Establish a proxy server from the controller to the log database.
Redirect query commands send from client to database then proxy back the db response.
Use parameter binding instead of fmt.Sprintf to prevent SQL injection.
Add function log aggregation and persistence using Fluentd and InfluxDB.
Fluentd and a helper sidecar run as a daemonset. The poolmgr sets up logging for each function pod, using the helper sidecar. Fluentd forwards logs to InfluxDB, which is run as a deployment and service. The client CLI directly queries InfluxDB for logs.
Fluentd supports many outputs besides InfluxDB, so we aren't very tied to InfluxDB.
The setup is somewhat manual, which we should be able to improve by integrating this into the helm chart.
Diagram of component interactions: https://cloud.githubusercontent.com/assets/202578/23100399/b0e3ea00-f6ba-11e6-8f2f-6588cfef2e84.png
Fixes#139. The code before this change was saving up pointers to the loop variable in a slice. So loop was useless and we always chose the last pod in the list, whether it was ready or not. With this fix, choosePod should always return a ready pod.
Also adds a check for the pod phase, before looping over the containers in the pod, and discard pods that aren't running yet.
