http://codyaray.com/2016/02/how-to-ingest-app-metrics-from-slack-into-elasticsearch

historical.py

#!/usr/bin/env python
from slackclient import SlackClient
from elasticsearch import Elasticsearch
from plugins.elastic.elastic import CHANNEL, USER_ID, process_message, to_metric
from datetime import datetime
import yaml
import json

ELASTIC_HOST = '[your-hostname]'
SIZE = 1000
OLDEST = 0
LATEST = datetime.now()

config = yaml.load(file('rtmbot.conf', 'r'))
sc = SlackClient(config["SLACK_TOKEN"])
client = Elasticsearch(ELASTIC_HOST)

response = json.loads(sc.api_call('channels.history', channel=CHANNEL, count=SIZE, oldest=OLDEST, latest=LATEST))
for message in response['messages']:
    if 'channel' not in message:
        message['channel'] = CHANNEL
    if 'user' not in message:
        message['user'] = USER_ID
    process_message(message)

while response['has_more']:
    oldest_ts = response['messages'][-1]['ts']
    response = json.loads(sc.api_call('channels.history', channel=CHANNEL, count=SIZE, oldest=OLDEST, latest=oldest_ts))
    for message in response['messages']:
        if 'channel' not in message:
            message['channel'] = CHANNEL
        if 'user' not in message:
            message['user'] = USER_ID
        process_message(message)

if 'is_limited' in response and response['is_limited']:
    print "We have more messages that we can't access. :'("