Launching a Play app on Windows
This page explains how to fix a common issue encountered while running a Play app in production on Windows.
Distribution
To build a package for your Play framework application, just run:
sbt dist
This will create a yourapp-1.0-SNAPSHOT.zip package in the target folder.
The zip contains a bin/ folder with some launchers.
The Linux one is working well out of the box, but usually the Windows launcher (yourapp.bat) cannot be run directly due to some limitation
in the length of the classpath line.
Fixing input line length issue
The generated .bat launcher contains a line setting the classpath which usually exceeds the maximum length allowed by Windows. If you run the .bat directly you may be getting the error:
The input line is too long.
The syntax of the command is incorrect.
Luckily there is an easy fix for that: open the .bat file, and find the APP_CLASSPATH definition (around line 43).
set "APP_CLASSPATH=%APP_LIB_DIR%\..\conf\;%APP_LIB_DIR%\holon-web.holon-web-1.0-SNAPSHOT-sans-externalized.jar;%APP_LIB_DIR%\org.scala-lang.scala-library-2.13.15.jar;%APP_LIB_DIR%\com.typesafe.play.twirl-api_2.13-1.6.8.jar;%APP_LIB_DIR%\com.typesafe.play.play-server_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-akka-http-server_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-logback_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-filters-helpers_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-java-forms_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-caffeine-cache_2.13-2.9.5.jar;%APP_LIB_DIR%\com.typesafe.play.play-guice_2.13-2.9.5.jar; ... and a lot more "
The solution is to replace this extensive definition by a single expression:
set "APP_CLASSPATH=%APP_LIB_DIR%\..\conf\;%APP_LIB_DIR%\*"
Then running the .bat file should work flawlessly.
Conclusion
In this article we saw how to fix a common issue while running the Windows launcher for a Play framework application.
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