How to load go plugins using kong helm chart?

Questions
10

Ah, ok, i figured it out. I was building the plugins without CGO, since in order to have cgo i had to apk add build-base and I assumed I didn’t need it… A few people belly-aching about it here: https://github.com/docker-library/golang/issues/153
Since go’s plugin package requires C functions, without CGO my plugin was probably causing a seg-fault or some kind of error inside the plugin.open() function which is why i saw failed to open plugin go-hello: plugin: not implemented

Things are working as expected now. Here is the final docker-file for building this:

FROM golang:1.14.2-alpine as go-builder

# Because the plugin package needs cgo (https://golang.org/pkg/plugin/) 
# You can see some C code here: https://golang.org/src/plugin/plugin_dlopen.go
RUN apk add --no-cache build-base

# Build golang plugin(s)
WORKDIR /build
COPY ./custom-go-plugins ./
WORKDIR /build/go-hello/src
RUN go get -insecure ./...
RUN go build -buildmode=plugin .

# Build golang pluginserver
RUN go get github.com/Kong/go-pluginserver@v0.3.1


FROM kong:2.0
# Add golang app
COPY --from=go-builder --chown=kong:root /build/go-hello/src/go-hello.so /custom-go-plugins/
# Add the pluginserver
ENV goPath=/go
COPY --from=go-builder --chown=kong:root ${goPath}/bin/go-pluginserver /usr/local/bin/

And here is the patch I made to _helpers.tpl to allow adding golang plugins alongside my config-mapped LUA plugins:

--- a/kong/kong-1.5.0/templates/_helpers.tpl
+++ b/kong/kong-1.5.0/templates/_helpers.tpl
@@ -296,6 +296,9 @@ The name of the service used for the ingress controller's validation webhook
 
 {{- define "kong.plugins" -}}
 {{ $myList := list "bundled" }}
+{{- range .Values.plugins.goPlugins -}}
+{{- $myList = append $myList .pluginName -}}
+{{- end -}}
 {{- range .Values.plugins.configMaps -}}
 {{- $myList = append $myList .pluginName -}}
 {{- end -}}

So my values.yaml file has a plugins block like this:

plugins: 
  configMaps:
  - name: kong-plugin-myheader
    pluginName: kong-plugin-myheader
  - name: kong-plugin-uuid-filter
    pluginName: uuid-filter
  - name: kong-plugin-jwt-extract-uuid
    pluginName: jwt-extract-uuid
  - name: kong-plugin-jwt-claims-headers
    pluginName: jwt-claims-headers
  - name: kong-plugin-uuid-req-transformer
    pluginName: uuid-req-transformer
  - name: kong-plugin-uuid-uri-rewrite
    pluginName: uuid-uri-rewrite
  goPlugins:
  - pluginName: go-hello

Happy to submit some pull-requests… I am just not sure where, or if this is how the maintainers want to do things going forward. Let me know.
Cheers!