ryansmith3136

def log(data)
  result = nil
  if data.key?(:measure)
    name = data.delete(:measure).insert(0, ENV["APP_NAME"] + ".")
  end
  if block_given?
    start = Time.now
    result = yield
    elapsed = (Time.now.to_f - start.to_f) * 1000
    data.merge!("measure.#{name}" => elapsed.round)

ryansmith3136

class RackTimer
  def initialize(app)
    @app = app
  end

  def call(env)
    start_request = Time.now
    status, headers, body = @app.call(env)
    elapsed = (Time.now - start_request) * 1000
    $stdout.puts("request-id=#{env['HTTP_HEROKU_REQUEST_ID']} measure.rack-request=#{elapsed.round}ms")

ryansmith3136

Predictable Failure

Building systems that fail in predictable ways promote safety and sanity.

Original Audience: Heroku Waza 2013

About

• @ryandotsmith
• Engineer at Heroku for almost 3 years.

ryansmith3136

Tales From a Heroku User

Here are some things I have learned along the way.

Last Updated: 2013-02-08

Original Audience: Hack Reactor

About

ryansmith3136

Komrade

Komrade is a message queue for your workers. Komrade will help you manage background jobs for web applications.

HTTP based queueing service.

• PUT Job
• POST Job's Heartbeat
• PUT Job Failure
• GET Jobs

ryansmith3136

CREATE AGGREGATE array_accum (anyarray)
(
    sfunc = array_cat,
    stype = anyarray,
    initcond = '{}'
);  

ryansmith3136

package main

import (
  "encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"sync"
	"time"
	"io/ioutil"

ryansmith3136

package main

import (
	"database/sql"
	"fmt"
	_ "github.com/bmizerany/pq"
	"strconv"
	"strings"
)

ryansmith3136

Service Visibility

The purpose of service visibility is to reconcile the execution of software with the agreement between the provider & customer of the service. Thus, the service must have customers who are aware that they are in fact customers of the service and furthermore are aware of the expected level of performance. In the case of an e-commerce site, the customers of the service are the visitors to the site and the agreed level of service is such that the customer views pages at some small epsilon + the speed of light. The service level agreement is arbitrary and can be estimated by the service provider. (e.g. 100ms)

Service providers need tools to help reconcile each customer's interaction with the service to understand if there are any breaches in agreement. When the agreement is breached, visibility tooling should provide help in debugging the violating component that lead to the breach. Surfacing information to service operators with the least amount of paing is a challenge accepted by makers

ryansmith3136

Have you ever wondered about the least amount of memory a C or Go program will use on a 64bit Linux machine? Kr & I have, here is the results of our curiosity:

A simple C program:

void
main()
{
  for (;;) {
 }