Slides from ScalaDays 2015 Amsterdam

1. 12 Factor App
Best Practices for Scala Deployment

2. 2005 2015
WAR files JAR files
App Servers Microservices
Java Scala
Hot-Deploy Continuous Deploy

3. Joe Kutner
@codefinger
JVM Platform Owner
@Heroku
Joe Kutner

4. 12 Factor App
a methodology
Scalability
Maintainability
Portability

5. • Immutable
• Ephemeral
• Declarative
• Automated

6. https://github.com/sbt/sbt-native-packager

7. addSbtPlugin(
"com.typesafe.sbt" % "sbt-native-packager" % "0.7.6"
)
project/plugins.sbt

8. $ sbt stage

9. without further ado…

10. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

11. Thank You!
Goodbye!
(just kidding)

12. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

13. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

14. Use Version Control

17. BAD

18. BAD
App #1 App #2

19. my-project
! build.sbt
! app
! conf
! public
! my-library
! build.sbt
! src
! main
! scala

20. my-project
! build.sbt
! app
! conf
! public
! my-library
! my-sub-project
! build.sbt
! src
! main
! scala
BAD

21. Submodules

22. $ git submodule add https://github.com/jkutner/play-sub-project

23. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

24. Don’t check JAR files into Git

26. Never rely on implicit
existence of system-wide
packages
Explicitly declare
and isolate
dependencies

27. global local
BAD GOOD
Dependencies
~/.m2
~/.ivy2
(ok in dev)
target/

28. Vendoring
GOOD

29. $ sbt stage
...
$ tree target/universal/stage/lib/
target/universal/stage/lib/
"## ch.qos.logback.logback-classic-1.1.1.jar
"## ch.qos.logback.logback-core-1.1.1.jar
"## com.fasterxml.jackson.core.jackson-annotations-2.3...
"## com.fasterxml.jackson.core.jackson-core-2.3.2.jar
"## com.fasterxml.jackson.core.jackson-databind-2.3.2.jar
"## com.google.guava.guava-16.0.1.jar
...

30. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

31. Don’t check passwords into Git

32. Or was it “DUH”?
😳

33. Can you make your app open source
at any moment, without compromising
any credentials?
Litmus Test

34. • Resource handles to the database,
Memcached, and other backing services
• Credentials to external services such as
Amazon S3 or Twitter
• Per-deploy values such as the canonical
hostname for the deploy
Anything that changes between
deployment environments:
(does not include things like conf/routes)
Configuration is…

35. Configuration belongs
in the environment,
not in the application
Configuration should
be strictly separated
from code

36. db.default.url=${DATABASE_URL}
conf/application.conf

37. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

38. db.default.url=${DATABASE_URL}
conf/application.conf

39. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

40. build, release, run

41. $ sbt stage
...
$ sbt deployHeroku
...
# in the cloud!
$ target/universal/stage/bin/my-app
build
release
run

42. $ sbt run
BAD
(in production)

43. simple build tool

44. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

45. DEMO!

46. $ sbt stage
...
$ sbt deployHeroku
...
# in the cloud!
$ target/universal/stage/bin/scaladays
build
release
run

47. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

48. Processes should be stateless

49. sticky sessions
😞

50. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

51. The twelve-factor app
is completely self-contained
The web app exports HTTP
as a service by binding to a port

52. .war
Traditional Deployment

53. .jar
Modern Deployment

54. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

55. Actors
Futures
Agents
RELAX BRO, I GOT THIS…

56. Scale Up
Scale Out

57. web.1
web.2
worker.1 clock.1
Workload Diversity
NumberofProcesses
worker.2
worker.3

58. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

59. Graceful shutdown
Quick startup
Resilience to failure

60. Servers are not pets
Servers are cattle

61. Application Servers are
not disposable

62. Microservices are
disposable

63. Easy to replace
Decoupled from
external infrastructure
Easy to modify

64. Microservices

65. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

66. dev
sqlite
postgres
stage
mysql
postgres
prod
postgres
postgres
=
≠
=
=
≠
=

67. dev
jetty
jetty
stage
tomcat
jetty
prod
jboss
jetty
=
≠
=
=
≠
=

68. dev
jetty
{}
stage
tomcat
{}
prod
jboss
{}
=
≠
=
=
≠
=

69. Dropwizard

70. disposable
reproducible
parity

71. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

72. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

73. Admin tasks should be
run in isolated processes

74. $ heroku run console
Running `console` attached to terminal... up, run.2581
Picked up JAVA_TOOL_OPTIONS: -Djava.rmi.server.useCode...
Failed to created JLineReader: java.lang.NoClassDefFou...
Falling back to SimpleReader.
Welcome to Scala version 2.11.1 (OpenJDK 64-Bit Server...
Type in expressions to have them evaluated.
Type :help for more information.
scala>

75. web1
web2
web3
admin

76. $ heroku run sbt console
?

77. simple build tool

78. addSbtPlugin(
"com.typesafe.sbt" % "sbt-native-packager" % "0.7.6"
)
project/plugins.sbt

79. console: target/universal/stage/bin/my-app
-main scala.tools.nsc.MainGenericRunner
-usejavacp
Procfile
worker: target/universal/stage/bin/my-app
-main com.example.MyWorker

80. The 12 Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes
• Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes

81. http://12factor.net
http://jkutner.github.io

82. Add sbt-native-packager1.
Run `sbt stage`2.
Deploy to Heroku?3.
Go to the sbt-native-packager talk4.
What next?

83. Joe Kutner
@codefinger
JVM Platform Owner
@Heroku
http://www.slideshare.net/jkutner/12-factor-scala