During dockerBuild, dockerCopyMappings doesn't retain file flags

[ckarenz]

The ENTRYPOINT directive requires its target to be executable. If this target is a script copied through dockerCopyMappings, the file doesn't retain its +x flag. Though the build succeeds, this ultimately causes the container to fail to start.

The workaround from Jesse works:

ENTRYPOINT ["sh", "-c", "chmod +x my_script; exec my_script"]

[jkinkead]

We use sbt's IO class for our copying, and it doesn't attempt to preserve file permissions. If we wish to do this for both files and directories, we'll need to replicate the copyDirectory behavior here, and setExecutable() iff the source file is executable.