How to use sbt from behind proxy?

sbt respects the usual environment variables for http proxy settings:

export JAVA_OPTS="$JAVA_OPTS -Dhttp.proxyHost=yourserver -Dhttp.proxyPort=8080 -Dhttp.proxyUser=username -Dhttp.proxyPassword=password"

(That's of course, assuming Unix (Linux/OSX etc). On windows you could just set the same environment variable (%JAVA_OPTS%) as usual in the Windows way.)

Then run sbt as usual:

sbt

Switching between proxy/no-proxy should be a matter of setting up a little script that you can 'slurp' in whenever you need it.

Gotchas

  • Don't include "http://" in the yourserver value
  • Don't include the port in the yourserver value
  • You probably also want to include https.proxyHost and https.proxyPort since a lot of stuff works over https
  • If your proxy requires authentication, don't even bother trying unless it just uses Basic Authentication as SBT doesn't support anything else. Also always beware clear texting credentials into environment variables! Be sure to remove the commands from your .bash_history using a text editing method that won't create trace files (technically you should shred or srm the entire file). If you are on Windows, don't worry about it, your security is already messed up you can't do any more harm.

sbt works in a fairly standard way comparing to the way other JVM-based projects are usually configured.

sbt is in fact two "subsystems" - the launcher and the core. It's usually xsbt.boot.Boot that gets executed before the core starts up with the features we all know (and some even like).

It's therefore a matter of how you execute sbt that says how you could set up a proxy for HTTP, HTTPS and FTP network traffic.

The following is the entire list of the available properties that can be set for any Java application, sbt including, that instruct the Java API to route communication through a proxy:

  • http_proxy
  • http_proxy_user
  • http_proxy_pass
  • http.proxyHost
  • http.proxyPort
  • http.proxyUser
  • http.proxyPassword

Replace http above with https and ftp to get the list of the properties for the services.

Some sbt scripts use JAVA_OPTS to set up the proxy settings with -Dhttp.proxyHost and -Dhttp.proxyPort amongst the others (listed above). See Java Networking and Proxies.

Some scripts come with their own way of setting up proxy configuration using the SBT_OPTS property, .sbtopts or (only on Windows) %SBT_HOME%\conf\sbtconfig.txt. You can use them to specifically set sbt to use proxies while the other JVM-based applications are not affected at all.

From the sbt command line tool:

# jvm options and output control
JAVA_OPTS          environment variable, if unset uses "$java_opts"
SBT_OPTS           environment variable, if unset uses "$default_sbt_opts"
.sbtopts           if this file exists in the current directory, it is
                   prepended to the runner args
/etc/sbt/sbtopts   if this file exists, it is prepended to the runner args
-Dkey=val          pass -Dkey=val directly to the java runtime
-J-X               pass option -X directly to the java runtime 
                   (-J is stripped)
-S-X               add -X to sbt's scalacOptions (-S is stripped)

And here comes an excerpt from sbt.bat:

@REM Envioronment:
@REM JAVA_HOME - location of a JDK home dir (mandatory)
@REM SBT_OPTS  - JVM options (optional)
@REM Configuration:
@REM sbtconfig.txt found in the SBT_HOME.

Be careful with sbtconfig.txt that just works on Windows only. When you use cygwin the file is not consulted and you will have to resort to using the other approaches.

I'm using sbt with the following script:

$JAVA_HOME/bin/java $SBT_OPTS -jar /Users/jacek/.ivy2/local/org.scala-sbt/sbt-launch/$SBT_LAUNCHER_VERSION-SNAPSHOT/jars/sbt-launch.jar "$@"

The point of the script is to use the latest version of sbt built from the sources (that's why I'm using /Users/jacek/.ivy2/local/org.scala-sbt/sbt-launch/$SBT_LAUNCHER_VERSION-SNAPSHOT/jars/sbt-launch.jar) with $SBT_OPTS property as a means of passing JVM properties to the JVM sbt uses.

The script above lets me to set proxy on command line on MacOS X as follows:

SBT_OPTS="-Dhttp.proxyHost=proxyhost -Dhttp.proxyPort=9999" sbt

As you can see, there are many approaches to set proxy for sbt that all pretty much boil down to set a proxy for the JVM sbt uses.

Tags:

Sbt

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