Building a cloud-friendly application

Larry Garfield


Larry implements Huggable
Software is eating the world, and cloud is eating software. (Source: @bassamtabbara)

What is cloud

What is
The Cloud?

These are separate questions...

The Cloud™: noun

Someone else's hard drive

Cloud computing: noun

Abstracting away physical infrastructure

Disposable application design

What makes an application

They're not rules

They're more like guidelines...

They're more like guidelines

Split code from content


  • Provided by developer
  • Carefully tested
  • Lives in version control
  • Read-only runtime


  • Provided by users
  • Frequently ad hoc
  • Lives in DB or filesystem
  • Writeable runtime
Don't mix the filesystems

Your application is disposable.
Your data is not.

Data flow

Code flows up to production, data flows down.

You don't get an in-between option


Cleanly separate "Dev provided" and "user provided" files

What is configuration?

Does config come from the developer or the user?

Git or Database?

Drupal Config Management

Drupal 8
  1. Configure in UI / DB
  2. Export to YAML
  3. Commit to Git
  4. Push / Pull
  5. Import back to DB



What happens at runtime
stays at runtime

Application slots into cluster

Dependency inject your environment

  • DB credentials (Solr, Redis, etc.)
  • API keys
  • All paths on disk
  • Domain names

Environment variables

          // PHP

          // Node.js

          // Go

          // Java


Need glue code / Symfony 3

// platform_parameters.php
    $relationships = json_decode(base64_decode(getenv('PLATFORM_RELATIONSHIPS')), true);

    foreach ($relationships['database'] as $endpoint) {
        if (!empty($endpoint['query']['is_master'])) {
            $container->setParameter('database_driver', 'pdo_'.$endpoint['scheme']);
            $container->setParameter('database_host', $endpoint['host']);
            $container->setParameter('database_port', $endpoint['port']);
            $container->setParameter('database_name', $endpoint['path']);
            $container->setParameter('database_user', $endpoint['username']);
            $container->setParameter('database_password', $endpoint['password']);
$container->setParameter('kernel.secret', getenv('PLATFORM_PROJECT_ENTROPY'));
 / Go

package conf
import (
  psh ""
var PshConfig = createPshConfigObj()

func createPshConfigObj() *psh.RuntimeConfig {
  config, _ := psh.NewRuntimeConfig()
  return config

package main

func main() {
  engine := gin.Default()
  // ...
  err := ginInstance.Run(":" + conf.PshConfig.Port())
 / Java Spring

package sh.platform.template;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import sh.platform.config.Config;
import sh.platform.config.MySQL;

import javax.sql.DataSource;

public class DataSourceConfig {
    @Bean(name = "dataSource")
    public DataSource getDataSource() {
        Config config = new Config();
        MySQL database = config.getCredential("database", MySQL::new);
        return database.get();
 / Kotlin

package sh.platform.template.spring.kotlin

import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import sh.platform.config.Config
import sh.platform.config.MySQL
import javax.sql.DataSource

class DataSourceConfig {

    @Bean(name = ["dataSource"])
    fun getDataSource(): DataSource {
        val config = Config()
        val database = config.getCredential("database") { MySQL(it) }
        return database.get()

Use DotEnv (.env files)

(Many to pick from in every language)

Trusted domains

(App-specific configuration)

Constants? Static config files?


Dependency inject your environment

User-configured connections


  1. Ask for DB credentials
  2. Ask user for basic site info
  3. Write credentials to config file
  4. Populate DB
  5. Write basic site info to config file/DB
  6. Profit!!!


Better installers

  • Pre-include connection glue
  • Installer skips pre-populated values
  • Do not download from installer

Avoid lock-in

Always be able to
take your business elsewhere.

Google has killed...

  • Reader
  • iGoogle
  • Google Talk
  • Google Health
  • Knol
  • Google Insights
  • Picnik
  • Buzz
  • Aardvark
  • Sidewiki
  • Notebook
  • Dictionary
  • Labs
  • Wave
  • SearchWiki
  • Dodgeball
  • Jaiku
  • Lively
  • Page Creator
  • Plus
  • Zeitgeist
  • Answers
  • Google X
  • Catalog
  • Web Accelerator
  • Video Player
  • Sets
  • SearchMash
  • Writely
  • Plus+

Source: WordStream (2015)

Use Free Software

Use replaceable services


  • MySQL/MariaDB
  • PostgreSQL
  • RabbitMQ
  • Solr/Elasticsearch
  • InfluxDB


  • Amazon RDS
  • Amazon DynamoDB
  • Azure Cosmos DB
  • Anything you can't replace in a day

Microservices: Threat or menace

What is a microservice?

There is no industry consensus yet regarding the properties of microservices, and an official definition is missing as well.


Properties of microservice design

(Sources: Wikipedia, Martin Fowler)

  • Single-purpose components
  • Dumb pipes (HTTP, IPC, etc.)
  • Separate teams
  • Independent releases

Every microservice treats every other microservice as a separate 3rd party
that may as well be a different company.


  • Different tools/languages
  • Small, focused, interdisiplinary teams
  • Strong separation of concerns
  • Scale/evolve/replace separately
Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization's communication structure.

Conway's Law


  • Network latency
  • Network points of failure (plural)
  • Transitioning code is 10x harder
  • API versioning
  • More staff needed
  • PHP startup time
"If one of your microservices going down means the others don't work, you don't have a microservice; you have a distributed monolith."

—A few dozen people

So if microservices aren't for me, what is?

Multi-Modal Monolith

Multi-Modal Monolith

  • Single team
  • Discrete components
  • Deploys as once
  • Usually one language (not required)
  • May share datastores

You've probably already done this

Multi-Modal Monolith


Cron jobs

Queue workers

"Admin" application

API app

All asynchronous

To summarize...

Remember what they say when you assume

Larry Garfield


Director of Developer Experience

The end-to-end web platform for agile teams

Stalk us at @PlatformSH

Buy my book!

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