Update README

README.md

@@ -1,7 +1,59 @@
-New analyzer build pipeline
 
-To run locally,
 
-- setup `config/pipeline.yml`
+## Overview
-- ensure that there are `runc` and `img` binaries available in `./opt`
+
-- run script to build manually e.g `bin/build_analyzer ruby`
+The platform has a single 'router' process and one or more worker processes.
+
+Worker processes come in 4 main flavours
+
+- builder (these can 'build' containers and release them to ECR)
+- static-analyser (these run 'x-analyzer' language analyzers)
+- recommender (these run 'x-analyzer' language analyzers)
+- test-runner (these run 'x-analyzer' language analyzers)
+
+For the latter 3, it's also possible to scope a worker to a particular track. Messages
+will be delivered to a track-scoped worker (if available), else to a generic worker
+(if available). If no workers are available (either due to scoping, or there not
+being any of the suitable type) then a request will error.
+
+## Requirements
+
+- A Linux environment
+- The runc and img binaries available
+- zeromq native library (and headers) available
+
+## Local running example
+
+To run locally a routing daemon, a generic test runner, and a 'ruby' test runner
+
+First spawn the router. It will need a location for it's configuration file, and
+can create a missing file from a 'seed' template. This configuration will be updated
+if clients request new container versions to be released.
+
+```
+$> bundle exec bin/router /tmp/pipeline.yml --seed config/pipeline.yml --force-worker-restart
+```
+
+Next we spawn a generic test-runner. This runner will bootstrap off the router process (which is addressed as an
+  argument) and will then prepare all the containers it needs (downloading images as needed from ECR).
+
+Worker state will be maintained in the working directory (here /tmp/envs-w1) which should not be
+shared between processes.
+
+```
+$> bundle exec bin/worker listen worker-1 tcp://localhost:5555/test_runners /tmp/envs-w1
+```
+
+Next we spawn a ruby test-runner. This runner will also bootstrap off the router process but will
+only prepare containers required to run ruby tests. It therefore starts quicker on initial bootstrap.
+Once up, this worker will take all relevant ruby work on the test_runners channel.
+
+```
+$> bundle exec bin/worker listen worker-2 tcp://localhost:5555/test_runners?topic=ruby /tmp/envs-w2
+```
+
+The router should load balance, so if we're seeing a lot of ruby traffic, we might want a second worker. E.g.
+
+```
+$> bundle exec bin/worker listen worker-3 tcp://localhost:5555/test_runners?topic=ruby /tmp/envs-w3
+```