How to install scala-cli without internet

[halloleo]

I need to install scala-cli on a Linux RHEL machine without internet.

I have downloaded cliBootstrapped-1.2.2.jar and moved it to that machine - but I don't have Coursier on that system.

On that machine I have Java (versions 8 and 17) and Scala (version 3.3.1) installed. Is this enough to run scala-cli? A simple java -jar cliBootstrapped-1.2.2.jar doesn't seem to return. (It might try to download something.)

How can I use cliBootstrapped-1.2.2.jar to run/install scala-cli?

[Gedochao]

cliBootstrapped-x.y.z.jar are self-executable (bootstrapped) jars.
You don't need the java -jar command, it can self execute on a Linux machine.

chmod +x cliBootstrapped-1.2.2.jar 
./cliBootstrapped-1.2.2.jar 
# Welcome to Scala 3.4.1 (17, Java OpenJDK 64-Bit Server VM).
# Type in expressions for evaluation. Or try :help.
#                                                                                                                  
# scala> 

the --offline flag will be your friend, as this is an experimental option which makes sure Scala CLI relies on its caches (rather than anything it gets from the net).
you normally would also need Bloop, but you can skip using (and downloading) Bloop with --server=false.

scala-cli -e 'println("Hello from offline mode")' --offline --server=false --power
# The `--offline` option is experimental
# Please bear in mind that non-ideal user experience should be expected.
# If you encounter any bugs or have feedback to share, make sure to reach out to the maintenance team at https://github.com/VirtusLab/scala-cli
# Hello from offline mode

What you will need, however, is prefilling your coursier cache with any dependencies you may want to use.
We don't really have a sub-command for prefilling caches, at this point it's a power-user thing.
What I would advise doing is running a Scala CLI command with any project dependencies you may have on a different machine with internet connection, and then copying the coursier caches over to the isolated machine you are setting up on.

Docs on coursier cache are here:
https://get-coursier.io/docs/cache

Alternatively prefilling your local ivy2 with any data you may need should also work.
If your cache contains all you need (Scala compiler, jdk, any deps of your project, potentially Bloop if you want to skip --server=false), running things with --offline should get you set.

In case of problems, let me know what doesn't work.

[halloleo]

Ok, this pointed me in the right direction, thank you: The JAVA_HOME is normally set to a Java 8 JDK, but when I set it to Java 17 the result makes more sense:

The --offline option is experimental
Please bear in mind that non-ideal user experience should be expected.
If you encounter any bugs or have feedback to share, make sure to reach out to the maintenance team at https://github.com/VirtusLab/scala-cli
[error] Error downloading org.scala-lang:scala3-compiler_3:3.4.1
not found: /home/me/.ivy2/local/org.scala-lang/scala3-compiler_3/3.4.1/ivys/ivy.xml
not found: /home/me/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-compiler_3/3.4.1/scala3-compiler_3-3.4.1.pom
not found: /home/me/.cache/scalacli/local-repo/1.2.2/org.scala-lang/scala3-compiler_3/3.4.1/ivys/ivy.xml
No fallback URL found

I guess I have to download these three files on another machine and then put them on the air-gapped machine in the listed locations...

Can I tell scala-cli to look in one directory I can put these three files in?

[Gedochao]

The default way to do it would be to prefill your Coursier cache:
https://get-coursier.io/docs/cache
We use Coursier for finding dependencies.

You can override where the cache should be with the COURSIER_CACHE env variable (more details can be found in the Coursier docs).

You can simply use the Coursier fetch sub-command on another machine and copy the cache from there.
https://get-coursier.io/docs/cli-fetch

So in your case, smth like this would do the trick:

cs fetch org.scala-lang:scala3-compiler_3:3.4.1

[Gedochao]

Note that you will likely need all of the Scala 3.4.1 artifacts we use, so it might also be a good idea to install it whole with install (https://get-coursier.io/docs/cli-install):

cs install scala:3.4.1

and also the scala3-sbt-bridge if you're running Bloop (not necessary with --server=false):

cs fetch org.scala-lang:scala3-sbt-bridge:3.4.1

[halloleo]

I will try this. Looks very promising!

[halloleo]

It works now! Installing coursier on an internet-connected machine and then copying the coursier cache over to the air-gapped machine (where no coursier is installed) does the trick!

Thanks a lot for patiently sticking with my issue!