This changeset imples that apisix and the java plugin runner are run by the same user: maybe this needs to be documented?

TIPS to user:
To improve security, it is strongly recommended to use a separate user for apisix-plugin-runner

To improve security, it is strongly recommended to use a separate user for apisix-plugin-runner

Which is not possible with the proposed change.

Either we set 770 and use a common group between Apisix and the plugin runner
Or we could use a mechanism based on ACL permissions

Cf patch

socket-permission.patch.txt

@chibenwa you can submit a new PR, your patch contains some java code, and I do not know if we need it

I will close this PR after you submit a new ^_^

Need more PMCs to review your changing if there are correct

Here we go @membphis

#318