Helm/Docker support for emqx-exproto and emqx-extension-hook

[daadu]

emqx-exproto and emqx-extension-hook are the newly released plugins, they require access to "custom code" written by user and "python3/java(coming soon)" runtime. Current Helm chart does not support this.

Possible Solution

1. Let user provide a docker registry that contains the code that needs to be executed, the Helm chart should make it a "sidecar" pod, the /code volume of the "sidecar" should be mounted to /extension. This is will give emqx access to user defined "code"
2. These plugins require "python3" or "java" runtimes inside the "emqx" docker, one solution that I can think of is to have variant of emqx docker images - emqx-4.2.3 tag for simple emqx, emqx-py3-4.2.3 tag for emqx+python3 and emqx-java-4.2.3 for emqx+java. The emqx-py3-* and emqx-java-* tagged docker images will have python and java runtimes inside the image. This could be done by using multi-stage docker build. Also an additional feature could be make the py3 and java runtimes tuneable - eg. user can change heap size of JVM, etc. using environment variables.

[daadu]

Please give me feedback on the proposed solution. I am interested on working on this feature.

[daadu]

Also could consider adding support for emqx-lua-hook

[Rory-Z]

Hi, @daadu
Thank you for your suggestion, we will further discuss the solution to this issue.
CC @HJianBo
Do you have any ideas ?

[daadu]

@zhanghongtong I have mentioned in Possible Solution section.

[HJianBo]

Hi @daadu We plan to refactor the implementation of these two plugins in 4.3. The new implementation will make procedure calls based on gRPC instead of the erlang port. In this way, the two plug-ins have a very flexible deployment approach