edpug 19/2/13
Heroku is a Platform As A Service (PAAS)
Supports the following languages:
Many others supported through "Buildpacks" https://devcenter.heroku.com/articles/third-party-buildpacks
facebook & heroku - September 2011.
http://developers.facebook.com/blog/post/558/
processes (the UNIX model)
Poka-yoke (ポカヨケ) - fail-safing/mistake-proofing
"to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur"
"a methodology for building software-as-a-service apps"
Get an account & grab the heroku toolbelt from https://toolbelt.heroku.com/
$ heroku login
Enter your Heroku credentials.
Email: enru@example.com
Password:
Could not find an existing public key.
Would you like to generate one? [Yn]
Generating new SSH public key.
Uploading ssh public key /Users/enru/.ssh/id_rsa.pub
Once you have logged in and sent a SSH key up to heroku you can create your app
with the heroku create command.
$ cd ~/myapp
$ heroku create
Creating stark-fog-398... done, stack is cedar
http://stark-fog-398.herokuapp.com/ | git@heroku.com:stark-fog-398.git
Git remote heroku added
heroku allows you to run as many processes as you like.
View your running process with heroku ps
By default, heroku provides one web process and tries to automatically identify your application type.
Commit a Procfile if you need more control over your processes.
$ cat Procfile
web: sh boot.sh
worker: php queue_runner.php
clock: php update_feed.php
Processes are scaled up ad down with heroku ps:scale web=2
We can store & display environment variables in heroku using the heroku config command.
$ heroku config:add MY_ENV_VAR=abc123
Setting config vars and restarting pacific-cove-5430... done, v11
MY_ENV_VAR: abc123
Storing the application's configuration in the environment makes it very easy to move between development, testing and production platforms.
It also reduces the risk of exposing confidential settings.
Local dev can be done using PHP's dev server.
Foreman (part of the heroku toolbelt) can also be used for local development
A local Procfile can be used to get Foreman to run the PHP dev server
$ cat Procfile.dev
web: php -S localhost:5000 -t .
$ foreman start -f Procfile.dev
21:32:27 web.1 | started with pid 25937
Our web app will now be available at http://localhost:5000/
dev/prod parity
Foreman also loads up any variables declared in a .env file into its environment
$ echo "STATUS=development" >>.env
There is an addon that will pull heroku config vars out into a local .env file that into can be used for local development with Foreman
https://github.com/ddollar/heroku-config
$ cat .env
STATUS=development
MY_ENV_VAR=abc123
heroku provides access to your application logs with heroku logs.
stdout and stderr go to logs.
Several filters to this command are available heroku logs --source app or heroku logs --ps web.
Logs can be tailed with heroku logs --tail.
Logs can be sent to syslogd on another machine.
$ heroku drains:add syslog://host1.example.com:514
Drain syslog://host1.example.com:514 added to myapp
Putting your app/site into maintenance mode is a simple as:
$ heroku maintenance:on
Visitors are redirected to the default maintenance page or the URL contained in the MAINTENANCE_PAGE_URL env var.
You can set a default 404 page by adding a ERROR_PAGE_URL variable to your heroku config.
heroku provides Postgres as a database solution
$ heroku addons:add heroku-postgresql:dev
Adding heroku-postgresql:dev to pacific... done, v69 (free)
Attached as HEROKU_POSTGRESQL_TEAL
Database has been created and is available
You can find info about your DB with heroku pg:info
heroku pg:psql will give you access to your production DB.
$ heroku pg:psql
psql (9.1.7, server 9.1.6)
SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)
Type "help" for help.
afhgf5r5y431vf=>
Pull/push your production DB into/from your dev DB with:
$ heroku db:pull $DATABASE_URL
$ heroku db:push $DATABASE_URL
...or dump/restore your DB using the heroku pgbackups addon:
$ heroku pgbackups:capture
$ curl -o latest.dump `heroku pgbackups:url`
$ heroku pgbackups:restore DATABASE 'https://s3.amazonaws.com/me/items/3H0q/latest.dump'
heroku provide a command to get your DB's Data Source Name
$ heroku pg:credentials DATABASE
Connection info string:
"dbname=vnb324vndgh23h host=ec2-123-45-678-910.compute-1.amazonaws.com port=6212 user=user1234 password=abcd123 sslmode=require"
This info is already in your environment.
https://github.com/enru/dsnfromenv
require 'enru/dsnfromenv.php';
try {
$dsn = new enru\DsnFromEnv();
$dbh = new PDO($dsn->parse());
}
catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "
";
die();
}
Deploying to heroku is done using git. A simple push is all that is required.
$ git push origin master
Counting objects: 5, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 4.39 KiB, done.
Total 3 (delta 1), reused 0 (delta 0)
-----> PHP app detected
-----> Bundling Apache version 2.2.22
-----> Bundling PHP version 5.3.10
-----> Discovering process types
Procfile declares types -> (none)
Default types for PHP -> web
-----> Compiled slug size: 9.6MB
-----> Launching... done, v12
http://pacific-cove-5430.herokuapp.com deployed to Heroku
To git@heroku.com:pacific-cove-5430.git
ba90ccb..4323b3d master -> master
heroku's buildpack for PHP looks for an index.php file.
If no Procfile the default process for the PHP buildpack is run, which is: `web: sh boot.sh`
$ cat boot.sh
for var in `env|cut -f1 -d=`; do
echo "PassEnv $var" >> /app/apache/conf/httpd.conf;
done
touch /app/apache/logs/error_log
touch /app/apache/logs/access_log
tail -F /app/apache/logs/error_log &
tail -F /app/apache/logs/access_log &
export LD_LIBRARY_PATH=/app/php/ext
export PHP_INI_SCAN_DIR=/app/www
echo "Launching apache"
exec /app/apache/bin/httpd -DNO_DETACH
bin/detect determines whether to apply this buildpack to an app.bin/compile used to perform the transformation steps on the app.bin/release provides metadata back to the runtime.How a tailor-made platform is created - choice of web-server, compiled PHP modules
$ heroku create myapp --buildpack https://github.com/some/buildpack.git
Set the BUILDPACK_URL to change the buildpack in use.
$ heroku config:add BUILDPACK_URL=https://github.com/some/buildpack.git -a myapp
Example buildpacks:
using a PAAS allows you to focus on development
ability to scale is there if/when needed
easy to move app/sites built in this way
many free/low-cost plans = cheap to execute ideas
good engineering principles encouraged