SRT - SubReddit Tracking

This has a few parts to it

Getting a list of new subreddits

Every 30 minutes or so check for new subreddits that are not yet accounted for and add them to the list of subreddits

Getting a count of subscribers for each subreddit

The reddit API asks that we make only 30 API calls / minute so if this app is tracking 30 subreddits they can all be updated in one minute.

To make sure I don't pass 30 calls/minute, I'm going to have a pool of api calls I'm allowed to make that gets filled at a rate of 1call/2000ms. Then every API call will go through this pool.

Will have to watch out for backpressure.

Calculating the "populatrity" metric

First round is the older version of the HN metric.

Given the age of the subreddit and the number of subscribers calculate a value.

Score = (S-1) / (T+2)^G

where,
S = Subscriber count (-1 negates the creator)
T = time since submission (in hours)
G = Gravity, defaults to 1.8 (will have to play wth this) 

Usage

Here's a simple go program that will print all the non 0 scores of recent subreddits. When you start the program, we start acquiring API calls. This will let us burst after our intial wait period. So after 2 minutes we will go get all the subreddits in quick succession.

package main

import (
	"fmt"
    "github.com/chuckha/srt"
)

func main() {
    srt.StartGetSubreddits(2)
	for k, sr := range srt.Tracking {
        fmt.Println(k, sr)
		if sr.Subscribers > 1 {
		    fmt.Println(sr.Score())
		}
	}
}