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Norman Maurer 3d6e6136a9
Decouple EventLoop details from the IO handling for each transport to… (#8680)
* Decouble EventLoop details from the IO handling for each transport to allow easy re-use of code and customization

Motiviation:

As today extending EventLoop implementations to add custom logic / metrics / instrumentations is only possible in a very limited way if at all. This is due the fact that most implementations are final or even package-private. That said even if these would be public there are the ability to do something useful with these is very limited as the IO processing and task processing are very tightly coupled. All of the mentioned things are a big pain point in netty 4.x and need improvement.

Modifications:

This changeset decoubled the IO processing logic from the task processing logic for the main transport (NIO, Epoll, KQueue) by introducing the concept of an IoHandler. The IoHandler itself is responsible to wait for IO readiness and process these IO events. The execution of the IoHandler itself is done by the SingleThreadEventLoop as part of its EventLoop processing. This allows to use the same EventLoopGroup (MultiThreadEventLoupGroup) for all the mentioned transports by just specify a different IoHandlerFactory during construction.

Beside this core API change this changeset also allows to easily extend SingleThreadEventExecutor / SingleThreadEventLoop to add custom logic to it which then can be reused by all the transports. The ideas are very similar to what is provided by ScheduledThreadPoolExecutor (that is part of the JDK). This allows for example things like:

  * Adding instrumentation / metrics:
    * how many Channels are registered on an SingleThreadEventLoop
    * how many Channels were handled during the IO processing in an EventLoop run
    * how many task were handled during the last EventLoop / EventExecutor run
    * how many outstanding tasks we have
    ...
    ...
  * Implementing custom strategies for choosing the next EventExecutor / EventLoop to use based on these metrics.
  * Use different Promise / Future / ScheduledFuture implementations
  * decorate Runnable / Callables when submitted to the EventExecutor / EventLoop

As a lot of functionalities are folded into the MultiThreadEventLoopGroup and SingleThreadEventLoopGroup this changeset also removes:

  * AbstractEventLoop
  * AbstractEventLoopGroup
  * EventExecutorChooser
  * EventExecutorChooserFactory
  * DefaultEventLoopGroup
  * DefaultEventExecutor
  * DefaultEventExecutorGroup

Result:

Fixes https://github.com/netty/netty/issues/8514 .
2019-01-23 08:32:05 +01:00
.github Use GitHub Issue/PR Template Feature 2016-12-07 11:40:26 -08:00
.mvn support publishing snapshots from docker based ci (#8634) 2018-12-07 06:16:39 +01:00
all Remove OIO transport (and transports that depend on it). (#8580) 2018-11-21 15:23:18 +01:00
bom Remove OIO transport (and transports that depend on it). (#8580) 2018-11-21 15:23:18 +01:00
buffer Java 8 migration. Remove ThreadLocalProvider and inline java.util.concurrent.ThreadLocalRandom.current() where necessary. (#8762) 2019-01-22 20:14:28 +01:00
codec Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
codec-dns Java 8 migration. Remove ThreadLocalProvider and inline java.util.concurrent.ThreadLocalRandom.current() where necessary. (#8762) 2019-01-22 20:14:28 +01:00
codec-haproxy Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-http Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
codec-http2 Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
codec-memcache Correcting Maven Dependencies (#8622) 2018-12-06 09:02:00 +01:00
codec-mqtt Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-redis Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-smtp Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-socks Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-stomp Remove support for marking reader and writerIndex in ByteBuf to reduce overhead and complexity. (#8636) 2018-12-11 14:00:49 +01:00
codec-xml Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
common Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
dev-tools Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
docker Update to latest JDK8 and JDK11 releases (#8725) 2019-01-17 09:14:42 +01:00
example Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
handler Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
handler-proxy Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
license Add the NOTICE of the forked portion of Apache Harmony 2018-01-30 11:22:51 +01:00
microbench Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
resolver Java 8 migration. Remove ThreadLocalProvider and inline java.util.concurrent.ThreadLocalRandom.current() where necessary. (#8762) 2019-01-22 20:14:28 +01:00
resolver-dns Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
tarball Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
testsuite Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
testsuite-autobahn Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
testsuite-http2 Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
testsuite-osgi Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
testsuite-shading Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
transport Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
transport-native-epoll Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
transport-native-kqueue Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
transport-native-unix-common Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
transport-native-unix-common-tests Correcting Maven Dependencies (#8622) 2018-12-06 09:02:00 +01:00
transport-sctp Decouple EventLoop details from the IO handling for each transport to… (#8680) 2019-01-23 08:32:05 +01:00
.fbprefs Updated Find Bugs configuration 2009-03-04 10:33:09 +00:00
.gitattributes Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
.gitignore Exclude mainframer related files from git 2018-10-14 13:20:18 +02:00
CONTRIBUTING.md Move the pull request guide to the developer guide 2014-03-12 13:13:58 +09:00
LICENSE.txt Relicensed to Apache License v2 2009-08-28 07:15:49 +00:00
mvnw Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
mvnw.cmd Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
NOTICE.txt Add the NOTICE of the forked portion of Apache Harmony 2018-01-30 11:22:51 +01:00
pom.xml Require Java8 as minimum (#8739) 2019-01-22 08:48:18 +01:00
README.md Provide an Automatic-Module-Name for the netty-all artifact fixes #7644 2018-01-27 20:31:16 +01:00
run-example.sh Add UptimeServer and adjust UptimeClient's code style. 2017-04-28 07:41:07 +02:00

Netty Project

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.

How to build

For the detailed information about building and developing Netty, please visit the developer guide. This page only gives very basic information.

You require the following to build Netty:

Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.

Branches to look

Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.

Usage with JDK 9

Netty can be used in modular JDK9 applications as a collection of automatic modules. The module names follow the reverse-DNS style, and are derived from subproject names rather than root packages due to historical reasons. They are listed below:

  • io.netty.all
  • io.netty.buffer
  • io.netty.codec
  • io.netty.codec.dns
  • io.netty.codec.haproxy
  • io.netty.codec.http
  • io.netty.codec.http2
  • io.netty.codec.memcache
  • io.netty.codec.mqtt
  • io.netty.codec.redis
  • io.netty.codec.smtp
  • io.netty.codec.socks
  • io.netty.codec.stomp
  • io.netty.codec.xml
  • io.netty.common
  • io.netty.handler
  • io.netty.handler.proxy
  • io.netty.resolver
  • io.netty.resolver.dns
  • io.netty.transport
  • io.netty.transport.epoll (native omitted - reserved keyword in Java)
  • io.netty.transport.kqueue (native omitted - reserved keyword in Java)
  • io.netty.transport.unix.common (native omitted - reserved keyword in Java)
  • io.netty.transport.rxtx
  • io.netty.transport.sctp
  • io.netty.transport.udt

Automatic modules do not provide any means to declare dependencies, so you need to list each used module separately in your module-info file.