Why doesn't sbt create project files?

Question

I have tried to install SBT on my macbook. When I run it, it doesn't ask me for any project definitions (e.g. title) and simply says

[info] Set current project to default (in build file:/Users/qui/Documents/Programming/test2/)

It then goes to what looks like the sbt interpreter.

When I look inside "test2", there is a project and target directory but I dont see a src directory to work with

Clearly I have gone wrong somewhere in my installation but I'm unsure where. Any ideas?

Update

So I just installed 0.10 on a fresh fedora install. And I am getting the exact same problem, same "info" message and it has only created a project and target directory

I must be doing something idiotic right? What am I doing wrong? :p

Answer 1

I work with SBT 0.13 so...your mileage may vary.

sbt's default behaviour

What you experience is the default behaviour of sbt. The tool expects that the project files are already in place or when there is no project files it doesn't bother to create them - the default values are just applied to the current directory that effectively becomes the project directory for a project called by the name of the directory it's in. SBT then opens sbt shell.

jacek:~/sandbox/stackoverflow/testaaa
$ tree
.

0 directories, 0 files

jacek:~/sandbox/stackoverflow/testaaa
$ sbt
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Updating {file:/Users/jacek/.sbt/0.13/plugins/}global-plugins...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] Set current project to testaaa (in build file:/Users/jacek/sandbox/stackoverflow/testaaa/)
[testaaa]>

Quoting Running from the official documentation of SBT.

Running sbt with no command line arguments starts it in interactive mode. Interactive mode has a command prompt (with tab completion and history!).

Example

In your case, when you started sbt in /Users/qui/Documents/Programming/test2/ it silently assumed it's the project directory and applied the default settings.

The following sbt session is in test2 directory, too. I use help to display the help of a setting key and then use the key to display its value.

jacek:~/sandbox/stackoverflow/test2
$ tree
.

0 directories, 0 files
jacek:~/sandbox/stackoverflow/test2
$ sbt
[info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
[info] Set current project to test2 (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> help name
Project name.
[test2]> name
[info] test2
[test2]> help organization
Organization/group ID.
[test2]> organization
[info] default
[test2]> help version
The version/revision of the current module.
[test2]> version
[info] 0.1-SNAPSHOT
[test2]> help scalaVersion
The version of Scala used for building.
[test2]> scalaVersion
[info] 2.10.2

(I've changed the prompt so the name of the project, i.e. the name of the directory sbt has been started in, is displayed before the >).

You can change the value of a key with the set command that Evaluates a Setting and applies it to the current project.

[test2]> help set
set [every] <setting-expression>

    Applies the given setting to the current project:
      1) Constructs the expression provided as an argument by compiling and loading it.
      2) Appends the new setting to the current project's settings.
      3) Re-evaluates the build's settings.

    This command does not rebuild the build definitions, plugins, or configurations.
    It does not automatically persist the setting(s) either.
    To persist the setting(s), run 'session save' or 'session save-all'.

    If 'every' is specified, the setting is evaluated in the current context
    and the resulting value is used in every scope.  This overrides the value
    bound to the key everywhere.

[test2]> set scalaVersion := "2.10.3"
[info] Defining *:scalaVersion
[info] The new value will be used by *:allDependencies, *:dependencyUpdatesData and 11 others.
[info]  Run `last` for details.
[info] Reapplying settings...
[info] Set current project to test2 (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> scalaVersion
[info] 2.10.3

In the other question on StackOverflow @regis-jean-gilles has showed how to set the other settings using the set command.

[test2]> set name := "My test2 sbt project"
[info] Defining *:name
[info] The new value will be used by *:description, *:normalizedName and 8 others.
[info]  Run `last` for details.
[info] Reapplying settings...
[info] Set current project to My test2 sbt project (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> set version := "1.0"
[info] Defining *:version
[info] The new value will be used by *:isSnapshot, *:projectId and 5 others.
[info]  Run `last` for details.
[info] Reapplying settings...
[info] Set current project to My test2 sbt project (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> set scalaVersion := "2.10.3"
[info] Defining *:scalaVersion
[info] The new value will be used by *:allDependencies, *:dependencyUpdatesData and 11 others.
[info]  Run `last` for details.
[info] Reapplying settings...
[info] Set current project to My test2 sbt project (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> session save
[info] Reapplying settings...
[info] Set current project to My test2 sbt project (in build file:/Users/jacek/sandbox/stackoverflow/test2/)
[test2]> exit

The build.sbt file will then contain all the settings as if there'd been set there in the first place.

$ cat build.sbt
name := "My test2 sbt project"

version := "1.0"

scalaVersion := "2.10.3"

By default, sbt creates various files in target directory. When you look inside the target directory, there are no files - just an empty directory. The same applies to project that also may or may not hold target directory. They're assumed to be available and if there's not, they're created by default.

When you change a setting in sbt's interactive shell (with set), you can save the session with session save.

[test2]> help session
session <command>

Manipulates session settings, which are temporary settings that do not persist past the current sbt execution (that is, the current session).
Valid commands are:

clear, clear-all

    Removes temporary settings added using 'set' and re-evaluates all settings.
    For 'clear', only the settings defined for the current project are cleared.
    For 'clear-all', all settings in all projects are cleared.

list, list-all

    Prints a numbered list of session settings defined.
    The numbers may be used to remove individual settings or ranges of settings using 'remove'.
    For 'list', only the settings for the current project are printed.
    For 'list-all', all settings in all projets are printed.

remove <range-spec>

    <range-spec> is a comma-separated list of individual numbers or ranges of numbers.
    For example, 'remove 1,3,5-7'.
    The temporary settings at the given indices for the current project are removed and all settings are re-evaluated.
    Use the 'list' command to see a numbered list of settings for the current project.

save, save-all

    Makes the session settings permanent by writing them to a '.sbt' configuration file.
    For 'save', only the current project's settings are saved (the settings for other projects are left alone).
    For 'save-all', the session settings are saved for all projects.
    The session settings defined for a project are appended to the first '.sbt' configuration file in that project.
    If no '.sbt' configuration file exists, the settings are written to 'build.sbt' in the project's base directory.
[test2]> session save
[info] Reapplying settings...
[info] Set current project to test2 (in build file:/Users/jacek/sandbox/stackoverflow/test2/)

Once you do that, a build.sbt with your own setting(s) is saved. That might be a good starting point for further configuration of a project.

jacek:~/sandbox/stackoverflow/test2
$ cat build.sbt
scalaVersion := "2.10.3"

Typesafe Activator

According to the home page of Typesafe Activator:

Typesafe Activator is a browser-based or command-line tool that helps developers get started with the Typesafe Reactive Platform.

Under the covers, Activator is a UI built atop of sbt as demo'ed by Josh Suereth in the screencast Introducing sbt 0.13.2.

It appears that that's the only blessed solution for setting up sbt projects out of the many templates available in Activator.

giter8 - sbt project (layout) templates

If you however need some help to lay out the directory structure and have a ready-to-use project setup, you may want to use giter8 that's a command line tool to apply templates defined on github

Say, you want to create a project with scalaz dependency. You may want to use adinapoli/scalaz-revolver (see the list of available templates).

jacek:~/sandbox/stackoverflow
$ g8 adinapoli/scalaz-revolver

Simple scala project with sbt-revolver

organization [org.example]: pl.japila
name [Scala sbt-revolver project]:
scala_version [2.9.2]: 2.10.3
version [0.1-SNAPSHOT]:

Template applied in ./scala-sbt-revolver-project

jacek:~/sandbox/stackoverflow
$ cd scala-sbt-revolver-project/

jacek:~/sandbox/stackoverflow/scala-sbt-revolver-project
$ tree
.
├── README
├── build.sbt
├── project
│   ├── Build.scala
│   ├── build.properties
│   └── plugins.sbt
└── src
    └── main
        └── scala
            └── pl
                └── japila
                    └── ScalaSbtrevolverProject.scala

6 directories, 6 files

See Create a project directory with source code to find out more.

np - new sbt project generation made simple(r)

As pointed out in the comments by @0__ below, there's another project that aims at simplifying how new projects in sbt are created - np. That seems exactly what you needed.

In https://github.com/softprops/np#for-sbt-013 there's a complete description of what's needed to set it up and create new sbt projects using the utility that boils down to:

1. Registering the sbt plugin. Add the following to ~/.sbt/0.13/plugins/np.sbt.

   addSbtPlugin("me.lessis" % "np" % "0.2.0")
   

2. Define a custom global overrides in ~/.sbt/0.13/np.sbt. Add the following to the file.

   seq(npSettings:_*)
   
   (NpKeys.defaults in (Compile, NpKeys.np)) ~= {
     _.copy(org="me.lessis", version="0.1.0-SNAPSHOT")
   }
   

3. Use the np plugin's command - np. Create an empty directory for the sbt project and run sbt np.

   jacek:~/sandbox/stackoverflow
   $ mkdir np-sandbox/
   jacek:~/sandbox/stackoverflow
   $ cd np-sandbox/
   jacek:~/sandbox/stackoverflow/np-sandbox
   $ sbt np
   [info] Loading global plugins from /Users/jacek/.sbt/0.13/plugins
   [info] Set current project to np-sandbox (in build file:/Users/jacek/sandbox/stackoverflow/np-sandbox/)
   [info] Generated build file
   [info] Generated source directories
   [success] Total time: 0 s, completed Dec 7, 2013 12:51:42 PM
   jacek:~/sandbox/stackoverflow/np-sandbox
   $ tree
   .
   ├── build.sbt
   ├── src
   │   ├── main
   │   │   ├── resources
   │   │   └── scala
   │   └── test
   │       ├── resources
   │       └── scala
   └── target
       └── streams
           └── compile
               └── np
                   └── $global
                       └── out
   
   12 directories, 2 files
   jacek:~/sandbox/stackoverflow/np-sandbox
   $ cat build.sbt
   organization := "me.lessis"
   
   name := "default"
   
   version := "0.1.0-SNAPSHOT"
   

Answer 2

No you're not doing something wrong, previous versions of sbt (0.7.x) did ask you if you wanted to create your project.

sbt version 0.10.x is a complete rewrite and does not act the same way (i.e. ask you to create a project on startup).

The old project was on googlecode but has since moved to github, you can find the documentation for 0.10.x at https://github.com/harrah/xsbt/wiki, in particular https://github.com/harrah/xsbt/wiki/Settings if you come from a 0.7.x background.

It's a bit hard to wrap your head around the new settings system at first, but trust me when I say you'll love it :)