Kong - custom plugins returning: custom-plugin plugin is enabled but not installed;

Question

I have an instance of Kong that I am running using Dockerfile with contents:

FROM kong:1.4.0

WORKDIR /files
COPY plugins kong/plugins
ENV KONG_LOG_LEVEL=debug
ENV KONG_PLUGINS custom-plugin
ENV KONG_LUA_PACKAGE_PATH /files/?.lua;;

However, on docker run, this returns

error loading plugin schemas: on plugin 'custom-plugin': custom-plugin plugin is enabled but not installed;

module 'kong.plugins.custom-plugin.handler' not found:No LuaRocks module found for kong.plugins.custom-plugin

I have confirmed that the files are in the correct structure, nested within the kong/plugins directory at runtime.

Can anyone help with solving this issue?

Dean Van Greunen · Accepted Answer · 2020-01-02T02:14:42.910

Check these resources out:

Bug Report from Kong: https://github.com/Kong/kong/issues/4696

I don't think it's the luarocks' problem
Indeed, I installed kong in docker whose image is built by a dockerfile.
In my docker file, I went into the folder which store the custom plugins,and then traverse and luarocks make them by shell.It looks like:

#install private plugins
cd APIGPlugins

for dir in `ls`; do
    if [ -d $dir ]; then
      cd $dir;
      luarocks make;
      cd ../;
    fi
done
and then, I run the docker images for a container by the directive:

sudo docker run -d --name kong \
    -e "KONG_DATABASE=off" \
    -e "KONG_DECLARATIVE_CONFIG=/etc/kong/kong.yml" \
    -e "KONG_PLUGINS=apig-response-transform" \
    -e "KONG_ADMIN_LISTEN=0.0.0.0:8001, 0.0.0.0:8444 ssl" \
    -p 8000:8000 \
    -p 8443:8443 \
    -p 8001:8001 \
    -p 8444:8444 \
    kong-plugin:v4
As u see, I set the kong plugin by the docker run env variable parameter for enable the plugin instead of setting in the kong.conf.
The logs were generated by directive of docker logs "container ID"
It works when I tried to install another custom plugin in this way,but not work when install the custom plugin I described before

Update

you need to install the lua-package manager luarocks

thank you for your answer. I tried running the solution as above, but the `luarocks make` line throws: Argument missing: please specify a rockspec to use on current directory. I'm running it in the plugins/custom-plugin directory, and I've also tried from within custom-plugin but I get the same error. — fuzzi, Jan 01 '20 at 21:57
you need to install the lua-package manager `luarocks` : [Documentaton Link](https://github.com/luarocks/luarocks/wiki/luarocks) | [Download Link](https://github.com/luarocks/luarocks/wiki/Download) — Dean Van Greunen, Jan 02 '20 at 02:12

score -1 · Answer 2 · answered Dec 16 '19 at 20:40

See if one of the instructions from Kong/kong-plugin-zipkin issue 5 (another plugin which depends on kong.plugins.custom-plugin.handler) would work for kong.plugins.custom-plugin.handler itself.

The gist of it is that the plugin should be available to Kong on disk, and added to the custom_plugins configuration property.

You can achieve this via various ways:

using Docker volumes,

creating your own image,

or even with projects or inspiration such as https://github.com/dojot/kong.

Don't forget that you can also specify configure Kong with environment variables, so using -e KONG_CUSTOM_PLUGINS=my-custom-plugin would also work.

The plugin also needs to be in the LUA_PATH (like PATH, but for Lua modules).

So, in short, one of the possible solutions would be to use volumes and environment variables:

Mount the plugin's code: -v /path/to/my-custom-plugin:/etc/kong/plugins/my-custom-plugin

Add the directory containing custom plugins to the LUA_PATH: -e KONG_LUA_PACKAGE_PATH=/etc/?.lua (Kong requires kong.plugins.custom-plugin.handler, which translates to /etc/kong/plugins/my-custom-plugin/handler.lua)

Instruct Kong to load the plugin with: -e KONG_CUSTOM_PLUGINS=my-custom-plugin

Follwing that, check first if this is a KONG_LUA_PATH problem, as in Kong/kong issue 3394.

This was about plugin migration, but might have an impact here as well.

as a short term solution, you should set your LUA_PATH environment variable to point to your custom plugin's installation path
(instead of lua_package_path in kong.conf or KONG_LUA_PACKAGE_PATH).

E.g. I just moved:
export KONG_LUA_PACKAGE_PATH="/path/to/some-custom-plugin/?.lua;;"
to:
export LUA_PATH="/path/to/some-custom-plugin/?.lua;$LUA_PATH"
And ran kong migrations up again, which successfully ran the plugin's migration.

That is because lua_package_path is only for runtime Kong (within nginx), and is not being considered by the CLI (the kong migrations command)

If I just commented the lua_package_path in kong.conf and exported LUA_PATH as you mentioned, it started giving me this error:
./kong:3: module 'luarocks.loader' not found:
The shell from which I am executing kong migrations up never had LUA_PATH set, even before. It appears luarocks internally creates LUA_PATH if it is not already set in the shell.

So the additional step I had to perform was to get the current LUA_PATH that's set internally by running "luarocks path" command and then take the result of that, and append my custom login plugin path to it and then export that LUA_PATH to get this to work.

Again, even this your current issue is not about migration, one of those variables might help.

Kong - custom plugins returning: custom-plugin plugin is enabled but not installed;

2 Answers2

Update