msg_perform_local_calc.md

perform_local_calc: perform a calculation on the local machine

A perform_local_calc request asks to perform a calculation on the local machine, using a Docker container. Example message:

request_id: 7bffaa8e985040afb9af8f634d38928c
content:
  perform_local_calc:
    calculation:
      let:
        in:
          function:
            account: mgh
            app: dosimetry
            args:
              - variable: x
              - value: 0.555123185675
            name: addition
        variables:
          x:
            function:
              account: mgh
              app: dosimetry
              args:
                - value: 0.319671638696
                - value: 0.157121711959
              name: addition
    context_id: 5dadeb4a004073e81b5e096255e83652

The fields are:

• request_id: identifies this request; set by the client
• context_id: see here
• calculation: the calculation to perform: an addition of three values, using an intermediate calculation setting variable x

Example response:

request_id: 7bffaa8e985040afb9af8f634d38928c
content:
  local_calc_result: 1.03191653633

The fields are:

• request_id: copied from the request message
• local_calc_result: the calculation result (the addition of the three input values)

Perform a calculation

The server recursively evaluates the specified calculation:

• A reference is resolved similar to a iss_object request.
• A function is executed on the Docker container, via the calculation supervisor; see below.
• Other calculation components are evaluated by the server itself.

Calculating functions

For calculating functions, the CRADLE server interacts with:

• Cache: stores function return values
• Docker daemon: creates and starts the Docker container
• Thinknode (via the daemon): provides the Docker image
• Calculation supervisor: performs function calculations, using the calculation provider
• Calculation provider (Docker container): to actually perform the function calculation