![Squeryl
● Lightweight ORM written in scala
class Workflow(override val id: Int) extends KeyedEntity[Int]](https://image.slidesharecdn.com/scalainawildenterprise-130414105446-phpapp02/85/Scala-in-a-wild-enterprise-31-320.jpg)
![Squeryl
● Lightweight ORM written in scala
class Workflow(override val id: Int) extends KeyedEntity[Int]
object GS extends Schema {
val workflows = table[Workflow]
}](https://image.slidesharecdn.com/scalainawildenterprise-130414105446-phpapp02/85/Scala-in-a-wild-enterprise-32-320.jpg)
![Squeryl
● Lightweight ORM written in scala
class Workflow(override val id: Int) extends KeyedEntity[Int]
object GS extends Schema {
val workflows = table[Workflow]
}
def find(workflowId: Int) = from(GS.workflows)(w =>
where(w.id === workflowId)
select (w)
orderBy(w.id desc)
)](https://image.slidesharecdn.com/scalainawildenterprise-130414105446-phpapp02/85/Scala-in-a-wild-enterprise-33-320.jpg)
![Web layer
● RESTfull web services
case class User (
@NotBlank username: String,
@Email @Size(min = 1, max = 256) email: String,
password: Option[String]
)
@Controller
@RequestMapping(Array("/rest/users"))
class UsersController {
@RequestMapping(method = Array(RequestMethod.POST))
@ResponseBody
def create(@RequestBody @Valid request: User): User = userService.create(request)
}](https://image.slidesharecdn.com/scalainawildenterprise-130414105446-phpapp02/85/Scala-in-a-wild-enterprise-45-320.jpg)
![Web layer
● RESTfull web services
● Easy to make Hypermedia REST with
implicits
@Controller
@RequestMapping(Array("/rest/users"))
class UsersController {
import com.griddynamics.genesis.rest.links.Hypermedia._
@RequestMapping(method = Array(RequestMethod.POST))
@ResponseBody
def create(@RequestBody @Valid request: User): Hypermedia[User] = {
userService.create(request).withLink("/rest/users", LinkType.SELF)
}](https://image.slidesharecdn.com/scalainawildenterprise-130414105446-phpapp02/85/Scala-in-a-wild-enterprise-46-320.jpg)
Scala in a wild enterprise
- 3. th e? Scala in a wild enterprise Rafael Bagmanov ( Grid Dynamics )
- 4. In what use cases (types of applications) does Scala make the least sense?
- 5. "Database front end, CRUD apps. Most of the boring apps that are built with Struts and Spring" David Pollak "Barriers to scala adoption" Infoq.com
- 8. OpenGenesis Deployment orchestration tool ● open source - open-genesis.org ● 2 years of development ● > 50 KLOC of scala code ● successfully deployed to production in one large american financial institution ● Buzzwords: continuous deployment, cloud, chef, devops, aws, openstack
- 9. Enterprise characteristics ● Integration with legacy apps and data (lots of SOAP and xml) ● sophisticated security policies ● IT department separated from development team ● J2EE Containers everywhere ● Risk averse
- 10. Typical "lightweight" j2ee stack Web layer Spring MVC Service layer Spring Data access layer JPA DB
- 11. j2ee stack. Scala edition Web layer Spring MVC + scala magic Service layer Spring + scala implicits Data access layer JPA Squeryl DB
- 12. j2ee stack. Scala edition WAR Spring MVC Web layer Spring Service layer Squeryl Data access layer DB
- 13. j2ee stack. Scala edition + scala goodness WAR Spring MVC Web layer Akka Spring Workflow distributed Service layer engine Squeryl Data access layer DB
- 15. Spring with scala ● DI fits almost nicely with scala
- 16. Spring with scala ● DI fits almost nicely with scala class GenesisRestController { @Autowired var genesisService: GenesisService = _ } class GenesisRestController { @BeanProperty var genesisService: GenesisService = _ } class GenesisRestController (genesisService: GenesisService) {}
- 17. Spring with scala ● DI fits almost nicely with scala ○ "Everything is a trait" approach can't be done
- 18. Spring with scala ● DI fits almost nicely with scala ○ "Everything is a trait" approach can't be done ○ Be aware of type inference in @Configuration bean trait Service class ServiceImpl extends Service @Configuration class ServiceContext { @Bean def service = new ServiceImpl }
- 19. Spring with scala ● DI fits almost nicely with scala ○ "Everything is a trait" approach can't be done ○ Be aware of type inference in @Configuration bean trait Service class ServiceImpl extends Service @Configuration class ServiceContext { @Bean def service: Service = new ServiceImpl }
- 20. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries.
- 21. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. springLdapTemplate.authenticate("user", "*", "password", new AuthenticationErrorCallback { def execute(e: Exception) {log.error(e)} })
- 22. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. springLdapTemplate.authenticate("user", "*", "password", new AuthenticationErrorCallback { def execute(e: Exception) {log.error(e)} })
- 23. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. springLdapTemplate.authenticate("user", "*", "password", new AuthenticationErrorCallback { def execute(e: Exception) {log.error(e)} }) springLdapTemplate.authenticate("user", "*", "password", log.error(_))
- 24. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. springLdapTemplate.authenticate("user", "*", "password", log.error(_)) implicit def authErrorCallbackWrapper(func:(Exception) => Any) = { new AuthenticationErrorCallback { def execute(exception: Exception): Unit = func(exception) } }
- 25. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. ● AOP for free (almost)
- 26. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. ● AOP for free (almost) ○ Be aware of naming in debug info def findUsers(projectId: Int) { dao.findUsers(projectId) } def findUsers2(projectId: Int) { dao.allUsers().filter(_.projectId == projectId) }
- 27. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. ● AOP for free (almost) ○ Be aware of naming in debug info def findUsers(projectId: Int) { // debugIfo: name "projectId" dao.findUsers(projectId) } def findUsers2(projectId: Int) { // debugInfo: name "projectId$" dao.allUsers().filter(_.projectId == projectId) }
- 28. Spring with scala ● DI fits almost nicely with scala ● Rich spring templates libraries. ● AOP for free (almost) ● Spring security just works
- 30. Squeryl ● Lightweight ORM written in scala
- 31. Squeryl ● Lightweight ORM written in scala class Workflow(override val id: Int) extends KeyedEntity[Int]
- 32. Squeryl ● Lightweight ORM written in scala class Workflow(override val id: Int) extends KeyedEntity[Int] object GS extends Schema { val workflows = table[Workflow] }
- 33. Squeryl ● Lightweight ORM written in scala class Workflow(override val id: Int) extends KeyedEntity[Int] object GS extends Schema { val workflows = table[Workflow] } def find(workflowId: Int) = from(GS.workflows)(w => where(w.id === workflowId) select (w) orderBy(w.id desc) )
- 34. Squeryl ● Lightweight ORM written in scala ○ First class support for scala collections, options, etc
- 35. Squeryl ● Lightweight ORM written in scala ○ First class support for scala collections, options, etc ○ Integrates with spring transaction management (not out of the box)
- 36. Squeryl ● Lightweight ORM written in scala ○ First class support for scala collections, options, etc ○ Integrates with spring transaction management (not out of the box) @Transactional(propagation = REQUIRES_NEW) def find(workflowId: Int) = from(GS.workflows)(w => where(w.id === workflowId) select (w) orderBy(w.id desc) )
- 37. Squeryl ● Lightweight ORM written in scala ○ Likes heap in the same proportion as Hibernate does hibernate squeryl
- 38. Squeryl ● Lightweight ORM written in scala ○ Likes heap in the same proportion as Hibernate does ○ Lot's of "black magic" in source code
- 39. Squeryl ● Lightweight ORM written in scala ● Internal scala DSL for writing queries ○ Type safe queries - compile time syntax check
- 40. Squeryl ● Lightweight ORM written in scala ● Internal scala DSL for writing queries ○ Lot's of "black magic" in source code
- 41. Squeryl ● Lightweight ORM written in scala ● Internal scala DSL for writing queries ○ Lot's of "black magic" in source code ○ Fallback on native sql is not easy
- 42. Squeryl ● Lightweight ORM written in scala ● Internal scala DSL for writing queries ○ Lot's of "black magic" in source code ○ Fallback on native sql is not easy ○ Lots of implicits drives IDE crazy and increases compilation time
- 43. Squeryl ● Lightweight ORM written in scala ● Internal scala DSL for writing queries ○ Lot's of "black magic" in source code ○ Fallback on native sql is not easy ○ Lots of implicits drives IDE crazy and increase compilation time ○ The approach is somewhat flawed (opinion)
- 44. Web layer: Spring MVC lift-json scala magic
- 45. Web layer ● RESTfull web services case class User ( @NotBlank username: String, @Email @Size(min = 1, max = 256) email: String, password: Option[String] ) @Controller @RequestMapping(Array("/rest/users")) class UsersController { @RequestMapping(method = Array(RequestMethod.POST)) @ResponseBody def create(@RequestBody @Valid request: User): User = userService.create(request) }
- 46. Web layer ● RESTfull web services ● Easy to make Hypermedia REST with implicits @Controller @RequestMapping(Array("/rest/users")) class UsersController { import com.griddynamics.genesis.rest.links.Hypermedia._ @RequestMapping(method = Array(RequestMethod.POST)) @ResponseBody def create(@RequestBody @Valid request: User): Hypermedia[User] = { userService.create(request).withLink("/rest/users", LinkType.SELF) }
- 47. Couple of words about AKKA
- 48. Ехал Акка через Акка Смотрит Акка в Акка Акка Сунул Акка Акка в Акка Акка Акка Акка Акка * * Ode to Akka in russian
- 50. Greatest challenge: People
- 51. Challenges ● Hiring is hard
- 52. Challenges ● Hiring is hard ○ Scala is a talent attraction
- 53. Challenges ● Hiring is hard ○ Scala is a talent attraction ○ In avg: 0.5 interview per month
- 54. Challenges ● Hiring is hard ● Settling team standards and code convention
- 55. Challenges ● Hiring is hard ● Settling team standards and code convention ○ Tools are not there yet
- 56. Challenges ● Hiring is hard ● Settling team standards and code convention ○ Tools are not there yet ○ Between "OCaml" and "Java" fires
- 57. Challenges ● Hiring is hard ● Settling team standards and code convention ○ Tools are not there yet ○ Between "OCaml" and "Java" fires ○ "Effective scala" by Twitter and "Scala style guide" might help (a bit)
- 58. The greatest code-review mystery of all times How to deal with scala.Option if (option.isDefined) { option match { case Some(x) => .. .. case None => .. ? } } option.foreach { .. }
- 59. The greatest code-review mystery of all times How to deal with scala.Option if (option.isDefined) { option match { case Some(x) => .. .. case None => .. ? } } option.foreach { .. }
- 61. aka
- 62. 5 stages of grief
- 63. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
- 64. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
- 65. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
- 66. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
- 67. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
- 68. 5 stages of grief 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance