The looper microservice runs a dozen calls to broker REST APIs in a loop. You can use this for performance and load testing. It calls the broker service via the mpRestClient from MicroProfile, and builds and passes the JWT that it requires.
Note it deliberately does not cause any changes in loyalty level, since Twitter will disable your account if you blast in too many tweets per second. It also doesn't talk to Watson, since you only get 2500 free calls per month before it starts charging you per call.
It responds to a GET ?count={count} REST request, where you pass in the count of how many iterations
to run. If you omit the count query param, it assumes 1 iteration.
For example, if you hit the http://localhost:9080/looper?count=5 URL, it would run 5 iterations. It
returns the output from the various calls (various collections of JSON) as text/plain.
Note that the call doesn't return until all the iterations are complete. So you might be waiting a
long time in a browser (or curl) if you request a high count. To address that, there's also a
command-line client that will also get installed to the pod running the looper servlet. Just
kubectl exec into the pod, and then run ./loopctl.sh, passing it parameters as explained when you
run it with no parameters. It will run a specified number of iterations, on a specified number of
parallel threads. You will see output from every iteration, with timings. Or you can build the
CLI client locally and run it from your laptop, passing the node port, ingress or route URL of
where the looper servlet is running.
There is also a Cleanup utility that gets built into the loopctl.jar, and a cleanup.sh script that
gets installed into the Looper pod, alongside the loopctl.sh script. Simple invoke it and pass it a
prefix string, and it will iterate through all portfolios in the system and call the delete operation
on any that start with the specified prefix. Note that all portfolios created by Looper start with the
string Looper, and all created by Ryan's Gatling-based client
start with the string gatling-. So if you had to abort a Looper or Gatling run part way through for
whatever reason, and thus have a bunch of leftovers that didn't get the chance to be deleted at the end
as usual, this script will clean those up, so you are ready for the next run. It can be invoked (once
'kubectl exec'd into the Looper pod) via ./cleanup.sh Looper (or ./cleanup.sh gatling-).
Use WebSphere Liberty helm chart to deploy Looper microservice:
helm repo add ibm-charts https://raw.githubusercontent.com/IBM/charts/master/repo/stable/
helm install ibm-charts/ibm-websphere-liberty -f <VALUES_YAML> -n <RELEASE_NAME> --tlsIn practice this means you'll run something like:
helm repo add ibm-charts https://raw.githubusercontent.com/IBM/charts/master/repo/stable/
helm install ibm-charts/ibm-websphere-liberty -f manifests/looper-values.yaml -n looper --namespace stock-trader --tls