Server Mode

Cromwell is best experienced in "server" mode, as discussed in the Modes section of the docs.


This tutorial page relies on completing the previous tutorials:


At the end of this tutorial you'll have run Cromwell in Server Mode, allowing you to submit more than one workflow in parallel, and query workflows even after they have completed.

Prepare Files

Paste the following into a file called hello.wdl:

task hello {
  String name

  command {
    echo 'Hello ${name}!'
  output {
    File response = stdout()

workflow test {
  call hello

Paste the following into a file called inputs.json:

  "": "World"

Run the server

  1. Run java -jar cromwell-[version].jar server (replace [version] with actual version). Note that there is a server argument, this is the special sauce!
  2. Visit localhost:8000 in your browser

Start the job

  1. Navigate to Workflows section and click "Show/Hide"
  2. Navigate to /workflows/{version} which has a green "POST" on the left.
  3. Find workflowSource file, "Choose File" and navigate to hello.wdl.
  4. Find inputs file and navigate to inputs.json.
  5. Navigate to the bottom of this section and click "Try it out!"
  6. Observe output from the server process.

What happened?

Next Steps

Nice job! Now that you have cromwell running in server mode you've reached the upper echilons of Cromwell prowess! After reaching these dizzy heights, you might also find the following pages interesting: