Keep watching and extending features of gRPC mercari.go #5

@kazegusuri ● Merpay Backend Engineer ● Architect Team 2015/11 2017/01 2018/01 SRE & Platform Platform Payment & Architect

Objective of this talk Just I talk about gRPC 01 Tell features of gRPC Just I talk about gRPC 03 02

⚠Disclaimers⚠ ● The contents are not for beginners of gRPC ● I am talking forever once started. You will fall asleep. ● The details are not described in this slide, just I talk ○ You are lucky! or unlucky for boring time ● This slide was originally created for internal meet up in merpay ○ for mercari employees

My information source of gRPC ● github.com/grpc/proposal ○ gRFC ● github.com/grpc/grpc-go ○ read almost all PRs ● github.com/grpc/grpc ○ no longer read ● Twitter ○ search grpc!!

gRFC ● Design proposals for substantial feature changes ● Public disucssion not only inside Google ○ Protobuf is still Google product.. not community ● Looks effective to keep consistent features in all language impls. ● Recommend to read merged docs for everyone

Recommended documentations ● github.com/grpc/grpc-go/Documentation ○ Docs for how to use features in grpc-go ○ Actively updated recently ● github.com/grpc/proposal ○ gRFC for new features ● github.com/grpc/grpc/doc ○ Useful specs still exist ○ not active for spec in favor of gRFC?

gRPC history ● 2015/02/25 Opensourced ● 2016/01/11 (First use in Mercari) ● 2016/07/26 (Protobuf3 v3.0.0) ● 2016/08/23 Generally available ● 2017/03/01 Became a CNCF project

Features of grpc-go Now I start to talk about new features of grpc-go for each releases

Before v1.0(GA) ● 2016/01/11 (First use in Mercari) ● 2016/01/26 Compression (deprecated) ● 2016/04/19 Server Interceptor ● 2016/04/23 (GoCon 2016 Spring) ● 2016/06/01 Balancer V1 (deprecated) ● 2016/06/29 Server Reflection ● 2016/07/27 Graceful Shutdown ● 2016/09/03 Client Interceptor

v1.0 2016/07/12 (~v1.2) ● stats 2017/01/10 ○ grpc.StatsHandler() ○ Various stats provided per requests/connections ○ OpenCensus uses this feature for instrumentation ● service config 2016/12/20 ○ grpc.WithServiceConfig() (deprecated) ○ services/methods configurations dynamically pupulated ● tap 2016/11/08 ○ grpc.InTapHandle() ○ called in very early stage after connected ○ I don’t know the use case...

v1.2 2017/03/21 ● keepalive ○ grpc.KeepaliveParams(), grpc.KeepaliveEnforcementPolicy() ○ Read grpc-go/Documentation/keepalive.md v1.3 2017/04/29 ● status ○ Introduced status package, which responsible for handling gRPC errors ○ Read grpc-go/Documentation/rpc-errors.md

v1.4 2017/06/08 ● CallOption ○ credentials.PerRPCCredentials ○ Set credential(metadata) per request ○ Read grpc-go/Documentation/grpc-auth-support.md ● CallOption ○ grpc.Max[Send,Recv]MsgSize, grpc.MaxCall[Send,Recv]MsgSize ○ Limit max message size in both client/server side v1.5 2017/07/20 ● No remarkable features

v1.6 2017/08/31 ● status ○ details support in server side ● DNS resolver (deprecated) ○ legacy resolver API called naming v1.7 2017/10/12 ● balancer, resolver ○ V2? API by gRFC L9 ○ Registration API for balancer, resolver ○ Resolver is used depending on scheme of an address in grpc.DialContext

v1.8 2017/11/27 ● client-side retry ○ transparent retry in client by gRFC A6 ○ retry to send a request when failure without sending any requests ● encoding ○ Registration API for grpc.Compressor interface for compress/decompress a message ○ Now server respects encoding/accept-encoding automatically! ○ Read grpc-go/Documentation/compression.md v1.9 2018/01/03 ● No remarkable features

v1.10 2018/02/16 ● encoding ○ Registration API for grpc.Codec interface for marshal/unmarshal a message ○ Now we can change a codec per call, not per connection(DialOption)! ○ Read grpc-go/Documentation/encoding.md v1.11 2018/03/28 ● credentials/alts ○ ALTS: Application Layer Transport Security

v1.12 2018/05/09 ● stickness ○ requested server is determined by sessionid value of metadata ● channelz ○ gRFC A14 ○ expose internal details about connections v1.13 2018/06/20 ● No remarkable features

v1.14 2018/08/01 ● client-side retry ○ gRFC A6 ○ client library handles retry by ServiceConfig per Method/StatusCode ● stickness ○ Reverted!!! ○ re-considering to implement balancer/resolver-base v1.15 2018/09/15 ● No remarkable features

v1.16 2018/10/24 ● healthcheck ○ Watch method in server ● channelz ○ added tracing event by gRFC A3 v1.17 2018/12/05 ● binarylog ○ gRFC A16 ○ official logging mechanism for message,metadata as protobuf ● healthcheck ○ client-side health check by gRFC A17

Extend the features ● interceptor ○ github.com/mercari/go-grpc-interceptor ■ no longer used… ○ internal usecase ■ DataDog for instrumentation ■ Notification with Sentry in case of unexpected errors like Unknown/Internal ○ middlewares for gRPC to resolve common use cases ● resolver ○ custom resolver for kubernetes specific named k8sdns ○ official dns resolver is not suitable for our use case

Extend the features ● reflection ○ kazegusuri/grpcurl ○ Easy to call gRPC method like curl without grpc-gateway ● channelz ○ kazegusuri/channelzcli ○ To observe state of gRPC connections for debugging

gRPC with protoc plugin ● kazegusuri/go-proto-zap-marshaler ○ generate go function to log proto message with zap ● kazegusuri/go-proto-anonymizer ○ generate go function to filter credentials or secrets fields in message

Extend the features (idea) ● service config ○ clients can know configs like retry policy, timeout ○ difficult to use DNS, how to provide…? e.g. custom resolver ● encoding (codec) ○ CSV/TSV codec…! ○ message passthrough gRPC proxy without any marshaling/unmarshaling ● stickness ○ use custom balancer instead ● binarylog ○ consider to use application log if better than interceptor