Set up caching

[jelmersnoeck]

We should set up a cache to enforce that a health check doesn't run too much unnecessarily.

Example:

• service A
  • health check 1 (validate db health)
• service B
  • health check 1 (validate db health)
  • health check 2 (validate health of service A)

When our LB does a health check on Service A, the result is cached for x amount of time. When the LB then does a health check for Service B, the result for Service A is re-used.

This allows us to not overload the health check endpoints with noise (if multiple sources validate this endpoint) and simply check when necessary.

[jelmersnoeck]

Closed by #4