Because in my operating system distribution has not default package sbt, I try compile from source and install sbt package locally (https://github.com/sbt/sbt). Unfortunately I can not do it and I can not find any guide to do this without installed sbt. To compile sbt from source is needed sbt? What can I to do to install sbt from source?
The answer is yes: to build sbt from source, you need to install sbt first (obviously, not from source). There are instructions for Building sbt from source and they start with
Install the current stable binary release of sbt (see Setup), which will be used to build sbt from source.
If you have a concrete problem installing sbt from binaries, you should solve it first. You can ask for help with it in a new question.
Related
There are multiple binary incompatible scala 2 versions, however the document says the installation is either via IDE or SBT.
DOWNLOAD SCALA 2
Then, install Scala:...either by installing an IDE such as IntelliJ, or sbt, Scala's build tool.
Spark 3 needs Scala 2.12.
Spark 3.1.2 uses Scala 2.12. You will need to use a compatible Scala version (2.12.x).
Then how can we make sure the scala version is 2.12 if we install sbt?
Or the documentation is not accurate and it should be "to use specific version of scala, need to download specific scala version on your own"?
Updates
As per the answer by mario-galic, in ONE-CLICK INSTALL FOR SCALA it is said:
Installing Scala has always been a task more challenging than necessary, with the potential to drive away beginners. Should I install Scala itself? sbt? Some other build tools? What about a better REPL like Ammonite? Oh and before all that I need to install Java?
To solve this problem, the Scala Center contracted Alexandre Archambault in January 2020 to add a one-click install of Scala through coursier. For example, on Linux, all we now need is:
$ curl -Lo cs https://git.io/coursier-cli-linux && chmod +x cs && ./cs setup
The Scala version is specified in the build.sbt file so SBT will download the appropriate version of Scala as necessary.
I personally use SDKMAN! to install Java and then SBT.
The key concept to understand is the difference between system-wide installation and project-specific version. System-wide installation ends up somewhere on the PATH like
/usr/local/bin/scala
and can be installed in various ways, personally I recommend coursier one-click install for Scala
curl -Lo cs https://git.io/coursier-cli-linux && chmod +x cs && ./cs setup
Project-specific version is specified by scalaVersion sbt settings which downloads Scala to coursier cache location. To see the Scala version and location used by the particular project try show scalaInstance which
inspect scalaInstance
[info] Task: sbt.internal.inc.ScalaInstance
[info] Description:
[info] Defines the Scala instance to use for compilation, running, and testing.
Scala should be binary compatible within minor version so Spark 3 or any other software built against any Scala 2.12.x version should work with any other Scala 2.12.x version where we have major.minor.patch. Note binary compatibility is not guaranteed for internal compiler APIs, so for example when publishing compiler plugins the best practice is to publish it against full specific Scala version. For example notice how kind-projector compiler plugin is published against full Scala version 2.13.6
https://repo1.maven.org/maven2/org/typelevel/kind-projector_2.13.6/
whilst scala-cats application-level library is published against any Scala 2.13.x version
https://repo1.maven.org/maven2/org/typelevel/cats-core_2.13/
Similarly spark is published against any Scala 2.12.x version
https://repo1.maven.org/maven2/org/apache/spark/spark-core_2.12/
Regarding system-wide installation one trick I do for quick switching of versions is to put scala-runners on the PATH and then different versions can be launched via --scala-version argument
scala --scala-version 2.12.14
Using coursier or scala-runners you can even switch JDK quickly via -C--jvm for example
scala --scala-version 2.12.14 -C--jvm=11
For a project, there should be no need to download manually a specific version of Scala. sbt either directly or indirectly via an IDE will download all the dependencies behind the scenes for you, so the only thing to specify is sbt setting scalaVersion.
Using Python as analogy to Scala, and Pipenv as anology to sbt, then python_version in Pipfile is similar to scalaVersion in build.sbt. After executing pipenv shell and pipenv install you end up with project-specific shell environment with project specific Python version and dependencies. sbt similarly downloads project specific Scala version and dependencies based of build.sbt although it has no need for lock files or for modifying your shell environment.
I'm working on 2 different projects in which the sbt version of project-1 in build.properties is 1.2.7 and the project-2 is 1.2.8, and I cannot make both versions of sbt in build.properties the same.
As a workaround 'how can I maintain 2 sbt versions on my windows 10 to run those 2 projects separately?
Thank you All in Advance.
The sbt project version does not need to match the installed sbt version. When you start sbt on a project that specifies v1.2.8 in its build.properties, the sbt launcher will download the appropriate sbt version if necessary and build your project with it. This mechanism is both backward and forward compatible.
Plugins in a given sbt project must be compatible with the version declared in build.properties, but not necessarily with the installed version.
My goal is to have a sbt jar file with all dependencies in order to create a debian package, so it could be install on machine without check/install package at first run.
Is it the right choice use sbt-assembly to build a sbt jar with all dependencies?
The sbt binary version doesn't come with dependecies and sbt download them at first run.
I don't fully understand your use case, but would sbt-native-packager .deb format be a good fit?
I want to install Apache Spark for testing purpose. For that I found out that Scala and sbt are necessary. I downloaded scala msi and installed it. For installing sbt I tried various methods but am unable to do so. Can someone tell me what am I doing wrong. What I did is
Install Scala msi
Download sbt msi and install it.
Set sbt_home and path variable to the location where sbt is extracted. Then I opened cmd to check my sbt version by using sbt sbt-version I am getting the following error **unresolved dependency:
org.fusesource.jansi#jansi;1.11: not found
Error during sbt execution: Error retrieving required libraries (see C:\Users\ashish-b\.sbt\boot\update.log for complete log) Error: Could not retrieve jansi 1.11 **
Whats wrong in it?
I saw this issue as well when connecting to the internet via a corporate proxy. In this case, sbt couldn't download its dependencies.
We work with a proxy Maven repository for depedencies. Configure sbt to use a proxy repo.
Our sbt repositories file looks like this:
[repositories]
local
local-maven: file:///C:/data/maven_repo/
aaa-ext-ivy-proxy: http://nexus-ext.company.net:8081/nexus/content/groups/ivy-public/, [organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]
aaa-ext-maven-proxy: http://nexus-ext.company.net:8081/nexus/content/groups/public/
aaa-int-maven-repo: http://nexus-int.company.net:8081/nexus/content/groups/public/
Or you can also configure the proxy server directly for SBT, see this question.
Reason I ask, is because it's possible to specify a Scala version in the build.sbt file (using scalaVersion setting), and once you do that, sbt will automatically download that Scala version to use with the project.
I also seem to remember that despite having Scala 2.11.1 on my system, sbt would compile and run with Scala 2.10 if no version was specified.
So the question is, do I need to install Scala separately if I got sbt installed?
No you don't need it. sbt will download Scala for you.
If you install sbt-extras (basically just a script) you don't even need to download sbt: it will automatically download the sbt launcher you need. Very handy since you just need to specify sbt.version in your build.properties and you're good to go.
Edit: removed my comment about not being able to do sbt console in an empty directory, since both sbt and sbt-extras support it now.