Compiling Remotely

As you may know, the fsc compiler, the recommended way to compile Scala, and used by the Scala interpreter by default, detaches a daemon service the first time it is run. After that, fsc will always call the daemon service to compile for it, to save time.

It does this through TCP, which begs the question... can I compile remotely? The answer is Yes! It's not documented, and it is a bit awkward, but...

First, you get fsc running on the server by running fsc -verbose, like this:

$fsc -verbose
[Server arguments: -d C:\Users\Daniel\Documents\Programas\. -verbose]
[VM arguments: ]
[Temp directory: C:\PROGRA~1\Scala\bin\..\var\scala-devel]
[Executed command: C:\PROGRA~1\Scala\bin\..\bin\scala.bat scala.tools.nsc.CompileServer]
[Port number: 1385]
[Connected to compilation daemon at port 1385]
Usage: fsc  
where possible standard options include:
  -g:                       Specify level of generated debugging info (none,source,line,vars,notailcalls)
  -nowarn                      Generate no warnings
  -verbose                     Output messages about what the compiler is doing
  -deprecation                 Output source locations where deprecated APIs are used
  -unchecked                   Enable detailed unchecked warnings
  -classpath             Specify where to find user class files
  -sourcepath            Specify where to find input source files
  -bootclasspath         Override location of bootstrap class files
  -extdirs               Override location of installed extensions
  -d                Specify where to place generated class files
  -encoding          Specify character encoding used by source files
  -target:             Specify for which target object files should be built (jvm-1.5,jvm-1.4,msil)
  -print                       Print program with all Scala-specific features removed
  -optimise                    Generates faster bytecode by applying optimisations to the program
  -explaintypes                Explain type errors in more detail
  -uniqid                      Print identifiers with unique names for debugging
  -version                     Print product version and exit
  -help                        Print a synopsis of standard options
  -X                           Print a synopsis of advanced options
  @<file>                      A text file containing compiler arguments (options and source files)

This will get you the port number. Next, you can compile whatever you like from a remote client like this:

$fsc -server 192.168.1.35:1385 strategy.scala

That's it. Cool, eh?