math

Math is a service in Go which is expandable in a modular way. I started it mainly to serve some math formulas with standard caching, monitoring and other details.

Each new endpoint, like /math/add is a Go strcuture that impletemnts the following interface:

type operation interface {
	Immutable() bool
	Calc(param []byte, end chan bool) ([]byte, error)
}

Adding a new endpoint will be one line code.

m.formulas["/math/add"] = formulate("add", &add.Add{}, cacheTTL)

It was mainly an exercise for

• Having a complete service that handles monitoring, timeout, caching, shutdown.
• instrumenting different calls automatically.
• dockerizing the whole setup so user goes not need anything beside docker to run the service.
• having a modular design that adding/removing a new call will only take one line change.
• caching the results automatically based on endpoint requirments.

Build

This setup is fully dockerized to all you need is to do:

docker build -t imagename:version .
# or use make file examples
make build

Example of how run locally

Makefile has some sample command to help in testing the service.

$ make run
2020/03/14 17:20:06 Listening at 8080

# Now open a new terminal and try some calls

$ make example-factorial 
curl -X POST -d '{"x":9}' 'http://127.0.0.1:8080/math/factorial'
362880

# Timeout is 1s by default. To test that we can try this
$ curl -X POST -d '{"x":900000000}' 'http://127.0.0.1:8080/math/factorial'
Operation timedout

$ make stop

# To see the metrics published by this service we can do
$ make check-metrics
curl 'http://127.0.0.1:8080/metrics'
factorial_accesses 1.0
factorial_cache_misses 1.0
factorial_cache_size 0.0
factorial_calculation_time_bucket{le="0.0005"} 1.0
...