Matt Heath - Technical Lead, Platform @mattheath dotGo, Oct 2014
4. Go
 Service Go
 Service Java Service Load Balancer C* C* C* API / Routing RabbitMQ Message Bus
 (federated clusters per AZ) us-east-1 eu-west-1 Go
 Service Go
 Service Java Service Load Balancer C* C* C* API / Routing RabbitMQ Message Bus
 (federated clusters per AZ)
5. hailo~2~api api.v1.customer service.customer hailo~2~api api.v1.customer service.customer
6. hailo~2~api api.v1.customer service.customer hailo~2~api api.v1.customer service.customer REQ REP REQ REP IN OUT IN OUT
7. // Req sends a request, and... func (c *Client) Req(req *Request, rsp proto.Message, options ...Options) errors.Error { ! go c.traceReq(req) responseMsg, err := c.doReq(req, options...) go c.traceRsp(req, responseMsg, err) if err != nil { return err } ! // Do other things... ! return nil }
8. // instrumentedHandler wraps the handler providing instrumentation func (ep *Endpoint) instrumentedHandler(req *Request) (proto.Message, errors.Error) { ! start := time.Now() var err errors.Error var msg proto.Message ! // Defer panic handling defer func() { stats.Record(ep, err, time.Since(start)) // oh crap i hope this never happens }() ! // Execute handler go traceIn(req) msg, err = ep.Handler(req) go traceOut(req, msg, err, time.Since(start)) return msg, err }
9. hailo~2~api api.v1.customer service.customer REQ RSP REQ RSP IN OUT IN OUT NSQ
10. Phosphor Host Instances Publish Service A Trace Library goroutine chan UDP Service B Trace Library goroutine chan UDP Trace Service In-memory Aggregates Optional
 persistant storage Dashboards Monitoring
11. Phosphor Host Instances Publish Service A Trace Library goroutine chan UDP Service B Trace Library goroutine chan UDP Trace Service In-memory Aggregates Optional
 persistant storage Dashboards Monitoring
12. var traceChan chan []byte ! func init() { // Use a buffered channel traceChan = make(chan []byte, 200) ! // Fire off a background worker for this channel defaultClient = NewClient(traceChan) go defaultClient.publisher() } ! // Send, drops trace if the backend is at capacity func Send(msg []byte) { select { case traceChan <- msg: // Success default: // Default case fired if channel is full // Ensures non blocking } }
13. Phosphor Trace Service Host Instances Publish Service A Trace Library goroutine chan UDP Service B Trace Library goroutine chan UDP In-memory Aggregates Optional
 persistant storage Dashboards Monitoring
14. func (w *worker) loop() { var b []byte timeout := time.NewTicker(bufferWindow) defer timeout.Stop() // Bonus points ! // Spin and forward on traces every time our // buffer fills, or when our time window elapses for { select { case b = <-w.ch: w.buf = append(w.buf, b) if len(w.buf) >= bufferSize { w.send() } case <-timeout.C: w.send() } } }
15. Tracing: 33eda743-f124-435c-71fc-3c872bbc98e6 ! 2014-09-07 02:20:19.867 [/] [START] → - 2014-09-07 02:20:19.867 [eu-west-1a/ip-10-11-3-51] [REQ] com.hailocab.hailo-2-api → com.hailocab.api.v1.customer.neardrivers - 2014-09-07 02:20:19.867 [eu-west-1a/ip-10-11-2-203] [IN] com.hailocab.hailo-2-api → com.hailocab.api.v1.customer.neardrivers - 2014-09-07 02:20:19.868 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.feature-flags.features - 2014-09-07 02:20:19.869 [eu-west-1a/ip-10-11-3-111] [IN] com.hailocab.api.v1.customer → com.hailocab.service.feature-flags.features - 2014-09-07 02:20:19.876 [eu-west-1a/ip-10-11-3-111] [REQ] com.hailocab.service.feature-flags → com.hailocab.service.hob.list - 2014-09-07 02:20:19.877 [eu-west-1a/ip-10-11-3-168] [IN] com.hailocab.service.hob → com.hailocab.service.config.compile - 2014-09-07 02:20:19.877 [eu-west-1a/ip-10-11-3-111] [IN] com.hailocab.service.feature-flags → com.hailocab.service.hob.list - 2014-09-07 02:20:19.877 [eu-west-1a/ip-10-11-3-111] [REQ] com.hailocab.service.hob → com.hailocab.service.config.compile - 2014-09-07 02:20:19.883 [eu-west-1a/ip-10-11-3-168] [OUT] com.hailocab.service.hob → com.hailocab.service.config.compile - 5.59 ms 2014-09-07 02:20:19.886 [eu-west-1a/ip-10-11-3-111] [REP] com.hailocab.service.hob → com.hailocab.service.config.compile - 8.40 ms 2014-09-07 02:20:19.887 [eu-west-1a/ip-10-11-3-111] [OUT] com.hailocab.service.feature-flags → com.hailocab.service.hob.list - 9.72 ms 2014-09-07 02:20:19.889 [eu-west-1a/ip-10-11-3-111] [REP] com.hailocab.service.feature-flags → com.hailocab.service.hob.list - 13.23 ms 2014-09-07 02:20:19.889 [eu-west-1a/ip-10-11-3-111] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.feature-flags.features - 20.58 ms 2014-09-07 02:20:19.890 [eu-west-1a/ip-10-11-2-203] [REP] com.hailocab.api.v1.customer → com.hailocab.service.feature-flags.features - 22.59 ms 2014-09-07 02:20:19.902 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.903 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.903 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.904 [eu-west-1a/ip-10-11-3-111] [IN] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.904 [eu-west-1a/ip-10-11-3-111] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 0.36 ms 2014-09-07 02:20:19.905 [eu-west-1a/ip-10-11-2-203] [REP] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 1.97 ms 2014-09-07 02:20:19.905 [eu-west-1a/ip-10-11-2-214] [IN] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.905 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.nearest-driver.search - 2014-09-07 02:20:19.905 [eu-west-1a/ip-10-11-2-214] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 0.10 ms
 ERR - com.hailocab.service.fare.basefare: Missing config at xxx 2014-09-07 02:20:19.906 [eu-west-1a/ip-10-11-2-214] [IN] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 2014-09-07 02:20:19.906 [eu-west-1a/ip-10-11-2-214] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.fare.basefare - 0.06 ms 
 ERR - com.hailocab.service.fare.basefare: Missing config at xxx 2014-09-07 02:20:19.907 [eu-west-1a/ip-10-11-3-58] [IN] com.hailocab.api.v1.customer → com.hailocab.service.nearest-driver.search - 2014-09-07 02:20:19.907 [eu-west-1a/ip-10-11-3-58] [REQ] com.hailocab.service.nearest-driver → com.hailocab.service.zoning.search - 2014-09-07 02:20:19.908 [eu-west-1a/ip-10-11-3-58] [IN] com.hailocab.service.nearest-driver → com.hailocab.service.zoning.search - 2014-09-07 02:20:19.908 [eu-west-1a/ip-10-11-3-58] [OUT] com.hailocab.service.nearest-driver → com.hailocab.service.zoning.search - 0.20 ms 2014-09-07 02:20:19.909 [eu-west-1a/ip-10-11-3-58] [REP] com.hailocab.service.nearest-driver → com.hailocab.service.zoning.search - 2.25 ms 2014-09-07 02:20:19.909 [eu-west-1a/ip-10-11-3-58] [REQ] com.hailocab.service.nearest-driver → com.hailocab.service.raziel.multisearch - 2014-09-07 02:20:19.912 [eu-west-1a/ip-10-11-3-227] [IN] com.hailocab.service.nearest-driver → com.hailocab.service.raziel.multisearch - 2014-09-07 02:20:19.919 [eu-west-1a/ip-10-11-3-58] [REP] com.hailocab.service.nearest-driver → com.hailocab.service.raziel.multisearch - 9.46 ms 2014-09-07 02:20:19.919 [eu-west-1a/ip-10-11-3-58] [REQ] com.hailocab.service.nearest-driver → com.hailocab.service.eta.multitraveltime - 2014-09-07 02:20:19.919 [eu-west-1a/ip-10-11-3-227] [OUT] com.hailocab.service.nearest-driver → com.hailocab.service.raziel.multisearch - 7.58 ms 2014-09-07 02:20:19.920 [eu-west-1a/ip-10-11-3-58] [IN] com.hailocab.service.nearest-driver → com.hailocab.service.eta.multitraveltime - 2014-09-07 02:20:19.920 [eu-west-1a/ip-10-11-3-58] [OUT] com.hailocab.service.nearest-driver → com.hailocab.service.eta.multitraveltime - 0.06 ms 2014-09-07 02:20:19.921 [eu-west-1a/ip-10-11-3-58] [REP] com.hailocab.service.nearest-driver → com.hailocab.service.eta.multitraveltime - 1.77 ms 2014-09-07 02:20:19.921 [eu-west-1a/ip-10-11-3-58] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.nearest-driver.search - 14.02 ms 2014-09-07 02:20:19.921 [eu-west-1a/ip-10-11-2-203] [REP] com.hailocab.api.v1.customer → com.hailocab.service.nearest-driver.search - 15.48 ms 2014-09-07 02:20:19.941 [eu-west-1a/ip-10-11-2-203] [REQ] com.hailocab.api.v1.customer → com.hailocab.service.experiment.readlastupdated - 2014-09-07 02:20:19.945 [eu-west-1a/ip-10-11-2-214] [IN] com.hailocab.api.v1.customer → com.hailocab.service.experiment.readlastupdated - 2014-09-07 02:20:19.947 [eu-west-1a/ip-10-11-2-214] [OUT] com.hailocab.api.v1.customer → com.hailocab.service.experiment.readlastupdated - 1.82 ms 2014-09-07 02:20:19.947 [eu-west-1a/ip-10-11-2-203] [REP] com.hailocab.api.v1.customer → com.hailocab.service.experiment.readlastupdated - 6.01 ms 2014-09-07 02:20:19.948 [eu-west-1a/ip-10-11-2-203] [OUT] com.hailocab.hailo-2-api → com.hailocab.api.v1.customer.neardrivers - 80.46 ms 2014-09-07 02:20:19.950 [eu-west-1a/ip-10-11-3-51] [REP] com.hailocab.hailo-2-api → com.hailocab.api.v1.customer.neardrivers - 82.71 ms
20. THANKS PS. We’re hiring! dotGo, Oct 2014