nmasse-itix / apicast-dynamic-router

Dynamic Routing for Apicast

Dynamic Routing for Apicast

Introduction

This project provides a dynamic routing module for Apicast. It routes the API request to the appropriate backend, based on an HTTP Header of the request.

A sample use case could be:

• A Load Balancer in front of Apicast identifies the source of the request (internal/external or dev/prod)
• The LB add the corresponding header (x-env: dev or x-env: prod for instance)
• Based on this header, the Apicast routes the API request to the corresponding backend

The API Backends are discovered by querying a Service Catalog. A sample service catalog is given with this project.

It is designed to be hosted on Apicast itself (or any nginx instance) in order to simplify the deployment.

Deployment

Put dynamic-router.conf in /opt/app-root/src/apicast.d/dynamic-router.conf:

oc create configmap apicast.d --from-file=apicast-module/dynamic-router.conf
oc volume dc/apicast-staging --add --name=apicastd --mount-path /opt/app-root/src/apicast.d/ --type=configmap --configmap-name=apicast.d

Put dynamic-router-upstream.conf and catalog.conf in /opt/app-root/src/sites.d/:

oc create configmap sites.d --from-file=apicast-module/dynamic-router-upstream.conf --from-file=catalog/catalog.conf
oc volume dc/apicast-staging --add --name=sitesd --mount-path /opt/app-root/src/sites.d/ --type=configmap --configmap-name=sites.d

Put catalog.lua and dynamic-router.lua in /opt/app-root/src/src/custom/:

oc create configmap apicast-custom-module --from-file=apicast-module/dynamic-router.lua --from-file=catalog/catalog.lua
oc volume dc/apicast-staging --add --name=apicast-custom-module --mount-path /opt/app-root/src/src/custom/ --type=configmap --configmap-name=apicast-custom-module

Set the configuration required by the catalog and the dynamic routing module as environment variables and re-deploy apicast:

oc env dc/apicast-staging APICAST_CUSTOM_CONFIG=custom/dynamic-router
oc env dc/apicast-staging DYNAMIC_ROUTER_CATALOG_URL=http://127.0.0.1:8082
oc env dc/apicast-staging DYNAMIC_ROUTER_ENVIRONMENT_HEADER_NAME=x-env
oc rollout latest apicast-staging

Once, you get it to work on apicast-staging, you can do the same on apicast-production.