playground-reactive-stacks

This is a playground project to learn and compare different JVM reactive stacks like:

• Akka-Http with Slick
• Spring-Webflux (Reactor) with R2DBC
• VertX-Web

Playground application

The playground application is a REST API for tracking Emoji usage, like EmojiTracker. The application is exposing a REST API with the following endpoints:

list	GET /emojis
create	POST /emojis
list recent	GET /emojis/recent?seconds={seconds}
get emoji by UTF-8 code	GET /emojis/{code}
delete by UTF-8 code	DELETE /emojis/{code}
create emoji usage at date	POST /emojis/{code}[?usedAt=2018-10-23T15:49:47Z]

Local environment

java --version
openjdk 11.0.1 2018-10-16
OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)

lshw -short
WARNING: you should run this program as super-user.
H/W path       Device       Class          Description
======================================================
                            system         Computer
/0                          bus            Motherboard
/0/0                        memory         15GiB System memory
/0/1                        processor      Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz
...

Benchmark

The benchmark scenario was to run a Locust test to post 1 random emoji usage and list 3 times the recent emoji usages of the last 30 seconds.

Locust settings:
min_wait: 50
max_wait: 2000
users: 200
hatch rate: 5

Everything was used with the default configuration, using Postgres DB.

Akka-Slick

JAR size: 33M
Lines of code: 543
Developer experience/productivity (IMO): 3.5/5
Startup time: ~2.5 sec

01/26/2019 16:30:00.1548516600
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
[INFO] [01/26/2019 16:30:01.786] [main] [Server(akka://app)] Creating server...
[INFO] [01/26/2019 16:30:02.463] [main] [Server(akka://app)] Serving requests on port 8010

Spring-R2DBC

At this time R2DBC is not in Release state. Connection pooling is not implemented yet.

(Akka and VertX opened almost two times more threads with the default configuration)

JAR size: 18M
Lines of code: 326
Developer experience/productivity (IMO): 5/5
Startup time: ~3.5 sec

2019-26-01 16:56:50.1548518210
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.0.RELEASE)

2019-01-26 16:56:51.557  INFO 32573 --- [           main] reactivestack.SpringBApplication         : Starting SpringBApplication on zoli-laptop2 with PID 32573 (/home/zoli/drive/work/code/github/playground-reactive-stacks/spring-r2dbc/build/libs/spring-r2dbc-0.0.1-SNAPSHOT.jar started by zoli in /home/zoli/drive/work/code/github/playground-reactive-stacks/spring-r2dbc/build/libs)
2019-01-26 16:56:51.565  INFO 32573 --- [           main] reactivestack.SpringBApplication         : No active profile set, falling back to default profiles: default
2019-01-26 16:56:52.431  WARN 32573 --- [           main] reactor.netty.tcp.TcpResources           : [http] resources will use the default LoopResources: DefaultLoopResources {prefix=reactor-http, daemon=true, selectCount=4, workerCount=4}
2019-01-26 16:56:52.431  WARN 32573 --- [           main] reactor.netty.tcp.TcpResources           : [http] resources will use the default ConnectionProvider: PooledConnectionProvider {name=http, poolFactory=reactor.netty.resources.ConnectionProvider$$Lambda$243/0x000000080036e840@4e07b95f}
2019-01-26 16:56:53.465  INFO 32573 --- [           main] o.s.b.web.embedded.netty.NettyWebServer  : Netty started on port(s): 8020
2019-01-26 16:56:53.469  INFO 32573 --- [           main] reactivestack.SpringBApplication         : Started SpringBApplication in 2.647 seconds (JVM running for 3.216)

At the end of the test some connection errors appeared:

2019-01-27 08:55:40.508 ERROR 16284 --- [tor-tcp-epoll-2] i.r.p.client.ReactorNettyClient          : Error: SEVERITY_LOCALIZED=FATAL, SEVERITY_NON_LOCALIZED=FATAL, CODE=53300, MESSAGE=sorry, too many clients already, FILE=proc.c, LINE=339, ROUTINE=InitProcess
2019-01-27 08:55:40.510  WARN 16284 --- [tor-tcp-epoll-2] io.netty.channel.DefaultChannelPipeline  : An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.

io.netty.channel.ChannelPipelineException: reactor.netty.channel.ChannelOperationsHandler.handlerRemoved() has thrown an exception.

....
Caused by: reactor.core.Exceptions$ErrorCallbackNotImplemented: reactor.netty.channel.AbortedException: Connection has been closed
Caused by: reactor.netty.channel.AbortedException: Connection has been closed

2019-01-27 08:55:42.644 ERROR 16284 --- [or-http-epoll-2] reactor.netty.tcp.TcpServer              : [id: 0xd8fc67fd, L:/0:0:0:0:0:0:0:1%0:8020 - R:/0:0:0:0:0:0:0:1%0:34342] onUncaughtException(SimpleConnection{channel=[id: 0xd8fc67fd, L:/0:0:0:0:0:0:0:1%0:8020 - R:/0:0:0:0:0:0:0:1%0:34342]})

io.netty.channel.unix.Errors$NativeIoException: syscall:read(..) failed: Connection reset by peer
	at io.netty.channel.unix.FileDescriptor.readAddress(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.31.Final.jar:4.1.31.Final]

VertX

JAR size: 14M
Lines of code: 887
Developer experience/productivity (IMO): 1/5 (without RxJava2 callbacks makes it cumbersome)
Startup time: ~2.5 sec

01/26/2019 19:54:46.1548528886
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Jan 26, 2019 7:54:47 PM io.vertx.config.impl.ConfigRetrieverImpl
INFO: Config file path: conf/config.json, format:json
Jan 26, 2019 7:54:47 PM io.vertx.ext.asyncsql.impl.PostgreSQLClientImpl
INFO: Creating configuration for localhost:5432
Jan 26, 2019 7:54:47 PM reactivestack.util.VertxHelper
INFO: Created DB connection
Jan 26, 2019 7:54:48 PM reactivestack.util.VertxHelper
INFO: Application is listening on port 8030

At the end of the test some errors appeared:

Jan 26, 2019 8:00:01 PM io.vertx.core.eventbus.impl.HandlerRegistration
SEVERE: Failed to handleMessage. address: __vertx.reply.3011
java.lang.IllegalStateException: Response is closed
	at io.vertx.core.http.impl.HttpServerResponseImpl.checkValid(HttpServerResponseImpl.java:564)
	at io.vertx.core.http.impl.HttpServerResponseImpl.putHeader