§Using the sbt console
You can manage the complete development cycle of a Play application with sbt. sbt has an interactive mode (shell), or you can enter commands one at a time. The interactive mode can be faster over time because sbt only needs to start once. When you enter commands one at a time, sbt restarts each time you run it.
§Single commands
You can run single sbt commands directly. For example, to build and run Play, change to the directory of your project and run:
$ sbt run
You will see something like:
[info] Loading project definition from /Users/play-developer/my-first-app/project
[info] Set current project to my-first-app (in build file:/Users/play-developer/my-first-app/)
--- (Running the application from sbt, auto-reloading is enabled) ---
[info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000
(Server started, use Enter to stop and go back to the console...)
The application starts directly. When you quit the server using Ctrl+D or Enter, the command prompt returns.
§Interactive mode
To launch sbt in the interactive mode, change into the top-level of your project and enter sbt with no arguments:
$ cd my-first-app
my-first-app $ sbt
You will see something like:
[info] Loading global plugins from /Users/play-developer/.sbt/1.0/plugins
[info] Loading project definition from /Users/play-developer/my-first-app/project
[info] Updating {file:/Users/play-developer/my-first-app/project/}my-first-app-build...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Set current project to my-first-app (in build file:/Users/play-developer/my-first-app/)
[my-first-app] $
Tip: you can also launch some commands before getting into sbt shell by running shell at the end of task list. For example:
$ sbt clean compile shell
§Development mode
In this mode, sbt launches Play with the auto-reload feature enabled. When you make a request, Play will automatically recompile and restart your server if any files have changed. If needed the application will restart automatically.
With sbt in the interactive mode, run the current application in development mode, use the run command:
[my-first-app] $ run
You will see something like:
$ sbt
[info] Loading global plugins from /Users/play-developer/.sbt/1.0/plugins
[info] Loading project definition from /Users/play-developer/tmp/my-first-app/project
[info] Done updating.
[info] Loading settings for project root from build.sbt ...
[info] Set current project to my-first-app (in build file:/Users/play-developer/tmp/my-first-app/)
[info] sbt server started at local:///Users/play-developer/.sbt/1.0/server/c9c53f40a402da68f71a/sock
[my-first-app] $ run
[info] Updating ...
[info] Done updating.
[warn] There may be incompatibilities among your library dependencies; run 'evicted' to see detailed eviction warnings.
--- (Running the application, auto-reloading is enabled) ---
[info] p.c.s.AkkaHttpServer - Listening for HTTP on /0:0:0:0:0:0:0:0:9000
(Server started, use Enter to stop and go back to the console...)
§Compiling only
You can also compile your application without running the HTTP server. The compile command displays any application errors in the command window. For example, in the interactive mode, enter:
[my-first-app] $ compile
And you will see something like:
[my-first-app] $ compile
[info] Compiling 1 Scala source to /Users/play-developer/my-first-app/target/scala-2.13/classes...
[error] /Users/play-developer/my-first-app/app/controllers/HomeController.scala:21: not found: value Actionx
[error] def index = Actionx { implicit request =>
[error] ^
[error] one error found
[error] (compile:compileIncremental) Compilation failed
[error] Total time: 1 s, completed Feb 6, 2017 2:00:07 PM
[my-first-app] $
If there are no errors with your code, you will see:
[my-first-app] $ compile
[info] Updating {file:/Users/play-developer/my-first-app/}root...
[info] Resolving jline#jline;2.12.2 ...
[info] Done updating.
[info] Compiling 8 Scala sources and 1 Java source to /Users/play-developer/my-first-app/target/scala-2.13/classes...
[success] Total time: 3 s, completed Feb 6, 2017 2:01:31 PM
[my-first-app] $
§Testing options
You can run tests without running the server. For example, in interactive mode, use the test command:
[my-first-app] $ test
The test commands will run all the tests in your project. You can also use testOnly to select specific tests:
[my-first-app] $ testOnly com.acme.SomeClassTest
§Launch the Scala console
Type console to enter the Scala console, which allows you to test your code interactively:
[my-first-app] $ console
To start application inside scala console (e.g. to access database):
import play.api._
val env = Environment(new java.io.File("."), this.getClass.getClassLoader, Mode.Dev)
val context = ApplicationLoader.Context.create(env)
val loader = ApplicationLoader(context)
val app = loader.load(context)
Play.start(app)§Debugging
You can ask Play to start a JPDA debug port when starting the console. You can then connect using Java debugger. Use the sbt -jvm-debug <port> command to do that:
$ sbt -jvm-debug 9999
When a JPDA port is available, the JVM will log this line during boot:
Listening for transport dt_socket at address: 9999
§Using sbt features
You can use sbt features such as triggered execution.
For example, using ~ compile:
[my-first-app] $ ~ compile
The compilation will be triggered each time you change a source file.
If you are using ~ run:
[my-first-app] $ ~ run
The triggered compilation will be enabled while a development server is running.
You can also do the same for ~ test, to continuously test your project each time you modify a source file:
[my-first-app] $ ~ test
This could be especially useful if you want to run just a small set of your tests using testOnly command. For instance:
[my-first-app] $ ~ testOnly com.acme.SomeClassTest
Will trigger the execution of com.acme.SomeClassTest test every time you modify a source file.
§Using the play commands directly
You can also run commands directly without entering the Play console. For example, enter sbt run:
$ sbt run
[info] Loading project definition from /Users/play-developer/my-first-app/project
[info] Set current project to my-first-app (in build file:/Users/play-developer/my-first-app/)
--- (Running the application from sbt, auto-reloading is enabled) ---
[info] play - Listening for HTTP on /0:0:0:0:0:0:0:0:9000
(Server started, use Enter to stop and go back to the console...)
The application starts directly. When you quit the server using Ctrl+D or Enter, you will come back to your OS prompt.
By default, the server runs on port 9000. A custom port (e.g. 8080) can be specified: sbt 'run 8080'
Of course, the triggered execution is available here as well:
$ sbt ~run
§Getting help
Use the help command to get basic help about the available commands. You can also use this with a specific command to get information about that command:
[my-first-app] $ help run