jupyter-scala download error

[cchang62]

I am facing the following error while I execute ./jupyter-scala

Getting coursier launcher...
Done
Error while downloading https://oss.sonatype.org/content/repositories/releases/io/get-coursier/coursier-cli_2.11/1.0.0-RC1/coursier-cli_2.11-1.0.0-RC1-standalone.jar: Connection refused (Connection refused), ignoring it

[animeshsrivastava24]

It is working fine for me.

@cchang62

[cequencer]

I ran into the exact identical issue and it is because I am running it behind firewall and proxy configuration is needed. Further information is tracked here:

coursier/coursier#888

Even I managed a hack to download all the artifacts to launch "jupyter-scala" behind firewall. I still do not know how to ask "jupyter-scala" to download the artifacts either via a local Nexus/Maven central repository or via a proxy server. I don't mean to hijack this issue, but just trying to make a progress for users who are confined behind a firewall.

[I 23:14:27.708 NotebookApp] Kernel started: NOTEBOOK_UUID
[W 23:14:38.173 NotebookApp] Timeout waiting for kernel_info reply from NOTEBOOK_UUID
Downloading https://repo1.maven.org/maven2/org/scala-lang/modules/scala-xml_2.11/1.0.5/scala-xml_2.11-1.0.5.pom.sha1
Downloading https://repo1.maven.org/maven2/org/scala-lang/modules/scala-xml_2.11/1.0.5/scala-xml_2.11-1.0.5.pom

I took the next step of trying out the proposed solution in issue #21 by editing the "kernel.json" file to include JVM_OPT for proxy configuration as follows:

{
  "language" : "scala",
  "display_name" : "Scala",
  "argv" : [
    "java",
    "-noverify",
    "-jar",
    "/home/userid/.local/share/jupyter/kernels/scala/launcher.jar",
    "launch",
    "-r",
    "http://mirror.nexus.behindfw.com:port/nexus/content/central",
    "-i",
    "ammonite",
    "-I",
    "ammonite:org.jupyter-scala:ammonite-runtime_2.11.11:0.8.3-1",
    "-I",
    "ammonite:org.jupyter-scala:scala-api_2.11.11:0.4.2",
    "org.jupyter-scala:scala-cli_2.11.11:0.4.2",
    "--",
    "--id",
    "scala",
    "--name",
    "Scala",
    "--quiet",
    "--connection-file",
    "{connection_file}"
  ],
  "env": {
    "JVM_OPT": "-Dhttp.proxyHost=http://proxy.company.com -Dhttp.proxyPort=8080 -Dhttps.proxyHost=http://proxy.company.com -Dhttps.proxyPort=8080"
  }
}

I still got the same error, as if my JVM_OPT variables are not being used. The solution for issue #21 was posted 3 years ago and the jupyter-scala code has been refactored to use coursier since.

It looks like this issue is no longer unique as there are few others like:

1. issue install doesn't work behind a proxy #157
2. issue jupyter-scala download error  #189
3. coursier-cli_2.11-1.0.0-RC1 is not proxy aware? coursier/coursier#888
4. coursier-cli_2.11-1.0.0-M15-standalone.jar: Connection timed out coursier/coursier#425
5. Stack Overflow issue

Not sure what to do as to trying to tie together the need to resolve proxy configuration so jupyter-scala can work behind firewalls.

Any clues are much appreciated.

[espears4sq]

I am experiencing this error as well. On Debian, I had to run the following commands (from a Dockerfile I'm working on), to get it to work:

apt-get install ca-certificates-java -y --no-install-recommends
cp /etc/ssl/certs/java/cacerts "/usr/lib/jvm/openjdk-${JAVA_VERSION}/lib/security/cacerts"

which you might need to modify for your configured jdk install location.

The install script ./jupyter-scala would fail otherwise, when using Java 9 or newer.